fix(plugin): reload late SDK plugins (#35576)

packages/core/src/event.ts

@@ -111,13 +111,26 @@ export type LogItem = Payload | EventLog.Synced
 
 export const isSynced = (item: LogItem): item is EventLog.Synced => item.type === "log.synced"
 
+export type SubscribePayload<D extends readonly Definition[]> = D[number] extends infer Item
+  ? Item extends Definition
+    ? Payload<Item>
+    : never
+  : never
+
+export interface Subscribe {
+  <D extends Definition>(definition: D): Stream.Stream<Payload<D>>
+  <const D extends readonly [Definition, ...Definition[]]>(definitions: D): Stream.Stream<SubscribePayload<D>>
+}
+
+const isDefinition = (input: Definition | readonly Definition[]): input is Definition => !Array.isArray(input)
+
 export interface Interface {
   readonly publish: <D extends Definition>(
     definition: D,
     data: Data<D>,
     options?: PublishOptions,
   ) => Effect.Effect<Payload<D>>
-  readonly subscribe: <D extends Definition>(definition: D) => Stream.Stream<Payload<D>>
+  readonly subscribe: Subscribe
   /**
    * Volatile live channel: every event published from now on, nothing before,
    * nothing across a disconnect. The only channel that carries non-durable
@@ -562,11 +575,21 @@ export const layerWith = (options?: LayerOptions) =>
           ),
         )
 
-      const subscribe = <D extends Definition>(definition: D): Stream.Stream<Payload<D>> =>
+      const subscribeOne = <D extends Definition>(definition: D): Stream.Stream<Payload<D>> =>
         local(Stream.unwrap(getOrCreate(definition).pipe(Effect.map((pubsub) => Stream.fromPubSub(pubsub))))).pipe(
           Stream.map((event) => event as Payload<D>),
         )
 
+      function subscribe<D extends Definition>(definition: D): Stream.Stream<Payload<D>>
+      function subscribe<const D extends readonly [Definition, ...Definition[]]>(
+        definitions: D,
+      ): Stream.Stream<SubscribePayload<D>>
+      function subscribe(input: Definition | readonly Definition[]): Stream.Stream<Payload> {
+        if (isDefinition(input)) return subscribeOne(input)
+        const types = new Set(input.map((definition) => definition.type))
+        return streamLive().pipe(Stream.filter((event) => types.has(event.type)))
+      }
+
       const streamLive = (): Stream.Stream<Payload> => local(Stream.fromPubSub(pubsub.live))
 
       const readAfter = (

packages/core/src/plugin/host.ts

@@ -18,6 +18,7 @@ import { ProviderV2 } from "../provider"
 import { Reference } from "../reference"
 import { AbsolutePath, type DeepMutable } from "../schema"
 import { SkillV2 } from "../skill"
+import { Tool } from "../tool/tool"
 import { Tools } from "../tool/tools"
 import { ToolHooks } from "../tool/hooks"
 import { WorkspaceV2 } from "../workspace"
@@ -298,7 +299,26 @@ export const make = Effect.fn("PluginHost.make")(function* (plugin: PluginV2.Int
         }),
     },
     tool: {
-      register: (input, options) => tools.register(input, options),
+      transform: (callback) =>
+        Effect.gen(function* () {
+          const registrations: Array<{
+            readonly name: string
+            readonly tool: Tool.AnyTool
+            readonly options?: Tool.RegisterOptions
+          }> = []
+          yield* Effect.sync(() =>
+            callback({
+              add: (name, tool, options) => {
+                registrations.push({ name, tool, ...(options ? { options } : {}) })
+              },
+            }),
+          )
+          yield* Effect.forEach(
+            registrations,
+            (registration) => tools.register({ [registration.name]: registration.tool }, registration.options),
+            { discard: true },
+          )
+        }),
       execute: {
         before: (callback) =>
           toolHooks.hook.before((event) => {

packages/core/src/plugin/sdk.ts

@@ -3,6 +3,9 @@ export * as SdkPlugins from "./sdk"
 import type { Plugin } from "@opencode-ai/plugin/v2/effect"
 import { Context, Effect, Layer } from "effect"
 import { makeGlobalNode } from "../effect/app-node"
+import { EventV2 } from "../event"
+
+export const Updated = EventV2.ephemeral({ type: "sdk.plugin.updated", schema: {} })
 
 export interface Store {
   readonly plugins: Map<string, Plugin>
@@ -16,9 +19,8 @@ const defaultStore = makeStore()
  * Holds the plugins an embedder (the `@opencode-ai/sdk-next` host) contributes,
  * so `PluginSupervisor` can add them on every Location boot through the ordinary
  * generation path that `PluginSupervisor` uses for plugins discovered from
- * config. A plugin registered after a Location has booted only
- * applies to Locations booted afterward, matching config-plugin timing;
- * embedders register at startup before creating Sessions.
+ * config. Registration publishes an unlocated update so every booted Location
+ * reloads its plugin generation from the shared store.
  *
  * The store is shared explicitly between the SDK construction graph and the
  * embedded route graph because `LocationServiceMap` builds Location layers lazily
@@ -36,6 +38,7 @@ export const layerWithStore = (store: Store) =>
   Layer.effect(
     Service,
     Effect.gen(function* () {
+      const events = yield* EventV2.Service
       yield* Effect.addFinalizer(() =>
         Effect.sync(() => {
           store.plugins.clear()
@@ -45,7 +48,7 @@ export const layerWithStore = (store: Store) =>
         register: (plugin) =>
           Effect.sync(() => {
             store.plugins.set(plugin.id, plugin)
-          }),
+          }).pipe(Effect.andThen(events.publish(Updated, {})), Effect.asVoid),
         all: () => [...store.plugins.values()],
       })
     }),
@@ -53,4 +56,4 @@ export const layerWithStore = (store: Store) =>
 
 export const layer = layerWithStore(defaultStore)
 
-export const node = makeGlobalNode({ service: Service, layer, deps: [] })
+export const node = makeGlobalNode({ service: Service, layer, deps: [EventV2.node] })

packages/core/src/plugin/supervisor.ts

@@ -276,7 +276,7 @@ const layer = Layer.effect(
         }),
       ),
     )
-    yield* events.subscribe(Event.Updated).pipe(
+    yield* events.subscribe([Event.Updated, SdkPlugins.Updated]).pipe(
       Stream.runForEach(() =>
         reload().pipe(Effect.catchCause((cause) => Effect.logError("failed to reload plugins", { cause }))),
       ),

packages/core/src/tool/apply-patch.ts

@@ -63,133 +63,136 @@ export const Plugin = {
     const permission = yield* PermissionV2.Service
 
     yield* ctx.tool
-      .register({
-        [name]: Tool.withPermission(
-          Tool.make({
-            description:
-              "Apply one patch containing add, update, and delete file operations. All targets are resolved and approved before target contents are read. Operations apply sequentially; if a later operation fails, earlier operations remain applied and the failure reports them explicitly. Moves and atomic rollback are not supported yet.",
-            input: Input,
-            output: Output,
-            toModelOutput: ({ output }) => [{ type: "text", text: toModelOutput(output) }],
-            execute: (input, context) => {
-              const applied: Array<typeof Applied.Type> = []
-              const fail = (path: string) => {
-                const prefix =
-                  applied.length === 0
-                    ? `Unable to apply patch at ${path}`
-                    : `Patch partially applied before failing at ${path}. Applied: ${applied.map((item) => item.resource).join(", ")}`
-                return new ToolFailure({ message: prefix })
-              }
-              return Effect.gen(function* () {
-                const source = {
-                  type: "tool" as const,
-                  messageID: context.assistantMessageID,
-                  callID: context.toolCallID,
+      .transform((draft) =>
+        draft.add(
+          name,
+          Tool.withPermission(
+            Tool.make({
+              description:
+                "Apply one patch containing add, update, and delete file operations. All targets are resolved and approved before target contents are read. Operations apply sequentially; if a later operation fails, earlier operations remain applied and the failure reports them explicitly. Moves and atomic rollback are not supported yet.",
+              input: Input,
+              output: Output,
+              toModelOutput: ({ output }) => [{ type: "text", text: toModelOutput(output) }],
+              execute: (input, context) => {
+                const applied: Array<typeof Applied.Type> = []
+                const fail = (path: string) => {
+                  const prefix =
+                    applied.length === 0
+                      ? `Unable to apply patch at ${path}`
+                      : `Patch partially applied before failing at ${path}. Applied: ${applied.map((item) => item.resource).join(", ")}`
+                  return new ToolFailure({ message: prefix })
                 }
-                if (!input.patchText.trim()) return yield* new ToolFailure({ message: "patchText is required" })
-                const hunks = yield* Effect.try({
-                  try: () => Patch.parse(input.patchText),
-                  catch: (cause) => new ToolFailure({ message: `apply_patch verification failed: ${String(cause)}` }),
-                })
-                if (hunks.length === 0) return yield* new ToolFailure({ message: "patch rejected: empty patch" })
-                const move = hunks.find((hunk) => hunk.type === "update" && hunk.movePath !== undefined)
-                if (move) return yield* new ToolFailure({ message: "apply_patch moves are not supported yet" })
+                return Effect.gen(function* () {
+                  const source = {
+                    type: "tool" as const,
+                    messageID: context.assistantMessageID,
+                    callID: context.toolCallID,
+                  }
+                  if (!input.patchText.trim()) return yield* new ToolFailure({ message: "patchText is required" })
+                  const hunks = yield* Effect.try({
+                    try: () => Patch.parse(input.patchText),
+                    catch: (cause) => new ToolFailure({ message: `apply_patch verification failed: ${String(cause)}` }),
+                  })
+                  if (hunks.length === 0) return yield* new ToolFailure({ message: "patch rejected: empty patch" })
+                  const move = hunks.find((hunk) => hunk.type === "update" && hunk.movePath !== undefined)
+                  if (move) return yield* new ToolFailure({ message: "apply_patch moves are not supported yet" })
 
-                const targets: Array<{ readonly hunk: Patch.Hunk; readonly target: LocationMutation.Target }> = []
-                for (const hunk of hunks)
-                  targets.push({ hunk, target: yield* mutation.resolve({ path: hunk.path, kind: "file" }) })
-                const externalDirectories = new Map<string, LocationMutation.ExternalDirectoryAuthorization>()
-                for (const { target } of targets) {
-                  const external = target.externalDirectory
-                  if (external) externalDirectories.set(external.resource, external)
-                }
-                for (const external of externalDirectories.values()) {
+                  const targets: Array<{ readonly hunk: Patch.Hunk; readonly target: LocationMutation.Target }> = []
+                  for (const hunk of hunks)
+                    targets.push({ hunk, target: yield* mutation.resolve({ path: hunk.path, kind: "file" }) })
+                  const externalDirectories = new Map<string, LocationMutation.ExternalDirectoryAuthorization>()
+                  for (const { target } of targets) {
+                    const external = target.externalDirectory
+                    if (external) externalDirectories.set(external.resource, external)
+                  }
+                  for (const external of externalDirectories.values()) {
+                    yield* permission.assert({
+                      ...LocationMutation.externalDirectoryPermission(external),
+                      sessionID: context.sessionID,
+                      agent: context.agent,
+                      source,
+                    })
+                  }
                   yield* permission.assert({
-                    ...LocationMutation.externalDirectoryPermission(external),
+                    action: "edit",
+                    resources: [...new Set(targets.map(({ target }) => target.resource))],
+                    save: ["*"],
                     sessionID: context.sessionID,
                     agent: context.agent,
                     source,
                   })
-                }
-                yield* permission.assert({
-                  action: "edit",
-                  resources: [...new Set(targets.map(({ target }) => target.resource))],
-                  save: ["*"],
-                  sessionID: context.sessionID,
-                  agent: context.agent,
-                  source,
-                })
 
-                const prepared: Prepared[] = []
-                for (const { hunk, target } of targets) {
-                  yield* Effect.gen(function* () {
-                    if (hunk.type === "add") {
+                  const prepared: Prepared[] = []
+                  for (const { hunk, target } of targets) {
+                    yield* Effect.gen(function* () {
+                      if (hunk.type === "add") {
+                        prepared.push({
+                          ...hunk,
+                          target,
+                          before: "",
+                          after:
+                            hunk.contents.endsWith("\n") || hunk.contents === "" ? hunk.contents : `${hunk.contents}\n`,
+                        })
+                        return
+                      }
+                      if ((yield* fs.stat(target.canonical)).type !== "File") yield* fail(hunk.path)
+                      const source = yield* fs.readFile(target.canonical)
+                      const original = new TextDecoder("utf-8", { ignoreBOM: true }).decode(source)
+                      const before = original.replace(/^\uFEFF/, "")
+                      if (hunk.type === "delete") {
+                        prepared.push({ ...hunk, target, before, after: "" })
+                        return
+                      }
+                      const update = Patch.derive(hunk.path, hunk.chunks, original)
                       prepared.push({
                         ...hunk,
                         target,
-                        before: "",
-                        after:
-                          hunk.contents.endsWith("\n") || hunk.contents === "" ? hunk.contents : `${hunk.contents}\n`,
+                        source,
+                        content: Patch.joinBom(update.content, update.bom),
+                        before,
+                        after: update.content,
                       })
-                      return
-                    }
-                    if ((yield* fs.stat(target.canonical)).type !== "File") yield* fail(hunk.path)
-                    const source = yield* fs.readFile(target.canonical)
-                    const original = new TextDecoder("utf-8", { ignoreBOM: true }).decode(source)
-                    const before = original.replace(/^\uFEFF/, "")
-                    if (hunk.type === "delete") {
-                      prepared.push({ ...hunk, target, before, after: "" })
-                      return
-                    }
-                    const update = Patch.derive(hunk.path, hunk.chunks, original)
-                    prepared.push({
-                      ...hunk,
-                      target,
-                      source,
-                      content: Patch.joinBom(update.content, update.bom),
-                      before,
-                      after: update.content,
-                    })
-                  }).pipe(Effect.mapError(() => fail(hunk.path)))
-                }
+                    }).pipe(Effect.mapError(() => fail(hunk.path)))
+                  }
 
-                const patchFiles = prepared.map(patchFile)
-                yield* Effect.forEach(
-                  prepared,
-                  (change) =>
-                    Effect.gen(function* () {
-                      if (change.type === "add") {
-                        const result = yield* files.create({
+                  const patchFiles = prepared.map(patchFile)
+                  yield* Effect.forEach(
+                    prepared,
+                    (change) =>
+                      Effect.gen(function* () {
+                        if (change.type === "add") {
+                          const result = yield* files.create({
+                            target: change.target,
+                            content:
+                              change.contents.endsWith("\n") || change.contents === ""
+                                ? change.contents
+                                : `${change.contents}\n`,
+                          })
+                          applied.push({ type: change.type, resource: result.resource, target: result.target })
+                          return
+                        }
+                        if (change.type === "delete") {
+                          const result = yield* files.remove({ target: change.target })
+                          applied.push({ type: change.type, resource: result.resource, target: result.target })
+                          return
+                        }
+                        const result = yield* files.writeIfUnchanged({
                           target: change.target,
-                          content:
-                            change.contents.endsWith("\n") || change.contents === ""
-                              ? change.contents
-                              : `${change.contents}\n`,
+                          expected: change.source,
+                          content: change.content,
                         })
                         applied.push({ type: change.type, resource: result.resource, target: result.target })
-                        return
-                      }
-                      if (change.type === "delete") {
-                        const result = yield* files.remove({ target: change.target })
-                        applied.push({ type: change.type, resource: result.resource, target: result.target })
-                        return
-                      }
-                      const result = yield* files.writeIfUnchanged({
-                        target: change.target,
-                        expected: change.source,
-                        content: change.content,
-                      })
-                      applied.push({ type: change.type, resource: result.resource, target: result.target })
-                    }).pipe(Effect.mapError(() => fail(change.path))),
-                  { discard: true },
-                )
-                return { applied, files: patchFiles }
-              }).pipe(Effect.mapError((error) => (error instanceof ToolFailure ? error : fail("patch"))))
-            },
-          }),
-          "edit",
+                      }).pipe(Effect.mapError(() => fail(change.path))),
+                    { discard: true },
+                  )
+                  return { applied, files: patchFiles }
+                }).pipe(Effect.mapError((error) => (error instanceof ToolFailure ? error : fail("patch"))))
+              },
+            }),
+            "edit",
+          ),
         ),
-      })
+      )
       .pipe(Effect.orDie)
   }),
 }

packages/core/src/tool/edit.ts

@@ -94,122 +94,125 @@ export const Plugin = {
     const permission = yield* PermissionV2.Service
 
     yield* ctx.tool
-      .register({
-        [name]: Tool.withPermission(
-          Tool.make({
-            description:
-              "Replace exact text in one file. Relative paths resolve within the active Location. Absolute paths inside the Location are accepted. Explicit external absolute paths require external_directory approval before edit approval.",
-            input: Input,
-            output: Output,
-            toModelOutput: ({ input, output }) => [
-              { type: "text", text: toModelOutput(output, input.oldString, input.newString) },
-            ],
-            execute: (input, context) => {
-              const unableToEdit = <A, E, R>(effect: Effect.Effect<A, E, R>) =>
-                effect.pipe(
-                  Effect.mapError((error) =>
-                    error instanceof FileMutation.StaleContentError
-                      ? new ToolFailure({
-                          message: "File changed after permission approval. Read it again before editing.",
-                        })
-                      : new ToolFailure({ message: `Unable to edit ${input.path}` }),
-                  ),
-                )
-
-              return Effect.gen(function* () {
-                const permissionSource = {
-                  type: "tool" as const,
-                  messageID: context.assistantMessageID,
-                  callID: context.toolCallID,
-                }
-                if (input.oldString === input.newString) {
-                  return yield* new ToolFailure({
-                    message: "No changes to apply: oldString and newString are identical.",
-                  })
-                }
-                if (input.oldString === "") {
-                  return yield* new ToolFailure({
-                    message: "oldString must not be empty. Use write to create or overwrite a file.",
-                  })
-                }
-
-                const target = yield* unableToEdit(mutation.resolve({ path: input.path, kind: "file" }))
-                const external = target.externalDirectory
-                if (external) {
+      .transform((draft) =>
+        draft.add(
+          name,
+          Tool.withPermission(
+            Tool.make({
+              description:
+                "Replace exact text in one file. Relative paths resolve within the active Location. Absolute paths inside the Location are accepted. Explicit external absolute paths require external_directory approval before edit approval.",
+              input: Input,
+              output: Output,
+              toModelOutput: ({ input, output }) => [
+                { type: "text", text: toModelOutput(output, input.oldString, input.newString) },
+              ],
+              execute: (input, context) => {
+                const unableToEdit = <A, E, R>(effect: Effect.Effect<A, E, R>) =>
+                  effect.pipe(
+                    Effect.mapError((error) =>
+                      error instanceof FileMutation.StaleContentError
+                        ? new ToolFailure({
+                            message: "File changed after permission approval. Read it again before editing.",
+                          })
+                        : new ToolFailure({ message: `Unable to edit ${input.path}` }),
+                    ),
+                  )
+
+                return Effect.gen(function* () {
+                  const permissionSource = {
+                    type: "tool" as const,
+                    messageID: context.assistantMessageID,
+                    callID: context.toolCallID,
+                  }
+                  if (input.oldString === input.newString) {
+                    return yield* new ToolFailure({
+                      message: "No changes to apply: oldString and newString are identical.",
+                    })
+                  }
+                  if (input.oldString === "") {
+                    return yield* new ToolFailure({
+                      message: "oldString must not be empty. Use write to create or overwrite a file.",
+                    })
+                  }
+
+                  const target = yield* unableToEdit(mutation.resolve({ path: input.path, kind: "file" }))
+                  const external = target.externalDirectory
+                  if (external) {
+                    yield* unableToEdit(
+                      permission.assert({
+                        ...LocationMutation.externalDirectoryPermission(external),
+                        sessionID: context.sessionID,
+                        agent: context.agent,
+                        source: permissionSource,
+                      }),
+                    )
+                  }
+
                   yield* unableToEdit(
                     permission.assert({
-                      ...LocationMutation.externalDirectoryPermission(external),
+                      action: "edit",
+                      resources: [target.resource],
+                      save: ["*"],
                       sessionID: context.sessionID,
                       agent: context.agent,
                       source: permissionSource,
                     }),
                   )
-                }
-
-                yield* unableToEdit(
-                  permission.assert({
-                    action: "edit",
-                    resources: [target.resource],
-                    save: ["*"],
-                    sessionID: context.sessionID,
-                    agent: context.agent,
-                    source: permissionSource,
-                  }),
-                )
-                const source = decodeUtf8(yield* unableToEdit(fs.readFile(target.canonical)))
-                const ending = detectLineEnding(source.text)
-                const oldString = convertToLineEnding(input.oldString, ending)
-                const newString = convertToLineEnding(input.newString, ending)
-                const replacements = countOccurrences(source.text, oldString)
-                if (replacements === 0) {
-                  return yield* new ToolFailure({
-                    message:
-                      "Could not find oldString in the file. It must match exactly, including whitespace and indentation.",
-                  })
-                }
-                if (replacements > 1 && input.replaceAll !== true) {
-                  return yield* new ToolFailure({
-                    message:
-                      "Found multiple exact matches for oldString. Provide more surrounding context or set replaceAll to true.",
-                  })
-                }
-
-                const replaced =
-                  input.replaceAll === true
-                    ? source.text.replaceAll(oldString, newString)
-                    : source.text.replace(oldString, newString)
-                const counts = diffLines(source.text, replaced).reduce(
-                  (result, item) => ({
-                    additions: result.additions + (item.added ? (item.count ?? 0) : 0),
-                    deletions: result.deletions + (item.removed ? (item.count ?? 0) : 0),
-                  }),
-                  { additions: 0, deletions: 0 },
-                )
-                const next = splitBom(replaced)
-                const result = yield* unableToEdit(
-                  files.writeIfUnchanged({
-                    target,
-                    expected: source.content,
-                    content: joinBom(next.text, source.bom || next.bom),
-                  }),
-                )
-                return {
-                  files: [
-                    {
-                      file: result.resource,
-                      patch: createTwoFilesPatch(result.resource, result.resource, source.text, replaced),
-                      status: "modified" as const,
-                      ...counts,
-                    },
-                  ],
-                  replacements,
-                } satisfies Output
-              })
-            },
-          }),
-          "edit",
+                  const source = decodeUtf8(yield* unableToEdit(fs.readFile(target.canonical)))
+                  const ending = detectLineEnding(source.text)
+                  const oldString = convertToLineEnding(input.oldString, ending)
+                  const newString = convertToLineEnding(input.newString, ending)
+                  const replacements = countOccurrences(source.text, oldString)
+                  if (replacements === 0) {
+                    return yield* new ToolFailure({
+                      message:
+                        "Could not find oldString in the file. It must match exactly, including whitespace and indentation.",
+                    })
+                  }
+                  if (replacements > 1 && input.replaceAll !== true) {
+                    return yield* new ToolFailure({
+                      message:
+                        "Found multiple exact matches for oldString. Provide more surrounding context or set replaceAll to true.",
+                    })
+                  }
+
+                  const replaced =
+                    input.replaceAll === true
+                      ? source.text.replaceAll(oldString, newString)
+                      : source.text.replace(oldString, newString)
+                  const counts = diffLines(source.text, replaced).reduce(
+                    (result, item) => ({
+                      additions: result.additions + (item.added ? (item.count ?? 0) : 0),
+                      deletions: result.deletions + (item.removed ? (item.count ?? 0) : 0),
+                    }),
+                    { additions: 0, deletions: 0 },
+                  )
+                  const next = splitBom(replaced)
+                  const result = yield* unableToEdit(
+                    files.writeIfUnchanged({
+                      target,
+                      expected: source.content,
+                      content: joinBom(next.text, source.bom || next.bom),
+                    }),
+                  )
+                  return {
+                    files: [
+                      {
+                        file: result.resource,
+                        patch: createTwoFilesPatch(result.resource, result.resource, source.text, replaced),
+                        status: "modified" as const,
+                        ...counts,
+                      },
+                    ],
+                    replacements,
+                  } satisfies Output
+                })
+              },
+            }),
+            "edit",
+          ),
         ),
-      })
+      )
       .pipe(Effect.orDie)
   }),
 }

packages/core/src/tool/glob.ts

@@ -43,68 +43,71 @@ export const Plugin = {
     const permission = yield* PermissionV2.Service
 
     yield* ctx.tool
-      .register({
-        [name]: Tool.make({
-          description:
-            "Find files by glob pattern within the active Location. Returns concise relative file resources. Use a relative path to narrow the search and limit to bound the result count.",
-          input: Input,
-          output: Output,
-          toModelOutput: ({ output }) => [
-            {
-              type: "text",
-              text: toModelOutput(
-                output.map((entry) => ({ ...entry, path: path.resolve(location.directory, entry.path) })),
-              ),
-            },
-          ],
-          execute: (input, context) =>
-            Effect.gen(function* () {
-              yield* permission.assert({
-                action: name,
-                resources: [input.pattern],
-                save: ["*"],
-                metadata: {
-                  root: input.path ?? ".",
-                  path: input.path,
-                  limit: input.limit,
-                },
-                sessionID: context.sessionID,
-                agent: context.agent,
-                source: { type: "tool", messageID: context.assistantMessageID, callID: context.toolCallID },
-              })
-              const cwd = path.resolve(location.directory, input.path ?? ".")
-              yield* fs
-                .stat(cwd)
-                .pipe(
-                  Effect.catchReason("PlatformError", "NotFound", () =>
-                    Effect.fail(new ToolFailure({ message: `Search path does not exist: ${input.path ?? "."}` })),
-                  ),
-                )
-              return yield* ripgrep
-                .glob({
-                  cwd,
-                  pattern: input.pattern,
-                  limit: input.limit ?? Number.MAX_SAFE_INTEGER,
+      .transform((draft) =>
+        draft.add(
+          name,
+          Tool.make({
+            description:
+              "Find files by glob pattern within the active Location. Returns concise relative file resources. Use a relative path to narrow the search and limit to bound the result count.",
+            input: Input,
+            output: Output,
+            toModelOutput: ({ output }) => [
+              {
+                type: "text",
+                text: toModelOutput(
+                  output.map((entry) => ({ ...entry, path: path.resolve(location.directory, entry.path) })),
+                ),
+              },
+            ],
+            execute: (input, context) =>
+              Effect.gen(function* () {
+                yield* permission.assert({
+                  action: name,
+                  resources: [input.pattern],
+                  save: ["*"],
+                  metadata: {
+                    root: input.path ?? ".",
+                    path: input.path,
+                    limit: input.limit,
+                  },
+                  sessionID: context.sessionID,
+                  agent: context.agent,
+                  source: { type: "tool", messageID: context.assistantMessageID, callID: context.toolCallID },
                 })
-                .pipe(
-                  Effect.map((result) =>
-                    result.map((entry) =>
-                      FileSystem.Entry.make({
-                        ...entry,
-                        path: RelativePath.make(path.relative(location.directory, path.resolve(cwd, entry.path))),
-                      }),
+                const cwd = path.resolve(location.directory, input.path ?? ".")
+                yield* fs
+                  .stat(cwd)
+                  .pipe(
+                    Effect.catchReason("PlatformError", "NotFound", () =>
+                      Effect.fail(new ToolFailure({ message: `Search path does not exist: ${input.path ?? "."}` })),
+                    ),
+                  )
+                return yield* ripgrep
+                  .glob({
+                    cwd,
+                    pattern: input.pattern,
+                    limit: input.limit ?? Number.MAX_SAFE_INTEGER,
+                  })
+                  .pipe(
+                    Effect.map((result) =>
+                      result.map((entry) =>
+                        FileSystem.Entry.make({
+                          ...entry,
+                          path: RelativePath.make(path.relative(location.directory, path.resolve(cwd, entry.path))),
+                        }),
+                      ),
                     ),
-                  ),
-                )
-            }).pipe(
-              Effect.mapError((error) =>
-                error instanceof ToolFailure
-                  ? error
-                  : new ToolFailure({ message: `Unable to find files matching ${input.pattern}` }),
+                  )
+              }).pipe(
+                Effect.mapError((error) =>
+                  error instanceof ToolFailure
+                    ? error
+                    : new ToolFailure({ message: `Unable to find files matching ${input.pattern}` }),
+                ),
               ),
-            ),
-        }),
-      })
+          }),
+        ),
+      )
       .pipe(Effect.orDie)
   }),
 }

packages/core/src/tool/grep.ts

@@ -57,85 +57,88 @@ export const Plugin = {
     const permission = yield* PermissionV2.Service
 
     yield* ctx.tool
-      .register({
-        [name]: Tool.make({
-          description:
-            "Search file contents by regular expression within the active Location or an absolute managed tool-output file. Use a path to narrow the search, include to filter files by glob, and limit to bound the match count. Returns concise file resources, line numbers, and bounded line previews.",
-          input: Input,
-          output: Output,
-          toModelOutput: ({ output }) => [
-            {
-              type: "text",
-              text: toModelOutput(
-                output.map((match) => ({
-                  ...match,
-                  entry: { ...match.entry, path: path.resolve(location.directory, match.entry.path) },
-                })),
-              ),
-            },
-          ],
-          execute: (input, context) =>
-            Effect.gen(function* () {
-              yield* permission.assert({
-                action: name,
-                resources: [input.pattern],
-                save: ["*"],
-                metadata: {
-                  root: ".",
-                  path: input.path,
-                  include: input.include,
-                  limit: input.limit,
-                },
-                sessionID: context.sessionID,
-                agent: context.agent,
-                source: { type: "tool", messageID: context.assistantMessageID, callID: context.toolCallID },
-              })
-              const target = path.resolve(location.directory, input.path ?? ".")
-              const info = yield* fs
-                .stat(target)
-                .pipe(
-                  Effect.catchReason("PlatformError", "NotFound", () =>
-                    Effect.fail(new ToolFailure({ message: `Search path does not exist: ${input.path ?? "."}` })),
-                  ),
-                )
-              return yield* ripgrep
-                .grep({
-                  cwd: info?.type === "Directory" ? target : path.dirname(target),
-                  pattern: input.pattern,
-                  file: info?.type === "File" ? path.basename(target) : undefined,
-                  include: input.include,
-                  limit: input.limit ?? Number.MAX_SAFE_INTEGER,
+      .transform((draft) =>
+        draft.add(
+          name,
+          Tool.make({
+            description:
+              "Search file contents by regular expression within the active Location or an absolute managed tool-output file. Use a path to narrow the search, include to filter files by glob, and limit to bound the match count. Returns concise file resources, line numbers, and bounded line previews.",
+            input: Input,
+            output: Output,
+            toModelOutput: ({ output }) => [
+              {
+                type: "text",
+                text: toModelOutput(
+                  output.map((match) => ({
+                    ...match,
+                    entry: { ...match.entry, path: path.resolve(location.directory, match.entry.path) },
+                  })),
+                ),
+              },
+            ],
+            execute: (input, context) =>
+              Effect.gen(function* () {
+                yield* permission.assert({
+                  action: name,
+                  resources: [input.pattern],
+                  save: ["*"],
+                  metadata: {
+                    root: ".",
+                    path: input.path,
+                    include: input.include,
+                    limit: input.limit,
+                  },
+                  sessionID: context.sessionID,
+                  agent: context.agent,
+                  source: { type: "tool", messageID: context.assistantMessageID, callID: context.toolCallID },
                 })
-                .pipe(
-                  Effect.map((result) =>
-                    result.map((match) =>
-                      FileSystem.Match.make({
-                        ...match,
-                        entry: FileSystem.Entry.make({
-                          ...match.entry,
-                          path: RelativePath.make(
-                            path.relative(
-                              location.directory,
-                              path.resolve(
-                                info?.type === "Directory" ? target : path.dirname(target),
-                                match.entry.path,
+                const target = path.resolve(location.directory, input.path ?? ".")
+                const info = yield* fs
+                  .stat(target)
+                  .pipe(
+                    Effect.catchReason("PlatformError", "NotFound", () =>
+                      Effect.fail(new ToolFailure({ message: `Search path does not exist: ${input.path ?? "."}` })),
+                    ),
+                  )
+                return yield* ripgrep
+                  .grep({
+                    cwd: info?.type === "Directory" ? target : path.dirname(target),
+                    pattern: input.pattern,
+                    file: info?.type === "File" ? path.basename(target) : undefined,
+                    include: input.include,
+                    limit: input.limit ?? Number.MAX_SAFE_INTEGER,
+                  })
+                  .pipe(
+                    Effect.map((result) =>
+                      result.map((match) =>
+                        FileSystem.Match.make({
+                          ...match,
+                          entry: FileSystem.Entry.make({
+                            ...match.entry,
+                            path: RelativePath.make(
+                              path.relative(
+                                location.directory,
+                                path.resolve(
+                                  info?.type === "Directory" ? target : path.dirname(target),
+                                  match.entry.path,
+                                ),
                               ),
                             ),
-                          ),
+                          }),
                         }),
-                      }),
+                      ),
                     ),
-                  ),
-                )
-            }).pipe(
-              Effect.mapError((error) =>
-                error instanceof ToolFailure
-                  ? error
-                  : new ToolFailure({ message: `Unable to grep for ${input.pattern}` }),
+                  )
+              }).pipe(
+                Effect.mapError((error) =>
+                  error instanceof ToolFailure
+                    ? error
+                    : new ToolFailure({ message: `Unable to grep for ${input.pattern}` }),
+                ),
               ),
-            ),
-        }),
-      })
+          }),
+        ),
+      )
       .pipe(Effect.orDie)
   }),
 }

packages/core/src/tool/question.ts

@@ -56,65 +56,68 @@ export const Plugin = {
     const permission = yield* PermissionV2.Service
 
     yield* ctx.tool
-      .register({
-        [name]: Tool.make({
-          description,
-          input: Input,
-          output: Output,
-          toModelOutput: ({ input, output }) => [
-            { type: "text", text: toModelOutput(input.questions, output.answers) },
-          ],
-          execute: (input, context) =>
-            permission
-              .assert({
-                action: "question",
-                resources: ["*"],
-                sessionID: context.sessionID,
-                agent: context.agent,
-                source: { type: "tool", messageID: context.assistantMessageID, callID: context.toolCallID },
-              })
-              .pipe(
-                Effect.mapError(() => new ToolFailure({ message: "Permission denied: question" })),
-                Effect.andThen(
-                  forms
-                    .ask({
-                      sessionID: context.sessionID,
-                      metadata: {
-                        kind: "question",
-                        tool: { messageID: context.assistantMessageID, callID: context.toolCallID },
-                      },
-                      mode: "form",
-                      fields: input.questions.map(
-                        (question, index): Form.Field => ({
-                          key: `q${index}`,
-                          title: question.header,
-                          description: question.question,
-                          type: question.multiple === true ? "multiselect" : "string",
-                          options: question.options.map((option) => ({
-                            value: option.label,
-                            label: option.label,
-                            description: option.description,
-                          })),
-                        custom: true,
-                        }),
-                      ),
+      .transform((draft) =>
+        draft.add(
+          name,
+          Tool.make({
+            description,
+            input: Input,
+            output: Output,
+            toModelOutput: ({ input, output }) => [
+              { type: "text", text: toModelOutput(input.questions, output.answers) },
+            ],
+            execute: (input, context) =>
+              permission
+                .assert({
+                  action: "question",
+                  resources: ["*"],
+                  sessionID: context.sessionID,
+                  agent: context.agent,
+                  source: { type: "tool", messageID: context.assistantMessageID, callID: context.toolCallID },
+                })
+                .pipe(
+                  Effect.mapError(() => new ToolFailure({ message: "Permission denied: question" })),
+                  Effect.andThen(
+                    forms
+                      .ask({
+                        sessionID: context.sessionID,
+                        metadata: {
+                          kind: "question",
+                          tool: { messageID: context.assistantMessageID, callID: context.toolCallID },
+                        },
+                        mode: "form",
+                        fields: input.questions.map(
+                          (question, index): Form.Field => ({
+                            key: `q${index}`,
+                            title: question.header,
+                            description: question.question,
+                            type: question.multiple === true ? "multiselect" : "string",
+                            options: question.options.map((option) => ({
+                              value: option.label,
+                              label: option.label,
+                              description: option.description,
+                            })),
+                            custom: true,
+                          }),
+                        ),
+                      })
+                      .pipe(Effect.orDie),
+                  ),
+                  Effect.flatMap((state) => {
+                    if (state.status === "cancelled") return Effect.die(new CancelledError())
+                    return Effect.succeed({
+                      answers: input.questions.map((_, index): QuestionV2.Answer => {
+                        const value = state.answer[`q${index}`]
+                        if (value === undefined) return []
+                        if (typeof value === "object") return Array.from(value)
+                        return [String(value)]
+                      }),
                     })
-                    .pipe(Effect.orDie),
+                  }),
                 ),
-                Effect.flatMap((state) => {
-                  if (state.status === "cancelled") return Effect.die(new CancelledError())
-                  return Effect.succeed({
-                    answers: input.questions.map((_, index): QuestionV2.Answer => {
-                      const value = state.answer[`q${index}`]
-                      if (value === undefined) return []
-                      if (typeof value === "object") return Array.from(value)
-                      return [String(value)]
-                    }),
-                  })
-                }),
-              ),
-        }),
-      })
+          }),
+        ),
+      )
       .pipe(Effect.orDie)
   }),
 }

packages/core/src/tool/read.ts

@@ -42,100 +42,105 @@ export const Plugin = {
     const location = yield* Location.Service
 
     yield* ctx.tool
-      .register({
-        [name]: Tool.make({
-          description:
-            "Read a text file or supported image, page through a large UTF-8 text file by line offset, or list a directory page. Relative paths resolve from the current location; absolute paths inside it are accepted, while external absolute paths require external_directory approval.",
-          input: Input,
-          output: Output,
-          toModelOutput: ({ input, output }) => {
-            if (!("encoding" in output) || output.encoding !== "base64" || !SUPPORTED_IMAGE_MIMES.has(output.mime))
-              return []
-            return [
-              { type: "text", text: "Image read successfully" },
-              { type: "file", data: output.content, mime: output.mime, name: input.path },
-            ]
-          },
-          execute: (input, context) => {
-            return Effect.gen(function* () {
-              const source = {
-                type: "tool" as const,
-                messageID: context.assistantMessageID,
-                callID: context.toolCallID,
-              }
-              const target = yield* mutation.resolve({ path: input.path, kind: "directory" })
-              const external = target.externalDirectory
-              if (external)
+      .transform((draft) =>
+        draft.add(
+          name,
+          Tool.make({
+            description:
+              "Read a text file or supported image, page through a large UTF-8 text file by line offset, or list a directory page. Relative paths resolve from the current location; absolute paths inside it are accepted, while external absolute paths require external_directory approval.",
+            input: Input,
+            output: Output,
+            toModelOutput: ({ input, output }) => {
+              if (!("encoding" in output) || output.encoding !== "base64" || !SUPPORTED_IMAGE_MIMES.has(output.mime))
+                return []
+              return [
+                { type: "text", text: "Image read successfully" },
+                { type: "file", data: output.content, mime: output.mime, name: input.path },
+              ]
+            },
+            execute: (input, context) => {
+              return Effect.gen(function* () {
+                const source = {
+                  type: "tool" as const,
+                  messageID: context.assistantMessageID,
+                  callID: context.toolCallID,
+                }
+                const target = yield* mutation.resolve({ path: input.path, kind: "directory" })
+                const external = target.externalDirectory
+                if (external)
+                  yield* permission.assert({
+                    ...LocationMutation.externalDirectoryPermission(external),
+                    sessionID: context.sessionID,
+                    agent: context.agent,
+                    source,
+                  })
+                const resource = target.resource
+                const absolute = AbsolutePath.make(target.canonical)
+                const type = yield* reader.inspect(absolute)
                 yield* permission.assert({
-                  ...LocationMutation.externalDirectoryPermission(external),
+                  action: name,
+                  resources: [resource],
+                  save: ["*"],
                   sessionID: context.sessionID,
                   agent: context.agent,
                   source,
                 })
-              const resource = target.resource
-              const absolute = AbsolutePath.make(target.canonical)
-              const type = yield* reader.inspect(absolute)
-              yield* permission.assert({
-                action: name,
-                resources: [resource],
-                save: ["*"],
-                sessionID: context.sessionID,
-                agent: context.agent,
-                source,
-              })
-              const content =
-                type === "directory"
-                  ? yield* reader.list(absolute, { offset: input.offset, limit: input.limit })
-                  : yield* reader.read(absolute, resource, {
-                      offset: input.offset,
-                      limit: input.limit,
-                    })
-              // After a successful read, discover nearby AGENTS.md walking up to the Location
-              // root exclusive and inject them as durable synthetic instructions. For a
-              // directory listing the walk starts at the directory itself (so its own AGENTS.md
-              // is discovered); for a file it starts at the file's dirname. External reads are
-              // skipped, and discovery failures never fail the read.
-              yield* Effect.gen(function* () {
-                if (target.externalDirectory !== undefined) return
-                const resolved = yield* fs.resolve(target.canonical)
-                const root = yield* fs.resolve(location.directory)
-                // up() searches its stop directory, so the Location-root AGENTS.md (already
-                // supplied by the core/instructions baseline) is dropped by the dirname filter.
-                const discovered = yield* fs.up({
-                  targets: [FILENAME],
-                  start: type === "directory" ? resolved : dirname(resolved),
-                  stop: root,
-                })
-                const candidates = (yield* Effect.forEach(discovered, fs.resolve)).filter((file) => dirname(file) !== root)
-                if (candidates.length === 0) return
-                yield* sessionInstructions.load({ sessionID: context.sessionID, paths: candidates })
+                const content =
+                  type === "directory"
+                    ? yield* reader.list(absolute, { offset: input.offset, limit: input.limit })
+                    : yield* reader.read(absolute, resource, {
+                        offset: input.offset,
+                        limit: input.limit,
+                      })
+                // After a successful read, discover nearby AGENTS.md walking up to the Location
+                // root exclusive and inject them as durable synthetic instructions. For a
+                // directory listing the walk starts at the directory itself (so its own AGENTS.md
+                // is discovered); for a file it starts at the file's dirname. External reads are
+                // skipped, and discovery failures never fail the read.
+                yield* Effect.gen(function* () {
+                  if (target.externalDirectory !== undefined) return
+                  const resolved = yield* fs.resolve(target.canonical)
+                  const root = yield* fs.resolve(location.directory)
+                  // up() searches its stop directory, so the Location-root AGENTS.md (already
+                  // supplied by the core/instructions baseline) is dropped by the dirname filter.
+                  const discovered = yield* fs.up({
+                    targets: [FILENAME],
+                    start: type === "directory" ? resolved : dirname(resolved),
+                    stop: root,
+                  })
+                  const candidates = (yield* Effect.forEach(discovered, fs.resolve)).filter(
+                    (file) => dirname(file) !== root,
+                  )
+                  if (candidates.length === 0) return
+                  yield* sessionInstructions.load({ sessionID: context.sessionID, paths: candidates })
+                }).pipe(
+                  Effect.catch(() => Effect.void),
+                  Effect.catchDefect(() => Effect.void),
+                )
+                if ("encoding" in content && content.encoding === "base64" && SUPPORTED_IMAGE_MIMES.has(content.mime)) {
+                  return yield* image
+                    .normalize(resource, { ...content, encoding: "base64" })
+                    .pipe(Effect.catchTag("Image.ResizerUnavailableError", () => Effect.succeed(content)))
+                }
+                if ("encoding" in content && content.encoding === "base64")
+                  return yield* Effect.fail(new ReadToolFileSystem.BinaryFileError({ resource }))
+                return content
               }).pipe(
-                Effect.catch(() => Effect.void),
-                Effect.catchDefect(() => Effect.void),
+                Effect.mapError((error) => {
+                  const message =
+                    error instanceof ReadToolFileSystem.BinaryFileError ||
+                    error instanceof ReadToolFileSystem.MediaIngestLimitError ||
+                    error instanceof Image.DecodeError ||
+                    error instanceof Image.SizeError
+                      ? error.message
+                      : `Unable to read ${input.path}`
+                  return new ToolFailure({ message })
+                }),
               )
-              if ("encoding" in content && content.encoding === "base64" && SUPPORTED_IMAGE_MIMES.has(content.mime)) {
-                return yield* image
-                  .normalize(resource, { ...content, encoding: "base64" })
-                  .pipe(Effect.catchTag("Image.ResizerUnavailableError", () => Effect.succeed(content)))
-              }
-              if ("encoding" in content && content.encoding === "base64")
-                return yield* Effect.fail(new ReadToolFileSystem.BinaryFileError({ resource }))
-              return content
-            }).pipe(
-              Effect.mapError((error) => {
-                const message =
-                  error instanceof ReadToolFileSystem.BinaryFileError ||
-                  error instanceof ReadToolFileSystem.MediaIngestLimitError ||
-                  error instanceof Image.DecodeError ||
-                  error instanceof Image.SizeError
-                    ? error.message
-                    : `Unable to read ${input.path}`
-                return new ToolFailure({ message })
-              }),
-            )
-          },
-        }),
-      })
+            },
+          }),
+        ),
+      )
       .pipe(Effect.orDie)
   }),
 }

packages/core/src/tool/shell.ts

@@ -58,8 +58,7 @@ const modelOutput = (output: Output): string | undefined => {
   const warnings = output.warnings?.length
     ? `\n\nWarnings:\n${output.warnings.map((warning) => `- ${warning}`).join("\n")}`
     : ""
-  if (output.status === "running")
-    return `${warnings.trimStart()}${warnings ? "\n\n" : ""}${BACKGROUND_INSTRUCTION}`
+  if (output.status === "running") return `${warnings.trimStart()}${warnings ? "\n\n" : ""}${BACKGROUND_INSTRUCTION}`
   if (output.timeout) return `${warnings.trimStart()}${warnings ? "\n\n" : ""}Command timed out before completion.`
   return `${warnings.trimStart()}${warnings ? "\n\n" : ""}Command exited with code ${output.exit}.`
 }
@@ -140,136 +139,142 @@ export const Plugin = {
     })
 
     yield* ctx.tool
-      .register({
-        [name]: Tool.make({
-          description: `Execute one shell command string with the host user's filesystem, process, and network authority. The active Location is the default working directory. Relative workdir values resolve from that Location. External workdir values require external_directory approval; best-effort command-argument path warnings are advisory only. Timeout values are milliseconds (default: ${DEFAULT_TIMEOUT_MS}; maximum: ${MAX_TIMEOUT_MS}). Uses the configured shell when set; otherwise uses /bin/sh on POSIX and COMSPEC or cmd.exe on Windows. Background mode (background=true) launches the command asynchronously and returns immediately; you are notified when it finishes.`,
-          input: Input,
-          output: Output,
-          structured: StructuredOutput,
-          toStructuredOutput: ({ output }) => ({
-            truncated: output.truncated,
-            ...(output.exit === undefined ? {} : { exit: output.exit }),
-            ...(output.shellID === undefined ? {} : { shellID: output.shellID }),
-            ...(output.timeout === undefined ? {} : { timeout: output.timeout }),
-          }),
-          toModelOutput: ({ output }) => {
-            const parts: Content[] = [{ type: "text", text: output.output }]
-            const model = modelOutput(output)
-            if (model) parts.push({ type: "text", text: model })
-            return parts
-          },
-          execute: (input, context) =>
-            Effect.gen(function* () {
-              const source = {
-                type: "tool" as const,
-                messageID: context.assistantMessageID,
-                callID: context.toolCallID,
-              }
-              const target = yield* mutation.resolve({ path: input.workdir ?? ".", kind: "directory" })
-              const external = target.externalDirectory
-              if (external)
+      .transform((draft) =>
+        draft.add(
+          name,
+          Tool.make({
+            description: `Execute one shell command string with the host user's filesystem, process, and network authority. The active Location is the default working directory. Relative workdir values resolve from that Location. External workdir values require external_directory approval; best-effort command-argument path warnings are advisory only. Timeout values are milliseconds (default: ${DEFAULT_TIMEOUT_MS}; maximum: ${MAX_TIMEOUT_MS}). Uses the configured shell when set; otherwise uses /bin/sh on POSIX and COMSPEC or cmd.exe on Windows. Background mode (background=true) launches the command asynchronously and returns immediately; you are notified when it finishes.`,
+            input: Input,
+            output: Output,
+            structured: StructuredOutput,
+            toStructuredOutput: ({ output }) => ({
+              truncated: output.truncated,
+              ...(output.exit === undefined ? {} : { exit: output.exit }),
+              ...(output.shellID === undefined ? {} : { shellID: output.shellID }),
+              ...(output.timeout === undefined ? {} : { timeout: output.timeout }),
+            }),
+            toModelOutput: ({ output }) => {
+              const parts: Content[] = [{ type: "text", text: output.output }]
+              const model = modelOutput(output)
+              if (model) parts.push({ type: "text", text: model })
+              return parts
+            },
+            execute: (input, context) =>
+              Effect.gen(function* () {
+                const source = {
+                  type: "tool" as const,
+                  messageID: context.assistantMessageID,
+                  callID: context.toolCallID,
+                }
+                const target = yield* mutation.resolve({ path: input.workdir ?? ".", kind: "directory" })
+                const external = target.externalDirectory
+                if (external)
+                  yield* permission.assert({
+                    ...LocationMutation.externalDirectoryPermission(external),
+                    sessionID: context.sessionID,
+                    agent: context.agent,
+                    source,
+                  })
+                const warnings = (yield* externalCommandDirectories(fsUtil, input.command, target.canonical)).map(
+                  (directory) =>
+                    `Command argument references external directory ${path.join(directory, "*").replaceAll("\\", "/")}. Shell runs with host-user filesystem, process, and network authority; this scan is advisory only.`,
+                )
                 yield* permission.assert({
-                  ...LocationMutation.externalDirectoryPermission(external),
+                  action: name,
+                  resources: [input.command],
+                  save: [input.command],
                   sessionID: context.sessionID,
                   agent: context.agent,
                   source,
                 })
-              const warnings = (yield* externalCommandDirectories(fsUtil, input.command, target.canonical)).map(
-                (directory) =>
-                  `Command argument references external directory ${path.join(directory, "*").replaceAll("\\", "/")}. Shell runs with host-user filesystem, process, and network authority; this scan is advisory only.`,
-              )
-              yield* permission.assert({
-                action: name,
-                resources: [input.command],
-                save: [input.command],
-                sessionID: context.sessionID,
-                agent: context.agent,
-                source,
-              })
 
-              if ((yield* fsUtil.stat(target.canonical)).type !== "Directory")
-                return yield* Effect.fail(new Error(`Working directory is not a directory: ${target.canonical}`))
+                if ((yield* fsUtil.stat(target.canonical)).type !== "Directory")
+                  return yield* Effect.fail(new Error(`Working directory is not a directory: ${target.canonical}`))
+
+                const timeout = input.timeout ?? DEFAULT_TIMEOUT_MS
+                const info = yield* shell.create({
+                  command: input.command,
+                  cwd: target.canonical,
+                  timeout,
+                  metadata: { sessionID: context.sessionID },
+                })
 
-              const timeout = input.timeout ?? DEFAULT_TIMEOUT_MS
-              const info = yield* shell.create({
-                command: input.command,
-                cwd: target.canonical,
-                timeout,
-                metadata: { sessionID: context.sessionID },
-              })
+                const settleShell = Effect.fn("ShellTool.settleShell")(function* () {
+                  const final = yield* shell.wait(info.id)
+                  const page = yield* shell.output(info.id, { limit: MAX_CAPTURE_BYTES })
 
-              const settleShell = Effect.fn("ShellTool.settleShell")(function* () {
-                const final = yield* shell.wait(info.id)
-                const page = yield* shell.output(info.id, { limit: MAX_CAPTURE_BYTES })
+                  if (final.status === "timeout") {
+                    return {
+                      exit: final.exit,
+                      output: `Command exceeded timeout of ${timeout} ms. Retry with a larger timeout if the command is expected to take longer.`,
+                      truncated: false,
+                      timeout: true,
+                      status: "completed" as const,
+                    }
+                  }
 
-                if (final.status === "timeout") {
+                  const truncated = page.size > page.cursor
+                  const body = page.output || "(no output)"
+                  const notice = truncated ? `\n\n[output truncated; full output saved to: ${final.file}]` : ""
                   return {
                     exit: final.exit,
-                    output: `Command exceeded timeout of ${timeout} ms. Retry with a larger timeout if the command is expected to take longer.`,
-                    truncated: false,
-                    timeout: true,
+                    output: `${body}${notice}`,
+                    truncated,
                     status: "completed" as const,
                   }
-                }
+                })
 
-                const truncated = page.size > page.cursor
-                const body = page.output || "(no output)"
-                const notice = truncated ? `\n\n[output truncated; full output saved to: ${final.file}]` : ""
-                return {
-                  exit: final.exit,
-                  output: `${body}${notice}`,
-                  truncated,
-                  status: "completed" as const,
-                }
-              })
+                const run = settleShell().pipe(
+                  Effect.map((output) => output.output),
+                  Effect.onInterrupt(() => shell.remove(info.id).pipe(Effect.ignore)),
+                )
+                const job = yield* runtime.job.start({
+                  id: context.toolCallID,
+                  type: name,
+                  title: input.command,
+                  metadata: { sessionID: context.sessionID, shellID: info.id },
+                  run,
+                })
 
-              const run = settleShell().pipe(
-                Effect.map((output) => output.output),
-                Effect.onInterrupt(() => shell.remove(info.id).pipe(Effect.ignore)),
-              )
-              const job = yield* runtime.job.start({
-                id: context.toolCallID,
-                type: name,
-                title: input.command,
-                metadata: { sessionID: context.sessionID, shellID: info.id },
-                run,
-              })
+                if (input.background === true) {
+                  yield* runtime.job.background(job.id)
+                  yield* notifyWhenDone(context.sessionID, context.toolCallID, input.command)
+                  return {
+                    output: BACKGROUND_STARTED,
+                    shellID: info.id,
+                    truncated: false,
+                    status: "running" as const,
+                    ...(warnings.length ? { warnings } : {}),
+                  }
+                }
 
-              if (input.background === true) {
-                yield* runtime.job.background(job.id)
-                yield* notifyWhenDone(context.sessionID, context.toolCallID, input.command)
-                return {
-                  output: BACKGROUND_STARTED,
-                  shellID: info.id,
-                  truncated: false,
-                  status: "running" as const,
-                  ...(warnings.length ? { warnings } : {}),
+                const result = yield* runtime.job
+                  .block({ id: job.id, sessionID: context.sessionID })
+                  .pipe(Effect.onInterrupt(() => runtime.job.cancel(job.id).pipe(Effect.ignore)))
+                if (result?.type === "backgrounded") {
+                  yield* notifyWhenDone(context.sessionID, context.toolCallID, input.command)
+                  return {
+                    output: BACKGROUND_STARTED,
+                    shellID: info.id,
+                    truncated: false,
+                    status: "running" as const,
+                    ...(warnings.length ? { warnings } : {}),
+                  }
                 }
-              }
+                if (result?.info.status === "error")
+                  return yield* Effect.fail(new Error(result.info.error ?? "Command failed"))
+                if (result?.info.status === "cancelled") return yield* Effect.fail(new Error("Command cancelled"))
 
-              const result = yield* runtime.job.block({ id: job.id, sessionID: context.sessionID }).pipe(
-                Effect.onInterrupt(() => runtime.job.cancel(job.id).pipe(Effect.ignore)),
-              )
-              if (result?.type === "backgrounded") {
-                yield* notifyWhenDone(context.sessionID, context.toolCallID, input.command)
                 return {
-                  output: BACKGROUND_STARTED,
-                  shellID: info.id,
-                  truncated: false,
-                  status: "running" as const,
+                  ...(yield* settleShell()),
                   ...(warnings.length ? { warnings } : {}),
                 }
-              }
-              if (result?.info.status === "error") return yield* Effect.fail(new Error(result.info.error ?? "Command failed"))
-              if (result?.info.status === "cancelled") return yield* Effect.fail(new Error("Command cancelled"))
-
-              return {
-                ...(yield* settleShell()),
-                ...(warnings.length ? { warnings } : {}),
-              }
-            }).pipe(Effect.mapError(() => new ToolFailure({ message: `Unable to execute command: ${input.command}` }))),
-        }),
-      })
+              }).pipe(
+                Effect.mapError(() => new ToolFailure({ message: `Unable to execute command: ${input.command}` })),
+              ),
+          }),
+        ),
+      )
       .pipe(Effect.orDie)
   }),
 }

packages/core/src/tool/skill.ts

@@ -59,43 +59,46 @@ export const Plugin = {
     const skills = yield* SkillV2.Service
     const permission = yield* PermissionV2.Service
     yield* ctx.tool
-      .register({
-        [name]: Tool.make({
-          description,
-          input: Input,
-          output: Output,
-          toModelOutput: ({ output }) => [{ type: "text", text: output.output }],
-          execute: (input, context) =>
-            Effect.gen(function* () {
-              const current = yield* skills.list()
-              const skill = current.find((skill) => skill.name === input.name)
-              if (!skill) return yield* unableToLoad(input.name)
-              return yield* Effect.gen(function* () {
-                yield* permission.assert({
-                  action: name,
-                  resources: [skill.name],
-                  save: [skill.name],
-                  sessionID: context.sessionID,
-                  agent: context.agent,
-                  source: { type: "tool", messageID: context.assistantMessageID, callID: context.toolCallID },
-                })
-                const directory = path.dirname(skill.location)
-                const files =
-                  path.basename(skill.location) === "SKILL.md"
-                    ? (yield* fs.glob("**/*", { cwd: directory, absolute: true, include: "file", dot: true }))
-                        .filter((file) => path.basename(file) !== "SKILL.md")
-                        .toSorted()
-                        .slice(0, FILE_LIMIT)
-                    : []
-                return {
-                  name: skill.name,
-                  directory,
-                  output: toModelOutput(skill, files),
-                }
-              }).pipe(Effect.mapError((error) => unableToLoad(input.name, error)))
-            }),
-        }),
-      })
+      .transform((draft) =>
+        draft.add(
+          name,
+          Tool.make({
+            description,
+            input: Input,
+            output: Output,
+            toModelOutput: ({ output }) => [{ type: "text", text: output.output }],
+            execute: (input, context) =>
+              Effect.gen(function* () {
+                const current = yield* skills.list()
+                const skill = current.find((skill) => skill.name === input.name)
+                if (!skill) return yield* unableToLoad(input.name)
+                return yield* Effect.gen(function* () {
+                  yield* permission.assert({
+                    action: name,
+                    resources: [skill.name],
+                    save: [skill.name],
+                    sessionID: context.sessionID,
+                    agent: context.agent,
+                    source: { type: "tool", messageID: context.assistantMessageID, callID: context.toolCallID },
+                  })
+                  const directory = path.dirname(skill.location)
+                  const files =
+                    path.basename(skill.location) === "SKILL.md"
+                      ? (yield* fs.glob("**/*", { cwd: directory, absolute: true, include: "file", dot: true }))
+                          .filter((file) => path.basename(file) !== "SKILL.md")
+                          .toSorted()
+                          .slice(0, FILE_LIMIT)
+                      : []
+                  return {
+                    name: skill.name,
+                    directory,
+                    output: toModelOutput(skill, files),
+                  }
+                }).pipe(Effect.mapError((error) => unableToLoad(input.name, error)))
+              }),
+          }),
+        ),
+      )
       .pipe(Effect.orDie)
   }),
 }

packages/core/src/tool/subagent.ts

@@ -93,80 +93,88 @@ export const Plugin = {
     })
 
     yield* ctx.tool
-      .register({
-        [name]: Tool.make({
-          description,
-          input: Input,
-          output: Output,
-          toModelOutput: ({ output }) => [{ type: "text", text: output.output }],
-          execute: (input, context) =>
-            Effect.gen(function* () {
-              const parent = yield* runtime.session
-                .get(context.sessionID)
-                .pipe(
-                  Effect.mapError(() => new ToolFailure({ message: `Parent session not found: ${context.sessionID}` })),
-                )
-              const agent = yield* agents.resolve(input.agent)
-              if (agent === undefined) return yield* new ToolFailure({ message: `Unknown agent: ${input.agent}` })
-              if (agent.mode === "primary")
-                return yield* new ToolFailure({ message: `Agent ${input.agent} cannot run as a subagent` })
-
-              // Model selection is policy/config/session state, not an LLM-facing tool argument.
-              const model = agent.model ?? parent.model
-              const child = yield* runtime.session
-                .create({
-                  parentID: context.sessionID,
+      .transform((draft) =>
+        draft.add(
+          name,
+          Tool.make({
+            description,
+            input: Input,
+            output: Output,
+            toModelOutput: ({ output }) => [{ type: "text", text: output.output }],
+            execute: (input, context) =>
+              Effect.gen(function* () {
+                const parent = yield* runtime.session
+                  .get(context.sessionID)
+                  .pipe(
+                    Effect.mapError(
+                      () => new ToolFailure({ message: `Parent session not found: ${context.sessionID}` }),
+                    ),
+                  )
+                const agent = yield* agents.resolve(input.agent)
+                if (agent === undefined) return yield* new ToolFailure({ message: `Unknown agent: ${input.agent}` })
+                if (agent.mode === "primary")
+                  return yield* new ToolFailure({ message: `Agent ${input.agent} cannot run as a subagent` })
+
+                // Model selection is policy/config/session state, not an LLM-facing tool argument.
+                const model = agent.model ?? parent.model
+                const child = yield* runtime.session
+                  .create({
+                    parentID: context.sessionID,
+                    title: input.description,
+                    agent: AgentV2.ID.make(input.agent),
+                    model,
+                    // TODO(opencode kkdvxn): derive restricted subagent permissions from the parent
+                    // session (V1 deriveSubagentSessionPermission). MVP uses the agent's own permissions.
+                  })
+                  .pipe(
+                    Effect.mapError(
+                      () => new ToolFailure({ message: `Parent session not found: ${context.sessionID}` }),
+                    ),
+                  )
+
+                const background = input.background === true
+
+                const run = Effect.gen(function* () {
+                  // The child session owns its agent/model (set at create); prompt only admits input.
+                  yield* runtime.session.prompt({ sessionID: child.id, prompt: { text: input.prompt }, resume: false })
+                  yield* runtime.session.resume(child.id)
+                  return yield* latestAssistantText(child.id)
+                }).pipe(Effect.onInterrupt(() => runtime.session.interrupt(child.id)))
+
+                const info = yield* runtime.job.start({
+                  id: child.id,
+                  type: name,
                   title: input.description,
-                  agent: AgentV2.ID.make(input.agent),
-                  model,
-                  // TODO(opencode kkdvxn): derive restricted subagent permissions from the parent
-                  // session (V1 deriveSubagentSessionPermission). MVP uses the agent's own permissions.
+                  metadata: {},
+                  run,
                 })
-                .pipe(
-                  Effect.mapError(() => new ToolFailure({ message: `Parent session not found: ${context.sessionID}` })),
-                )
 
-              const background = input.background === true
-
-              const run = Effect.gen(function* () {
-                // The child session owns its agent/model (set at create); prompt only admits input.
-                yield* runtime.session.prompt({ sessionID: child.id, prompt: { text: input.prompt }, resume: false })
-                yield* runtime.session.resume(child.id)
-                return yield* latestAssistantText(child.id)
-              }).pipe(Effect.onInterrupt(() => runtime.session.interrupt(child.id)))
-
-              const info = yield* runtime.job.start({
-                id: child.id,
-                type: name,
-                title: input.description,
-                metadata: {},
-                run,
-              })
-
-              if (background) {
-                yield* runtime.job.background(info.id)
-                yield* notifyWhenDone(context.sessionID, child.id, input.description)
-                return { sessionID: child.id, status: "running" as const, output: BACKGROUND_STARTED }
-              }
-
-              const result = yield* runtime.job.block({ id: child.id, sessionID: context.sessionID }).pipe(
-                Effect.onInterrupt(() =>
-                  Effect.all([runtime.session.interrupt(child.id), runtime.job.cancel(child.id)], {
-                    discard: true,
-                  }),
-                ),
-              )
-              if (result?.type === "backgrounded") {
-                yield* notifyWhenDone(context.sessionID, child.id, input.description)
-                return { sessionID: child.id, status: "running" as const, output: BACKGROUND_STARTED }
-              }
-              if (result?.info.status === "error")
-                return yield* new ToolFailure({ message: result.info.error ?? "Subagent failed" })
-              if (result?.info.status === "cancelled") return yield* new ToolFailure({ message: "Subagent cancelled" })
-              return { sessionID: child.id, status: "completed" as const, output: result?.info.output ?? NO_TEXT }
-            }),
-        }),
-      })
+                if (background) {
+                  yield* runtime.job.background(info.id)
+                  yield* notifyWhenDone(context.sessionID, child.id, input.description)
+                  return { sessionID: child.id, status: "running" as const, output: BACKGROUND_STARTED }
+                }
+
+                const result = yield* runtime.job.block({ id: child.id, sessionID: context.sessionID }).pipe(
+                  Effect.onInterrupt(() =>
+                    Effect.all([runtime.session.interrupt(child.id), runtime.job.cancel(child.id)], {
+                      discard: true,
+                    }),
+                  ),
+                )
+                if (result?.type === "backgrounded") {
+                  yield* notifyWhenDone(context.sessionID, child.id, input.description)
+                  return { sessionID: child.id, status: "running" as const, output: BACKGROUND_STARTED }
+                }
+                if (result?.info.status === "error")
+                  return yield* new ToolFailure({ message: result.info.error ?? "Subagent failed" })
+                if (result?.info.status === "cancelled")
+                  return yield* new ToolFailure({ message: "Subagent cancelled" })
+                return { sessionID: child.id, status: "completed" as const, output: result?.info.output ?? NO_TEXT }
+              }),
+          }),
+        ),
+      )
       .pipe(Effect.orDie)
   }),
 }

packages/core/src/tool/todowrite.ts

@@ -27,28 +27,31 @@ export const Plugin = {
     const permission = yield* PermissionV2.Service
 
     yield* ctx.tool
-      .register({
-        [name]: Tool.make({
-          description:
-            "Create and maintain a structured task list for the current coding session. Use it to track progress during multi-step work and keep todo statuses current.",
-          input: Input,
-          output: Output,
-          toModelOutput: ({ output }) => [{ type: "text", text: toModelOutput(output) }],
-          execute: (input, context) =>
-            Effect.gen(function* () {
-              yield* permission.assert({
-                action: name,
-                resources: ["*"],
-                save: ["*"],
-                sessionID: context.sessionID,
-                agent: context.agent,
-                source: { type: "tool", messageID: context.assistantMessageID, callID: context.toolCallID },
-              })
-              yield* todos.update({ sessionID: context.sessionID, todos: input.todos })
-              return { todos: input.todos }
-            }).pipe(Effect.mapError(() => new ToolFailure({ message: "Unable to update todos" }))),
-        }),
-      })
+      .transform((draft) =>
+        draft.add(
+          name,
+          Tool.make({
+            description:
+              "Create and maintain a structured task list for the current coding session. Use it to track progress during multi-step work and keep todo statuses current.",
+            input: Input,
+            output: Output,
+            toModelOutput: ({ output }) => [{ type: "text", text: toModelOutput(output) }],
+            execute: (input, context) =>
+              Effect.gen(function* () {
+                yield* permission.assert({
+                  action: name,
+                  resources: ["*"],
+                  save: ["*"],
+                  sessionID: context.sessionID,
+                  agent: context.agent,
+                  source: { type: "tool", messageID: context.assistantMessageID, callID: context.toolCallID },
+                })
+                yield* todos.update({ sessionID: context.sessionID, todos: input.todos })
+                return { todos: input.todos }
+              }).pipe(Effect.mapError(() => new ToolFailure({ message: "Unable to update todos" }))),
+          }),
+        ),
+      )
       .pipe(Effect.orDie)
   }),
 }

packages/core/src/tool/webfetch.ts

@@ -119,60 +119,63 @@ export const Plugin = {
     const permission = yield* PermissionV2.Service
 
     yield* ctx.tool
-      .register({
-        [name]: Tool.make({
-          description,
-          input: Input,
-          output: Output,
-          toModelOutput: ({ output }) => [{ type: "text", text: output.output }],
-          execute: (input, context) =>
-            Effect.gen(function* () {
-              yield* Effect.try({
-                try: () => assertHttpUrl(new URL(input.url)),
-                catch: (error) => error,
-              })
-
-              yield* permission.assert({
-                action: name,
-                resources: [input.url],
-                save: ["*"],
-                metadata: input,
-                sessionID: context.sessionID,
-                agent: context.agent,
-                source: { type: "tool", messageID: context.assistantMessageID, callID: context.toolCallID },
-              })
-
-              const { body, contentType } = yield* Effect.gen(function* () {
-                const response = yield* execute(http, input.url, input.format).pipe(
-                  Effect.catchIf(isCloudflareChallenge, () => execute(http, input.url, input.format, "opencode")),
+      .transform((draft) =>
+        draft.add(
+          name,
+          Tool.make({
+            description,
+            input: Input,
+            output: Output,
+            toModelOutput: ({ output }) => [{ type: "text", text: output.output }],
+            execute: (input, context) =>
+              Effect.gen(function* () {
+                yield* Effect.try({
+                  try: () => assertHttpUrl(new URL(input.url)),
+                  catch: (error) => error,
+                })
+
+                yield* permission.assert({
+                  action: name,
+                  resources: [input.url],
+                  save: ["*"],
+                  metadata: input,
+                  sessionID: context.sessionID,
+                  agent: context.agent,
+                  source: { type: "tool", messageID: context.assistantMessageID, callID: context.toolCallID },
+                })
+
+                const { body, contentType } = yield* Effect.gen(function* () {
+                  const response = yield* execute(http, input.url, input.format).pipe(
+                    Effect.catchIf(isCloudflareChallenge, () => execute(http, input.url, input.format, "opencode")),
+                  )
+                  const contentType = response.headers["content-type"] || ""
+                  const mime = mimeFrom(contentType)
+                  if (isImageAttachment(mime))
+                    return yield* Effect.fail(new Error(`Unsupported fetched image content type: ${mime}`))
+                  if (!isTextualMime(mime))
+                    return yield* Effect.fail(new Error(`Unsupported fetched file content type: ${mime}`))
+                  return { body: yield* collectBody(response), contentType }
+                }).pipe(
+                  Effect.timeoutOrElse({
+                    duration: Duration.seconds(input.timeout ?? DEFAULT_TIMEOUT_SECONDS),
+                    orElse: () => Effect.fail(new Error("Request timed out")),
+                  }),
                 )
-                const contentType = response.headers["content-type"] || ""
-                const mime = mimeFrom(contentType)
-                if (isImageAttachment(mime))
-                  return yield* Effect.fail(new Error(`Unsupported fetched image content type: ${mime}`))
-                if (!isTextualMime(mime))
-                  return yield* Effect.fail(new Error(`Unsupported fetched file content type: ${mime}`))
-                return { body: yield* collectBody(response), contentType }
-              }).pipe(
-                Effect.timeoutOrElse({
-                  duration: Duration.seconds(input.timeout ?? DEFAULT_TIMEOUT_SECONDS),
-                  orElse: () => Effect.fail(new Error("Request timed out")),
-                }),
-              )
-              const content = new TextDecoder().decode(body)
-              const output = yield* Effect.try({
-                try: () => convert(content, contentType, input.format),
-                catch: (error) => error,
-              })
-              return {
-                url: input.url,
-                contentType,
-                format: input.format,
-                output,
-              }
-            }).pipe(Effect.mapError(() => new ToolFailure({ message: `Unable to fetch ${input.url}` }))),
-        }),
-      })
+                const content = new TextDecoder().decode(body)
+                const output = yield* Effect.try({
+                  try: () => convert(content, contentType, input.format),
+                  catch: (error) => error,
+                })
+                return {
+                  url: input.url,
+                  contentType,
+                  format: input.format,
+                  output,
+                }
+              }).pipe(Effect.mapError(() => new ToolFailure({ message: `Unable to fetch ${input.url}` }))),
+          }),
+        ),
+      )
       .pipe(Effect.orDie)
   }),
 }

packages/core/src/tool/websearch.ts

@@ -195,58 +195,63 @@ export const Plugin = {
     const permission = yield* PermissionV2.Service
 
     yield* ctx.tool
-      .register({
-        [name]: Tool.make({
-          description,
-          input: Input,
-          output: Output,
-          toModelOutput: ({ output }) => [{ type: "text", text: output.text }],
-          execute: (input, context) => {
-            const provider = selectProvider(context.sessionID, config, config.provider)
-            return Effect.gen(function* () {
-              yield* permission.assert({
-                action: name,
-                resources: [input.query],
-                save: ["*"],
-                metadata: { ...input, provider },
-                sessionID: context.sessionID,
-                agent: context.agent,
-                source: { type: "tool", messageID: context.assistantMessageID, callID: context.toolCallID },
-              })
-
-              const text =
-                provider === "exa"
-                  ? yield* callMcp(http, exaUrl(config.exaApiKey), "web_search_exa", ExaArgs, {
-                      query: input.query,
-                      type: input.type || "auto",
-                      numResults: input.numResults || 8,
-                      livecrawl: input.livecrawl || "fallback",
-                      contextMaxCharacters: input.contextMaxCharacters,
-                    })
-                  : yield* callMcp(
-                      http,
-                      PARALLEL_URL,
-                      "web_search",
-                      ParallelArgs,
-                      {
-                        objective: input.query,
-                        search_queries: [input.query],
-                        session_id: context.sessionID,
-                        // V2 invocation context does not safely expose the model yet.
-                      },
-                      {
-                        "User-Agent": `opencode/${InstallationVersion}`,
-                        ...(config.parallelApiKey ? { Authorization: `Bearer ${config.parallelApiKey}` } : {}),
-                      },
-                    )
-              return {
-                provider,
-                text: text ?? NO_RESULTS,
-              }
-            }).pipe(Effect.mapError(() => new ToolFailure({ message: `Unable to search the web for ${input.query}` })))
-          },
-        }),
-      })
+      .transform((draft) =>
+        draft.add(
+          name,
+          Tool.make({
+            description,
+            input: Input,
+            output: Output,
+            toModelOutput: ({ output }) => [{ type: "text", text: output.text }],
+            execute: (input, context) => {
+              const provider = selectProvider(context.sessionID, config, config.provider)
+              return Effect.gen(function* () {
+                yield* permission.assert({
+                  action: name,
+                  resources: [input.query],
+                  save: ["*"],
+                  metadata: { ...input, provider },
+                  sessionID: context.sessionID,
+                  agent: context.agent,
+                  source: { type: "tool", messageID: context.assistantMessageID, callID: context.toolCallID },
+                })
+
+                const text =
+                  provider === "exa"
+                    ? yield* callMcp(http, exaUrl(config.exaApiKey), "web_search_exa", ExaArgs, {
+                        query: input.query,
+                        type: input.type || "auto",
+                        numResults: input.numResults || 8,
+                        livecrawl: input.livecrawl || "fallback",
+                        contextMaxCharacters: input.contextMaxCharacters,
+                      })
+                    : yield* callMcp(
+                        http,
+                        PARALLEL_URL,
+                        "web_search",
+                        ParallelArgs,
+                        {
+                          objective: input.query,
+                          search_queries: [input.query],
+                          session_id: context.sessionID,
+                          // V2 invocation context does not safely expose the model yet.
+                        },
+                        {
+                          "User-Agent": `opencode/${InstallationVersion}`,
+                          ...(config.parallelApiKey ? { Authorization: `Bearer ${config.parallelApiKey}` } : {}),
+                        },
+                      )
+                return {
+                  provider,
+                  text: text ?? NO_RESULTS,
+                }
+              }).pipe(
+                Effect.mapError(() => new ToolFailure({ message: `Unable to search the web for ${input.query}` })),
+              )
+            },
+          }),
+        ),
+      )
       .pipe(Effect.orDie)
   }),
 }

packages/core/src/tool/write.ts

@@ -50,44 +50,47 @@ export const Plugin = {
     const permission = yield* PermissionV2.Service
 
     yield* ctx.tool
-      .register({
-        [name]: Tool.withPermission(
-          Tool.make({
-            description:
-              "Write content to one file. Relative paths resolve within the active Location. Absolute paths inside the Location are accepted. Explicit external absolute paths require external_directory approval before edit approval.",
-            input: Input,
-            output: Output,
-            toModelOutput: ({ output }) => [{ type: "text", text: toModelOutput(output) }],
-            execute: (input, context) =>
-              Effect.gen(function* () {
-                const source = {
-                  type: "tool" as const,
-                  messageID: context.assistantMessageID,
-                  callID: context.toolCallID,
-                }
-                const target = yield* mutation.resolve({ path: input.path, kind: "file" })
-                const external = target.externalDirectory
-                if (external)
+      .transform((draft) =>
+        draft.add(
+          name,
+          Tool.withPermission(
+            Tool.make({
+              description:
+                "Write content to one file. Relative paths resolve within the active Location. Absolute paths inside the Location are accepted. Explicit external absolute paths require external_directory approval before edit approval.",
+              input: Input,
+              output: Output,
+              toModelOutput: ({ output }) => [{ type: "text", text: toModelOutput(output) }],
+              execute: (input, context) =>
+                Effect.gen(function* () {
+                  const source = {
+                    type: "tool" as const,
+                    messageID: context.assistantMessageID,
+                    callID: context.toolCallID,
+                  }
+                  const target = yield* mutation.resolve({ path: input.path, kind: "file" })
+                  const external = target.externalDirectory
+                  if (external)
+                    yield* permission.assert({
+                      ...LocationMutation.externalDirectoryPermission(external),
+                      sessionID: context.sessionID,
+                      agent: context.agent,
+                      source,
+                    })
                   yield* permission.assert({
-                    ...LocationMutation.externalDirectoryPermission(external),
+                    action: "edit",
+                    resources: [target.resource],
+                    save: ["*"],
                     sessionID: context.sessionID,
                     agent: context.agent,
                     source,
                   })
-                yield* permission.assert({
-                  action: "edit",
-                  resources: [target.resource],
-                  save: ["*"],
-                  sessionID: context.sessionID,
-                  agent: context.agent,
-                  source,
-                })
-                return yield* files.writeTextPreservingBom({ target, content: input.content })
-              }).pipe(Effect.mapError(() => new ToolFailure({ message: `Unable to write ${input.path}` }))),
-          }),
-          "edit",
+                  return yield* files.writeTextPreservingBom({ target, content: input.content })
+                }).pipe(Effect.mapError(() => new ToolFailure({ message: `Unable to write ${input.path}` }))),
+            }),
+            "edit",
+          ),
         ),
-      })
+      )
       .pipe(Effect.orDie)
   }),
 }

packages/core/test/event.test.ts

@@ -61,6 +61,12 @@ const GlobalMessage = EventV2.ephemeral({
     text: Schema.String,
   },
 })
+const CountMessage = EventV2.ephemeral({
+  type: "test.count",
+  schema: {
+    count: Schema.Number,
+  },
+})
 
 const VersionedMessage = EventV2.durable({
   type: "test.versioned",
@@ -90,6 +96,26 @@ const it = testEffect(
 const itWithoutLocation = testEffect(AppNodeBuilder.build(LayerNode.group([Database.node, EventV2.node])))
 
 describe("EventV2", () => {
+  it.effect("subscribes to multiple event definitions with a discriminated payload union", () =>
+    Effect.gen(function* () {
+      const events = yield* EventV2.Service
+      // @ts-expect-error multi-definition subscriptions require at least one definition
+      events.subscribe([])
+      const fiber = yield* events
+        .subscribe([Message, CountMessage])
+        .pipe(Stream.take(2), Stream.runCollect, Effect.forkScoped)
+      yield* Effect.yieldNow
+
+      yield* events.publish(Message, { text: "hello" })
+      yield* events.publish(CountMessage, { count: 2 })
+
+      const received = Array.from(yield* Fiber.join(fiber)).map((event) =>
+        event.type === "test.message" ? event.data.text : event.data.count,
+      )
+      expect(received).toEqual(["hello", 2])
+    }),
+  )
+
   it.effect("publishes events with the current location", () =>
     Effect.gen(function* () {
       const events = yield* EventV2.Service

packages/core/test/lib/tool.ts

@@ -2,6 +2,7 @@ import { AgentV2 } from "@opencode-ai/core/agent"
 import type { PermissionV2 } from "@opencode-ai/core/permission"
 import { SessionMessage } from "@opencode-ai/core/session/message"
 import { ToolRegistry } from "@opencode-ai/core/tool/registry"
+import { Tool } from "@opencode-ai/core/tool/tool"
 import { Tools } from "@opencode-ai/core/tool/tools"
 import type { PluginContext } from "@opencode-ai/plugin/v2/effect"
 import { Effect, type Scope } from "effect"
@@ -49,7 +50,24 @@ export const registerToolPlugin = <R>(plugin: {
     const tools = yield* Tools.Service
     const context: Pick<PluginContext, "tool"> = {
       tool: {
-        register: tools.register,
+        transform: (callback) =>
+          Effect.gen(function* () {
+            const registrations: Array<{
+              readonly name: string
+              readonly tool: Tool.AnyTool
+              readonly options?: Tool.RegisterOptions
+            }> = []
+            callback({
+              add: (name, tool, options) => {
+                registrations.push({ name, tool, ...(options ? { options } : {}) })
+              },
+            })
+            yield* Effect.forEach(
+              registrations,
+              (registration) => tools.register({ [registration.name]: registration.tool }, registration.options),
+              { discard: true },
+            )
+          }),
         execute: {
           before: () => Effect.die("registerToolPlugin does not support tool hooks"),
           after: () => Effect.die("registerToolPlugin does not support tool hooks"),

packages/core/test/plugin.test.ts

@@ -165,14 +165,17 @@ describe("PluginV2", () => {
         id: "tool-plugin",
         effect: (ctx) =>
           ctx.tool
-            .register({
-              plugin_tool: Tool.make({
-                description: "Plugin tool",
-                input: Schema.Struct({}),
-                output: Schema.Struct({ ok: Schema.Boolean }),
-                execute: () => Effect.succeed({ ok: true }),
-              }),
-            })
+            .transform((draft) =>
+              draft.add(
+                "plugin_tool",
+                Tool.make({
+                  description: "Plugin tool",
+                  input: Schema.Struct({}),
+                  output: Schema.Struct({ ok: Schema.Boolean }),
+                  execute: () => Effect.succeed({ ok: true }),
+                }),
+              ),
+            )
             .pipe(Effect.orDie),
       })
 
@@ -202,13 +205,13 @@ describe("PluginV2", () => {
       const plugin = define({
         id: "grouped-tools",
         effect: (ctx) =>
-          Effect.gen(function* () {
-            yield* ctx.tool.register({ plain: tool("Plain") }).pipe(Effect.orDie)
-            yield* ctx.tool.register({ "look/up": tool("Lookup") }, { group: "context 7" }).pipe(Effect.orDie)
-            yield* ctx.tool
-              .register({ search: tool("Search") }, { group: "context 7", deferred: true })
-              .pipe(Effect.orDie)
-          }),
+          ctx.tool
+            .transform((draft) => {
+              draft.add("plain", tool("Plain"))
+              draft.add("look/up", tool("Lookup"), { group: "context 7" })
+              draft.add("search", tool("Search"), { group: "context 7", deferred: true })
+            })
+            .pipe(Effect.orDie),
       })
 
       yield* plugins.activate([{ plugin }])
@@ -236,14 +239,17 @@ describe("PluginV2", () => {
         effect: (ctx) =>
           Effect.gen(function* () {
             yield* ctx.tool
-              .register({
-                echo: Tool.make({
-                  description: "Echo",
-                  input: Schema.Struct({ text: Schema.String }),
-                  output: Schema.Struct({ text: Schema.String }),
-                  execute: ({ text }) => Effect.sync(() => executed.push({ text })).pipe(Effect.as({ text })),
-                }),
-              })
+              .transform((draft) =>
+                draft.add(
+                  "echo",
+                  Tool.make({
+                    description: "Echo",
+                    input: Schema.Struct({ text: Schema.String }),
+                    output: Schema.Struct({ text: Schema.String }),
+                    execute: ({ text }) => Effect.sync(() => executed.push({ text })).pipe(Effect.as({ text })),
+                  }),
+                ),
+              )
               .pipe(Effect.orDie)
 
             yield* ctx.tool.execute

packages/core/test/plugin/host.ts

@@ -71,7 +71,7 @@ export function host(overrides: Overrides = {}): PluginContext {
       reload: () => Effect.die("unused skill.reload"),
     },
     tool: overrides.tool ?? {
-      register: () => Effect.die("unused tool.register"),
+      transform: () => Effect.die("unused tool.transform"),
       execute: {
         before: () => Effect.die("unused tool.execute.before"),
         after: () => Effect.die("unused tool.execute.after"),

packages/plugin/src/v2/effect/index.ts

@@ -10,5 +10,5 @@ export type { IntegrationDraft, IntegrationHooks, IntegrationMethodRegistration
 export type { ReferenceDraft, ReferenceHooks } from "./reference.js"
 export type { SkillDraft, SkillHooks } from "./skill.js"
 export * as Tool from "./tool.js"
-export type { ToolDomain, ToolExecuteBeforeEvent, ToolExecuteAfterEvent } from "./tool.js"
+export type { ToolDomain, ToolDraft, ToolExecuteBeforeEvent, ToolExecuteAfterEvent } from "./tool.js"
 export type { SessionHooks } from "./runtime.js"

packages/plugin/src/v2/effect/tool.ts

@@ -249,10 +249,11 @@ export interface RegisterOptions {
   readonly deferred?: boolean
 }
 
+export interface ToolDraft {
+  add(name: string, tool: AnyTool, options?: RegisterOptions): void
+}
+
 export interface ToolDomain {
-  readonly register: (
-    tools: Readonly<Record<string, AnyTool>>,
-    options?: RegisterOptions,
-  ) => Effect.Effect<void, RegistrationError, Scope.Scope>
+  readonly transform: (callback: (draft: ToolDraft) => void) => Effect.Effect<void, RegistrationError, Scope.Scope>
   readonly execute: Hooks<{ before: ToolExecuteBeforeEvent; after: ToolExecuteAfterEvent }>
 }

packages/sdk-next/README.md

@@ -11,7 +11,7 @@ const opencode = yield * OpenCode.create()
 const session = yield * opencode.sessions.get({ sessionID })
 ```
 
-It also exports `Tool` for plugins that register tools with `ctx.tool.register(...)`. Embedded plugins run through the ordinary discovery flow and register tools into each Location's `ToolRegistry` through the normal `Tools.Service.register(...)` path. Closing the owning Effect Scope releases router resources, location services, fibers, and scoped tool registrations.
+It also exports `Tool` for plugins that add tools with `ctx.tool.transform(...)`. Embedded plugins run through the ordinary discovery flow and register tools into each Location's `ToolRegistry` through the normal `Tools.Service.register(...)` path. Closing the owning Effect Scope releases router resources, location services, fibers, and scoped tool registrations.
 
 `sessions.events({ sessionID, after })` replays durable events after the optional aggregate sequence, then emits newly committed durable events. `sessions.interrupt(...)` targets execution owned by this host, and `sessions.message(...)` retrieves one projected Session message.
 

packages/sdk-next/src/opencode.ts

@@ -1,6 +1,7 @@
 import { OpenCode } from "@opencode-ai/client/effect"
 import { AppNodeBuilder } from "@opencode-ai/core/effect/app-node-builder"
 import { LayerNode } from "@opencode-ai/core/effect/layer-node"
+import { EventV2 } from "@opencode-ai/core/event"
 import { PermissionSaved } from "@opencode-ai/core/permission/saved"
 import { SdkPlugins } from "@opencode-ai/core/plugin/sdk"
 import { Project } from "@opencode-ai/core/project"
@@ -13,7 +14,7 @@ export const create = Effect.fn("OpenCode.create")(function* () {
   const memoMap = yield* Layer.makeMemoMap
   const sdkPlugins = SdkPlugins.makeStore()
   const context = yield* Layer.buildWithMemoMap(
-    AppNodeBuilder.build(LayerNode.group([PermissionSaved.node, Project.node, SdkPlugins.node]), [
+    AppNodeBuilder.build(LayerNode.group([EventV2.node, PermissionSaved.node, Project.node, SdkPlugins.node]), [
       [SdkPlugins.node, SdkPlugins.layerWithStore(sdkPlugins)],
     ]),
     memoMap,

packages/sdk-next/test/embedded.test.ts

@@ -1,6 +1,8 @@
+import fs from "fs/promises"
+import path from "path"
 import { expect } from "bun:test"
 import { Flag } from "@opencode-ai/core/flag/flag"
-import { Deferred, Effect, Latch, Layer, Option, Schema, Stream } from "effect"
+import { Deferred, Effect, Latch, Layer, Option, Ref, Schema, Stream } from "effect"
 import { testEffect } from "../../core/test/lib/effect"
 import { tmpdir } from "../../core/test/fixture/tmpdir"
 import type { OpenCodeEvent } from "../src"
@@ -26,6 +28,118 @@ const sessionID = (fixture: Fixture) => fixture.sdk.Session.ID.create()
 const location = (fixture: Fixture) =>
   fixture.sdk.Location.Ref.make({ directory: fixture.sdk.AbsolutePath.make(fixture.directory) })
 
+it.live(
+  "reloads every booted Location after SDK plugin registration",
+  () =>
+    withEmbedded("opencode-embedded-plugin-reload-", (fixture) =>
+      Effect.gen(function* () {
+        const opencode = yield* fixture.sdk.OpenCode.create()
+        const booted = yield* Deferred.make<void>()
+        const activated = yield* Deferred.make<boolean>()
+        const bootCount = yield* Ref.make(0)
+        const activationCount = yield* Ref.make(0)
+        const secondDirectory = path.join(fixture.directory, "second")
+        yield* Effect.promise(() => fs.mkdir(secondDirectory))
+        const refs = [
+          location(fixture),
+          fixture.sdk.Location.Ref.make({ directory: fixture.sdk.AbsolutePath.make(secondDirectory) }),
+        ]
+        const bootstrapID = `bootstrap-sdk-${crypto.randomUUID()}`
+        const id = `late-sdk-${crypto.randomUUID()}`
+
+        yield* opencode.plugin({
+          id: bootstrapID,
+          effect: (ctx) =>
+            Effect.gen(function* () {
+              yield* ctx.tool
+                .transform((draft) =>
+                  draft.add(
+                    "bootstrap_sdk_tool",
+                    fixture.sdk.Tool.make({
+                      description: "Marks the initial Location plugin generation",
+                      input: Schema.Struct({}),
+                      output: Schema.Void,
+                      execute: () => Effect.void,
+                    }),
+                  ),
+                )
+                .pipe(Effect.orDie)
+              if (yield* Ref.updateAndGet(bootCount, (count) => count + 1).pipe(Effect.map((count) => count === 2))) {
+                yield* Deferred.succeed(booted, undefined)
+              }
+            }),
+        })
+        yield* Effect.all(
+          refs.map((ref) => opencode.plugin.list({ location: ref })),
+          { discard: true },
+        )
+        yield* Deferred.await(booted).pipe(Effect.timeout("4 seconds"))
+        yield* opencode.plugin({
+          id,
+          effect: (ctx) =>
+            Effect.gen(function* () {
+              yield* ctx.tool
+                .transform((draft) =>
+                  draft.add(
+                    "late_sdk_tool",
+                    fixture.sdk.Tool.make({
+                      description: "Tool registered after Location boot",
+                      input: Schema.Struct({}),
+                      output: Schema.Void,
+                      execute: () => Effect.void,
+                    }),
+                  ),
+                )
+                .pipe(Effect.orDie)
+              if (
+                yield* Ref.updateAndGet(activationCount, (count) => count + 1).pipe(Effect.map((count) => count === 2))
+              ) {
+                yield* Deferred.succeed(activated, true)
+              }
+            }),
+        })
+
+        expect(yield* Deferred.await(activated).pipe(Effect.timeout("10 seconds"))).toBe(true)
+      }),
+    ),
+  25_000,
+)
+
+it.live(
+  "keeps SDK plugin registration isolated between embedded hosts",
+  () =>
+    withEmbedded("opencode-embedded-plugin-isolation-", (fixture) =>
+      Effect.gen(function* () {
+        const first = yield* fixture.sdk.OpenCode.create()
+        const second = yield* fixture.sdk.OpenCode.create()
+        const firstReady = yield* Deferred.make<void>()
+        const secondReady = yield* Deferred.make<void>()
+        const activated = yield* Deferred.make<void>()
+        const ref = location(fixture)
+        const id = `isolated-sdk-${crypto.randomUUID()}`
+
+        yield* first.plugin({
+          id: `first-ready-${crypto.randomUUID()}`,
+          effect: () => Deferred.succeed(firstReady, undefined),
+        })
+        yield* second.plugin({
+          id: `second-ready-${crypto.randomUUID()}`,
+          effect: () => Deferred.succeed(secondReady, undefined),
+        })
+        yield* Effect.all([first.plugin.list({ location: ref }), second.plugin.list({ location: ref })], {
+          discard: true,
+        })
+        yield* Effect.all([Deferred.await(firstReady), Deferred.await(secondReady)], { discard: true })
+
+        yield* first.plugin({ id, effect: () => Deferred.succeed(activated, undefined) })
+        yield* Deferred.await(activated).pipe(Effect.timeout("5 seconds"))
+
+        expect((yield* second.plugin.list({ location: ref })).data.map((plugin) => String(plugin.id))).not.toContain(id)
+      }),
+    ),
+  15_000,
+)
+
 it.live(
   "embedded client uses the real router and handlers",
   () =>
@@ -42,14 +156,17 @@ it.live(
           id: `embedded-tools-${crypto.randomUUID()}`,
           effect: (ctx) =>
             ctx.tool
-              .register({
-                embedded_tool: fixture.sdk.Tool.make({
-                  description: "Embedded test tool",
-                  input: Schema.Struct({}),
-                  output: Schema.Struct({ ok: Schema.Boolean }),
-                  execute: () => Effect.succeed({ ok: true }),
-                }),
-              })
+              .transform((draft) =>
+                draft.add(
+                  "embedded_tool",
+                  fixture.sdk.Tool.make({
+                    description: "Embedded test tool",
+                    input: Schema.Struct({}),
+                    output: Schema.Struct({ ok: Schema.Boolean }),
+                    execute: () => Effect.succeed({ ok: true }),
+                  }),
+                ),
+              )
               .pipe(Effect.orDie),
         })