fix(config): drop malformed top-level fields instead of crashing the load

Reported by Ben Matthews on Discord against v1.14.45: a `skills:` field
shaped as an array (rather than the schema's `{paths?, urls?}` object)
caused the entire config load to fail with ConfigInvalidError, the
server returned 500, and the desktop app couldn't start.

Per Kit:
> for all of these things that we load from the user's computer, they
> should be kind of tolerant. We can have warnings that we log
> somewhere, but Jesus. It shouldn't break opencode.

This makes `ConfigParse.effectSchema` field-tolerant:

- Unknown top-level keys are stripped (with a warning log) instead of
  throwing `unrecognized_keys`.
- Top-level fields whose value fails decoding are dropped (with a
  warning log naming the field + the issue summary), the rest of the
  config decodes normally.
- Root-level errors (e.g. data is not an object at all) and post-strip
  failures still throw the original `InvalidError` so we don't silently
  swallow truly broken configs.

Three new tests cover the reported shape (skills as array), unknown
keys, and multi-bad-field cases. Two existing tests that asserted the
strict-throw behavior were updated to the new tolerant contract.

Pre-fix: opencode unstartable for users with malformed configs.
Post-fix: opencode starts, the bad field is ignored, the user sees a
warning in the log naming what was dropped.

packages/opencode/src/config/parse.ts

@@ -2,10 +2,13 @@ export * as ConfigParse from "./parse"
 
 import { type ParseError as JsoncParseError, parse as parseJsoncImpl, printParseErrorCode } from "jsonc-parser"
 import { Cause, Exit, Schema as EffectSchema, SchemaIssue } from "effect"
+import * as Log from "@opencode-ai/core/util/log"
 import z from "zod"
 import type { DeepMutable } from "@opencode-ai/core/schema"
 import { InvalidError, JsonError } from "./error"
 
+const log = Log.create({ service: "config.parse" })
+
 type ZodSchema<T> = z.ZodType<T>
 
 export function jsonc(text: string, filepath: string): unknown {
@@ -50,34 +53,70 @@ export function effectSchema<S extends EffectSchema.Decoder<unknown, never>>(
   data: unknown,
   source: string,
 ): DeepMutable<S["Type"]> {
+  // The user's config lives on disk and may legitimately be stale, hand-edited,
+  // or carry leftover keys from older versions. Crashing the whole load on a
+  // single bad field would make opencode unstartable for those users (see Ben
+  // Matthews / Discord, v1.14.45). Strip the malformed top-level fields and
+  // keep going — log every drop so users can see what was ignored and fix it.
+  const cleaned = stripUnknownTopLevelKeys(schema, data, source)
+  return decodeWithFieldTolerance(schema, cleaned, source)
+}
+
+function stripUnknownTopLevelKeys(schema: EffectSchema.Top, data: unknown, source: string): unknown {
+  if (typeof data !== "object" || data === null || Array.isArray(data)) return data
   const extra = topLevelExtraKeys(schema, data)
-  if (extra.length) {
-    throw new InvalidError({
-      path: source,
-      issues: [
-        {
-          code: "unrecognized_keys",
-          keys: extra,
-          path: [],
-          message: `Unrecognized key${extra.length === 1 ? "" : "s"}: ${extra.join(", ")}`,
-        } as z.core.$ZodIssue,
-      ],
-    })
-  }
+  if (extra.length === 0) return data
+  log.warn("ignoring unrecognized config keys", { source, keys: extra })
+  const obj = data as Record<string, unknown>
+  return Object.fromEntries(Object.entries(obj).filter(([key]) => !extra.includes(key)))
+}
 
+function decodeWithFieldTolerance<S extends EffectSchema.Decoder<unknown, never>>(
+  schema: S,
+  data: unknown,
+  source: string,
+): DeepMutable<S["Type"]> {
+  // Try a clean decode first. If it succeeds we're done — common path.
   const decoded = EffectSchema.decodeUnknownExit(schema)(data, { errors: "all", propertyOrder: "original" })
   if (Exit.isSuccess(decoded)) return decoded.value as DeepMutable<S["Type"]>
   const error = Cause.squash(decoded.cause)
+  const issues = EffectSchema.isSchemaError(error)
+    ? (SchemaIssue.makeFormatterStandardSchemaV1()(error.issue).issues as z.core.$ZodIssue[])
+    : ([{ code: "custom", message: String(error), path: [] }] as z.core.$ZodIssue[])
+
+  // Identify malformed top-level fields. Anything with a non-empty path is a
+  // field-scoped issue we can drop and retry. Issues with an empty path are
+  // root-level (e.g. data is not an object at all) and can't be field-recovered.
+  const badFields = collectTopLevelFieldNames(issues)
+  if (badFields.size === 0 || typeof data !== "object" || data === null || Array.isArray(data)) {
+    throw new InvalidError({ path: source, issues }, { cause: error })
+  }
+
+  log.warn("ignoring invalid config fields", {
+    source,
+    fields: [...badFields],
+    summary: issues
+      .filter((issue) => issue.path && issue.path.length > 0)
+      .map((issue) => `${issue.path?.join(".")}: ${issue.message}`)
+      .slice(0, 8),
+  })
+
+  const obj = data as Record<string, unknown>
+  const cleaned = Object.fromEntries(Object.entries(obj).filter(([key]) => !badFields.has(key)))
+  // Retry without the bad fields. If THIS fails, we're past field-tolerance —
+  // fall back to the original strict error so the user sees the real cause.
+  const retry = EffectSchema.decodeUnknownExit(schema)(cleaned, { errors: "all", propertyOrder: "original" })
+  if (Exit.isSuccess(retry)) return retry.value as DeepMutable<S["Type"]>
+  throw new InvalidError({ path: source, issues }, { cause: error })
+}
 
-  throw new InvalidError(
-    {
-      path: source,
-      issues: EffectSchema.isSchemaError(error)
-        ? (SchemaIssue.makeFormatterStandardSchemaV1()(error.issue).issues as z.core.$ZodIssue[])
-        : ([{ code: "custom", message: String(error), path: [] }] as z.core.$ZodIssue[]),
-    },
-    { cause: error },
-  )
+function collectTopLevelFieldNames(issues: z.core.$ZodIssue[]): Set<string> {
+  const names = new Set<string>()
+  for (const issue of issues) {
+    const head = issue.path?.[0]
+    if (typeof head === "string") names.add(head)
+  }
+  return names
 }
 
 function topLevelExtraKeys(schema: EffectSchema.Top, data: unknown) {

packages/opencode/test/config/config.test.ts

@@ -558,20 +558,22 @@ test("handles file inclusion with replacement tokens", async () => {
   })
 })
 
-test("validates config schema and throws on invalid fields", async () => {
+test("config loader is tolerant: drops unknown fields, keeps the rest", async () => {
   await using tmp = await tmpdir({
     init: async (dir) => {
       await writeConfig(dir, {
         $schema: "https://opencode.ai/config.json",
-        invalid_field: "should cause error",
+        username: "kept",
+        invalid_field: "should be dropped, not crash the app",
       })
     },
   })
   await provideTestInstance({
     directory: tmp.path,
     fn: async () => {
-      // Strict schema should throw an error for invalid fields
-      await expect(load()).rejects.toThrow()
+      const config = await load()
+      expect(config.username).toBe("kept")
+      expect((config as Record<string, unknown>).invalid_field).toBeUndefined()
     },
   })
 })
@@ -1681,7 +1683,70 @@ test("permission config preserves user key order", async () => {
   })
 })
 
-test("Effect config parser preserves permission order while rejecting unknown top-level keys", () => {
+// Discord bug report (Ben Matthews, v1.14.45): a malformed `skills:` field
+// (array instead of object) made the WHOLE config fail to load, the server
+// returned 500, and the desktop app couldn't start. Per Kit:
+//   "for all of these things that we load from the user's computer, they
+//    should be kind of tolerant. ... It shouldn't break opencode."
+// The contract: drop the malformed top-level field, log a warning, keep
+// the rest of the config so the app starts.
+test("config parser is tolerant: drops malformed top-level fields, keeps the rest", () => {
+  const config = ConfigParse.effectSchema(
+    Config.Info,
+    {
+      $schema: "https://opencode.ai/config.json",
+      username: "ben",
+      // Wrong shape — schema expects { paths?, urls? }, user has an array
+      // (looks like the LOADED skills list got pasted into the config).
+      skills: [
+        { name: "scss-layout-accessibility", path: ".opencode/skills/scss-layout-accessibility.md" },
+        { name: "testing", path: ".opencode/skills/testing.md" },
+      ],
+    },
+    "test",
+  )
+
+  // Pre-fix this throws ConfigInvalidError and the user can't start opencode.
+  // Post-fix the bad field is dropped and the rest of the config loads.
+  expect(config.username).toBe("ben")
+  expect(config.skills).toBeUndefined()
+})
+
+test("config parser is tolerant: drops unrecognized top-level keys instead of throwing", () => {
+  const config = ConfigParse.effectSchema(
+    Config.Info,
+    {
+      $schema: "https://opencode.ai/config.json",
+      username: "ben",
+      // Typo or stale key — pre-fix this threw `unrecognized_keys`.
+      autoshrare: true,
+    },
+    "test",
+  )
+
+  expect(config.username).toBe("ben")
+  expect((config as Record<string, unknown>).autoshrare).toBeUndefined()
+})
+
+test("config parser is tolerant: drops multiple bad fields in one pass", () => {
+  const config = ConfigParse.effectSchema(
+    Config.Info,
+    {
+      $schema: "https://opencode.ai/config.json",
+      username: "ben",
+      skills: ["wrong shape"],
+      autoshare: 42, // wrong type — schema wants string literal | undefined
+      not_a_real_key: "ignore me",
+    },
+    "test",
+  )
+
+  expect(config.username).toBe("ben")
+  expect(config.skills).toBeUndefined()
+  expect(config.autoshare).toBeUndefined()
+})
+
+test("Effect config parser preserves permission order while dropping unknown top-level keys", () => {
   const config = ConfigParse.effectSchema(
     Config.Info,
     {
@@ -1695,13 +1760,10 @@ test("Effect config parser preserves permission order while rejecting unknown to
   )
 
   expect(Object.keys(config.permission!)).toEqual(["bash", "*", "edit"])
-  try {
-    ConfigParse.effectSchema(Config.Info, { invalid_field: true }, "test")
-    throw new Error("expected config parse to fail")
-  } catch (err) {
-    const error = err as { data?: { issues?: Array<{ code?: string; keys?: string[]; path?: string[] }> } }
-    expect(error.data?.issues?.[0]).toMatchObject({ code: "unrecognized_keys", keys: ["invalid_field"], path: [] })
-  }
+  // Tolerant parser: unknown keys are stripped (with a warning log) instead
+  // of failing the entire config load.
+  const stripped = ConfigParse.effectSchema(Config.Info, { invalid_field: true }, "test")
+  expect((stripped as Record<string, unknown>).invalid_field).toBeUndefined()
 })
 
 // MCP config merging tests