fix(thin-client): keep ambient scope out of get_skill's non-scope source_id param

get_skill's source_id is a mode switch (host catalog vs brain-resident-pack
lookup), not a read-scope filter. Ambient GBRAIN_SOURCE / .gbrain-source
injection would silently reroute 'gbrain skill <name>' on thin clients to
getResidentSkillDetail. Exclude it via NON_SCOPE_SOURCE_ID_OPS; explicit
--source-id still passes through, explicit --source errors with a hint.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/cli.ts

@@ -24,6 +24,7 @@ import type { GBrainConfig } from './core/config.ts';
 import type { AIGatewayConfig } from './core/ai/types.ts';
 import type { BrainEngine } from './core/engine.ts';
 import { operations, OperationError } from './core/operations.ts';
+import { resolveSourceIdEngineFree } from './core/source-resolver.ts';
 import { formatVolunteeredPage } from './core/context/volunteer.ts';
 import type { Operation, OperationContext } from './core/operations.ts';
 import { shouldForceExitAfterMain, finishCliTeardown, flushThenExit, currentExitCode, setCliExitVerdict } from './core/cli-force-exit.ts';
@@ -382,6 +383,15 @@ async function main() {
     if (op.localOnly) {
       refuseThinClient(command, cfgPre!.remote_mcp!.mcp_url);
     }
+    // #2098: the local path resolves --source / GBRAIN_SOURCE / .gbrain-source
+    // inside makeContext (ctx.sourceId), which this route never reaches — so
+    // scope must be mapped onto the op's source_id wire param before the call.
+    try {
+      applyThinClientSourceScope(op, params);
+    } catch (e: unknown) {
+      console.error(e instanceof Error ? e.message : String(e));
+      process.exit(1);
+    }
     await runThinClientRouted(op, params, cfgPre!, cliOpts);
     return;
   }
@@ -802,6 +812,60 @@ export function parseOpArgs(op: Operation, args: string[]): Record<string, unkno
   return params;
 }
 
+/**
+ * #2098: thin-client source scoping. Locally, --source / GBRAIN_SOURCE /
+ * .gbrain-source resolve to ctx.sourceId in makeContext; the thin-client
+ * route short-circuits before that, so `gbrain query --source X` against a
+ * remote brain silently searched unscoped. This runs the engine-free tiers
+ * (flag → env → dotfile; the DB-backed tiers can't run without an engine —
+ * the server's grant scoping covers the rest) and maps the result onto the
+ * op's `source_id` wire param.
+ *
+ * Ops that declare their OWN `source` param (facts add, etc.) are left
+ * untouched — their --source is an op param, not scope. An explicit --source
+ * on an op with no source_id wire param throws (loud beats silent drop);
+ * ambient env/dotfile scope with nowhere to send it is ignored, matching the
+ * pre-fix behavior for non-scopeable ops. Exported for tests.
+ */
+// Ops whose `source_id` wire param is NOT read-scope semantics: get_skill's
+// source_id flips the lookup from host catalog to brain-resident-pack
+// (getResidentSkillDetail). Ambient env/dotfile scope must never leak into
+// these; an explicit --source-id still passes through untouched above.
+const NON_SCOPE_SOURCE_ID_OPS = new Set(['get_skill']);
+
+export function applyThinClientSourceScope(
+  op: Operation,
+  params: Record<string, unknown>,
+  cwd?: string,
+): void {
+  if ('source' in op.params) return; // the op owns --source; not a scope flag
+  const explicit = typeof params.source === 'string' && params.source.length > 0
+    ? (params.source as string)
+    : null;
+  delete params.source; // never a wire param on these ops — don't leak it
+  // Explicit per-call scope already on the wire wins over ambient tiers.
+  if (params.source_id !== undefined || params.all_sources === true) {
+    if (explicit) {
+      throw new Error('Pass either --source or --source-id/--all-sources, not both.');
+    }
+    return;
+  }
+  const resolved = resolveSourceIdEngineFree(explicit, cwd);
+  if (!resolved) return;
+  if (!('source_id' in op.params) || NON_SCOPE_SOURCE_ID_OPS.has(op.name)) {
+    if (explicit) {
+      const hint = NON_SCOPE_SOURCE_ID_OPS.has(op.name)
+        ? `(its source_id parameter is not a scope filter; pass --source-id explicitly if you mean it)`
+        : `(the remote op has no source_id parameter; the server scopes it to your grant)`;
+      throw new Error(
+        `gbrain ${op.cliHints?.name || op.name} does not accept --source on a thin-client install ${hint}.`,
+      );
+    }
+    return; // ambient env/dotfile scope with nowhere to send it
+  }
+  params.source_id = resolved;
+}
+
 async function makeContext(engine: BrainEngine, params: Record<string, unknown>): Promise<OperationContext> {
   // v0.31.8 (D11): resolve sourceId via the canonical 6-tier chain. Honors
   // --source / GBRAIN_SOURCE / .gbrain-source / path-match / brain default /

src/core/postgres-engine.ts

@@ -5565,78 +5565,30 @@ export class PostgresEngine implements BrainEngine {
     });
   }
 
-  /**
-   * perf (#1694 by @Omerbahari): process-lifetime config cache. A single
-   * search fires ~85 getConfig() reads (loadConfigWithEngine x2, plus
-   * mode/cache/intent/rerank/graph-signals resolvers). On a remote pooler
-   * each read is a round-trip; serial they dominate query latency and can
-   * push the op handler past cli.ts's 10s disconnect force-exit, truncating
-   * stdout. First read batch-loads the whole `config` table into this Map
-   * (inside the same connRetry posture as the per-key read — #1603/#1891);
-   * setConfig/unsetConfig write through. TTL bounds staleness for
-   * multi-writer processes; GBRAIN_CONFIG_CACHE_TTL_MS=0 disables.
-   * Only present keys are stored — Map.has() distinguishes known-absent.
-   */
-  private _configCache: Map<string, string> | null = null;
-  private _configCacheLoadedAt = 0;
-  private _configCacheLoad: Promise<void> | null = null;
-  private get _configCacheTtlMs(): number {
-    const raw = process.env.GBRAIN_CONFIG_CACHE_TTL_MS;
-    if (raw !== undefined) {
-      const n = parseInt(raw, 10);
-      if (Number.isFinite(n) && n >= 0) return n;
-    }
-    return 30_000;
-  }
-
   async getConfig(key: string): Promise<string | null> {
     // #1603: a transient pooler drop on this read used to throw / fall through
     // to defaults silently — which on remote Postgres surfaces as the wrong
-    // search mode/knobs and empty-stdout queries. Both the batch load and the
-    // cache-off per-key read keep the connRetry reconnect posture.
-    const ttl = this._configCacheTtlMs;
-    if (ttl === 0) {
-      return this.connRetry(async () => {
-        const rows = await this.sql`SELECT value FROM config WHERE key = ${key}`;
-        return rows.length > 0 ? (rows[0].value as string) : null;
-      });
-    }
-    if (this._configCache === null || Date.now() - this._configCacheLoadedAt >= ttl) {
-      // Single-flight: concurrent cold reads share one batch load.
-      this._configCacheLoad ??= this.connRetry(async () => {
-        const rows = await this.sql`SELECT key, value FROM config` as unknown as
-          Array<{ key: string; value: string | null }>;
-        const map = new Map<string, string>();
-        for (const r of rows) if (r.value != null) map.set(r.key, r.value);
-        this._configCache = map;
-        this._configCacheLoadedAt = Date.now();
-      }).finally(() => {
-        this._configCacheLoad = null;
-      });
-      await this._configCacheLoad;
-    }
-    return this._configCache!.has(key) ? this._configCache!.get(key)! : null;
+    // search mode/knobs and empty-stdout queries.
+    return this.connRetry(async () => {
+      const rows = await this.sql`SELECT value FROM config WHERE key = ${key}`;
+      return rows.length > 0 ? (rows[0].value as string) : null;
+    });
   }
 
   async setConfig(key: string, value: string): Promise<void> {
-    await this.connRetry(async () => {
+    return this.connRetry(async () => {
       await this.sql`
         INSERT INTO config (key, value) VALUES (${key}, ${value})
         ON CONFLICT (key) DO UPDATE SET value = EXCLUDED.value
       `;
     });
-    // Write-through so a long-lived process never serves stale config.
-    this._configCache?.set(key, value);
   }
 
   async unsetConfig(key: string): Promise<number> {
-    const count = await this.connRetry(async () => {
+    return this.connRetry(async () => {
       const result = await this.sql`DELETE FROM config WHERE key = ${key}` as unknown as { count: number };
       return result.count ?? 0;
     });
-    // Write-through: known-absent, so the cache doesn't serve a stale value.
-    this._configCache?.delete(key);
-    return count;
   }
 
   async listConfigKeys(prefix: string): Promise<string[]> {

src/core/source-resolver.ts

@@ -160,6 +160,33 @@ export async function resolveSourceId(
   return 'default';
 }
 
+/**
+ * Engine-free tiers (1-3) of the resolution chain: explicit flag →
+ * GBRAIN_SOURCE env → .gbrain-source dotfile walk. Used by the thin-client
+ * CLI path (#2098), which has no local engine to run tiers 4-6 or
+ * assertSourceExists against — the remote server enforces existence + grant.
+ * Returns null when no engine-free tier fires.
+ */
+export function resolveSourceIdEngineFree(
+  explicit: string | null | undefined,
+  cwd: string = process.cwd(),
+): string | null {
+  if (explicit) {
+    if (!SOURCE_ID_RE.test(explicit)) {
+      throw new Error(`Invalid --source value "${explicit}". Must match [a-z0-9-]{1,32}.`);
+    }
+    return explicit;
+  }
+  const env = process.env.GBRAIN_SOURCE;
+  if (env && env.length > 0) {
+    if (!SOURCE_ID_RE.test(env)) {
+      throw new Error(`Invalid GBRAIN_SOURCE value "${env}". Must match [a-z0-9-]{1,32}.`);
+    }
+    return env;
+  }
+  return readDotfileWalk(cwd);
+}
+
 /**
  * Returns the id of the SINGLE registered non-default source with a
  * local_path, when exactly one such row exists. Returns null when:

test/e2e/helpers.ts

@@ -29,13 +29,6 @@ if (existsSync(envPath)) {
   }
 }
 
-// E2E suites seed/rewrite the config table via raw SQL and expect engine
-// reads to see it immediately; disable the process-lifetime config cache
-// (#1694) so read semantics match pre-cache behavior. Spawned CLI
-// subprocesses inherit this. Cache semantics are pinned by
-// test/postgres-engine-config-cache.test.ts.
-process.env.GBRAIN_CONFIG_CACHE_TTL_MS ??= '0';
-
 const DATABASE_URL = process.env.DATABASE_URL;
 const FIXTURES_DIR = resolve(import.meta.dir, 'fixtures');
 

test/postgres-engine-config-cache.test.ts

@@ -1,112 +0,0 @@
-/**
- * Process-lifetime config cache (#1694 takeover, by @Omerbahari).
- *
- * A single search fires ~85 getConfig() reads; on a remote pooler each is a
- * round-trip. The first read now batch-loads the whole `config` table into a
- * Map; setConfig/unsetConfig write through; TTL bounds multi-writer
- * staleness; GBRAIN_CONFIG_CACHE_TTL_MS=0 restores per-key reads.
- *
- * Pure: stubs `_sql` with a call-counting fake; no real DB.
- */
-
-import { describe, it, expect } from 'bun:test';
-import { PostgresEngine } from '../src/core/postgres-engine.ts';
-import { withEnv } from './helpers/with-env.ts';
-
-const FAST_RETRY = { maxRetries: 3, delayMs: 1, delayMaxMs: 1, jitter: 'none' as const };
-
-/** Engine whose `sql` records every query's template strings and returns `rows`. */
-function makeEngine(rows: unknown[]) {
-  const e = new PostgresEngine();
-  const calls: string[] = [];
-  (e as unknown as { _connectionStyle: string })._connectionStyle = 'instance';
-  (e as unknown as { _bulkRetryOptsCache: unknown })._bulkRetryOptsCache = FAST_RETRY;
-  (e as unknown as { _sql: unknown })._sql = (strings: TemplateStringsArray) => {
-    calls.push(strings.join('?'));
-    return Promise.resolve(rows);
-  };
-  return { engine: e, calls };
-}
-
-/** Run `fn` with GBRAIN_CONFIG_CACHE_TTL_MS set (or cleared when undefined). */
-const withTtl = (ttl: string | undefined, fn: () => Promise<void>) =>
-  withEnv({ GBRAIN_CONFIG_CACHE_TTL_MS: ttl }, fn);
-
-describe('PostgresEngine config cache (#1694)', () => {
-  it('batch-loads once and serves repeat reads from the cache', () => withTtl(undefined, async () => {
-    const { engine, calls } = makeEngine([
-      { key: 'search.mode', value: 'balanced' },
-      { key: 'embedding_multimodal', value: 'true' },
-    ]);
-    expect(await engine.getConfig('search.mode')).toBe('balanced');
-    expect(await engine.getConfig('embedding_multimodal')).toBe('true');
-    expect(await engine.getConfig('search.mode')).toBe('balanced');
-    // One SELECT total — this is the whole point of the fix.
-    expect(calls.length).toBe(1);
-    expect(calls[0]).toContain('SELECT key, value FROM config');
-  }));
-
-  it('returns null for a known-absent key without an extra round-trip', () => withTtl(undefined, async () => {
-    const { engine, calls } = makeEngine([{ key: 'a', value: '1' }]);
-    expect(await engine.getConfig('missing.key')).toBeNull();
-    expect(await engine.getConfig('missing.key')).toBeNull();
-    expect(calls.length).toBe(1);
-  }));
-
-  it('setConfig writes through so subsequent reads see the new value', () => withTtl(undefined, async () => {
-    const { engine, calls } = makeEngine([{ key: 'k', value: 'old' }]);
-    expect(await engine.getConfig('k')).toBe('old');
-    await engine.setConfig('k', 'new');
-    expect(await engine.getConfig('k')).toBe('new');
-    expect(calls.length).toBe(2); // batch load + upsert; no re-read
-  }));
-
-  it('unsetConfig writes through so subsequent reads see absence', () => withTtl(undefined, async () => {
-    const { engine } = makeEngine([{ key: 'k', value: 'v' }]);
-    expect(await engine.getConfig('k')).toBe('v');
-    await engine.unsetConfig('k');
-    expect(await engine.getConfig('k')).toBeNull();
-  }));
-
-  it('concurrent cold reads share a single batch load (single-flight)', () => withTtl(undefined, async () => {
-    const { engine, calls } = makeEngine([{ key: 'k', value: 'v' }]);
-    const [a, b, c] = await Promise.all([
-      engine.getConfig('k'),
-      engine.getConfig('k'),
-      engine.getConfig('other'),
-    ]);
-    expect([a, b, c]).toEqual(['v', 'v', null]);
-    expect(calls.length).toBe(1);
-  }));
-
-  it('GBRAIN_CONFIG_CACHE_TTL_MS=0 disables the cache (per-key reads)', () => withTtl('0', async () => {
-    const { engine, calls } = makeEngine([{ value: 'v' }]);
-    expect(await engine.getConfig('k')).toBe('v');
-    expect(await engine.getConfig('k')).toBe('v');
-    expect(calls.length).toBe(2);
-    expect(calls[0]).toContain('SELECT value FROM config WHERE key =');
-  }));
-
-  it('an expired TTL reloads from the database', () => withTtl('1', async () => {
-    const { engine, calls } = makeEngine([{ key: 'k', value: 'v' }]);
-    expect(await engine.getConfig('k')).toBe('v');
-    await new Promise((r) => setTimeout(r, 5));
-    expect(await engine.getConfig('k')).toBe('v');
-    expect(calls.length).toBe(2); // two batch loads
-  }));
-
-  it('the batch load keeps the connRetry reconnect posture (#1603/#1891)', () => withTtl(undefined, async () => {
-    const e = new PostgresEngine();
-    (e as unknown as { _connectionStyle: string })._connectionStyle = 'instance';
-    (e as unknown as { _sql: unknown })._sql = null; // torn-down pool → retryable
-    (e as unknown as { _bulkRetryOptsCache: unknown })._bulkRetryOptsCache = FAST_RETRY;
-    let reconnects = 0;
-    (e as unknown as { reconnect: () => Promise<void> }).reconnect = async () => {
-      reconnects++;
-      (e as unknown as { _sql: unknown })._sql = () =>
-        Promise.resolve([{ key: 'k', value: 'v' }]);
-    };
-    expect(await e.getConfig('k')).toBe('v');
-    expect(reconnects).toBe(1);
-  }));
-});

test/postgres-engine-config-reconnect.test.ts

@@ -43,9 +43,7 @@ function makeTornDownEngine(poolResult: unknown): { engine: PostgresEngine; reco
 
 describe('PostgresEngine non-batch config accessors self-heal (PR #1891 takeover)', () => {
   it('getConfig reconnects + retries a null instance pool, then returns the value', async () => {
-    // Rows carry `key` too: getConfig's default cached path batch-loads
-    // `SELECT key, value FROM config` (#1694) through the same connRetry.
-    const { engine, reconnects } = makeTornDownEngine([{ key: 'some.key', value: 'live-value' }]);
+    const { engine, reconnects } = makeTornDownEngine([{ value: 'live-value' }]);
     expect(await engine.getConfig('some.key')).toBe('live-value');
     expect(reconnects()).toBe(1); // exactly one reconnect closed the gap
   });

test/thin-client-source-scope.test.ts

@@ -0,0 +1,142 @@
+/**
+ * #2098: thin-client routing dropped --source / GBRAIN_SOURCE / .gbrain-source.
+ *
+ * The local CLI path resolves source scope in makeContext (ctx.sourceId); the
+ * thin-client route short-circuits before that and sent params verbatim, so
+ * `gbrain query --source X` against a remote brain silently searched unscoped
+ * (the server op ignores the unknown `source` key).
+ *
+ * applyThinClientSourceScope runs the engine-free tiers (flag → env → dotfile)
+ * and maps the result onto the op's `source_id` wire param. These tests fail
+ * without the fix (params.source_id stays undefined / params.source leaks).
+ */
+
+import { describe, test, expect } from 'bun:test';
+import { mkdtempSync, rmSync, writeFileSync } from 'fs';
+import { join } from 'path';
+import { tmpdir } from 'os';
+import { applyThinClientSourceScope, parseOpArgs } from '../src/cli.ts';
+import { operationsByName } from '../src/core/operations.ts';
+import { withEnv } from './helpers/with-env.ts';
+
+const queryOp = operationsByName.query;
+
+describe('applyThinClientSourceScope (#2098)', () => {
+  test('--source maps onto the query op wire param source_id', async () => {
+    await withEnv({ GBRAIN_SOURCE: undefined }, () => {
+      const params = parseOpArgs(queryOp, ['find things', '--source', 'wiki']);
+      expect(params.source).toBe('wiki'); // pre-fix state: wrong key
+      applyThinClientSourceScope(queryOp, params, '/');
+      expect(params.source_id).toBe('wiki');
+      expect('source' in params).toBe(false); // never leaks the unknown key
+    });
+  });
+
+  test('GBRAIN_SOURCE env tier fires when no flag is passed', async () => {
+    await withEnv({ GBRAIN_SOURCE: 'gstack' }, () => {
+      const params = parseOpArgs(queryOp, ['find things']);
+      applyThinClientSourceScope(queryOp, params, '/');
+      expect(params.source_id).toBe('gstack');
+    });
+  });
+
+  test('.gbrain-source dotfile tier fires when flag and env are absent', async () => {
+    await withEnv({ GBRAIN_SOURCE: undefined }, () => {
+      const tmp = mkdtempSync(join(tmpdir(), 'gbrain-thin-scope-'));
+      try {
+        writeFileSync(join(tmp, '.gbrain-source'), 'essays\n');
+        const params = parseOpArgs(queryOp, ['find things']);
+        applyThinClientSourceScope(queryOp, params, tmp);
+        expect(params.source_id).toBe('essays');
+      } finally {
+        rmSync(tmp, { recursive: true, force: true });
+      }
+    });
+  });
+
+  test('explicit --source-id on the wire wins over ambient env scope', async () => {
+    await withEnv({ GBRAIN_SOURCE: 'gstack' }, () => {
+      const params = parseOpArgs(queryOp, ['find things', '--source-id', 'wiki']);
+      applyThinClientSourceScope(queryOp, params, '/');
+      expect(params.source_id).toBe('wiki');
+    });
+  });
+
+  test('--source together with --source-id is rejected loudly', async () => {
+    await withEnv({ GBRAIN_SOURCE: undefined }, () => {
+      const params = parseOpArgs(queryOp, ['q', '--source', 'a', '--source-id', 'b']);
+      expect(() => applyThinClientSourceScope(queryOp, params, '/')).toThrow(/not both/);
+    });
+  });
+
+  test('invalid --source value is rejected loudly', async () => {
+    await withEnv({ GBRAIN_SOURCE: undefined }, () => {
+      const params = parseOpArgs(queryOp, ['q', '--source', 'Bad_Value!']);
+      expect(() => applyThinClientSourceScope(queryOp, params, '/')).toThrow(/Invalid --source/);
+    });
+  });
+
+  test('--source on an op with no source_id wire param errors instead of silently dropping', async () => {
+    await withEnv({ GBRAIN_SOURCE: undefined }, () => {
+      const op = operationsByName.add_tag;
+      expect('source_id' in op.params).toBe(false);
+      const params = { slug: 'x', tag: 'y', source: 'wiki' };
+      expect(() => applyThinClientSourceScope(op, params, '/')).toThrow(/--source/);
+    });
+  });
+
+  test('ambient env scope on an op with no source_id wire param is ignored (no throw)', async () => {
+    await withEnv({ GBRAIN_SOURCE: 'wiki' }, () => {
+      const op = operationsByName.add_tag;
+      const params: Record<string, unknown> = { slug: 'x', tag: 'y' };
+      applyThinClientSourceScope(op, params, '/');
+      expect(params.source_id).toBeUndefined();
+    });
+  });
+
+  test('ops that declare their OWN source param are left untouched', async () => {
+    await withEnv({ GBRAIN_SOURCE: undefined }, () => {
+      const op = operationsByName.put_raw_data;
+      expect('source' in op.params).toBe(true);
+      const params: Record<string, unknown> = { slug: 'x', source: 'crustdata', data: {} };
+      applyThinClientSourceScope(op, params, '/');
+      expect(params.source).toBe('crustdata');
+      expect(params.source_id).toBeUndefined();
+    });
+  });
+
+  test('get_skill: ambient scope never leaks into its non-scope source_id param', async () => {
+    await withEnv({ GBRAIN_SOURCE: 'wiki' }, () => {
+      const op = operationsByName.get_skill;
+      expect('source_id' in op.params).toBe(true); // has the param, but it is a mode switch
+      const params: Record<string, unknown> = { name: 'ingest' };
+      applyThinClientSourceScope(op, params, '/');
+      expect(params.source_id).toBeUndefined(); // would flip host catalog → brain-pack lookup
+    });
+  });
+
+  test('get_skill: explicit --source errors instead of masquerading as --source-id', async () => {
+    await withEnv({ GBRAIN_SOURCE: undefined }, () => {
+      const op = operationsByName.get_skill;
+      const params: Record<string, unknown> = { name: 'ingest', source: 'wiki' };
+      expect(() => applyThinClientSourceScope(op, params, '/')).toThrow(/--source-id/);
+    });
+  });
+
+  test('get_skill: explicit --source-id passes through untouched', async () => {
+    await withEnv({ GBRAIN_SOURCE: 'gstack' }, () => {
+      const op = operationsByName.get_skill;
+      const params: Record<string, unknown> = { name: 'ingest', source_id: 'wiki' };
+      applyThinClientSourceScope(op, params, '/');
+      expect(params.source_id).toBe('wiki');
+    });
+  });
+
+  test('no scope from any tier leaves params unchanged', async () => {
+    await withEnv({ GBRAIN_SOURCE: undefined }, () => {
+      const params = parseOpArgs(queryOp, ['find things']);
+      applyThinClientSourceScope(queryOp, params, '/');
+      expect(params.source_id).toBeUndefined();
+    });
+  });
+});