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/commands/sync.ts

@@ -197,7 +197,7 @@ export interface SyncResult {
   /** Pages re-embedded during this sync's auto-embed step. 0 if --no-embed or skipped. */
   embedded: number;
   pagesAffected: string[];
-  failedFiles?: number; // count of per-file import/sync failures (Bug 9)
+  failedFiles?: number; // count of parse failures (Bug 9)
   /**
    * v0.41.13.0 partial-sync fields (only set when status === 'partial').
    *
@@ -3183,7 +3183,7 @@ async function performSyncInner(engine: BrainEngine, opts: SyncOpts): Promise<Sy
     await clearOpCheckpoint(engine, ckpt.target);
   };
 
-  // issue #1939 adversarial finding #1: a file that failed to import (open ledger
+  // issue #1939 adversarial finding #1: a file that failed to parse (open ledger
   // row) and is then deleted/renamed-away never re-enters failedFiles and never
   // imports, so its row would never clear and would age doctor to a permanent
   // FAIL. Treat removed paths as resolved so the ledger self-heals.
@@ -3215,9 +3215,9 @@ async function performSyncInner(engine: BrainEngine, opts: SyncOpts): Promise<Sy
     } else {
       const fileFailCount = failedFiles.filter(f => isSkippablePath(f.path)).length;
       serr(
-        `\nSync blocked: ${fileFailCount} file(s) failed to import:\n` +
+        `\nSync blocked: ${fileFailCount} file(s) failed to parse:\n` +
         `${codeBreakdown}\n\n` +
-        `Fix the listed file errors and re-run, or use 'gbrain sync --skip-failed' to ` +
+        `Fix the frontmatter and re-run, or use 'gbrain sync --skip-failed' to ` +
         `acknowledge and move on. A file that keeps failing auto-skips after ` +
         `${resolveAutoSkipThreshold()} consecutive syncs.`,
       );
@@ -5355,7 +5355,7 @@ function printSyncResult(result: SyncResult, sink: NodeJS.WriteStream = process.
     case 'dry_run':
       break; // already printed in performSync
     case 'blocked_by_failures':
-      write(`Sync BLOCKED at ${result.toCommit.slice(0, 8)}: ${result.failedFiles ?? 0} file(s) failed to import.`);
+      write(`Sync BLOCKED at ${result.toCommit.slice(0, 8)}: ${result.failedFiles ?? 0} file(s) failed to parse.`);
       write(`  See ~/.gbrain/sync-failures.jsonl for details, or run 'gbrain doctor'.`);
       write(`  Fix the files then re-run 'gbrain sync', or 'gbrain sync --skip-failed' to move on.`);
       break;

src/core/pglite-engine.ts

@@ -1058,16 +1058,6 @@ export class PGLiteEngine implements BrainEngine {
        RETURNING id, source_id, slug, type, title, compiled_truth, timeline, frontmatter, content_hash, created_at, updated_at, effective_date, effective_date_source, import_filename, source_kind, source_uri, ingested_via, ingested_at`,
       [sourceId, slug, page.type, pageKind, page.title, page.compiled_truth, page.timeline || '', JSON.stringify(frontmatter), hash, effectiveDate, effectiveDateSource, importFilename, chunkerVersion, sourcePath, sourceKind, sourceUri, ingestedVia, ingestedAt]
     );
-    // #2189: an INSERT … ON CONFLICT DO UPDATE … RETURNING that yields 0 rows
-    // (e.g. a BEFORE trigger suppressing the write) previously crashed in
-    // rowToPage with an opaque "undefined is not an object (row.deleted_at)".
-    // Throw a diagnosable error naming the row instead. Mirrors postgres-engine.ts.
-    if (!rows[0]) {
-      throw new Error(
-        `putPage: INSERT … RETURNING produced no row for slug='${slug}' source_id='${sourceId}'. ` +
-        `A trigger or rule on the pages table may be suppressing the write.`
-      );
-    }
     return rowToPage(rows[0] as Record<string, unknown>);
   }
 

src/core/postgres-engine.ts

@@ -1119,16 +1119,6 @@ export class PostgresEngine implements BrainEngine {
         ingested_at           = COALESCE(EXCLUDED.ingested_at,           pages.ingested_at)
       RETURNING id, source_id, slug, type, title, compiled_truth, timeline, frontmatter, content_hash, created_at, updated_at, effective_date, effective_date_source, import_filename, source_kind, source_uri, ingested_via, ingested_at
     `;
-    // #2189: an INSERT … ON CONFLICT DO UPDATE … RETURNING that yields 0 rows
-    // (e.g. a BEFORE trigger suppressing the write) previously crashed in
-    // rowToPage with an opaque "undefined is not an object (row.deleted_at)".
-    // Throw a diagnosable error naming the row instead. Mirrors pglite-engine.ts.
-    if (!rows[0]) {
-      throw new Error(
-        `putPage: INSERT … RETURNING produced no row for slug='${slug}' source_id='${sourceId}'. ` +
-        `A trigger or rule on the pages table may be suppressing the write.`
-      );
-    }
     return rowToPage(rows[0]);
   }
 

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/putpage-returning-guard.test.ts

@@ -1,74 +0,0 @@
-// #2189 regression guard: putPage's INSERT … ON CONFLICT DO UPDATE … RETURNING
-// can yield 0 rows when brain-local DB state (e.g. a BEFORE INSERT trigger)
-// suppresses the write. Pre-fix, rowToPage(rows[0]) crashed with the opaque
-// "undefined is not an object (evaluating 'row.deleted_at')" that failed
-// ~all files of a code sync. Post-fix, putPage throws a descriptive error
-// naming the slug + source_id so the failure is diagnosable per-file.
-//
-// Same guard lands in postgres-engine.ts (engine-parity invariant); this test
-// exercises the PGLite side, where the issue was reported.
-
-import { describe, expect, test, beforeAll, afterAll } from 'bun:test';
-import { PGLiteEngine } from '../src/core/pglite-engine.ts';
-
-let engine: PGLiteEngine;
-
-beforeAll(async () => {
-  engine = new PGLiteEngine();
-  await engine.connect({});
-  await engine.initSchema();
-  // Simulate the reporter's state-dependent failure: a trigger that
-  // suppresses inserts for one slug, making RETURNING produce no row.
-  await engine.executeRaw(`
-    CREATE OR REPLACE FUNCTION suppress_pages_insert() RETURNS trigger AS $$
-    BEGIN
-      IF NEW.slug = 'suppressed-page' THEN RETURN NULL; END IF;
-      RETURN NEW;
-    END;
-    $$ LANGUAGE plpgsql;
-  `);
-  await engine.executeRaw(`
-    CREATE TRIGGER suppress_pages_insert_trg
-    BEFORE INSERT ON pages
-    FOR EACH ROW EXECUTE FUNCTION suppress_pages_insert();
-  `);
-});
-
-afterAll(async () => {
-  await engine.executeRaw('DROP TRIGGER IF EXISTS suppress_pages_insert_trg ON pages');
-  await engine.executeRaw('DROP FUNCTION IF EXISTS suppress_pages_insert');
-  await engine.disconnect();
-});
-
-describe('putPage RETURNING guard (#2189)', () => {
-  test('0-row RETURNING throws a descriptive error, not row.deleted_at TypeError', async () => {
-    let err: Error | undefined;
-    try {
-      await engine.putPage('suppressed-page', {
-        type: 'code',
-        title: 'Suppressed',
-        compiled_truth: 'x',
-        timeline: '',
-      });
-    } catch (e) {
-      err = e as Error;
-    }
-    expect(err).toBeDefined();
-    expect(err!.message).toContain('putPage');
-    expect(err!.message).toContain("slug='suppressed-page'");
-    expect(err!.message).toContain("source_id='default'");
-    // The pre-fix crash signature must be gone.
-    expect(err!.message).not.toContain('deleted_at');
-  });
-
-  test('unsuppressed slugs still upsert normally with the trigger installed', async () => {
-    const page = await engine.putPage('normal-page', {
-      type: 'concept',
-      title: 'Normal',
-      compiled_truth: 'y',
-      timeline: '',
-    });
-    expect(page.slug).toBe('normal-page');
-    expect(page.source_id).toBe('default');
-  });
-});

test/sync.test.ts

@@ -375,31 +375,6 @@ describe('performSync dry-run never writes', () => {
     expect(messages.some(m => m.includes('git pull failed'))).toBe(false);
   });
 
-  test('first PGLite code sync imports code files without runtime failures', async () => {
-    const { performSync } = await import('../src/commands/sync.ts');
-    mkdirSync(join(repoPath, 'src'), { recursive: true });
-    writeFileSync(
-      join(repoPath, 'src/example.ts'),
-      'export function add(left: number, right: number) { return left + right; }\n',
-    );
-    execSync('git add -A && git commit -m "add code file"', { cwd: repoPath, stdio: 'pipe' });
-
-    const result = await performSync(engine, {
-      repoPath,
-      noPull: true,
-      noEmbed: true,
-      noExtract: true,
-      strategy: 'code',
-    });
-
-    expect(result.status).toBe('first_sync');
-    expect(result.added).toBe(1);
-    expect(result.failedFiles ?? 0).toBe(0);
-    const page = await engine.getPage('src-example-ts');
-    expect(page?.type).toBe('code');
-    expect(page?.frontmatter).toMatchObject({ file: 'src/example.ts', language: 'typescript' });
-  });
-
   test('incremental dry-run does NOT write to DB or advance the bookmark', async () => {
     const { performSync } = await import('../src/commands/sync.ts');
     // First do a real sync to seed the bookmark.

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();
+    });
+  });
+});