fix(minions): subagent default client resolves config-stored Anthropic key (#2048)

The legacy subagent path constructed a bare new Anthropic() (env-only), so
launchd/MCP workers whose key lives in gbrain config (anthropic_api_key)
failed auth. anthropic-key.ts now exports resolveAnthropicKey() (env first,
then config; hasAnthropicKey delegates) and makeSubagentHandler passes it as
apiKey.

Partial takeover of #2048 — only the auth patch; the path patches were
superseded by the outputRoot mechanism (#2415).

Co-authored-by: JiraiyaETH <JiraiyaETH@users.noreply.github.com>
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/core/ai/anthropic-key.ts

@@ -18,12 +18,22 @@
 import { loadConfig } from '../config.ts';
 
 export function hasAnthropicKey(): boolean {
-  if (process.env.ANTHROPIC_API_KEY) return true;
+  return resolveAnthropicKey() !== undefined;
+}
+
+/**
+ * Resolve the actual key value: env first, then the gbrain config file.
+ * Callers constructing an Anthropic client directly (e.g. the legacy
+ * subagent path) must pass this as `apiKey` — a bare `new Anthropic()`
+ * only sees env, so launchd/MCP workers with config-stored keys fail.
+ */
+export function resolveAnthropicKey(): string | undefined {
+  if (process.env.ANTHROPIC_API_KEY) return process.env.ANTHROPIC_API_KEY;
   try {
     const cfg = loadConfig();
-    if (cfg?.anthropic_api_key) return true;
+    if (cfg?.anthropic_api_key) return cfg.anthropic_api_key;
   } catch {
     // loadConfig may throw on first-run installs; treat as no key available.
   }
-  return false;
+  return undefined;
 }

src/core/minions/handlers/subagent.ts

@@ -48,6 +48,7 @@ import {
   logSubagentHeartbeat,
 } from './subagent-audit.ts';
 import { resolveModel, isAnthropicProvider, TIER_DEFAULTS } from '../../model-config.ts';
+import { resolveAnthropicKey } from '../../ai/anthropic-key.ts';
 import { buildSystemPrompt, DEFAULT_SUBAGENT_SYSTEM } from '../system-prompt.ts';
 import { toolLoop as gatewayToolLoop } from '../../ai/gateway.ts';
 import type { ChatToolDef, ChatMessage, ChatBlock, ChatResult, ToolHandler } from '../../ai/gateway.ts';
@@ -186,7 +187,10 @@ export function makeSubagentHandler(deps: SubagentDeps) {
   // lives at sdk.messages.create. Assigning sdk.messages directly gets the
   // right object; JS method-call semantics preserve `this` at the call
   // site (subagent.ts invokes client.create(...) with client === sdk.messages).
-  const makeAnthropic = deps.makeAnthropic ?? (() => new Anthropic());
+  // Resolve the key env-first, then config (anthropic_api_key) — a bare
+  // new Anthropic() only reads env, so launchd/MCP workers whose key lives
+  // in the gbrain config file would fail auth (#2048).
+  const makeAnthropic = deps.makeAnthropic ?? (() => new Anthropic({ apiKey: resolveAnthropicKey() }));
   const client: MessagesClient = deps.client ?? makeAnthropic().messages;
   const config = deps.config ?? loadConfig() ?? ({ engine: 'postgres' } as GBrainConfig);
   const rateLeaseKey = deps.rateLeaseKey ?? DEFAULT_RATE_KEY;

test/ai/anthropic-key.test.ts

@@ -10,7 +10,7 @@ import { mkdtempSync, mkdirSync, writeFileSync, rmSync } from 'node:fs';
 import { tmpdir } from 'node:os';
 import { join } from 'node:path';
 import { withEnv } from '../helpers/with-env.ts';
-import { hasAnthropicKey } from '../../src/core/ai/anthropic-key.ts';
+import { hasAnthropicKey, resolveAnthropicKey } from '../../src/core/ai/anthropic-key.ts';
 
 const tmpDirs: string[] = [];
 function freshHome(withConfig?: Record<string, unknown>): string {
@@ -62,3 +62,35 @@ describe('hasAnthropicKey', () => {
     );
   });
 });
+
+describe('resolveAnthropicKey (#2048 — subagent config-key auth)', () => {
+  test('env wins over config', async () => {
+    const home = freshHome({ anthropic_api_key: 'sk-from-config' });
+    await withEnv(
+      { ANTHROPIC_API_KEY: 'sk-from-env', GBRAIN_HOME: home, DATABASE_URL: undefined, GBRAIN_DATABASE_URL: undefined },
+      async () => {
+        expect(resolveAnthropicKey()).toBe('sk-from-env');
+      },
+    );
+  });
+
+  test('config key returned when env unset', async () => {
+    const home = freshHome({ anthropic_api_key: 'sk-from-config' });
+    await withEnv(
+      { ANTHROPIC_API_KEY: undefined, GBRAIN_HOME: home, DATABASE_URL: undefined, GBRAIN_DATABASE_URL: undefined },
+      async () => {
+        expect(resolveAnthropicKey()).toBe('sk-from-config');
+      },
+    );
+  });
+
+  test('neither → undefined', async () => {
+    const home = freshHome();
+    await withEnv(
+      { ANTHROPIC_API_KEY: undefined, GBRAIN_HOME: home, DATABASE_URL: undefined, GBRAIN_DATABASE_URL: undefined },
+      async () => {
+        expect(resolveAnthropicKey()).toBeUndefined();
+      },
+    );
+  });
+});