fix(pi): inherit default model and api key for embedded agent

src/backends/piEmbedded.test.ts

@@ -100,6 +100,27 @@ describe('PiEmbeddedBackend', () => {
     }
   });
 
+  it('surfaces agent state error when no assistant text is produced', async () => {
+    const mod = createModule(`
+      export class Agent {
+        constructor() {
+          this.state = { messages: [], error: undefined };
+        }
+        async prompt() {
+          this.state.error = "Missing API key for default provider";
+        }
+      }
+    `);
+
+    try {
+      const backend = new PiEmbeddedBackend({ module: mod.moduleUrl, timeoutMs: 2000 });
+      await expect(backend.process({ prompt: 'hello', history: [] }))
+        .rejects.toThrow('Missing API key for default provider');
+    } finally {
+      mod.cleanup();
+    }
+  });
+
   it('throws when module cannot be loaded', async () => {
     const backend = new PiEmbeddedBackend({ module: '/definitely/missing/pi-module.mjs', timeoutMs: 2000 });
     await expect(backend.process({ prompt: 'hello', history: [] }))

src/backends/piEmbedded.ts

@@ -33,6 +33,8 @@ interface PiModelFactoryModuleLike extends PiModuleLike {
 export interface PiEmbeddedBackendOptions {
   timeoutMs?: number;
   model?: string;
+  defaultModelSpec?: string;
+  getApiKey?: (provider: string) => string | undefined | Promise<string | undefined>;
   systemPromptMode?: PiSystemPromptMode;
   module?: string;
 }
@@ -197,12 +199,16 @@ export class PiEmbeddedBackend implements ExternalBackend {
   readonly name = 'pi_embedded' as const;
   private readonly timeoutMs: number;
   private readonly model?: string;
+  private readonly defaultModelSpec?: string;
+  private readonly getApiKey?: (provider: string) => string | undefined | Promise<string | undefined>;
   private readonly systemPromptMode: PiSystemPromptMode;
   private readonly moduleOverride?: string;
 
   constructor(options: PiEmbeddedBackendOptions = {}) {
     this.timeoutMs = options.timeoutMs ?? DEFAULT_TIMEOUT_MS;
     this.model = options.model;
+    this.defaultModelSpec = options.defaultModelSpec;
+    this.getApiKey = options.getApiKey;
     this.systemPromptMode = options.systemPromptMode ?? 'hybrid';
     this.moduleOverride = options.module;
   }
@@ -294,14 +300,28 @@ export class PiEmbeddedBackend implements ExternalBackend {
     input: ExternalBackendRequest,
     moduleName: string,
   ): Promise<string> {
-    const agent = new AgentCtor();
+    const modelSpec = this.model ?? this.defaultModelSpec;
+    const model = modelSpec
+      ? await this.resolvePiModel(modelSpec, moduleName)
+      : undefined;
+
+    const agentOptions: Record<string, unknown> = {};
+    if (model) {
+      agentOptions.initialState = { model };
+    }
+    if (this.getApiKey) {
+      agentOptions.getApiKey = this.getApiKey;
+    }
+
+    const agent = Object.keys(agentOptions).length > 0
+      ? new AgentCtor(agentOptions)
+      : new AgentCtor();
     if (!agent || typeof agent !== 'object') {
       throw new Error('Pi Agent constructor returned an invalid object');
     }
     const agentObj = agent as PiSessionLike;
 
-    if (this.model) {
-      const model = await this.resolvePiModel(this.model, moduleName);
+    if (model) {
       const setModel = agentObj.setModel;
       if (typeof setModel === 'function') {
         await Promise.resolve(setModel.call(agent, model));
@@ -348,6 +368,10 @@ export class PiEmbeddedBackend implements ExternalBackend {
       }
     }
 
+    const stateError = (state as PiSessionLike).error;
+    if (typeof stateError === 'string' && stateError.trim().length > 0) {
+      throw new Error(`Pi Agent runtime produced no assistant text: ${stateError}`);
+    }
     throw new Error('Pi Agent runtime produced no assistant text');
   }
 

src/daemon/index.ts

@@ -44,11 +44,39 @@ import {
   type ExternalBackendName,
 } from '../backends/index.js';
 
+function collectModelApiKeys(config: Config): Record<string, string> {
+  const keys: Record<string, string> = {};
+  const candidates = [
+    config.models.default,
+    config.models.fast,
+    config.models.complex,
+    config.models.local,
+    ...Object.values(config.models.local_providers ?? {}),
+  ];
+
+  for (const candidate of candidates) {
+    if (!candidate?.provider || !candidate.api_key) {
+      continue;
+    }
+    if (candidate.api_key.trim().length === 0) {
+      continue;
+    }
+    keys[candidate.provider] = candidate.api_key;
+  }
+
+  return keys;
+}
+
+function defaultPiModelSpec(config: Config): string {
+  return `${config.models.default.provider}:${config.models.default.model}`;
+}
+
 export function createConfiguredExternalBackends(config: Config): {
   externalBackends: Partial<Record<ExternalBackendName, ExternalBackend>>;
   defaultName?: ExternalBackendName;
 } {
   const backends: Partial<Record<ExternalBackendName, ExternalBackend>> = {};
+  const modelApiKeys = collectModelApiKeys(config);
 
   if (config.backends.claude_code.enabled) {
     backends.claude_code = new ClaudeCodeBackend(
@@ -82,6 +110,8 @@ export function createConfiguredExternalBackends(config: Config): {
     backends.pi_embedded = new PiEmbeddedBackend({
       timeoutMs: config.backends.pi_embedded.timeout_ms,
       model: config.backends.pi_embedded.model,
+      defaultModelSpec: defaultPiModelSpec(config),
+      getApiKey: (provider) => modelApiKeys[provider],
       systemPromptMode: config.backends.pi_embedded.system_prompt_mode,
       module: config.backends.pi_embedded.module,
     });