feat(backends): add optional pi_embedded backend and config wiring

src/config/schema.test.ts

@@ -403,12 +403,18 @@ describe('configSchema — agent_configs', () => {
           tool_profile: 'coding',
           sandbox: true,
         },
+        pi_canary: {
+          model_tier: 'default',
+          backend: 'pi_embedded',
+          tool_profile: 'messaging',
+        },
       },
     });
     expect(result.agent_configs.assistant.system_prompt).toBe('You are helpful.');
     expect(result.agent_configs.assistant.backend).toBe('codex');
     expect(result.agent_configs.assistant.tool_profile).toBe('messaging');
     expect(result.agent_configs.coder.sandbox).toBe(true);
+    expect(result.agent_configs.pi_canary.backend).toBe('pi_embedded');
   });
 });
 
@@ -500,20 +506,31 @@ describe('configSchema — backends', () => {
     expect(result.backends.opencode.args).toEqual([]);
     expect(result.backends.codex.enabled).toBe(false);
     expect(result.backends.gemini.enabled).toBe(false);
+    expect(result.backends.pi_embedded.enabled).toBe(false);
+    expect(result.backends.pi_embedded.no_tools_mode).toBe(true);
+    expect(result.backends.pi_embedded.system_prompt_mode).toBe('hybrid');
     expect(result.backends.native.enabled).toBe(true);
   });
 
-  it('accepts explicit codex/gemini backend config', () => {
+  it('accepts explicit codex/gemini/pi_embedded backend config', () => {
     const result = configSchema.parse({
       ...minimalConfig,
       backends: {
-        default: 'codex',
+        default: 'pi_embedded',
         codex: { enabled: true, path: '/usr/local/bin/codex', args: ['run'], timeout_ms: 300000 },
         gemini: { enabled: true, path: '/usr/local/bin/gemini', args: ['chat'], timeout_ms: 60000 },
+        pi_embedded: {
+          enabled: true,
+          timeout_ms: 45000,
+          no_tools_mode: false,
+          model: 'openclaw-default',
+          system_prompt_mode: 'flynn',
+          module: '@badlogic/pi-agent-core',
+        },
       },
     });
 
-    expect(result.backends.default).toBe('codex');
+    expect(result.backends.default).toBe('pi_embedded');
     expect(result.backends.codex.enabled).toBe(true);
     expect(result.backends.codex.path).toBe('/usr/local/bin/codex');
     expect(result.backends.codex.args).toEqual(['run']);
@@ -522,6 +539,12 @@ describe('configSchema — backends', () => {
     expect(result.backends.gemini.path).toBe('/usr/local/bin/gemini');
     expect(result.backends.gemini.args).toEqual(['chat']);
     expect(result.backends.gemini.timeout_ms).toBe(60000);
+    expect(result.backends.pi_embedded.enabled).toBe(true);
+    expect(result.backends.pi_embedded.timeout_ms).toBe(45000);
+    expect(result.backends.pi_embedded.no_tools_mode).toBe(false);
+    expect(result.backends.pi_embedded.model).toBe('openclaw-default');
+    expect(result.backends.pi_embedded.system_prompt_mode).toBe('flynn');
+    expect(result.backends.pi_embedded.module).toBe('@badlogic/pi-agent-core');
   });
 });
 

src/config/schema.ts

@@ -184,7 +184,7 @@ const modelsSchema = z.object({
 });
 
 const backendsSchema = z.object({
-  default: z.enum(['claude_code', 'opencode', 'codex', 'gemini']).optional(),
+  default: z.enum(['claude_code', 'opencode', 'codex', 'gemini', 'pi_embedded']).optional(),
   claude_code: z.object({
     enabled: z.boolean().default(false),
     path: z.string().optional(),
@@ -209,6 +209,14 @@ const backendsSchema = z.object({
     args: z.array(z.string()).default([]),
     timeout_ms: z.number().min(1_000).max(600_000).default(120_000),
   }).default({ enabled: false }),
+  pi_embedded: z.object({
+    enabled: z.boolean().default(false),
+    timeout_ms: z.number().min(1_000).max(600_000).default(120_000),
+    no_tools_mode: z.boolean().default(true),
+    model: z.string().optional(),
+    system_prompt_mode: z.enum(['flynn', 'pi_default', 'hybrid']).default('hybrid'),
+    module: z.string().optional(),
+  }).default({ enabled: false }),
   native: z.object({
     enabled: z.boolean().default(true),
   }).default({ enabled: true }),
@@ -853,7 +861,7 @@ const sandboxSchema = z.object({
 const agentConfigEntrySchema = z.object({
   system_prompt: z.string().optional(),
   model_tier: modelTierEnum.optional(),
-  backend: z.enum(['native', 'claude_code', 'opencode', 'codex', 'gemini']).optional(),
+  backend: z.enum(['native', 'claude_code', 'opencode', 'codex', 'gemini', 'pi_embedded']).optional(),
   tool_profile: toolProfileEnum.optional(),
   tool_overrides: toolOverrideSchema.optional(),
   sandbox: z.boolean().default(false),