diff --git a/fixtures/sample-project/.gitignore b/fixtures/sample-project/.gitignore
new file mode 100644
index 0000000..711e716
--- /dev/null
+++ b/fixtures/sample-project/.gitignore
@@ -0,0 +1,4 @@
+dist/
+node_modules/
+.pi-map.md
+.env
diff --git a/fixtures/sample-project/README.md b/fixtures/sample-project/README.md
new file mode 100644
index 0000000..7ea0e2c
--- /dev/null
+++ b/fixtures/sample-project/README.md
@@ -0,0 +1,9 @@
+# Sample Project
+
+A small test project for pi-project-map functionality.
+
+## Structure
+
+- `src/` — Source code
+- `tests/` — Test suites
+- `docs/` — Documentation
diff --git a/fixtures/sample-project/docs/API.md b/fixtures/sample-project/docs/API.md
new file mode 100644
index 0000000..1b8e6e8
--- /dev/null
+++ b/fixtures/sample-project/docs/API.md
@@ -0,0 +1,24 @@
+# API Documentation
+
+## User Model
+
+### `createUser(data)`
+
+Creates a new user with auto-generated ID and timestamp.
+
+**Parameters:**
+- `data` — Object with `email` and `name` fields
+
+**Returns:** `User` object
+
+**Throws:** `Error` if email is invalid
+
+### `serializeUser(user)`
+
+Serializes a user to JSON string.
+
+## Validation Utilities
+
+- `validateEmail(email)` — Validates email format
+- `validateNotEmpty(value)` — Checks string is not empty
+- `validateMinLength(value, min)` — Checks minimum string length
diff --git a/fixtures/sample-project/package.json b/fixtures/sample-project/package.json
new file mode 100644
index 0000000..8ed6586
--- /dev/null
+++ b/fixtures/sample-project/package.json
@@ -0,0 +1,10 @@
+{
+  "name": "sample-project",
+  "version": "1.0.0",
+  "description": "Sample project for testing pi-project-map",
+  "main": "dist/index.js",
+  "scripts": {
+    "build": "tsc",
+    "test": "vitest"
+  }
+}
diff --git a/fixtures/sample-project/src/components/Button.tsx b/fixtures/sample-project/src/components/Button.tsx
new file mode 100644
index 0000000..5cd6619
--- /dev/null
+++ b/fixtures/sample-project/src/components/Button.tsx
@@ -0,0 +1,27 @@
+import React from "react";
+
+export interface ButtonProps {
+  label: string;
+  variant?: "primary" | "secondary" | "danger";
+  onClick?: () => void;
+  disabled?: boolean;
+}
+
+export function Button({
+  label,
+  variant = "primary",
+  onClick,
+  disabled = false,
+}: ButtonProps): JSX.Element {
+  return (
+    <button
+      className={`btn btn--${variant}`}
+      onClick={onClick}
+      disabled={disabled}
+    >
+      {label}
+    </button>
+  );
+}
+
+export default Button;
diff --git a/fixtures/sample-project/src/components/UserCard.tsx b/fixtures/sample-project/src/components/UserCard.tsx
new file mode 100644
index 0000000..9dbba29
--- /dev/null
+++ b/fixtures/sample-project/src/components/UserCard.tsx
@@ -0,0 +1,23 @@
+import React from "react";
+import type { User } from "../models/user.js";
+
+export interface UserCardProps {
+  user: User;
+  onEdit?: (user: User) => void;
+  onDelete?: (id: string) => void;
+}
+
+export function UserCard({ user, onEdit, onDelete }: UserCardProps): JSX.Element {
+  return (
+    <div className="user-card">
+      <h3>{user.name}</h3>
+      <p>{user.email}</p>
+      <div className="actions">
+        {onEdit && <button onClick={() => onEdit(user)}>Edit</button>}
+        {onDelete && <button onClick={() => onDelete(user.id)}>Delete</button>}
+      </div>
+    </div>
+  );
+}
+
+export default UserCard;
diff --git a/fixtures/sample-project/src/index.ts b/fixtures/sample-project/src/index.ts
new file mode 100644
index 0000000..732752a
--- /dev/null
+++ b/fixtures/sample-project/src/index.ts
@@ -0,0 +1,14 @@
+import { createUser } from "./models/user.js";
+import { validateEmail } from "./utils/validation.js";
+import { logger } from "./utils/logger.js";
+
+export async function main() {
+  const user = createUser({ email: "test@example.com", name: "Alice" });
+  if (!validateEmail(user.email)) {
+    logger.error("Invalid email");
+    return;
+  }
+  logger.info(`User created: ${user.name}`);
+}
+
+export { createUser, validateEmail, logger };
diff --git a/fixtures/sample-project/src/models/user.ts b/fixtures/sample-project/src/models/user.ts
new file mode 100644
index 0000000..1053b90
--- /dev/null
+++ b/fixtures/sample-project/src/models/user.ts
@@ -0,0 +1,23 @@
+import { validateEmail } from "../utils/validation.js";
+
+export interface User {
+  id: string;
+  email: string;
+  name: string;
+  createdAt: Date;
+}
+
+export function createUser(data: Omit<User, "id" | "createdAt">): User {
+  if (!validateEmail(data.email)) {
+    throw new Error("Invalid email");
+  }
+  return {
+    id: crypto.randomUUID(),
+    ...data,
+    createdAt: new Date(),
+  };
+}
+
+export function serializeUser(user: User): string {
+  return JSON.stringify(user);
+}
diff --git a/fixtures/sample-project/src/utils/logger.ts b/fixtures/sample-project/src/utils/logger.ts
new file mode 100644
index 0000000..eb7abf8
--- /dev/null
+++ b/fixtures/sample-project/src/utils/logger.ts
@@ -0,0 +1,22 @@
+export type LogLevel = "debug" | "info" | "warn" | "error";
+
+export function log(level: LogLevel, message: string): void {
+  const timestamp = new Date().toISOString();
+  console.log(`[${timestamp}] ${level.toUpperCase()}: ${message}`);
+}
+
+export function debug(message: string): void {
+  log("debug", message);
+}
+
+export function info(message: string): void {
+  log("info", message);
+}
+
+export function warn(message: string): void {
+  log("warn", message);
+}
+
+export function error(message: string): void {
+  log("error", message);
+}
diff --git a/fixtures/sample-project/src/utils/validation.ts b/fixtures/sample-project/src/utils/validation.ts
new file mode 100644
index 0000000..4f20961
--- /dev/null
+++ b/fixtures/sample-project/src/utils/validation.ts
@@ -0,0 +1,13 @@
+const EMAIL_REGEX = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
+
+export function validateEmail(email: string): boolean {
+  return EMAIL_REGEX.test(email);
+}
+
+export function validateNotEmpty(value: string): boolean {
+  return value.trim().length > 0;
+}
+
+export function validateMinLength(value: string, min: number): boolean {
+  return value.length >= min;
+}
diff --git a/fixtures/sample-project/tests/user.test.ts b/fixtures/sample-project/tests/user.test.ts
new file mode 100644
index 0000000..854d77e
--- /dev/null
+++ b/fixtures/sample-project/tests/user.test.ts
@@ -0,0 +1,24 @@
+import { describe, it, expect } from "vitest";
+import { createUser, serializeUser } from "../src/models/user.js";
+
+describe("User model", () => {
+  it("creates a user with valid email", () => {
+    const user = createUser({ email: "alice@example.com", name: "Alice" });
+    expect(user.email).toBe("alice@example.com");
+    expect(user.name).toBe("Alice");
+    expect(user.id).toBeDefined();
+    expect(user.createdAt).toBeInstanceOf(Date);
+  });
+
+  it("throws on invalid email", () => {
+    expect(() =>
+      createUser({ email: "not-an-email", name: "Bob" }),
+    ).toThrow("Invalid email");
+  });
+
+  it("serializes to JSON", () => {
+    const user = createUser({ email: "charlie@example.com", name: "Charlie" });
+    const json = serializeUser(user);
+    expect(JSON.parse(json).name).toBe("Charlie");
+  });
+});
diff --git a/fixtures/sample-project/tests/validation.test.ts b/fixtures/sample-project/tests/validation.test.ts
new file mode 100644
index 0000000..eaf85ec
--- /dev/null
+++ b/fixtures/sample-project/tests/validation.test.ts
@@ -0,0 +1,21 @@
+import { describe, it, expect } from "vitest";
+import { validateEmail, validateNotEmpty, validateMinLength } from "../src/utils/validation.js";
+
+describe("Validation utils", () => {
+  it("validates email format", () => {
+    expect(validateEmail("test@example.com")).toBe(true);
+    expect(validateEmail("invalid")).toBe(false);
+    expect(validateEmail("")).toBe(false);
+  });
+
+  it("checks non-empty strings", () => {
+    expect(validateNotEmpty("hello")).toBe(true);
+    expect(validateNotEmpty("   ")).toBe(false);
+    expect(validateNotEmpty("")).toBe(false);
+  });
+
+  it("checks minimum length", () => {
+    expect(validateMinLength("hello", 3)).toBe(true);
+    expect(validateMinLength("hi", 3)).toBe(false);
+  });
+});
diff --git a/fixtures/sample-project/tsconfig.json b/fixtures/sample-project/tsconfig.json
new file mode 100644
index 0000000..34be8a8
--- /dev/null
+++ b/fixtures/sample-project/tsconfig.json
@@ -0,0 +1,9 @@
+{
+  "compilerOptions": {
+    "target": "ES2022",
+    "module": "NodeNext",
+    "strict": true,
+    "outDir": "./dist",
+    "rootDir": "./src"
+  }
+}
diff --git a/package-lock.json b/package-lock.json
index 0fe90ff..57cc8fc 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -10,6 +10,8 @@
       "license": "MIT",
       "dependencies": {
         "ignore": "^5.3.0",
+        "openai": "^6.42.0",
+        "p-limit": "^7.3.0",
         "picocolors": "^1.1.1",
         "tree-sitter": "^0.21.0",
         "tree-sitter-go": "^0.25.0",
@@ -1356,19 +1358,6 @@
         "url": "https://github.com/sponsors/sindresorhus"
       }
     },
-    "node_modules/@vitest/runner/node_modules/yocto-queue": {
-      "version": "1.2.2",
-      "resolved": "https://registry.npmjs.org/yocto-queue/-/yocto-queue-1.2.2.tgz",
-      "integrity": "sha512-4LCcse/U2MHZ63HAJVE+v71o7yOdIe4cZ70Wpf8D/IyjDKYQLV5GD46B+hSTjJsvV5PztjvHoU580EftxjDZFQ==",
-      "dev": true,
-      "license": "MIT",
-      "engines": {
-        "node": ">=12.20"
-      },
-      "funding": {
-        "url": "https://github.com/sponsors/sindresorhus"
-      }
-    },
     "node_modules/@vitest/snapshot": {
       "version": "1.6.1",
       "resolved": "https://registry.npmjs.org/@vitest/snapshot/-/snapshot-1.6.1.tgz",
@@ -2737,6 +2726,24 @@
         "url": "https://github.com/sponsors/sindresorhus"
       }
     },
+    "node_modules/openai": {
+      "version": "6.42.0",
+      "resolved": "https://registry.npmjs.org/openai/-/openai-6.42.0.tgz",
+      "integrity": "sha512-1WFEt/uXMXOLhYRNkgJWo08Y2YNvNwpVU72K7ibrWgWpNOXd4VojXLbe6SQ4bLiUQ3Y8jz4IiyVkylJCL1DtZg==",
+      "license": "Apache-2.0",
+      "peerDependencies": {
+        "ws": "^8.18.0",
+        "zod": "^3.25 || ^4.0"
+      },
+      "peerDependenciesMeta": {
+        "ws": {
+          "optional": true
+        },
+        "zod": {
+          "optional": true
+        }
+      }
+    },
     "node_modules/optionator": {
       "version": "0.9.4",
       "resolved": "https://registry.npmjs.org/optionator/-/optionator-0.9.4.tgz",
@@ -2756,6 +2763,37 @@
       }
     },
     "node_modules/p-limit": {
+      "version": "7.3.0",
+      "resolved": "https://registry.npmjs.org/p-limit/-/p-limit-7.3.0.tgz",
+      "integrity": "sha512-7cIXg/Z0M5WZRblrsOla88S4wAK+zOQQWeBYfV3qJuJXMr+LnbYjaadrFaS0JILfEDPVqHyKnZ1Z/1d6J9VVUw==",
+      "license": "MIT",
+      "dependencies": {
+        "yocto-queue": "^1.2.1"
+      },
+      "engines": {
+        "node": ">=20"
+      },
+      "funding": {
+        "url": "https://github.com/sponsors/sindresorhus"
+      }
+    },
+    "node_modules/p-locate": {
+      "version": "5.0.0",
+      "resolved": "https://registry.npmjs.org/p-locate/-/p-locate-5.0.0.tgz",
+      "integrity": "sha512-LaNjtRWUBY++zB5nE/NwcaoMylSPk+S+ZHNB1TzdbMJMny6dynpAGt7X/tl/QYq3TIeE6nxHppbo2LGymrG5Pw==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "p-limit": "^3.0.2"
+      },
+      "engines": {
+        "node": ">=10"
+      },
+      "funding": {
+        "url": "https://github.com/sponsors/sindresorhus"
+      }
+    },
+    "node_modules/p-locate/node_modules/p-limit": {
       "version": "3.1.0",
       "resolved": "https://registry.npmjs.org/p-limit/-/p-limit-3.1.0.tgz",
       "integrity": "sha512-TYOanM3wGwNGsZN2cVTYPArw454xnXj5qmWF1bEoAc4+cU/ol7GVh7odevjp1FNHduHc3KZMcFduxU5Xc6uJRQ==",
@@ -2771,15 +2809,12 @@
         "url": "https://github.com/sponsors/sindresorhus"
       }
     },
-    "node_modules/p-locate": {
-      "version": "5.0.0",
-      "resolved": "https://registry.npmjs.org/p-locate/-/p-locate-5.0.0.tgz",
-      "integrity": "sha512-LaNjtRWUBY++zB5nE/NwcaoMylSPk+S+ZHNB1TzdbMJMny6dynpAGt7X/tl/QYq3TIeE6nxHppbo2LGymrG5Pw==",
+    "node_modules/p-locate/node_modules/yocto-queue": {
+      "version": "0.1.0",
+      "resolved": "https://registry.npmjs.org/yocto-queue/-/yocto-queue-0.1.0.tgz",
+      "integrity": "sha512-rVksvsnNCdJ/ohGc6xgPwyN8eheCxsiLM8mxuE/t/mOVqJewPuO1miLpTHQiRgTKCLexL4MeAFVagts7HmNZ2Q==",
       "dev": true,
       "license": "MIT",
-      "dependencies": {
-        "p-limit": "^3.0.2"
-      },
       "engines": {
         "node": ">=10"
       },
@@ -4116,13 +4151,12 @@
       "license": "ISC"
     },
     "node_modules/yocto-queue": {
-      "version": "0.1.0",
-      "resolved": "https://registry.npmjs.org/yocto-queue/-/yocto-queue-0.1.0.tgz",
-      "integrity": "sha512-rVksvsnNCdJ/ohGc6xgPwyN8eheCxsiLM8mxuE/t/mOVqJewPuO1miLpTHQiRgTKCLexL4MeAFVagts7HmNZ2Q==",
-      "dev": true,
+      "version": "1.2.2",
+      "resolved": "https://registry.npmjs.org/yocto-queue/-/yocto-queue-1.2.2.tgz",
+      "integrity": "sha512-4LCcse/U2MHZ63HAJVE+v71o7yOdIe4cZ70Wpf8D/IyjDKYQLV5GD46B+hSTjJsvV5PztjvHoU580EftxjDZFQ==",
       "license": "MIT",
       "engines": {
-        "node": ">=10"
+        "node": ">=12.20"
       },
       "funding": {
         "url": "https://github.com/sponsors/sindresorhus"
diff --git a/package.json b/package.json
index 01707c5..758173f 100644
--- a/package.json
+++ b/package.json
@@ -42,6 +42,8 @@
   },
   "dependencies": {
     "ignore": "^5.3.0",
+    "openai": "^6.42.0",
+    "p-limit": "^7.3.0",
     "picocolors": "^1.1.1",
     "tree-sitter": "^0.21.0",
     "tree-sitter-go": "^0.25.0",
diff --git a/src/cli.ts b/src/cli.ts
index 3878f3f..ca74a4d 100644
--- a/src/cli.ts
+++ b/src/cli.ts
@@ -4,6 +4,8 @@ import { patchFile } from "./patch.js";
 import { validateMaps } from "./validate.js";
 import { reinitPath } from "./init.js";
 import { discoverProject } from "./discover.js";
+import { createLLMClient, LLMError } from "./llm-client.js";
+import { loadConfig } from "./config.js";
 import pc from "picocolors";
 
 const args = process.argv.slice(2);
@@ -31,11 +33,22 @@ function printUsage() {
 	console.log(
 		`  project-map ${pc.cyan("--version")}              Show version\n`,
 	);
+	console.log(`${pc.bold("Options:")}`);
+	console.log(
+		`  --llm-provider=openai|kimi  LLM provider (default: config or openai)`,
+	);
+	console.log(
+		`  --llm-model=<model>         LLM model name (or set LLM_MODEL env var)`,
+	);
+	console.log(`  --llm-base-url=<url>        Custom base URL for LLM API\n`);
 	console.log(`${pc.bold("Examples:")}`);
 	console.log(`  project-map init`);
 	console.log(`  project-map patch src/components/Button.tsx`);
 	console.log(`  project-map validate --fix`);
 	console.log(`  project-map reinit`);
+	console.log(
+		`  project-map init --llm-provider=kimi --llm-model=kimi-k2-6`,
+	);
 }
 
 function printVersion() {
@@ -50,17 +63,49 @@ function formatCount(count: number, label: string): string {
 	return `${pc.bold(String(count))} ${count === 1 ? label : plural}`;
 }
 
-function parseValidateArgs(args: string[]): { path: string; fix: boolean } {
+function parseArgs(args: string[]): {
+	path: string;
+	fix: boolean;
+	llmProvider?: string;
+	llmModel?: string;
+	llmBaseUrl?: string;
+	positional: string[];
+} {
 	let path = ".";
 	let fix = false;
+	let llmProvider: string | undefined;
+	let llmModel: string | undefined;
+	let llmBaseUrl: string | undefined;
+	const positional: string[] = [];
+
 	for (const arg of args.slice(1)) {
 		if (arg === "--fix") {
 			fix = true;
+		} else if (arg.startsWith("--llm-provider=")) {
+			llmProvider = arg.slice("--llm-provider=".length);
+		} else if (arg.startsWith("--llm-model=")) {
+			llmModel = arg.slice("--llm-model=".length);
+		} else if (arg.startsWith("--llm-base-url=")) {
+			llmBaseUrl = arg.slice("--llm-base-url=".length);
 		} else if (!arg.startsWith("-")) {
+			positional.push(arg);
 			path = arg;
 		}
 	}
-	return { path, fix };
+
+	return { path, fix, llmProvider, llmModel, llmBaseUrl, positional };
+}
+
+function createClientFromArgs(args: ReturnType<typeof parseArgs>) {
+	const config = loadConfig();
+	const provider = (args.llmProvider || config.llmProvider) as
+		| "openai"
+		| "kimi"
+		| "pi";
+	return createLLMClient(provider, {
+		model: args.llmModel || config.llmModel || process.env.LLM_MODEL,
+		baseUrl: args.llmBaseUrl || config.llmBaseUrl,
+	});
 }
 
 async function main() {
@@ -74,13 +119,16 @@ async function main() {
 		process.exit(0);
 	}
 
+	const parsed = parseArgs(args);
+
 	switch (command) {
 		case "init": {
-			const targetPath = args[1] || ".";
+			const targetPath = parsed.positional[0] || ".";
 			const start = Date.now();
 			const entries = discoverProject(targetPath);
 			console.log(`Scanning ${formatCount(entries.length, "directory")}...`);
-			await initProject(targetPath, { verbose: false });
+			const client = createClientFromArgs(parsed);
+			await initProject(targetPath, { verbose: false, llmClient: client });
 			const elapsed = ((Date.now() - start) / 1000).toFixed(1);
 			console.log(
 				`${pc.green("✓")} Generated ${formatCount(entries.length, ".pi-map.md file")} in ${elapsed}s`,
@@ -88,18 +136,19 @@ async function main() {
 			break;
 		}
 		case "patch": {
-			if (!args[1]) {
+			if (!parsed.positional[0]) {
 				console.error(
 					`${pc.red("Error:")} Missing file path. Usage: project-map patch <file>`,
 				);
 				process.exit(1);
 			}
-			await patchFile(args[1]);
+			const client = createClientFromArgs(parsed);
+			await patchFile(parsed.positional[0], client);
 			console.log(`${pc.green("✓")} Patched`);
 			break;
 		}
 		case "validate": {
-			const { path, fix } = parseValidateArgs(args);
+			const { path, fix } = parsed;
 			const result = await validateMaps(path, { fix, verbose: true });
 			if (result.clean) {
 				console.log(`${pc.green("✓")} All .pi-map.md files are clean.`);
@@ -123,13 +172,14 @@ async function main() {
 			break;
 		}
 		case "reinit": {
-			const targetPath = args[1] || ".";
+			const targetPath = parsed.positional[0] || ".";
 			const start = Date.now();
 			const entries = discoverProject(targetPath);
 			console.log(
 				`Regenerating ${formatCount(entries.length, ".pi-map.md file")}...`,
 			);
-			await reinitPath(targetPath, { verbose: false });
+			const client = createClientFromArgs(parsed);
+			await reinitPath(targetPath, { verbose: false, llmClient: client });
 			const elapsed = ((Date.now() - start) / 1000).toFixed(1);
 			console.log(`${pc.green("✓")} Regenerated in ${elapsed}s`);
 			break;
@@ -142,6 +192,10 @@ async function main() {
 }
 
 main().catch((err) => {
-	console.error(`${pc.red("Error:")} ${err.message}`);
+	if (err instanceof LLMError) {
+		console.error(`${pc.red("LLM Error:")} ${err.message}`);
+	} else {
+		console.error(`${pc.red("Error:")} ${err.message}`);
+	}
 	process.exit(1);
 });
diff --git a/src/config.ts b/src/config.ts
index 6c02c8a..5ad7ca4 100644
--- a/src/config.ts
+++ b/src/config.ts
@@ -4,7 +4,9 @@ import { join } from "path";
 export interface SkillConfig {
 	ignorePatterns: string[];
 	smallPackageThreshold: number;
+	llmProvider: "openai" | "kimi" | "pi";
 	llmModel: string;
+	llmBaseUrl?: string;
 	contextBudget: number;
 	autoInjectPrompt: boolean;
 }
@@ -32,6 +34,7 @@ export const DEFAULT_CONFIG: SkillConfig = {
 		".prettiercache",
 	],
 	smallPackageThreshold: 10,
+	llmProvider: "openai",
 	llmModel: "gpt-4o-mini",
 	contextBudget: 4000,
 	autoInjectPrompt: true,
diff --git a/src/external-llm-client.ts b/src/external-llm-client.ts
new file mode 100644
index 0000000..d0fd630
--- /dev/null
+++ b/src/external-llm-client.ts
@@ -0,0 +1,50 @@
+import OpenAI from "openai";
+import { LLMError } from "./llm-error.js";
+import type { LLMClient, LLMClientOptions } from "./llm-client.js";
+
+export class ExternalLLMClient implements LLMClient {
+	private client: OpenAI;
+	private model: string;
+
+	constructor(options: LLMClientOptions = {}) {
+		const apiKey = options.apiKey || process.env.OPENAI_API_KEY;
+		if (!apiKey) {
+			throw new LLMError(
+				"No OpenAI API key provided. Set OPENAI_API_KEY environment variable or pass apiKey in options.",
+			);
+		}
+		this.client = new OpenAI({
+			apiKey,
+			baseURL: options.baseUrl,
+		});
+		this.model =
+			options.model ||
+			process.env.OPENAI_MODEL ||
+			process.env.LLM_MODEL ||
+			"gpt-4o-mini";
+	}
+
+	async complete(prompt: string): Promise<string> {
+		try {
+			const response = await this.client.chat.completions.create({
+				model: this.model,
+				messages: [
+					{
+						role: "system",
+						content:
+							"You are a code analysis assistant. Analyze the provided file and respond with concise, structured information.",
+					},
+					{ role: "user", content: prompt },
+				],
+				temperature: 0.1,
+				max_tokens: 256,
+			});
+			return response.choices[0]?.message?.content?.trim() || "";
+		} catch (err: any) {
+			throw new LLMError(
+				`External LLM request failed: ${err.message || String(err)}`,
+				err,
+			);
+		}
+	}
+}
diff --git a/src/init.ts b/src/init.ts
index 584adb1..9f31ed5 100644
--- a/src/init.ts
+++ b/src/init.ts
@@ -9,34 +9,45 @@ import { extractFileAST } from "./ast-extract.js";
 import { mergeFileData } from "./merge.js";
 import { writeFileSync } from "fs";
 import { join } from "path";
+import type { LLMClient } from "./llm-client.js";
+
+export interface InitOptions {
+	verbose?: boolean;
+	llmClient?: LLMClient;
+}
 
 export async function initProject(
 	rootPath: string,
-	options?: { verbose?: boolean },
+	options: InitOptions = {},
 ): Promise<void> {
 	const entries = discoverProject(rootPath);
 
 	for (const entry of entries) {
-		await generateDirectoryMap(entry);
+		await generateDirectoryMap(entry, options.llmClient);
 	}
 
-	if (options?.verbose !== false) {
+	if (options.verbose !== false) {
 		console.log(`Generated ${entries.length} .pi-map.md files`);
 	}
 }
 
 export async function generateDirectoryMap(
 	entry: DirectoryEntry,
+	llmClient?: LLMClient,
 ): Promise<FileEntry[]> {
 	const fileData: FileEntry[] = [];
 	for (const file of entry.files) {
 		const filePath = join(entry.dirPath, file);
-		const llmData = await extractFileLLM(filePath);
+		const llmData = await extractFileLLM(filePath, llmClient);
 		const astData = await extractFileAST(filePath);
 		fileData.push(mergeFileData(file, llmData, astData));
 	}
 
-	const packageData = await extractPackageLLM(entry.relativePath, fileData);
+	const packageData = await extractPackageLLM(
+		entry.relativePath,
+		fileData,
+		llmClient,
+	);
 
 	const mapData: PackageMapData = {
 		path: entry.relativePath,
@@ -53,7 +64,7 @@ export async function generateDirectoryMap(
 
 export async function reinitPath(
 	path: string,
-	options?: { verbose?: boolean },
+	options: InitOptions = {},
 ): Promise<void> {
 	// Full regeneration clears all dirty markers by overwriting every .pi-map.md
 	await initProject(path, options);
diff --git a/src/kimi-llm-client.ts b/src/kimi-llm-client.ts
new file mode 100644
index 0000000..2a916bb
--- /dev/null
+++ b/src/kimi-llm-client.ts
@@ -0,0 +1,79 @@
+import { LLMError } from "./llm-error.js";
+import type { LLMClient, LLMClientOptions } from "./llm-client.js";
+
+/**
+ * Kimi.com LLM Client.
+ *
+ * Uses the Anthropic-based API at https://api.kimi.com/coding/
+ * Set KIMI_API_KEY environment variable or pass apiKey in options.
+ */
+export class KimiLLMClient implements LLMClient {
+	private apiKey: string;
+	private model: string;
+	private baseUrl: string;
+
+	constructor(options: LLMClientOptions = {}) {
+		const apiKey =
+			options.apiKey ||
+			process.env.KIMI_API_KEY ||
+			process.env.KIMI_COM_API_KEY;
+		if (!apiKey) {
+			throw new LLMError(
+				"No Kimi API key provided. Set KIMI_API_KEY environment variable or pass apiKey in options.",
+			);
+		}
+		this.apiKey = apiKey;
+		this.model =
+			options.model ||
+			process.env.KIMI_MODEL ||
+			process.env.LLM_MODEL ||
+			"kimi-k2-6";
+		this.baseUrl = options.baseUrl || "https://api.kimi.com/coding";
+	}
+
+	async complete(prompt: string): Promise<string> {
+		try {
+			const response = await fetch(`${this.baseUrl}/v1/messages`, {
+				method: "POST",
+				headers: {
+					"Content-Type": "application/json",
+					"x-api-key": this.apiKey,
+					"anthropic-version": "2023-06-01",
+				},
+				body: JSON.stringify({
+					model: this.model,
+					max_tokens: 256,
+					messages: [
+						{
+							role: "user",
+							content: prompt,
+						},
+					],
+				}),
+			});
+
+			if (!response.ok) {
+				const text = await response.text();
+				throw new LLMError(`Kimi API error ${response.status}: ${text}`);
+			}
+
+			const data = (await response.json()) as {
+				content?: Array<{ type: string; text?: string }>;
+				error?: { message: string };
+			};
+
+			if (data.error) {
+				throw new LLMError(`Kimi error: ${data.error.message}`);
+			}
+
+			const text = data.content?.[0]?.text?.trim() || "";
+			return text;
+		} catch (err: any) {
+			if (err instanceof LLMError) throw err;
+			throw new LLMError(
+				`Kimi request failed: ${err.message || String(err)}`,
+				err,
+			);
+		}
+	}
+}
diff --git a/src/llm-batch.ts b/src/llm-batch.ts
new file mode 100644
index 0000000..61631e0
--- /dev/null
+++ b/src/llm-batch.ts
@@ -0,0 +1,68 @@
+import pLimit from "p-limit";
+import { LLMError } from "./llm-error.js";
+
+export interface BatchOptions {
+	concurrency?: number;
+	batchDelayMs?: number;
+	maxRetries?: number;
+	retryDelaysMs?: number[];
+}
+
+const DEFAULT_OPTIONS: Required<BatchOptions> = {
+	concurrency: 4,
+	batchDelayMs: 100,
+	maxRetries: 3,
+	retryDelaysMs: [1000, 2000, 4000],
+};
+
+function sleep(ms: number): Promise<void> {
+	return new Promise((resolve) => setTimeout(resolve, ms));
+}
+
+export async function withRetry<T>(
+	fn: () => Promise<T>,
+	options: Pick<BatchOptions, "maxRetries" | "retryDelaysMs"> = {},
+): Promise<T> {
+	const maxRetries = options.maxRetries ?? DEFAULT_OPTIONS.maxRetries;
+	const delays = options.retryDelaysMs ?? DEFAULT_OPTIONS.retryDelaysMs;
+
+	let lastError: unknown;
+	for (let attempt = 0; attempt <= maxRetries; attempt++) {
+		try {
+			return await fn();
+		} catch (err) {
+			lastError = err;
+			if (attempt < maxRetries) {
+				const delay = delays[attempt] ?? delays[delays.length - 1] ?? 1000;
+				await sleep(delay);
+			}
+		}
+	}
+	throw lastError;
+}
+
+export async function processFiles<T, R>(
+	files: T[],
+	processor: (file: T) => Promise<R>,
+	options: BatchOptions = {},
+): Promise<R[]> {
+	const opts = { ...DEFAULT_OPTIONS, ...options };
+	const limit = pLimit(opts.concurrency);
+
+	const results: R[] = [];
+	let batchCount = 0;
+
+	const tasks = files.map((file, index) =>
+		limit(async () => {
+			// Small delay between batches based on index
+			if (index > 0 && index % opts.concurrency === 0) {
+				batchCount++;
+				await sleep(opts.batchDelayMs);
+			}
+			return withRetry(() => processor(file), opts);
+		}),
+	);
+
+	const settled = await Promise.all(tasks);
+	return settled;
+}
diff --git a/src/llm-cache.ts b/src/llm-cache.ts
new file mode 100644
index 0000000..da7ba87
--- /dev/null
+++ b/src/llm-cache.ts
@@ -0,0 +1,46 @@
+import { readFileSync, writeFileSync, existsSync, mkdirSync, renameSync } from "fs";
+import { join } from "path";
+import { homedir } from "os";
+
+const CACHE_DIR = join(homedir(), ".cache", "pi-project-map");
+const CACHE_FILE = join(CACHE_DIR, "llm-cache.json");
+
+interface CacheEntry {
+	result: string;
+	ts: number;
+}
+
+function ensureCacheDir(): void {
+	if (!existsSync(CACHE_DIR)) {
+		mkdirSync(CACHE_DIR, { recursive: true });
+	}
+}
+
+function loadCache(): Record<string, CacheEntry> {
+	if (!existsSync(CACHE_FILE)) return {};
+	try {
+		const raw = readFileSync(CACHE_FILE, "utf8");
+		return JSON.parse(raw) as Record<string, CacheEntry>;
+	} catch {
+		// Corrupted cache — start fresh
+		return {};
+	}
+}
+
+function saveCache(cache: Record<string, CacheEntry>): void {
+	ensureCacheDir();
+	const tmp = CACHE_FILE + ".tmp";
+	writeFileSync(tmp, JSON.stringify(cache, null, 2));
+	renameSync(tmp, CACHE_FILE);
+}
+
+export function getCached(hash: string): string | undefined {
+	const cache = loadCache();
+	return cache[hash]?.result;
+}
+
+export function setCached(hash: string, result: string): void {
+	const cache = loadCache();
+	cache[hash] = { result, ts: Date.now() };
+	saveCache(cache);
+}
diff --git a/src/llm-client.ts b/src/llm-client.ts
new file mode 100644
index 0000000..e01e7e5
--- /dev/null
+++ b/src/llm-client.ts
@@ -0,0 +1,31 @@
+import { LLMError } from "./llm-error.js";
+import { ExternalLLMClient } from "./external-llm-client.js";
+import { KimiLLMClient } from "./kimi-llm-client.js";
+import { PiLLMClient } from "./pi-llm-client.js";
+
+export interface LLMClient {
+	complete(prompt: string): Promise<string>;
+}
+
+export interface LLMClientOptions {
+	apiKey?: string;
+	model?: string;
+	baseUrl?: string;
+	// Pi-specific
+	extensionContext?: unknown;
+}
+
+export function createLLMClient(
+	mode: "pi" | "openai" | "kimi",
+	options: LLMClientOptions = {},
+): LLMClient {
+	if (mode === "pi") {
+		return new PiLLMClient(options.extensionContext);
+	}
+	if (mode === "kimi") {
+		return new KimiLLMClient(options);
+	}
+	return new ExternalLLMClient(options);
+}
+
+export { LLMError };
diff --git a/src/llm-error.ts b/src/llm-error.ts
new file mode 100644
index 0000000..898de7b
--- /dev/null
+++ b/src/llm-error.ts
@@ -0,0 +1,9 @@
+export class LLMError extends Error {
+	constructor(
+		message: string,
+		public readonly cause?: unknown,
+	) {
+		super(message);
+		this.name = "LLMError";
+	}
+}
diff --git a/src/llm-extract.ts b/src/llm-extract.ts
index a787540..c0559e3 100644
--- a/src/llm-extract.ts
+++ b/src/llm-extract.ts
@@ -1,11 +1,15 @@
-import { readFileSync } from "fs";
+import { readFileSync, statSync } from "fs";
 import { createHash } from "crypto";
 import { extname, basename } from "path";
+import type { LLMClient } from "./llm-client.js";
+import { getCached, setCached } from "./llm-cache.js";
+import { LLMError } from "./llm-error.js";
 
 interface LLMFileData {
 	purpose: string;
 	exports: string[];
 	deps: string[];
+	concepts: string[];
 }
 
 interface LLMPackageData {
@@ -13,9 +17,11 @@ interface LLMPackageData {
 	arch: string;
 }
 
-const cache = new Map<string, LLMFileData>();
+const MAX_FILE_SIZE = 50 * 1024; // 50KB
+const CONTEXT_BUDGET = 4000; // tokens
+const CHARS_PER_TOKEN = 4; // approximate for ASCII
 
-// Heuristic patterns for common file types
+// Heuristic patterns for common file types (used as fallback + for tests)
 const FILE_TYPE_PURPOSES: Record<string, string> = {
 	".ts": "TypeScript module",
 	".tsx": "React component",
@@ -51,236 +57,178 @@ const FILE_TYPE_PURPOSES: Record<string, string> = {
 	".svelte": "Svelte component",
 };
 
-export async function extractFileLLM(filePath: string): Promise<LLMFileData> {
+function truncateForContext(content: string, promptLength: number): string {
+	const maxChars = CONTEXT_BUDGET * CHARS_PER_TOKEN - promptLength;
+	if (content.length <= maxChars) return content;
+	return content.slice(0, maxChars - 20) + "\n[...truncated]";
+}
+
+function buildFilePrompt(filePath: string, content: string): string {
+	const name = basename(filePath);
+	const ext = extname(filePath).toLowerCase();
+	const typeHint = FILE_TYPE_PURPOSES[ext] || FILE_TYPE_PURPOSES[name.toLowerCase()] || ext || "file";
+
+	return `Analyze this ${typeHint} file. Respond in this exact format (one line each):
+PURPOSE: <concise one-sentence description of what this file does>
+DEPS: <comma-separated list of key dependencies/modules it relies on, or "none">
+CONCEPTS: <comma-separated list of key concepts/patterns used, or "none">
+
+File: ${name}
+\`\`\`
+${content}
+\`\`\`
+`;
+}
+
+function parseFileResponse(response: string): { purpose: string; deps: string[]; concepts: string[] } {
+	const lines = response.split("\n");
+	let purpose = "";
+	let deps: string[] = [];
+	let concepts: string[] = [];
+
+	for (const line of lines) {
+		const trimmed = line.trim();
+		if (trimmed.startsWith("PURPOSE:")) {
+			purpose = trimmed.slice("PURPOSE:".length).trim();
+		} else if (trimmed.startsWith("DEPS:")) {
+			const depsStr = trimmed.slice("DEPS:".length).trim();
+			deps = depsStr === "none" ? [] : depsStr.split(",").map((s) => s.trim()).filter(Boolean);
+		} else if (trimmed.startsWith("CONCEPTS:")) {
+			const conceptsStr = trimmed.slice("CONCEPTS:".length).trim();
+			concepts = conceptsStr === "none" ? [] : conceptsStr.split(",").map((s) => s.trim()).filter(Boolean);
+		}
+	}
+
+	return { purpose, deps, concepts };
+}
+
+function buildPackagePrompt(relativePath: string, fileSummaries: { name: string; purpose: string }[]): string {
+	const filesList = fileSummaries.map((f) => `- ${f.name}: ${f.purpose}`).join("\n");
+	return `Analyze this code package/directory. Respond in this exact format (one line each):
+ROLE: <concise one-sentence description of this package's role in the project>
+ARCH: <concise description of architecture/patterns used in this package>
+
+Directory: ${relativePath}
+Files:
+${filesList}
+`;
+}
+
+function parsePackageResponse(response: string): { role: string; arch: string } {
+	const lines = response.split("\n");
+	let role = "";
+	let arch = "";
+
+	for (const line of lines) {
+		const trimmed = line.trim();
+		if (trimmed.startsWith("ROLE:")) {
+			role = trimmed.slice("ROLE:".length).trim();
+		} else if (trimmed.startsWith("ARCH:")) {
+			arch = trimmed.slice("ARCH:".length).trim();
+		}
+	}
+
+	return { role, arch };
+}
+
+// ============================================================================
+// PRODUCTION: Real LLM calls
+// ============================================================================
+
+export async function extractFileLLM(
+	filePath: string,
+	client?: LLMClient,
+): Promise<LLMFileData> {
 	const content = readFileSync(filePath, "utf8");
 	const hash = createHash("sha256").update(content).digest("hex");
 
-	if (cache.has(hash)) {
-		return cache.get(hash)!;
+	// Check disk cache
+	const cached = getCached(hash);
+	if (cached) {
+		const parsed = parseFileResponse(cached);
+		return {
+			purpose: parsed.purpose,
+			exports: [], // AST provides precise exports
+			deps: parsed.deps,
+			concepts: parsed.concepts,
+		};
 	}
 
-	const ext = extname(filePath).toLowerCase();
-	const name = basename(filePath);
-	const baseName = basename(filePath, ext);
-
-	// Extract exports via heuristics
-	const exports = extractExports(content, ext, name);
-
-	// Extract dependencies via heuristics
-	const deps = extractDeps(content, ext);
-
-	// Generate purpose from filename + content heuristics
-	const purpose = generatePurpose(name, ext, baseName, content, exports);
-
-	const result: LLMFileData = { purpose, exports, deps };
-	cache.set(hash, result);
-	return result;
-}
-
-function extractExports(
-	content: string,
-	ext: string,
-	_filename: string,
-): string[] {
-	const exports: string[] = [];
-
-	if ([".ts", ".tsx", ".js", ".jsx", ".mjs"].includes(ext)) {
-		// ES module exports — only match at start of line (after optional whitespace)
-		// Handles: export function foo, export async function foo, export class Foo,
-		// export const foo, export { foo, bar }, export default foo
-		const exportRegex =
-			/(?:^|\n)\s*export\s+(?:default\s+)?(?:async\s+)?(?:function\s+|class\s+|const\s+|let\s+|var\s+|interface\s+|type\s+|enum\s+)?([A-Za-z_$][A-Za-z0-9_$]*)/g;
-		let match: RegExpExecArray | null;
-		match = exportRegex.exec(content);
-		while (match !== null) {
-			exports.push(match[1]);
-			match = exportRegex.exec(content);
-		}
-
-		// Named export destructuring: export { foo, bar }
-		const namedExportRegex = /(?:^|\n)\s*export\s*\{\s*([^}]+)\s*\}/g;
-		match = namedExportRegex.exec(content);
-		while (match !== null) {
-			const names = match[1].split(",").map((s) =>
-				s
-					.trim()
-					.split(/\s+as\s+/)[0]
-					.trim(),
-			);
-			exports.push(...names);
-			match = namedExportRegex.exec(content);
-		}
-	} else if (ext === ".py") {
-		// Python exports (top-level functions/classes)
-		const pyRegex =
-			/^(?:async\s+)?def\s+([A-Za-z_][A-Za-z0-9_]*)|class\s+([A-Za-z_][A-Za-z0-9_]*)/gm;
-		let match: RegExpExecArray | null = pyRegex.exec(content);
-		while (match !== null) {
-			exports.push(match[1] || match[2]);
-			match = pyRegex.exec(content);
-		}
-	} else if (ext === ".go") {
-		// Go exports (capitalized functions/types)
-		const goRegex = /^(?:func|type|var|const)\s+([A-Z][A-Za-z0-9_]*)/gm;
-		let match: RegExpExecArray | null = goRegex.exec(content);
-		while (match !== null) {
-			exports.push(match[1]);
-			match = goRegex.exec(content);
-		}
-	} else if (ext === ".rs") {
-		// Rust exports (pub items)
-		const rsRegex =
-			/pub\s+(?:fn|struct|enum|trait|type|const|static|use)\s+([A-Za-z_][A-Za-z0-9_]*)/g;
-		let match: RegExpExecArray | null = rsRegex.exec(content);
-		while (match !== null) {
-			exports.push(match[1]);
-			match = rsRegex.exec(content);
-		}
+	// Skip very large files
+	const size = statSync(filePath).size;
+	if (size > MAX_FILE_SIZE) {
+		return {
+			purpose: "Large/generated file",
+			exports: [],
+			deps: [],
+			concepts: [],
+		};
 	}
 
-	// Deduplicate while preserving order
-	return [...new Set(exports)];
-}
-
-function extractDeps(content: string, ext: string): string[] {
-	const deps: string[] = [];
-
-	if ([".ts", ".tsx", ".js", ".jsx", ".mjs"].includes(ext)) {
-		// ES imports
-		const importRegex =
-			/import\s+(?:(?:type\s+)?\{[^}]*\}|\*\s+as\s+\w+|\w+)\s+from\s+['"]([^'"]+)['"]/g;
-		let match: RegExpExecArray | null = importRegex.exec(content);
-		while (match !== null) {
-			deps.push(match[1]);
-			match = importRegex.exec(content);
-		}
-		// CommonJS requires
-		const requireRegex = /require\s*\(\s*['"]([^'"]+)['"]\s*\)/g;
-		match = requireRegex.exec(content);
-		while (match !== null) {
-			deps.push(match[1]);
-			match = requireRegex.exec(content);
-		}
-	} else if (ext === ".py") {
-		// Python imports
-		const pyImportRegex = /^(?:from|import)\s+([A-Za-z_][A-Za-z0-9_.]*)/gm;
-		let match: RegExpExecArray | null = pyImportRegex.exec(content);
-		while (match !== null) {
-			deps.push(match[1]);
-			match = pyImportRegex.exec(content);
-		}
-	} else if (ext === ".go") {
-		// Go imports
-		const goImportRegex = /"([^"]+)"/g;
-		let match: RegExpExecArray | null = goImportRegex.exec(content);
-		while (match !== null) {
-			if (match[1].includes("/")) deps.push(match[1]);
-			match = goImportRegex.exec(content);
-		}
-	} else if (ext === ".rs") {
-		// Rust use statements
-		const rsUseRegex = /use\s+([A-Za-z_][A-Za-z0-9_:]*)/g;
-		let match: RegExpExecArray | null = rsUseRegex.exec(content);
-		while (match !== null) {
-			deps.push(match[1]);
-			match = rsUseRegex.exec(content);
-		}
+	// If no LLM client provided, fall back to heuristics (for backward compat / tests)
+	if (!client) {
+		return extractFileHeuristic(filePath, content);
 	}
 
-	// Deduplicate
-	return [...new Set(deps)];
-}
+	const prompt = buildFilePrompt(filePath, truncateForContext(content, 200));
+	const response = await client.complete(prompt);
+	setCached(hash, response);
 
-function generatePurpose(
-	name: string,
-	ext: string,
-	_baseName: string,
-	_content: string,
-	exports: string[],
-): string {
-	// Check for specific file patterns
-	if (/test|spec/i.test(name) && exports.length === 0) {
-		return "Test suite";
-	}
-	if (/config|settings/i.test(name)) return "Configuration";
-	if (/util|helper/i.test(name)) return "Utility functions";
-	if (/types?\.d?\.ts$/.test(name)) return "Type definitions";
-	if (/index\./.test(name)) return "Module entry point";
-	if (/middleware/.test(name)) return "Middleware";
-	if (/route/.test(name)) return "Route handlers";
-	if (/controller/.test(name)) return "Controller";
-	if (/service/.test(name)) return "Service layer";
-	if (/model/.test(name)) return "Data model";
-	if (/schema/.test(name)) return "Data schema";
-	if (
-		/component/.test(name) ||
-		/\.tsx$/.test(name) ||
-		/\.vue$/.test(name) ||
-		/\.svelte$/.test(name)
-	) {
-		return "UI component";
-	}
-	if (/hook|use[A-Z]/.test(name)) return "React hook";
-	if (/style|\.css|\.scss|\.less/.test(name)) return "Styling";
-	if (/docker/i.test(name)) return "Container definition";
-	if (/\.env/.test(name)) return "Environment variables";
-	if (/readme/i.test(name)) return "Project documentation";
-
-	// Use exports to infer purpose
-	if (exports.length > 0) {
-		const firstFew = exports.slice(0, 3).join(", ");
-		if (exports.length <= 3) return `Exports: ${firstFew}`;
-		return `Exports ${exports.length} symbols: ${firstFew}...`;
-	}
-
-	// Fallback to file type
-	return (
-		FILE_TYPE_PURPOSES[ext] ||
-		(ext ? `${ext.slice(1).toUpperCase()} file` : `${name} file`)
-	);
+	const parsed = parseFileResponse(response);
+	return {
+		purpose: parsed.purpose,
+		exports: [], // AST provides precise exports
+		deps: parsed.deps,
+		concepts: parsed.concepts,
+	};
 }
 
 export async function extractPackageLLM(
 	relativePath: string,
 	fileData: { name: string; purpose: string }[],
+	client?: LLMClient,
 ): Promise<LLMPackageData> {
-	const dirName = basename(relativePath);
-
-	// Infer role from directory name
-	let role = dirName === "." ? "Project root" : `Package ${dirName}`;
-	if (dirName === "src" || dirName === "lib" || dirName === "source") {
-		role = "Source code";
-	} else if (dirName === "test" || dirName === "tests" || dirName === "spec") {
-		role = "Test suite";
-	} else if (dirName === "docs" || dirName === "doc") {
-		role = "Documentation";
-	} else if (dirName === "config" || dirName === "configuration") {
-		role = "Configuration";
-	} else if (
-		dirName === "utils" ||
-		dirName === "helpers" ||
-		dirName === "util"
-	) {
-		role = "Utility functions";
-	} else if (dirName === "types" || dirName === "type") {
-		role = "Type definitions";
-	} else if (dirName === "components" || dirName === "component") {
-		role = "UI components";
-	} else if (dirName === "hooks" || dirName === "hook") {
-		role = "Custom hooks";
-	} else if (dirName === "api" || dirName === "apis") {
-		role = "API endpoints/handlers";
-	} else if (
-		dirName === "db" ||
-		dirName === "database" ||
-		dirName === "models"
-	) {
-		role = "Database layer";
-	} else if (dirName === "auth" || dirName === "authentication") {
-		role = "Authentication layer";
+	if (!client) {
+		return extractPackageHeuristic(relativePath, fileData);
 	}
 
-	// Infer architecture from file patterns
+	const prompt = buildPackagePrompt(relativePath, fileData);
+	const response = await client.complete(prompt);
+	const parsed = parsePackageResponse(response);
+
+	return {
+		role: parsed.role || dirNameToRole(relativePath),
+		arch: parsed.arch || `Contains ${fileData.length} files.`,
+	};
+}
+
+// ============================================================================
+// HEURISTIC FALLBACK (for tests / no-LLM mode)
+// ============================================================================
+
+export async function extractFileHeuristic(
+	filePath: string,
+	content?: string,
+): Promise<LLMFileData> {
+	const fileContent = content ?? readFileSync(filePath, "utf8");
+	const ext = extname(filePath).toLowerCase();
+	const name = basename(filePath);
+	const baseName = basename(filePath, ext);
+
+	const exports = extractExportsHeuristic(fileContent, ext, name);
+	const deps = extractDepsHeuristic(fileContent, ext);
+	const purpose = generatePurpose(name, ext, baseName, exports);
+
+	return { purpose, exports, deps, concepts: [] };
+}
+
+export async function extractPackageHeuristic(
+	relativePath: string,
+	fileData: { name: string; purpose: string }[],
+): Promise<LLMPackageData> {
+	const dirName = basename(relativePath);
+	const role = dirNameToRole(dirName);
+
 	const purposes = fileData.map((f) => f.purpose);
 	const hasTests = purposes.some((p) => p.includes("Test"));
 	const hasTypes = purposes.some((p) => p.includes("Type"));
@@ -298,3 +246,140 @@ export async function extractPackageLLM(
 
 	return { role, arch: arch.trim() };
 }
+
+// ============================================================================
+// INTERNAL HEURISTIC HELPERS
+// ============================================================================
+
+function dirNameToRole(dirName: string): string {
+	if (dirName === ".") return "Project root";
+	if (dirName === "src" || dirName === "lib" || dirName === "source") return "Source code";
+	if (dirName === "test" || dirName === "tests" || dirName === "spec") return "Test suite";
+	if (dirName === "docs" || dirName === "doc") return "Documentation";
+	if (dirName === "config" || dirName === "configuration") return "Configuration";
+	if (dirName === "utils" || dirName === "helpers" || dirName === "util") return "Utility functions";
+	if (dirName === "types" || dirName === "type") return "Type definitions";
+	if (dirName === "components" || dirName === "component") return "UI components";
+	if (dirName === "hooks" || dirName === "hook") return "Custom hooks";
+	if (dirName === "api" || dirName === "apis") return "API endpoints/handlers";
+	if (dirName === "db" || dirName === "database" || dirName === "models") return "Database layer";
+	if (dirName === "auth" || dirName === "authentication") return "Authentication layer";
+	return `Package ${dirName}`;
+}
+
+function extractExportsHeuristic(content: string, ext: string, _filename: string): string[] {
+	const exports: string[] = [];
+
+	if ([".ts", ".tsx", ".js", ".jsx", ".mjs"].includes(ext)) {
+		const exportRegex = /(?:^|\n)\s*export\s+(?:default\s+)?(?:async\s+)?(?:function\s+|class\s+|const\s+|let\s+|var\s+|interface\s+|type\s+|enum\s+)?([A-Za-z_$][A-Za-z0-9_$]*)/g;
+		let match: RegExpExecArray | null;
+		match = exportRegex.exec(content);
+		while (match !== null) {
+			exports.push(match[1]);
+			match = exportRegex.exec(content);
+		}
+
+		const namedExportRegex = /(?:^|\n)\s*export\s*\{\s*([^}]+)\s*\}/g;
+		match = namedExportRegex.exec(content);
+		while (match !== null) {
+			const names = match[1].split(",").map((s) => s.trim().split(/\s+as\s+/)[0].trim());
+			exports.push(...names);
+			match = namedExportRegex.exec(content);
+		}
+	} else if (ext === ".py") {
+		const pyRegex = /^(?:async\s+)?def\s+([A-Za-z_][A-Za-z0-9_]*)|class\s+([A-Za-z_][A-Za-z0-9_]*)/gm;
+		let match: RegExpExecArray | null = pyRegex.exec(content);
+		while (match !== null) {
+			exports.push(match[1] || match[2]);
+			match = pyRegex.exec(content);
+		}
+	} else if (ext === ".go") {
+		const goRegex = /^(?:func|type|var|const)\s+([A-Z][A-Za-z0-9_]*)/gm;
+		let match: RegExpExecArray | null = goRegex.exec(content);
+		while (match !== null) {
+			exports.push(match[1]);
+			match = goRegex.exec(content);
+		}
+	} else if (ext === ".rs") {
+		const rsRegex = /pub\s+(?:fn|struct|enum|trait|type|const|static|use)\s+([A-Za-z_][A-Za-z0-9_]*)/g;
+		let match: RegExpExecArray | null = rsRegex.exec(content);
+		while (match !== null) {
+			exports.push(match[1]);
+			match = rsRegex.exec(content);
+		}
+	}
+
+	return [...new Set(exports)];
+}
+
+function extractDepsHeuristic(content: string, ext: string): string[] {
+	const deps: string[] = [];
+
+	if ([".ts", ".tsx", ".js", ".jsx", ".mjs"].includes(ext)) {
+		const importRegex = /import\s+(?:(?:type\s+)?\{[^}]*\}|\*\s+as\s+\w+|\w+)\s+from\s+['"]([^'"]+)['"]/g;
+		let match: RegExpExecArray | null = importRegex.exec(content);
+		while (match !== null) {
+			deps.push(match[1]);
+			match = importRegex.exec(content);
+		}
+		const requireRegex = /require\s*\(\s*['"]([^'"]+)['"]\s*\)/g;
+		match = requireRegex.exec(content);
+		while (match !== null) {
+			deps.push(match[1]);
+			match = requireRegex.exec(content);
+		}
+	} else if (ext === ".py") {
+		const pyImportRegex = /^(?:from|import)\s+([A-Za-z_][A-Za-z0-9_.]*)/gm;
+		let match: RegExpExecArray | null = pyImportRegex.exec(content);
+		while (match !== null) {
+			deps.push(match[1]);
+			match = pyImportRegex.exec(content);
+		}
+	} else if (ext === ".go") {
+		const goImportRegex = /"([^"]+)"/g;
+		let match: RegExpExecArray | null = goImportRegex.exec(content);
+		while (match !== null) {
+			if (match[1].includes("/")) deps.push(match[1]);
+			match = goImportRegex.exec(content);
+		}
+	} else if (ext === ".rs") {
+		const rsUseRegex = /use\s+([A-Za-z_][A-Za-z0-9_:]*)/g;
+		let match: RegExpExecArray | null = rsUseRegex.exec(content);
+		while (match !== null) {
+			deps.push(match[1]);
+			match = rsUseRegex.exec(content);
+		}
+	}
+
+	return [...new Set(deps)];
+}
+
+function generatePurpose(name: string, ext: string, _baseName: string, exports: string[]): string {
+	if (/test|spec/i.test(name) && exports.length === 0) return "Test suite";
+	if (/config|settings/i.test(name)) return "Configuration";
+	if (/util|helper/i.test(name)) return "Utility functions";
+	if (/types?\.d?\.ts$/.test(name)) return "Type definitions";
+	if (/index\./.test(name)) return "Module entry point";
+	if (/middleware/.test(name)) return "Middleware";
+	if (/route/.test(name)) return "Route handlers";
+	if (/controller/.test(name)) return "Controller";
+	if (/service/.test(name)) return "Service layer";
+	if (/model/.test(name)) return "Data model";
+	if (/schema/.test(name)) return "Data schema";
+	if (/component/.test(name) || /\.tsx$/.test(name) || /\.vue$/.test(name) || /\.svelte$/.test(name)) {
+		return "UI component";
+	}
+	if (/hook|use[A-Z]/.test(name)) return "React hook";
+	if (/style|\.css|\.scss|\.less/.test(name)) return "Styling";
+	if (/docker/i.test(name)) return "Container definition";
+	if (/\.env/.test(name)) return "Environment variables";
+	if (/readme/i.test(name)) return "Project documentation";
+
+	if (exports.length > 0) {
+		const firstFew = exports.slice(0, 3).join(", ");
+		if (exports.length <= 3) return `Exports: ${firstFew}`;
+		return `Exports ${exports.length} symbols: ${firstFew}...`;
+	}
+
+	return FILE_TYPE_PURPOSES[ext] || (ext ? `${ext.slice(1).toUpperCase()} file` : `${name} file`);
+}
diff --git a/src/patch.ts b/src/patch.ts
index bc6e2a4..95304ae 100644
--- a/src/patch.ts
+++ b/src/patch.ts
@@ -6,10 +6,14 @@ import { extractFileAST } from "./ast-extract.js";
 import { mergeFileData } from "./merge.js";
 import { generateDirectoryMap } from "./init.js";
 import { readdirSync, statSync } from "fs";
+import type { LLMClient } from "./llm-client.js";
 
 const SMALL_PACKAGE_THRESHOLD = 10;
 
-export async function patchFile(filePath: string): Promise<void> {
+export async function patchFile(
+	filePath: string,
+	llmClient?: LLMClient,
+): Promise<void> {
 	const dirPath = dirname(filePath);
 	const mapPath = join(dirPath, ".pi-map.md");
 
@@ -31,18 +35,21 @@ export async function patchFile(filePath: string): Promise<void> {
 			return st.isFile();
 		});
 		const relDir = relative(process.cwd(), dirPath) || ".";
-		await generateDirectoryMap({
-			dirPath,
-			relativePath: relDir,
-			files,
-		});
+		await generateDirectoryMap(
+			{
+				dirPath,
+				relativePath: relDir,
+				files,
+			},
+			llmClient,
+		);
 		console.log(
 			`Full rewrite of ${mapPath} (small package: ${allFiles.length} files)`,
 		);
 	} else {
 		// Section-level patch
 		const existing = parsePackageMap(readFileSync(mapPath, "utf8"));
-		const llmData = await extractFileLLM(filePath);
+		const llmData = await extractFileLLM(filePath, llmClient);
 		const astData = await extractFileAST(filePath);
 		const fileName = basename(filePath);
 		const updatedFile = mergeFileData(fileName, llmData, astData);
diff --git a/src/pi-llm-client.ts b/src/pi-llm-client.ts
new file mode 100644
index 0000000..029c048
--- /dev/null
+++ b/src/pi-llm-client.ts
@@ -0,0 +1,21 @@
+import { LLMError } from "./llm-error.js";
+import type { LLMClient } from "./llm-client.js";
+
+/**
+ * Pi LLM Client — calls Pi's built-in LLM via ExtensionAPI.
+ *
+ * TODO: This is a stub. When running inside Pi, the extension context
+ * should provide access to the configured model. The exact API shape
+ * depends on the Pi runtime version. For now, this throws a clear error
+ * directing users to use the external LLM client instead.
+ */
+export class PiLLMClient implements LLMClient {
+	constructor(private _extensionContext?: unknown) {}
+
+	async complete(_prompt: string): Promise<string> {
+		throw new LLMError(
+			"Pi native LLM client is not yet implemented. " +
+				"Use the external LLM client by setting OPENAI_API_KEY and running in CLI mode.",
+		);
+	}
+}
diff --git a/tests/llm-batch.test.ts b/tests/llm-batch.test.ts
new file mode 100644
index 0000000..6e4ab9f
--- /dev/null
+++ b/tests/llm-batch.test.ts
@@ -0,0 +1,56 @@
+import { describe, it, expect } from "vitest";
+import { withRetry, processFiles } from "../src/llm-batch.js";
+import { LLMError } from "../src/llm-error.js";
+
+describe("withRetry", () => {
+	it("returns result on first success", async () => {
+		const result = await withRetry(async () => "success");
+		expect(result).toBe("success");
+	});
+
+	it("retries on failure and eventually succeeds", async () => {
+		let attempts = 0;
+		const result = await withRetry(async () => {
+			attempts++;
+			if (attempts < 3) throw new Error("transient");
+			return "success";
+		});
+		expect(result).toBe("success");
+		expect(attempts).toBe(3);
+	});
+
+	it("throws after max retries", async () => {
+		let attempts = 0;
+		await expect(
+			withRetry(async () => {
+				attempts++;
+				throw new Error("persistent");
+			}, { maxRetries: 2, retryDelaysMs: [10, 20] }),
+		).rejects.toThrow("persistent");
+		expect(attempts).toBe(3); // initial + 2 retries
+	});
+});
+
+describe("processFiles", () => {
+	it("processes all files in parallel", async () => {
+		const files = [1, 2, 3, 4, 5];
+		const results = await processFiles(files, async (n) => n * 2, {
+			concurrency: 2,
+		});
+		expect(results).toEqual([2, 4, 6, 8, 10]);
+	});
+
+	it("retries failed files", async () => {
+		let attempts = 0;
+		const results = await processFiles(
+			[1],
+			async () => {
+				attempts++;
+				if (attempts < 2) throw new Error("fail");
+				return "ok";
+			},
+			{ maxRetries: 2, retryDelaysMs: [10, 20] },
+		);
+		expect(results).toEqual(["ok"]);
+	});
+});
diff --git a/tests/llm-cache.test.ts b/tests/llm-cache.test.ts
new file mode 100644
index 0000000..ccf7513
--- /dev/null
+++ b/tests/llm-cache.test.ts
@@ -0,0 +1,40 @@
+import { describe, it, expect, beforeEach, afterEach } from "vitest";
+import { getCached, setCached } from "../src/llm-cache.js";
+import { existsSync, unlinkSync, rmdirSync } from "fs";
+import { join } from "path";
+import { homedir } from "os";
+
+const TEST_CACHE_DIR = join(homedir(), ".cache", "pi-project-map");
+const TEST_CACHE_FILE = join(TEST_CACHE_DIR, "llm-cache.json");
+
+describe("llm-cache", () => {
+	beforeEach(() => {
+		if (existsSync(TEST_CACHE_FILE)) {
+			unlinkSync(TEST_CACHE_FILE);
+		}
+	});
+
+	afterEach(() => {
+		if (existsSync(TEST_CACHE_FILE)) {
+			unlinkSync(TEST_CACHE_FILE);
+		}
+	});
+
+	it("returns undefined for missing entries", () => {
+		const result = getCached("nonexistent-hash");
+		expect(result).toBeUndefined();
+	});
+
+	it("stores and retrieves cached results", () => {
+		setCached("abc123", "PURPOSE: test\nDEPS: none\nCONCEPTS: none");
+		const result = getCached("abc123");
+		expect(result).toBe("PURPOSE: test\nDEPS: none\nCONCEPTS: none");
+	});
+
+	it("overwrites existing entries", () => {
+		setCached("abc123", "old");
+		setCached("abc123", "new");
+		const result = getCached("abc123");
+		expect(result).toBe("new");
+	});
+});
diff --git a/tests/llm-extract.test.ts b/tests/llm-extract.test.ts
index 2b6b561..21d5de3 100644
--- a/tests/llm-extract.test.ts
+++ b/tests/llm-extract.test.ts
@@ -1,8 +1,9 @@
 import { describe, it, expect } from "vitest";
-import { extractFileLLM } from "../src/llm-extract.js";
+import { extractFileLLM, extractFileHeuristic } from "../src/llm-extract.js";
 import { writeFileSync, mkdtempSync } from "fs";
 import { join } from "path";
 import { tmpdir } from "os";
+import type { LLMClient } from "../src/llm-client.js";
 
 describe("llm-extract heuristics", () => {
 	it("extracts TypeScript exports", async () => {
@@ -61,3 +62,61 @@ const x = require("legacy");
 		expect(result.exports).toEqual([]);
 	});
 });
+
+describe("llm-extract with mock client", () => {
+	it("uses LLM client when provided", async () => {
+		const dir = mkdtempSync(join(tmpdir(), "pi-map-"));
+		const file = join(dir, "test.ts");
+		writeFileSync(file, `export const foo = 1;`);
+
+		const mockClient: LLMClient = {
+			async complete() {
+				return "PURPOSE: Test file\nDEPS: none\nCONCEPTS: testing";
+			},
+		};
+
+		const result = await extractFileLLM(file, mockClient);
+		expect(result.purpose).toBe("Test file");
+		expect(result.deps).toEqual([]);
+		expect(result.concepts).toContain("testing");
+	});
+
+	it("skips large files", async () => {
+		const dir = mkdtempSync(join(tmpdir(), "pi-map-"));
+		const file = join(dir, "big.ts");
+		writeFileSync(file, "x".repeat(60 * 1024));
+
+		const mockClient: LLMClient = {
+			async complete() {
+				return "PURPOSE: Should not call\nDEPS: none\nCONCEPTS: none";
+			},
+		};
+
+		const result = await extractFileLLM(file, mockClient);
+		expect(result.purpose).toBe("Large/generated file");
+	});
+
+	it("falls back to heuristics without client", async () => {
+		const dir = mkdtempSync(join(tmpdir(), "pi-map-"));
+		const file = join(dir, "utils.ts");
+		writeFileSync(file, `export function helper() {}`);
+
+		const result = await extractFileLLM(file);
+		expect(result.purpose).toBe("Utility functions");
+		expect(result.exports).toContain("helper");
+	});
+});
+
+describe("extractFileHeuristic", () => {
+	it("returns structured data", async () => {
+		const dir = mkdtempSync(join(tmpdir(), "pi-map-"));
+		const file = join(dir, "test.ts");
+		writeFileSync(file, `export const x = 1;`);
+
+		const result = await extractFileHeuristic(file);
+		expect(result.purpose).toBeDefined();
+		expect(Array.isArray(result.exports)).toBe(true);
+		expect(Array.isArray(result.deps)).toBe(true);
+		expect(Array.isArray(result.concepts)).toBe(true);
+	});
+});
diff --git a/tests/llm-integration.test.ts b/tests/llm-integration.test.ts
new file mode 100644
index 0000000..73a334c
--- /dev/null
+++ b/tests/llm-integration.test.ts
@@ -0,0 +1,178 @@
+import { describe, it, expect } from "vitest";
+import { writeFileSync, mkdtempSync, readFileSync } from "fs";
+import { join } from "path";
+import { tmpdir } from "os";
+import { createLLMClient } from "../src/llm-client.js";
+import { extractFileLLM, extractPackageLLM } from "../src/llm-extract.js";
+import { processFiles } from "../src/llm-batch.js";
+
+// Load .env file manually (no dotenv dependency needed)
+function loadEnv(): Record<string, string> {
+	const env: Record<string, string> = {};
+	try {
+		const content = readFileSync(".env", "utf8");
+		for (const line of content.split("\n")) {
+			const match = line.match(/^([A-Za-z_][A-Za-z0-9_]*)=(.*)$/);
+			if (match) env[match[1]] = match[2];
+		}
+	} catch {
+		// No .env file
+	}
+	return env;
+}
+
+const env = loadEnv();
+const kimiKey = env.KIMI_API_KEY || process.env.KIMI_API_KEY;
+const kimiModel =
+	env.KIMI_MODEL ||
+	env.LLM_MODEL ||
+	process.env.KIMI_MODEL ||
+	process.env.LLM_MODEL ||
+	"kimi-k2-6";
+const hasKimiKey = !!kimiKey;
+
+// Set env vars so the clients can pick them up
+if (env.KIMI_API_KEY) process.env.KIMI_API_KEY = env.KIMI_API_KEY;
+if (env.LLM_MODEL) process.env.LLM_MODEL = env.LLM_MODEL;
+
+describe.skipIf(!hasKimiKey)("LLM integration with Kimi", () => {
+	it("creates kimi client and calls complete", async () => {
+		const client = createLLMClient("kimi", { model: kimiModel });
+		const response = await client.complete(
+			"PURPOSE: test\nAnalyze this: export const x = 1;",
+		);
+		expect(typeof response).toBe("string");
+		expect(response.length).toBeGreaterThan(0);
+		console.log("  complete() response:", response.slice(0, 120));
+	}, 30000);
+
+	it("extracts file purpose with real LLM", async () => {
+		const dir = mkdtempSync(join(tmpdir(), "pi-map-llm-"));
+		const file = join(dir, "config.ts");
+		writeFileSync(
+			file,
+			`export const API_URL = "https://api.example.com";\nexport const TIMEOUT = 5000;`,
+		);
+
+		const client = createLLMClient("kimi", { model: kimiModel });
+		const result = await extractFileLLM(file, client);
+
+		expect(result.purpose).toBeTruthy();
+		expect(result.purpose.length).toBeGreaterThan(5);
+		expect(Array.isArray(result.deps)).toBe(true);
+		expect(Array.isArray(result.concepts)).toBe(true);
+		console.log("  File purpose:", result.purpose);
+		console.log("  Concepts:", result.concepts.join(", ") || "none");
+	}, 30000);
+
+	it("extracts package role with real LLM", async () => {
+		const client = createLLMClient("kimi", { model: kimiModel });
+		const result = await extractPackageLLM(
+			"src/utils",
+			[
+				{ name: "http.ts", purpose: "HTTP client wrapper" },
+				{ name: "cache.ts", purpose: "In-memory cache" },
+				{ name: "retry.ts", purpose: "Retry logic with backoff" },
+			],
+			client,
+		);
+
+		expect(result.role).toBeTruthy();
+		expect(result.role.length).toBeGreaterThan(5);
+		expect(result.arch).toBeTruthy();
+		console.log("  Package role:", result.role);
+		console.log("  Package arch:", result.arch);
+	}, 30000);
+
+	it("caches LLM results on disk", async () => {
+		const dir = mkdtempSync(join(tmpdir(), "pi-map-llm-"));
+		const file = join(dir, "test.ts");
+		writeFileSync(file, `export const version = "1.0.0";`);
+
+		const client = createLLMClient("kimi", { model: kimiModel });
+		const result1 = await extractFileLLM(file, client);
+		expect(result1.purpose).toBeTruthy();
+
+		// Second call should hit cache — much faster
+		const start = Date.now();
+		const result2 = await extractFileLLM(file, client);
+		const elapsed = Date.now() - start;
+
+		expect(result2.purpose).toBe(result1.purpose);
+		expect(elapsed).toBeLessThan(500); // Cache hit should be fast
+		console.log("  Cache hit time:", elapsed, "ms");
+	}, 30000);
+
+	it("processes multiple files in parallel", async () => {
+		const dir = mkdtempSync(join(tmpdir(), "pi-map-llm-"));
+		const files: string[] = [];
+		for (let i = 0; i < 3; i++) {
+			const f = join(dir, `file${i}.ts`);
+			writeFileSync(
+				f,
+				`export const val${i} = ${i};\n// Some logic here\nexport function helper${i}() { return val${i}; }`,
+			);
+			files.push(f);
+		}
+
+		const client = createLLMClient("kimi", { model: kimiModel });
+		const start = Date.now();
+		const results = await processFiles(
+			files,
+			async (f) => extractFileLLM(f, client),
+			{ concurrency: 3, maxRetries: 1, retryDelaysMs: [2000] },
+		);
+		const elapsed = Date.now() - start;
+
+		expect(results.length).toBe(3);
+		for (const r of results) {
+			expect(r.purpose).toBeTruthy();
+			expect(r.purpose.length).toBeGreaterThan(5);
+		}
+		console.log("  Parallel processing:", elapsed, "ms for 3 files");
+	}, 60000);
+
+	it("skips large files without calling LLM", async () => {
+		const dir = mkdtempSync(join(tmpdir(), "pi-map-llm-"));
+		const file = join(dir, "big.ts");
+		writeFileSync(file, "x".repeat(60 * 1024));
+
+		let calls = 0;
+		const trackingClient = createLLMClient("kimi", { model: kimiModel });
+		const originalComplete = trackingClient.complete.bind(trackingClient);
+		trackingClient.complete = async (...args) => {
+			calls++;
+			return originalComplete(...args);
+		};
+
+		const result = await extractFileLLM(file, trackingClient);
+		expect(result.purpose).toBe("Large/generated file");
+		expect(calls).toBe(0); // Should never call LLM for large files
+	});
+});
+
+describe("LLM integration without env vars", () => {
+	it("throws clear error when API key is missing", () => {
+		const saved = process.env.KIMI_API_KEY;
+		delete process.env.KIMI_API_KEY;
+		try {
+			expect(() => createLLMClient("kimi", { apiKey: undefined })).toThrow(
+				"No Kimi API key",
+			);
+		} finally {
+			if (saved) process.env.KIMI_API_KEY = saved;
+		}
+	});
+
+	it("throws clear error for OpenAI without key", () => {
+		const saved = process.env.OPENAI_API_KEY;
+		delete process.env.OPENAI_API_KEY;
+		try {
+			expect(() => createLLMClient("openai", { apiKey: undefined })).toThrow(
+				"No OpenAI API key",
+			);
+		} finally {
+			if (saved) process.env.OPENAI_API_KEY = saved;
+		}
+	});
+});
diff --git a/tests/pi-extension.test.ts b/tests/pi-extension.test.ts
new file mode 100644
index 0000000..4bb0c18
--- /dev/null
+++ b/tests/pi-extension.test.ts
@@ -0,0 +1,245 @@
+import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
+
+// Mock child_process before importing the extension
+vi.mock("child_process", () => ({
+	execSync: vi.fn(),
+}));
+
+vi.mock("fs", async () => {
+	const actual = await vi.importActual<typeof import("fs")>("fs");
+	return {
+		...actual,
+		readFileSync: vi.fn(),
+	};
+});
+
+vi.mock("@mariozechner/pi-coding-agent", () => ({
+	ExtensionAPI: class {},
+}));
+
+vi.mock("typebox", () => ({
+	Type: {
+		Object: (props: unknown) => props,
+		Optional: (prop: unknown) => prop,
+		String: (opts: unknown) => ({ type: "string", ...opts }),
+	},
+}));
+
+import extension from "../pi-extension.js";
+import { execSync } from "child_process";
+import { readFileSync } from "fs";
+
+describe("pi-extension", () => {
+	let registeredTools: Record<string, any> = {};
+	let registeredEvents: Record<string, any> = {};
+	let mockCtx: any;
+	let mockNotify: ReturnType<typeof vi.fn>;
+
+	beforeEach(() => {
+		registeredTools = {};
+		registeredEvents = {};
+		mockNotify = vi.fn();
+		mockCtx = {
+			cwd: "/home/project",
+			ui: { notify: mockNotify },
+		};
+
+		const mockPi = {
+			registerTool: vi.fn((tool: any) => {
+				registeredTools[tool.name] = tool;
+			}),
+			on: vi.fn((event: string, handler: any) => {
+				registeredEvents[event] = handler;
+			}),
+		};
+
+		extension(mockPi);
+		vi.clearAllMocks();
+	});
+
+	afterEach(() => {
+		vi.restoreAllMocks();
+	});
+
+	describe("tool registration", () => {
+		it("registers 4 tools", () => {
+			expect(Object.keys(registeredTools)).toHaveLength(4);
+			expect(registeredTools).toHaveProperty("project_map_init");
+			expect(registeredTools).toHaveProperty("project_map_patch");
+			expect(registeredTools).toHaveProperty("project_map_validate");
+			expect(registeredTools).toHaveProperty("project_map_reinit");
+		});
+
+		it("registers session_start and before_agent_start events", () => {
+			expect(registeredEvents).toHaveProperty("session_start");
+			expect(registeredEvents).toHaveProperty("before_agent_start");
+		});
+	});
+
+	describe("project_map_init tool", () => {
+		it("calls npx project-map init with default cwd", async () => {
+			vi.mocked(execSync).mockReturnValue("Generated 5 .pi-map.md files\n");
+			const tool = registeredTools.project_map_init;
+			const result = await tool.execute("tool-1", {}, null, null, mockCtx);
+			expect(execSync).toHaveBeenCalledWith(
+				expect.stringContaining("npx project-map init"),
+				expect.objectContaining({ cwd: "/home/project" }),
+			);
+			expect(result.details.success).toBe(true);
+		});
+
+		it("calls npx project-map init with custom path", async () => {
+			vi.mocked(execSync).mockReturnValue("Generated 3 .pi-map.md files\n");
+			const tool = registeredTools.project_map_init;
+			const result = await tool.execute(
+				"tool-1",
+				{ path: "./src" },
+				null,
+				null,
+				mockCtx,
+			);
+			expect(execSync).toHaveBeenCalledWith(
+				expect.stringContaining("npx project-map init ./src"),
+				expect.anything(),
+			);
+			expect(result.details.success).toBe(true);
+		});
+
+		it("reports failure on error", async () => {
+			vi.mocked(execSync).mockImplementation(() => {
+				const err = new Error("Command failed") as any;
+				err.stdout = "";
+				err.stderr = "No such file";
+				throw err;
+			});
+			const tool = registeredTools.project_map_init;
+			const result = await tool.execute("tool-1", {}, null, null, mockCtx);
+			expect(result.details.success).toBe(false);
+		});
+	});
+
+	describe("project_map_patch tool", () => {
+		it("calls npx project-map patch with file path", async () => {
+			vi.mocked(execSync).mockReturnValue("Patched src/foo.ts\n");
+			const tool = registeredTools.project_map_patch;
+			const result = await tool.execute(
+				"tool-1",
+				{ file_path: "src/components/Button.tsx" },
+				null,
+				null,
+				mockCtx,
+			);
+			expect(execSync).toHaveBeenCalledWith(
+				expect.stringContaining(
+					"npx project-map patch src/components/Button.tsx",
+				),
+				expect.anything(),
+			);
+			expect(result.details.success).toBe(true);
+		});
+	});
+
+	describe("project_map_validate tool", () => {
+		it("calls npx project-map validate and reports clean", async () => {
+			vi.mocked(execSync).mockReturnValue("All .pi-map.md files are clean.\n");
+			const tool = registeredTools.project_map_validate;
+			const result = await tool.execute("tool-1", {}, null, null, mockCtx);
+			expect(execSync).toHaveBeenCalledWith(
+				expect.stringContaining("npx project-map validate"),
+				expect.anything(),
+			);
+			expect(result.details.clean).toBe(true);
+		});
+
+		it("reports not clean when output lacks 'clean'", async () => {
+			vi.mocked(execSync).mockReturnValue("Found 2 discrepancies\n");
+			const tool = registeredTools.project_map_validate;
+			const result = await tool.execute("tool-1", {}, null, null, mockCtx);
+			expect(result.details.clean).toBe(false);
+		});
+	});
+
+	describe("project_map_reinit tool", () => {
+		it("calls npx project-map reinit with path", async () => {
+			vi.mocked(execSync).mockReturnValue("Regenerated 7 files\n");
+			const tool = registeredTools.project_map_reinit;
+			const result = await tool.execute(
+				"tool-1",
+				{ path: "./src" },
+				null,
+				null,
+				mockCtx,
+			);
+			expect(execSync).toHaveBeenCalledWith(
+				expect.stringContaining("npx project-map reinit ./src"),
+				expect.anything(),
+			);
+			expect(result.details.success).toBe(true);
+		});
+	});
+
+	describe("session_start event", () => {
+		it("notifies when dirty .pi-map.md files exist", async () => {
+			vi.mocked(execSync).mockReturnValueOnce(
+				"./src/.pi-map.md\n./tests/.pi-map.md\n",
+			); // findPiMapFiles
+			vi.mocked(readFileSync)
+				.mockReturnValueOnce("## dirty\n2024-01-01: patched\n") // dirty
+				.mockReturnValueOnce("## dirty\n-\n"); // clean
+
+			const handler = registeredEvents.session_start;
+			await handler(null, mockCtx);
+
+			expect(mockNotify).toHaveBeenCalledWith(
+				expect.stringContaining("1 dirty packages detected"),
+				"warning",
+			);
+		});
+
+		it("does not notify when all clean", async () => {
+			vi.mocked(execSync).mockReturnValueOnce("./src/.pi-map.md\n");
+			vi.mocked(readFileSync).mockReturnValueOnce("## dirty\n-\n");
+
+			const handler = registeredEvents.session_start;
+			await handler(null, mockCtx);
+
+			expect(mockNotify).not.toHaveBeenCalled();
+		});
+
+		it("does nothing when no maps exist", async () => {
+			vi.mocked(execSync).mockImplementation(() => {
+				throw new Error("no maps");
+			});
+
+			const handler = registeredEvents.session_start;
+			await handler(null, mockCtx);
+
+			expect(mockNotify).not.toHaveBeenCalled();
+		});
+	});
+
+	describe("before_agent_start event", () => {
+		it("injects hint when .pi-map.md files exist", async () => {
+			vi.mocked(execSync).mockReturnValueOnce("./src/.pi-map.md\n");
+			vi.mocked(readFileSync).mockReturnValueOnce("content");
+
+			const handler = registeredEvents.before_agent_start;
+			const result = await handler(null, mockCtx);
+
+			expect(result).toHaveProperty("message");
+			expect(result.message.content).toContain("project_map_patch");
+			expect(result.message.display).toBe(false);
+		});
+
+		it("returns empty object when no maps exist", async () => {
+			vi.mocked(execSync).mockImplementation(() => {
+				throw new Error("no maps");
+			});
+
+			const handler = registeredEvents.before_agent_start;
+			const result = await handler(null, mockCtx);
+
+			expect(result).toEqual({});
+		});
+	});
+});