feat(agent): expand tool registry — file, git, shell, web fetch (#126) (#138)

Co-authored-by: Jason Woltje <jason@diversecanvas.com>
Co-committed-by: Jason Woltje <jason@diversecanvas.com>

apps/gateway/src/agent/tools/git-tools.ts

@@ -0,0 +1,135 @@
+import { Type } from '@sinclair/typebox';
+import type { ToolDefinition } from '@mariozechner/pi-coding-agent';
+import { exec } from 'node:child_process';
+import { promisify } from 'node:util';
+
+const execAsync = promisify(exec);
+
+const GIT_TIMEOUT_MS = 15_000;
+const MAX_OUTPUT_BYTES = 100 * 1024; // 100 KB
+
+async function runGit(
+  args: string[],
+  cwd?: string,
+): Promise<{ stdout: string; stderr: string; error?: string }> {
+  // Only allow specific safe read-only git subcommands
+  const allowedSubcommands = ['status', 'log', 'diff', 'show', 'branch', 'tag', 'ls-files'];
+  const subcommand = args[0];
+  if (!subcommand || !allowedSubcommands.includes(subcommand)) {
+    return {
+      stdout: '',
+      stderr: '',
+      error: `Blocked: git subcommand "${subcommand}" is not allowed. Permitted: ${allowedSubcommands.join(', ')}`,
+    };
+  }
+
+  const cmd = `git ${args.map((a) => JSON.stringify(a)).join(' ')}`;
+  try {
+    const { stdout, stderr } = await execAsync(cmd, {
+      cwd,
+      timeout: GIT_TIMEOUT_MS,
+      maxBuffer: MAX_OUTPUT_BYTES,
+    });
+    return { stdout, stderr };
+  } catch (err: unknown) {
+    const e = err as { stdout?: string; stderr?: string; message?: string };
+    return {
+      stdout: e.stdout ?? '',
+      stderr: e.stderr ?? '',
+      error: e.message ?? String(err),
+    };
+  }
+}
+
+export function createGitTools(defaultCwd?: string): ToolDefinition[] {
+  const gitStatus: ToolDefinition = {
+    name: 'git_status',
+    label: 'Git Status',
+    description: 'Show the working tree status (staged, unstaged, untracked files).',
+    parameters: Type.Object({
+      cwd: Type.Optional(Type.String({ description: 'Repository working directory.' })),
+    }),
+    async execute(_toolCallId, params) {
+      const { cwd } = params as { cwd?: string };
+      const result = await runGit(['status', '--short', '--branch'], cwd ?? defaultCwd);
+      const text = result.error
+        ? `Error: ${result.error}\n${result.stderr}`
+        : result.stdout || '(no output)';
+      return {
+        content: [{ type: 'text' as const, text: text }],
+        details: undefined,
+      };
+    },
+  };
+
+  const gitLog: ToolDefinition = {
+    name: 'git_log',
+    label: 'Git Log',
+    description: 'Show recent commit history.',
+    parameters: Type.Object({
+      limit: Type.Optional(Type.Number({ description: 'Number of commits to show (default 20)' })),
+      oneline: Type.Optional(
+        Type.Boolean({ description: 'Compact one-line format (default true)' }),
+      ),
+      cwd: Type.Optional(Type.String({ description: 'Repository working directory.' })),
+    }),
+    async execute(_toolCallId, params) {
+      const { limit, oneline, cwd } = params as {
+        limit?: number;
+        oneline?: boolean;
+        cwd?: string;
+      };
+      const args = ['log', `--max-count=${limit ?? 20}`];
+      if (oneline !== false) args.push('--oneline');
+      const result = await runGit(args, cwd ?? defaultCwd);
+      const text = result.error
+        ? `Error: ${result.error}\n${result.stderr}`
+        : result.stdout || '(no commits)';
+      return {
+        content: [{ type: 'text' as const, text: text }],
+        details: undefined,
+      };
+    },
+  };
+
+  const gitDiff: ToolDefinition = {
+    name: 'git_diff',
+    label: 'Git Diff',
+    description: 'Show changes between commits, working tree, or staged changes.',
+    parameters: Type.Object({
+      staged: Type.Optional(
+        Type.Boolean({ description: 'Show staged (cached) changes instead of unstaged' }),
+      ),
+      ref: Type.Optional(
+        Type.String({ description: 'Compare against this ref (commit SHA, branch, or tag)' }),
+      ),
+      path: Type.Optional(
+        Type.String({ description: 'Limit diff to a specific file or directory' }),
+      ),
+      cwd: Type.Optional(Type.String({ description: 'Repository working directory.' })),
+    }),
+    async execute(_toolCallId, params) {
+      const { staged, ref, path, cwd } = params as {
+        staged?: boolean;
+        ref?: string;
+        path?: string;
+        cwd?: string;
+      };
+      const args = ['diff'];
+      if (staged) args.push('--cached');
+      if (ref) args.push(ref);
+      args.push('--');
+      if (path) args.push(path);
+      const result = await runGit(args, cwd ?? defaultCwd);
+      const text = result.error
+        ? `Error: ${result.error}\n${result.stderr}`
+        : result.stdout || '(no diff)';
+      return {
+        content: [{ type: 'text' as const, text: text }],
+        details: undefined,
+      };
+    },
+  };
+
+  return [gitStatus, gitLog, gitDiff];
+}