Implement bash-mcp package to expose sandboxed bash via mcp

packages/bash-mcp/package.json

@@ -0,0 +1,32 @@
+{
+  "name": "@capsule-run/bash-mcp",
+  "version": "0.1.0",
+  "description": "MCP server exposing sandboxed bash made for agents",
+  "type": "module",
+  "main": "./src/index.ts",
+  "types": "./src/index.ts",
+  "exports": {
+    ".": "./src/index.ts"
+  },
+  "bin": {
+    "bash-mcp": "./src/index.ts"
+  },
+  "scripts": {
+    "start": "node --import tsx/esm src/index.ts",
+    "dev": "tsx watch src/index.ts",
+    "build": "tsup src/index.ts --format esm --dts"
+  },
+  "license": "Apache-2.0",
+  "packageManager": "pnpm@10.21.0",
+  "devDependencies": {
+    "tsup": "^8.0.0",
+    "tsx": "^4.0.0"
+  },
+  "dependencies": {
+    "@capsule-run/bash": "workspace:*",
+    "@capsule-run/bash-types": "workspace:*",
+    "@capsule-run/bash-wasm": "workspace:*",
+    "@modelcontextprotocol/sdk": "^1.10.2",
+    "zod": "^3.25.0"
+  }
+}

packages/bash-mcp/src/index.ts

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+import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
+import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";
+import { z } from "zod";
+import { Bash } from "@capsule-run/bash";
+import { WasmRuntime } from "@capsule-run/bash-wasm";
+
+
+const sessions = new Map<string, Bash>();
+
+function getSession(sessionId: string): Bash {
+    if (!sessions.has(sessionId)) {
+        sessions.set(sessionId, new Bash({ runtime: new WasmRuntime(), hostWorkspace: `.capsule/sessions/${sessionId}` }));
+    }
+    return sessions.get(sessionId)!;
+}
+
+
+const server = new McpServer({
+    name: "@capsule-run/bash-mcp",
+    version: "0.1.0",
+});
+
+server.registerTool(
+    "run",
+    {
+        description: "Run a bash command inside the sandboxed Capsule environment. Returns stdout, stderr, exit code, filesystem diff, and current shell state (cwd + env).",
+        inputSchema: {
+            command: z.string().describe("The bash command to execute."),
+            session_id: z
+                .string()
+                .optional()
+                .default("default")
+                .describe(
+                    "Identifier for the shell session. Commands within the same session share cwd, env, and filesystem state. Defaults to 'default'."
+                ),
+        },
+    },
+    async ({ command, session_id }) => {
+        const bash = getSession(session_id ?? "default");
+        const result = await bash.run(command);
+
+        const text = JSON.stringify(
+            {
+                stdout: result.stdout,
+                stderr: result.stderr,
+                exitCode: result.exitCode,
+                diff: result.diff ?? null,
+                state: result.state ?? null,
+            },
+            null,
+            2
+        );
+
+        return {
+            content: [{ type: "text", text }],
+            isError: result.exitCode !== 0,
+        };
+    }
+);
+
+server.registerTool(
+    "reset",
+    {
+        description: "Reset the sandboxed filesystem and shell state (cwd, env vars) for a session back to their initial values.",
+        inputSchema: {
+            session_id: z
+                .string()
+                .optional()
+                .default("default")
+                .describe("The session to reset. Defaults to 'default'."),
+        },
+    },
+    async ({ session_id }) => {
+        const bash = getSession(session_id ?? "default");
+        bash.reset();
+
+        return {
+            content: [
+                {
+                    type: "text",
+                    text: JSON.stringify({ ok: true, session_id: session_id ?? "default" }),
+                },
+            ],
+        };
+    }
+);
+
+server.registerTool(
+    "sessions",
+    {
+        description: "List all active shell sessions.",
+    },
+    async () => {
+        return {
+            content: [
+                {
+                    type: "text",
+                    text: JSON.stringify({ sessions: Array.from(sessions.keys()) }),
+                },
+            ],
+        };
+    }
+);
+
+const transport = new StdioServerTransport();
+await server.connect(transport);

packages/bash-mcp/tsconfig.json

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+{
+  "extends": "../../tsconfig.json",
+  "compilerOptions": {
+    "outDir": "./dist",
+    "rootDir": "./src"
+  },
+  "include": ["src/**/*"]
+}