Add warm agent pool example

[kaisoz]

No description provided.

[gemini-code-assist]

Code Review

This pull request introduces a 'Warm Agent Pool' architecture under development/examples/code-reviewer-pool/, replacing the single code-reviewer server with a manager-worker model that leases workers using signed HMAC tokens. It also expands the local Kubernetes development mesh from three to five nodes and updates the documentation. The reviewer feedback highlights several robustness improvements: validating tool call responses before parsing them, adding error listeners to child.stdin when spawning subprocesses to prevent unhandled crashes, and wrapping asynchronous server initialization in a try-catch block to handle startup failures gracefully.

[gemini-code-assist]

Accessing res.content[0].text directly without checking if res.content is defined and non-empty can lead to a TypeError if the tool call returns no content or fails. It is safer to validate the presence of res.content before parsing.

    const res = await node.callTool({ name: "find_remote_tools", arguments: {} });
    if (!res.content || res.content.length === 0) {
      throw new Error("No content returned from find_remote_tools");
    }
    const rows = JSON.parse(res.content[0].text); // [{peer_id, tool_name, ...}]

[gemini-code-assist]

When spawning a child process and writing to its stdin, an unhandled EPIPE or ERR_STREAM_WRITE_AFTER_END error can occur if the process fails to start or exits prematurely. Adding an error listener to child.stdin prevents potential unhandled crashes.

    child.on("error", reject);
    child.stdin.on("error", reject);

[gemini-code-assist]

The asynchronous initialization logic inside app.listen is not wrapped in a try-catch block. If node.connect or discover fails during startup, it will result in an unhandled promise rejection, which can leave the server in a semi-broken state or crash the process. Wrapping this in a try-catch block ensures the error is handled gracefully.

Suggested change

	app.listen(PORT, "0.0.0.0", async () => {
	console.log(`pool-manager MCP server on :${PORT}/mcp (pooling '${POOL_SERVICE}')`);
	const transport = new StreamableHTTPClientTransport(new URL(NODE_URL), {
	requestInit: { headers: { Authorization: `Bearer ${API_TOKEN}` } },
	});
	await node.connect(transport);
	await discover();
	setInterval(discover, DISCOVERY_MS);
	});
	app.listen(PORT, "0.0.0.0", async () => {
	console.log("pool-manager MCP server on :" + PORT + "/mcp (pooling '" + POOL_SERVICE + "')");
	try {
	const transport = new StreamableHTTPClientTransport(new URL(NODE_URL), {
	requestInit: { headers: { Authorization: `Bearer ${API_TOKEN}` } },
	});
	await node.connect(transport);
	await discover();
	setInterval(discover, DISCOVERY_MS);
	} catch (err) {
	console.error("Failed to initialize MCP client connection: " + (err?.message ?? err));
	}
	});