// Minimal stdio-based tool server that exposes a `say_hello` tool.
// Reads newline-delimited JSON requests from stdin:
// { "id": <optional>, "tool": "say_hello", "args": { "name": "Alice" } }
// Responds with newline-delimited JSON:
// { "id": <same id|null>, "result": "Hello, Alice! 👋" }
const tools = {
say_hello: ({ name } = {}) => {
const n = typeof name === 'string' ? name : '';
return `Hello, ${n}! 👋`;
},
// Call an external HTTP API. Provide either a full `path` (absolute URL)
// or a path relative to `process.env.EXTERNAL_API_BASE`.
// args: { path, method, headers, body }
call_api: async ({ path, method = 'GET', headers = {}, body = null } = {}) => {
try {
const base = process.env.EXTERNAL_API_BASE;
const url = base ? new URL(path, base).toString() : path;
const fetchOpts = { method, headers };
if (body != null) {
// allow object bodies
fetchOpts.body = typeof body === 'string' ? body : JSON.stringify(body);
if (!fetchOpts.headers['content-type'] && !fetchOpts.headers['Content-Type']) {
fetchOpts.headers['Content-Type'] = 'application/json';
}
}
const res = await fetch(url, fetchOpts);
const text = await res.text();
let parsed;
try { parsed = JSON.parse(text); } catch { parsed = text; }
// return status, headers (simple object) and body
const hdrs = {};
for (const [k, v] of res.headers.entries()) hdrs[k] = v;
return { status: res.status, headers: hdrs, body: parsed };
} catch (err) {
return { error: (err && err.message) ? err.message : String(err) };
}
}
};
process.stdin.setEncoding('utf8');
let buffer = '';
process.stdin.on('data', (chunk) => {
buffer += chunk;
const lines = buffer.split('\n');
buffer = lines.pop();
for (const line of lines) {
if (!line.trim()) continue;
try {
const req = JSON.parse(line);
const id = Object.prototype.hasOwnProperty.call(req, 'id') ? req.id : null;
if (req.tool && typeof req.tool === 'string' && tools[req.tool]) {
// Support async tools by resolving the return value (may be a Promise).
Promise.resolve(tools[req.tool](req.args || {}))
.then((result) => {
const res = { id, result };
process.stdout.write(JSON.stringify(res) + '\n');
})
.catch((err) => {
const res = { id, error: (err && err.message) ? err.message : String(err) };
process.stdout.write(JSON.stringify(res) + '\n');
});
} else {
const res = { id, error: `Unknown tool: ${String(req.tool)}` };
process.stdout.write(JSON.stringify(res) + '\n');
}
} catch (err) {
const res = { id: null, error: (err && err.message) ? err.message : String(err) };
process.stdout.write(JSON.stringify(res) + '\n');
}
}
});
process.stdin.on('end', () => {
process.exit(0);
});
