Write Zot Extension

package main

import (
    "encoding/json"
    "github.com/patriceckhart/zot/packages/agent/ext"
)

func main() {
    e := ext.New("weather", "1.0.0")

    e.Command("weather", "current weather for a city",
        func(args string) ext.Response {
            return ext.Prompt("Tell me the weather for " + args)
        })

    e.Tool("weather", "Get current weather for a city.",
        json.RawMessage(`{"type":"object","properties":{"city":{"type":"string"}},"required":["city"]}`),
        func(args json.RawMessage) ext.ToolResult {
            var in struct{ City string `json:"city"` }
            if err := json.Unmarshal(args, &in); err != nil {
                return ext.TextErrorResult("invalid args")
            }
            return ext.TextResult(in.City + ": sunny, 21°C (fake)")
        })

    // Optional: register project-specific commands after hello_ack.
    e.OnHello(func(host ext.HostInfo) {
        if host.CWD != "" {
            e.Command("cwd", "show the current project directory", func(args string) ext.Response {
                return ext.Display(host.CWD)
            })
        }
    })

    if err := e.Run(); err != nil {
        e.Logf("fatal: %v", err)
    }
}

{"name":"weather","version":"1.0.0","exec":"./weather","language":"go","enabled":true}

{"name":"scratchpad","version":"1.0.0","exec":"tsx","args":["index.ts"],"language":"typescript","enabled":true}

// index.ts (excerpt; see examples/extensions/scratchpad/index.ts for the full version)
import { createInterface } from "node:readline";
import { stderr, stdin, stdout } from "node:process";

function send(o: object) { stdout.write(JSON.stringify(o) + "\n"); }
function log(s: string) { stderr.write(`[scratchpad] ${s}\n`); }

send({ type: "hello", name: "scratchpad", version: "1.0.0",
       capabilities: ["commands", "tools"] });

const rl = createInterface({ input: stdin, crlfDelay: Infinity });
rl.on("line", (line) => {
  const f = JSON.parse(line);
  if (f.type === "hello_ack") {
    // f.cwd is the user's project directory.
    send({ type: "register_command", name: "note", description: "append a note" });
    send({ type: "register_tool", name: "read_notes",
           description: "Read the user's scratchpad notes.",
           schema: { type: "object", properties: {} } });
    send({ type: "ready" });
  } else if (f.type === "command_invoked" && f.name === "note") {
    send({ type: "command_response", id: f.id, action: "display",
           display: `noted: ${f.args}` });
  } else if (f.type === "tool_call" && f.name === "read_notes") {
    send({ type: "tool_result", id: f.id,
           content: [{ type: "text", text: "(notes go here)" }] });
  } else if (f.type === "shutdown") {
    send({ type: "shutdown_ack" });
    rl.close();
  }
});

{"name":"hello-py","version":"1.0.0","exec":"./hello.py","language":"python","enabled":true}

#!/usr/bin/env python3
import json, sys

def emit(o): sys.stdout.write(json.dumps(o) + "\n"); sys.stdout.flush()

emit({"type": "hello", "name": "hello-py", "version": "1.0.0", "capabilities": ["commands"]})

for line in sys.stdin:
    msg = json.loads(line)
    if msg["type"] == "hello_ack":
        # msg["cwd"] is the user's project directory.
        emit({"type": "register_command", "name": "hellopy", "description": "say hi (python)"})
        emit({"type": "ready"})
    elif msg["type"] == "command_invoked":
        emit({"type": "command_response", "id": msg["id"],
              "action": "prompt", "prompt": "Say hi briefly."})
    elif msg["type"] == "shutdown":
        emit({"type": "shutdown_ack"})
        break

zot ext install ./weather       # copy into $ZOT_HOME/extensions/
zot --ext ./weather             # run from disk for one zot session (no install)
zot --ext .                     # cwd is the extension dir
zot ext list                    # show installed extensions
zot ext logs weather            # cat the extension's stderr
zot ext logs weather -f         # tail it
zot ext disable weather         # keep installed but skip on launch
zot ext enable weather
zot ext remove weather

{
  printf '%s\n' '{"type":"hello_ack","protocol_version":1,"zot_version":"x","provider":"a","model":"o","cwd":"/tmp"}'
  sleep 0.2
  printf '%s\n' '{"type":"command_invoked","id":"1","name":"weather","args":"Berlin"}'
  sleep 0.5
  printf '%s\n' '{"type":"shutdown"}'
} | ./weather