mirror of
https://github.com/NousResearch/hermes-agent.git
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9bf2dac6b9
Live Tier-3 testing (CLI agent -> a2a tools -> live peer gateway -> model) surfaced two bugs the kwarg-style unit tests masked: 1. registry.dispatch calls handlers as handler(args, **kwargs) — args is the whole dict positional. The handlers used keyword params (url=, agent=), so the dict bound to the first param and .strip() raised 'dict object has no attribute strip'. Rewrote all three handlers to take args: dict (matching the spotify/google_meet convention). Added a registry-dispatch regression test that exercises the real call path the direct-kwarg tests never hit. 2. The model repeatedly reached for agent_name= instead of agent= (6 retries before success). Accept agent_name/name and message/text/task aliases so a reasonable guess succeeds first try. Verified live: client agent discovers the peer's Agent Card, calls it, and gets the reply back (PONG round-trip confirmed on both client audit log and peer conversation log). 39 plugin tests pass.
315 lines
11 KiB
Python
315 lines
11 KiB
Python
"""
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A2A client tools — let the Hermes agent talk to *other* agents as a peer.
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Tools (registered in the ``a2a`` toolset):
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- a2a_discover(url) -> fetch + summarize a peer's Agent Card
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- a2a_call(agent, message) -> send a task to a peer, return its reply
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- a2a_list() -> list configured peers + persisted conversations
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Peers are resolved from config.yaml under ``a2a_agents``::
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a2a_agents:
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researcher:
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url: "http://localhost:9999"
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auth: { type: bearer, token: "sk-..." }
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timeout: 120
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Transport is stdlib urllib (no a2a-sdk dependency). The wire format is the A2A
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JSON-RPC ``message/send`` method, so any A2A-compliant peer works.
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"""
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from __future__ import annotations
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import json
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import logging
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import os
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import urllib.error
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import urllib.request
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from typing import Any, Optional
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from . import protocol, security
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logger = logging.getLogger(__name__)
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_DEFAULT_TIMEOUT = 120
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# --------------------------------------------------------------------------
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# Peer resolution
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# --------------------------------------------------------------------------
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def _load_config() -> dict:
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try:
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from hermes_cli.config import load_config
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return load_config() or {}
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except Exception:
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return {}
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def _resolve_peer(agent: str) -> Optional[dict]:
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"""Resolve a peer name to {url, auth, timeout}, or treat ``agent`` as a URL."""
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if agent.startswith("http://") or agent.startswith("https://"):
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return {"url": agent, "auth": {}, "timeout": _DEFAULT_TIMEOUT}
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cfg = _load_config()
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peers = cfg.get("a2a_agents") or {}
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entry = peers.get(agent)
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if not entry:
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return None
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return {
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"url": entry.get("url", ""),
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"auth": entry.get("auth", {}) or {},
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"timeout": int(entry.get("timeout", _DEFAULT_TIMEOUT)),
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}
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def _auth_header(auth: dict) -> dict:
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if auth and auth.get("type") == "bearer" and auth.get("token"):
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return {"Authorization": f"Bearer {auth['token']}"}
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return {}
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# --------------------------------------------------------------------------
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# HTTP
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# --------------------------------------------------------------------------
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def _http_get_json(url: str, headers: dict, timeout: int) -> dict:
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req = urllib.request.Request(url, headers=headers, method="GET")
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with urllib.request.urlopen(req, timeout=timeout) as resp: # noqa: S310 (configured peers)
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return json.loads(resp.read().decode("utf-8"))
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def _http_post_json(url: str, body: dict, headers: dict, timeout: int) -> dict:
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data = json.dumps(body).encode("utf-8")
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hdrs = {"Content-Type": "application/json", **headers}
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req = urllib.request.Request(url, data=data, headers=hdrs, method="POST")
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with urllib.request.urlopen(req, timeout=timeout) as resp: # noqa: S310 (configured peers)
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return json.loads(resp.read().decode("utf-8"))
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def _card_url(base_url: str) -> str:
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return base_url.rstrip("/") + "/.well-known/agent.json"
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def _rpc_url(base_url: str, card: Optional[dict]) -> str:
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# Prefer the URL the card advertises; fall back to the base.
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if card and isinstance(card.get("url"), str) and card["url"]:
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return card["url"]
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return base_url.rstrip("/")
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# --------------------------------------------------------------------------
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# Tool handlers
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# --------------------------------------------------------------------------
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def a2a_discover(args: dict, **_: Any) -> str:
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"""Fetch and summarize the Agent Card at ``url``."""
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url = str(args.get("url") or "").strip()
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if not url:
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return "Error: 'url' is required (e.g. http://localhost:9999)."
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try:
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card = _http_get_json(_card_url(url), {}, _DEFAULT_TIMEOUT)
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except urllib.error.HTTPError as e:
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return f"Error: discovery failed — HTTP {e.code} from {url}."
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except Exception as e:
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return f"Error: could not reach {url} — {e}."
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name = card.get("name", "?")
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desc = card.get("description", "")
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caps = card.get("capabilities", {}) or {}
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skills = card.get("skills", []) or []
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auth = "yes" if card.get("security") else "no"
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lines = [
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f"Agent: {name}",
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f"Description: {desc}",
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f"URL: {card.get('url', url)}",
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f"Streaming: {bool(caps.get('streaming'))} Auth required: {auth}",
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f"Skills ({len(skills)}):",
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]
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for s in skills[:20]:
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lines.append(f" - {s.get('name', s.get('id', '?'))}: {s.get('description', '')}")
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return "\n".join(lines)
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def a2a_call(args: dict, **_: Any) -> str:
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"""Send a task to a peer agent and return its reply.
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``agent`` is a configured peer name (from ``a2a_agents``) or a direct URL.
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``context_id`` continues a prior exchange (multi-turn) when provided.
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"""
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# Accept common aliases models reach for (observed live: 'agent_name').
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agent = str(args.get("agent") or args.get("agent_name") or args.get("name") or "").strip()
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message = str(args.get("message") or args.get("text") or args.get("task") or "").strip()
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context_id = str(args.get("context_id") or args.get("contextId") or "").strip()
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if not agent or not message:
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return "Error: both 'agent' and 'message' are required."
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peer = _resolve_peer(agent)
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if not peer or not peer.get("url"):
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return (
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f"Error: unknown agent '{agent}'. Configure it under 'a2a_agents' in "
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f"config.yaml or pass a full http(s):// URL."
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)
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base_url = peer["url"]
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headers = _auth_header(peer["auth"])
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timeout = peer["timeout"]
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# Best-effort card fetch (to learn the rpc URL); non-fatal on failure.
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card = None
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try:
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card = _http_get_json(_card_url(base_url), headers, min(timeout, 30))
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except Exception:
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pass
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ctx = context_id or protocol.new_context_id()
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safe_message = security.redact_outbound(message)
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rpc_body = {
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"jsonrpc": "2.0",
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"id": protocol.new_task_id(),
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"method": "message/send",
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"params": {"message": protocol.text_message("user", safe_message)},
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}
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if context_id:
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rpc_body["params"]["message"]["contextId"] = context_id
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security.audit("outbound", agent, rpc_body["id"], safe_message)
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protocol.persist_message(ctx, "user", safe_message, rpc_body["id"])
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try:
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resp = _http_post_json(_rpc_url(base_url, card), rpc_body, headers, timeout)
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except urllib.error.HTTPError as e:
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if e.code in (401, 403):
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return f"Error: peer '{agent}' rejected auth (HTTP {e.code}). Check the configured token."
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return f"Error: call to '{agent}' failed — HTTP {e.code}."
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except Exception as e:
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return f"Error: call to '{agent}' failed — {e}."
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if "error" in resp:
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err = resp["error"]
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return f"Peer '{agent}' returned an error: {err.get('message', err)}"
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result = resp.get("result", {})
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reply = _reply_text_from_result(result)
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reply_ctx = result.get("contextId", ctx) if isinstance(result, dict) else ctx
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protocol.persist_message(reply_ctx, "agent", reply, rpc_body["id"])
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state = ""
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if isinstance(result, dict):
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state = (result.get("status") or {}).get("state", "")
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header = f"[{agent} · context {reply_ctx}"
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if state:
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header += f" · {state}"
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header += "]"
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return f"{header}\n{reply or '(no text reply)'}"
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def _reply_text_from_result(result: Any) -> str:
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if not isinstance(result, dict):
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return str(result)
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# Artifacts first (final output), then status message (interim/clarify).
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for artifact in result.get("artifacts", []) or []:
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txt = protocol.extract_text(artifact)
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if txt:
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return txt
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status = result.get("status", {}) or {}
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msg = status.get("message")
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if msg:
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return protocol.extract_text(msg)
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# Bare message result (message/send may return a Message instead of a Task)
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return protocol.extract_text(result)
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def a2a_list(args: dict | None = None, **_: Any) -> str:
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"""List configured A2A peers and any persisted conversations."""
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cfg = _load_config()
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peers = cfg.get("a2a_agents") or {}
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lines = []
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if peers:
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lines.append(f"Configured peers ({len(peers)}):")
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for name, entry in peers.items():
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auth = (entry.get("auth") or {}).get("type", "none")
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lines.append(f" - {name}: {entry.get('url', '?')} (auth: {auth})")
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else:
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lines.append("No peers configured. Add them under 'a2a_agents' in config.yaml.")
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convos = protocol.list_conversations()
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if convos:
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lines.append("")
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lines.append(f"Persisted conversations ({len(convos)}):")
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for c in convos[:25]:
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lines.append(f" - {c}")
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return "\n".join(lines)
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# --------------------------------------------------------------------------
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# Tool schemas + registration
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# --------------------------------------------------------------------------
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_SCHEMAS = {
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"a2a_discover": {
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"type": "function",
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"function": {
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"name": "a2a_discover",
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"description": (
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"Fetch and summarize another agent's A2A Agent Card from a URL "
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"(its name, description, capabilities, and skills). Use this to "
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"find out what a remote agent can do before calling it."
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),
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"parameters": {
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"type": "object",
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"properties": {
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"url": {"type": "string", "description": "Base URL of the remote A2A agent, e.g. http://localhost:9999"},
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},
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"required": ["url"],
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},
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},
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},
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"a2a_call": {
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"type": "function",
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"function": {
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"name": "a2a_call",
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"description": (
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"Send a natural-language task to a remote A2A agent and return "
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"its reply. The agent is a peer (any A2A-compliant framework), "
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"not a sub-agent you control. Pass 'context_id' from a previous "
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"reply to continue a multi-turn exchange."
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),
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"parameters": {
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"type": "object",
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"properties": {
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"agent": {"type": "string", "description": "Configured peer name (from a2a_agents) or a full http(s):// URL."},
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"message": {"type": "string", "description": "The task / message to send the peer, in natural language."},
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"context_id": {"type": "string", "description": "Optional: context id from a prior reply, to continue the conversation."},
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},
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"required": ["agent", "message"],
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},
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},
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},
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"a2a_list": {
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"type": "function",
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"function": {
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"name": "a2a_list",
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"description": "List configured A2A peer agents and persisted A2A conversations.",
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"parameters": {"type": "object", "properties": {}},
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},
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},
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}
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_HANDLERS = {
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"a2a_discover": a2a_discover,
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"a2a_call": a2a_call,
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"a2a_list": a2a_list,
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}
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def register_tools(ctx) -> None:
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"""Register the three client tools in the ``a2a`` toolset."""
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for name, schema in _SCHEMAS.items():
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ctx.register_tool(
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name=name,
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toolset="a2a",
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schema=schema,
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handler=_HANDLERS[name],
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description=schema["function"]["description"],
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emoji="\U0001f9e9", # puzzle piece
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)
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