forked from molecule-ai/molecule-core
81c4c1321c
Manual-test failure surfaced what was hidden behind the MCP-path bug:
once delegate_task could actually fire, every cross-workspace call
came back as JSON-RPC -32600 "Invalid Request" with the underlying
pydantic ValidationError:
params.message.role
Input should be 'agent' or 'user' [type=enum,
input_value='ROLE_USER', input_type=str]
PR #2184's a2a-sdk 1.x migration sweep over-corrected: it changed
every `"role": "user"` literal in JSON-RPC payload construction to
`"role": "ROLE_USER"` to match the protobuf enum names of the 1.x
native types (a2a.types.Role.ROLE_USER / ROLE_AGENT). That was
correct for in-process Message construction (which the SDK
serialises before wire transmission) but WRONG for the 8 sites that
hand-build JSON-RPC payloads. The workspace's own a2a-sdk runs
inbound requests through the v0.3 compat adapter
(/usr/local/lib/python3.11/site-packages/a2a/compat/v0_3/) because
main.py sets enable_v0_3_compat=True for backwards compatibility,
and that adapter validates against the v0.3 Pydantic Role enum
(`agent` | `user` lowercase). The protobuf-style names blow it up.
Reverted the 8 wire-payload sites to lowercase:
- workspace/a2a_client.py:74
- workspace/a2a_cli.py:74, 111
- workspace/heartbeat.py:378
- workspace/main.py:464, 563
- workspace/builtin_tools/a2a_tools.py:60
- workspace/builtin_tools/delegation.py:272
Native-type usage at workspace/a2a_executor.py:471 (`Role.ROLE_AGENT`)
stays — that's an in-process Message construction; the SDK handles
wire serialisation correctly.
Updated the misleading comment at main.py:255-257 (which said
"outbound payloads are now 1.x-shaped (ROLE_USER)") to spell out
the actual rule: outbound JSON-RPC wire payloads MUST use v0.3
shape, native types are only for in-process construction.
New regression test test_jsonrpc_wire_role_format.py greps the 6
wire-payload-emitting files for any "ROLE_USER" / "ROLE_AGENT"
string literal and fails loud — cheapest possible drift detector.
Why E2E missed it: the priority-runtimes harness sends a single
message canvas → workspace, but the canvas already used lowercase
"user" (it never went through the migration sweep). The bug only
surfaces on workspace → workspace delegation, which the harness
doesn't exercise. Same gap as #131 (extend smoke to call main()
against a stub).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
91 lines
3.4 KiB
Python
91 lines
3.4 KiB
Python
"""A2A communication tools — framework-agnostic delegation and peer discovery.
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These are plain async functions that any adapter can wrap in its native tool format.
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The LangChain @tool versions are in tools/delegation.py.
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"""
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import os
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import uuid
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import httpx
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PLATFORM_URL = os.environ.get("PLATFORM_URL", "http://host.docker.internal:8080")
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WORKSPACE_ID = os.environ.get("WORKSPACE_ID", "")
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async def list_peers() -> list[dict]:
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"""Get this workspace's peers from the platform registry."""
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async with httpx.AsyncClient(timeout=10.0) as client:
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try:
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resp = await client.get(f"{PLATFORM_URL}/registry/{WORKSPACE_ID}/peers")
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if resp.status_code == 200:
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return resp.json()
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return []
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except Exception:
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return []
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async def delegate_task(workspace_id: str, task: str) -> str:
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"""Send a task to a peer workspace via A2A and return the response text."""
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async with httpx.AsyncClient(timeout=120.0) as client:
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# Discover target URL
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try:
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resp = await client.get(
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f"{PLATFORM_URL}/registry/discover/{workspace_id}",
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headers={"X-Workspace-ID": WORKSPACE_ID},
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)
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if resp.status_code != 200:
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return f"Error: cannot reach workspace {workspace_id} (status {resp.status_code})"
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target_url = resp.json().get("url", "")
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if not target_url:
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return f"Error: workspace {workspace_id} has no URL"
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except Exception as e:
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return f"Error discovering workspace: {e}"
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# Send A2A message. X-Workspace-ID identifies us as the source —
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# without it the platform's a2a_receive logger writes
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# source_id=NULL and the recipient's My Chat tab renders the
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# delegation as if a human user typed it. Same hazard fixed
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# in heartbeat.py / a2a_client.py / main.py initial+idle flows.
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try:
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a2a_resp = await client.post(
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target_url,
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headers={"X-Workspace-ID": WORKSPACE_ID},
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json={
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"jsonrpc": "2.0",
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"id": str(uuid.uuid4()),
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"method": "message/send",
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"params": {
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"message": {
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"role": "user",
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"messageId": str(uuid.uuid4()),
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"parts": [{"kind": "text", "text": task}],
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},
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},
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},
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)
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data = a2a_resp.json()
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if "result" in data:
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parts = data["result"].get("parts", [])
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return parts[0].get("text", "(no text)") if parts else str(data["result"])
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elif "error" in data:
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return f"Error: {data['error'].get('message', str(data['error']))}"
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return str(data)
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except Exception as e:
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return f"Error sending A2A message: {e}"
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async def get_peers_summary() -> str:
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"""Return a formatted string of available peers for system prompts."""
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peers = await list_peers()
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if not peers:
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return "No peers available."
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lines = []
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for p in peers:
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name = p.get("name", "Unknown")
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pid = p.get("id", "")
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role = p.get("role", "")
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status = p.get("status", "")
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lines.append(f"- {name} (ID: {pid}) — {role} [{status}]")
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return "Available peers:\n" + "\n".join(lines)
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