@aramisfa/openclaw-a2a-outbound

OpenClaw outbound A2A delegation plugin with a zero-config local onboarding CLI.

openclaw plugins install @aramisfa/openclaw-a2a-outbound
openclaw a2a demo run

openclaw a2a demo run starts the packaged local demo peer, configures a temporary local-demo target in memory, exercises list_targets, task-bearing send, watch, status, and continuation replay, then prints the returned summary.continuation.

This package registers:

• the openclaw a2a CLI family for demos and diagnostics
• one optional OpenClaw tool, remote_agent, with actions list_targets, send, watch, status, and cancel

For a raw payload walkthrough, see docs/quickstart.md.

Installation

openclaw plugins install @aramisfa/openclaw-a2a-outbound

Pin the exact published version if you want reproducible installs:

openclaw plugins install @aramisfa/openclaw-a2a-outbound --pin

Optional guided setup helper:

clawhub install a2a-delegation-setup

The ClawHub skill is an optional guided setup helper for installing, enabling, configuring, verifying, updating, and troubleshooting @aramisfa/openclaw-a2a-outbound. The plugin itself still installs through openclaw plugins install @aramisfa/openclaw-a2a-outbound.

Routing Boundary

@aramisfa/openclaw-a2a-outbound is the only outbound A2A continuation surface in this repository.

• summary.continuation is for remote_agent follow-up only.
• Do not replay summary.continuation back through inbound channel delivery on channel a2a.
• Do not treat an inbound A2A channel turn, OriginatingChannel, OriginatingTo, or inbound capabilities.reply as proof that generic channel-level queued follow-up is supported.
• If you see A2A_OUTBOUND_DELIVERY_UNSUPPORTED, OpenClaw tried to route a queued follow-up through openclaw-a2a-inbound; switch the workflow back to persisted summary.continuation plus remote_agent.

Requirements

• Node.js >=22.12.0
• OpenClaw 2026.4.15

CLI

openclaw a2a demo run [--json] [--write-continuation <path>]
openclaw a2a demo serve [--port <port>] [--json]
openclaw a2a doctor [--alias <alias>] [--json]

• demo run: self-contained first-success path.
• demo serve: long-lived local peer that prints exact config commands and raw remote_agent payloads.
• doctor: read-only install/config/target/card diagnostics for real targets.

OpenClaw Plugin Config

openclaw plugins install enables the plugin at the OpenClaw system level automatically — no separate openclaw plugins enable step is required. However, the remote_agent tool is gated by the plugin's own "enabled" flag inside its configuration object. Set "enabled": true under plugin id openclaw-a2a-outbound in your OpenClaw plugin config to activate the tool:

{
  "enabled": true,
  "defaults": {
    "timeoutMs": 120000,
    "cardPath": "/.well-known/agent-card.json",
    "preferredTransports": ["JSONRPC", "HTTP+JSON"],
    "serviceParameters": {}
  },
  "targets": [
    {
      "alias": "support",
      "baseUrl": "https://support.example",
      "description": "Primary support lane",
      "tags": ["support"],
      "examples": ["Summarize this incident and propose immediate actions."],
      "default": true
    }
  ],
  "taskHandles": {
    "ttlMs": 86400000,
    "maxEntries": 1000
  },
  "policy": {
    "acceptedOutputModes": [],
    "normalizeBaseUrl": true,
    "enforceSupportedTransports": true,
    "allowTargetUrlOverride": false
  }
}

Call list_targets first to discover configured aliases and refreshed peer-card metadata. Prefer target_alias over target_url; use target_url only when policy allows direct URL routing.

Unified Tool Contract

remote_agent accepts a flattened request object with top-level fields:

• action: required for every request.
• target_alias: preferred routing key for send, watch, status, and cancel.
• target_url: explicit remote base URL when policy allows it or when it matches a configured target.
• parts: required non-empty array for send; each part is text, file, or data.
• message_id: optional client-supplied message id for send.
• task_handle: opaque delegated-task handle. send, watch, status, and cancel all accept it.
• task_id: for send, continue an existing remote task when no task_handle is available; for watch/status/cancel, fallback follow-up key when no live task_handle is available.
• context_id: optional remote conversation context id for send only. Use it either with task_id or by itself to start a new task inside an existing conversation. Flat context_id must not be used for watch, status, or cancel.
• reference_task_ids: optional related task ids for send. task_id continues an existing task; reference_task_ids references prior tasks without continuing them.
• task_requirement: optional send contract. Defaults to "optional"; set task_requirement="required" to require a real task.
• follow_updates: stream the initial send. follow_updates=true means “stream the initial send”; it does not guarantee task creation unless task_requirement="required".
• accepted_output_modes: optional per-call output mode override for send.
• blocking: optional non-stream send knob. Rejected when follow_updates=true.
• history_length: optional history window for send and status.
• push_notification_config: optional push callback config for send.
• timeout_ms: per-request timeout override.
• service_parameters: optional outbound service parameters.
• metadata: optional metadata payload for send.

Snake_case tool fields are translated internally to the A2A SDK camelCase request payload. Action-specific validation rejects unsupported fields for each action, so keep requests flat and action-focused.

Actions

• list_targets: discover configured targets, aliases, examples, and hydrated peer-card metadata.
• send: send one or more message parts to a remote agent, either as a new turn or as a follow-up turn on an existing task/conversation.
• watch: resubscribe to a running delegated task and stream updates.
• status: fetch the latest task snapshot.
• cancel: request cancellation for a delegated task.

Failed send and sendStream calls include error.details.capability_diagnostics so remote validation or content-type rejections can be compared against the stored peer card without blocking permissive runtime sends.

Continuation Rules

This package returns continuation metadata under summary.continuation. Persist that subtree verbatim and use it to choose the next action.

• summary.continuation.target: the canonical persisted routing contract for machine follow-up. Persist target_url, card_path, and preferred_transports verbatim; target_alias is optional descriptive metadata.
• summary.continuation.task: the only machine-readable signal that a real remote task exists. Read task_handle, task_id, status, can_resume_send, can_watch, and the deprecated alias can_send from here, and use it for follow-up send, watch, status, and cancel.
• summary.continuation.conversation: send-only conversation continuity. Read context_id from here and use it only for follow-up send.
• response_kind: descriptive wire-shape classification only. response_kind="message" means the peer returned a Message; response_kind="task" means a task-bearing response or event appeared. response_kind does not replace summary.continuation.
• summary.target_* and other top-level compatibility aliases are descriptive only. Do not infer lifecycle continuity from flat task_id, flat context_id, or other top-level fields.
• watch, status, and cancel require summary.continuation.task.
• Conversation-only follow-up uses context_id, not task actions.
• summary.continuation is not a license to route follow-ups through channel a2a; it is the persisted contract for remote_agent only.

Supported send modes:

• new task: send with target_alias/target_url or a configured default target, and no continuation fields
• existing task continuation: send with a persisted continuation; flat task_handle, or task_id plus target_alias/target_url, remain manual compatibility inputs only
• related new task: send with reference_task_ids, optionally plus context_id, plus target_alias/target_url or a configured default target
• new task in an existing conversation: send with a persisted conversation-only continuation; flat context_id plus target_alias/target_url remains manual compatibility only

When a delegated task pauses in input-required or an approval workflow, resume it with send again. If the nested task_handle is expired or unavailable, the plugin automatically falls back within that nested contract to continuation.target + continuation.task.task_id; callers should not flatten persisted follow-up state back into target_alias/task_id.

Choose the next action based on the continuation shape:

const continuation = result.summary.continuation
const task = continuation?.task
const conversation = continuation?.conversation

if (task) {
  const followUp = { action: "status", continuation }
} else if (conversation) {
  const followUp = {
    action: "send",
    continuation,
    parts: [{ kind: "text", text: "Start a related task in the same conversation." }],
  }
}

Examples

Discover Available Targets

{ "action": "list_targets" }

{
  "ok": true,
  "operation": "remote_agent",
  "action": "list_targets",
  "summary": {
    "targets": [
      {
        "target_alias": "support",
        "target_url": "https://support.example/",
        "default": true,
        "tags": ["support"],
        "examples": ["Summarize this incident and propose immediate actions."],
        "target_name": "Support Agent",
        "description": "Primary support lane",
        "streaming_supported": true,
        "peer_card": {
          "preferred_transport": "JSONRPC",
          "additional_interfaces": [
            {
              "transport": "JSONRPC",
              "url": "https://support.example/a2a/jsonrpc"
            },
            {
              "transport": "HTTP+JSON",
              "url": "https://support.example/a2a/rest"
            }
          ],
          "capabilities": {
            "streaming": true,
            "push_notifications": true,
            "state_transition_history": true
          },
          "default_input_modes": ["text/plain"],
          "default_output_modes": ["text/plain"],
          "skills": [
            {
              "id": "triage",
              "name": "Incident Triage",
              "description": "Summarize incidents and propose next actions.",
              "tags": ["support"],
              "examples": ["Summarize this incident and propose immediate actions."],
              "input_modes": ["application/json"],
              "output_modes": ["application/pdf"]
            }
          ]
        }
      }
    ]
  },
  "raw": [
    {
      "target": {
        "baseUrl": "https://support.example/",
        "cardPath": "/.well-known/agent-card.json",
        "preferredTransports": ["JSONRPC", "HTTP+JSON"],
        "alias": "support",
        "displayName": "Support Agent",
        "description": "Primary support lane",
        "streamingSupported": true
      },
      "configuredDescription": "Primary support lane",
      "default": true,
      "tags": ["support"],
      "examples": ["Summarize this incident and propose immediate actions."],
      "card": {
        "displayName": "Support Agent",
        "description": "Summarize incidents and propose next actions.",
        "preferredTransport": "JSONRPC",
        "additionalInterfaces": [
          {
            "transport": "JSONRPC",
            "url": "https://support.example/a2a/jsonrpc"
          },
          {
            "transport": "HTTP+JSON",
            "url": "https://support.example/a2a/rest"
          }
        ],
        "capabilities": {
          "streaming": true,
          "pushNotifications": true,
          "stateTransitionHistory": true
        },
        "defaultInputModes": ["text/plain"],
        "defaultOutputModes": ["text/plain"],
        "skills": [
          {
            "id": "triage",
            "name": "Incident Triage",
            "description": "Summarize incidents and propose next actions.",
            "tags": ["support"],
            "examples": ["Summarize this incident and propose immediate actions."],
            "inputModes": ["application/json"],
            "outputModes": ["application/pdf"]
          }
        ],
        "lastRefreshedAt": "2026-03-12T10:00:00.000Z"
      }
    }
  ]
}

Send To An Explicit target_alias

{
  "action": "send",
  "target_alias": "support",
  "parts": [
    {
      "kind": "text",
      "text": "Summarize this bug report for triage."
    }
  ],
  "metadata": {
    "ticket_id": "INC-42"
  }
}

{
  "ok": true,
  "operation": "remote_agent",
  "action": "send",
  "summary": {
    "target_alias": "support",
    "target_url": "https://support.example/",
    "response_kind": "message",
    "message_text": "Triage summary: reproduce, collect logs, and notify the on-call engineer."
  },
  "raw": {
    "kind": "message"
  }
}

Require A Durable Task

{
  "action": "send",
  "target_alias": "support",
  "task_requirement": "required",
  "parts": [
    {
      "kind": "text",
      "text": "Start a trackable task and return immediately."
    }
  ]
}

Start Related Work Without Continuing A Task

{
  "action": "send",
  "target_alias": "support",
  "context_id": "ctx-123",
  "reference_task_ids": ["task-101", "task-102"],
  "parts": [
    {
      "kind": "text",
      "text": "Start a related task in the same conversation."
    }
  ]
}

Send Using The Configured Default Target

If one target is marked "default": true, send can omit target_alias:

{
  "action": "send",
  "parts": [
    {
      "kind": "text",
      "text": "Draft a reply to the customer update."
    }
  ],
  "follow_updates": true
}

{
  "ok": true,
  "operation": "remote_agent",
  "action": "send",
  "summary": {
    "target_alias": "support",
    "target_url": "https://support.example/",
    "response_kind": "task",
    "continuation": {
      "target": {
        "target_url": "https://support.example/",
        "card_path": "/.well-known/agent-card.json",
        "preferred_transports": ["JSONRPC", "HTTP+JSON"],
        "target_alias": "support"
      },
      "task": {
        "task_handle": "rah_0a3ff8c2-4a6d-48cb-a57d-4ae6f3c589d0",
        "task_id": "task-456",
        "status": "completed",
        "can_resume_send": false,
        "can_send": false,
        "can_status": true,
        "can_cancel": false,
        "can_watch": false
      },
      "conversation": {
        "context_id": "ctx-456",
        "can_send": true
      }
    }
  },
  "raw": {
    "events": [
      {
        "kind": "task",
        "id": "task-456",
        "contextId": "ctx-456",
        "status": {
          "state": "submitted"
        }
      },
      {
        "kind": "status-update",
        "taskId": "task-456",
        "contextId": "ctx-456",
        "status": {
          "state": "completed"
        },
        "final": true
      }
    ],
    "finalEvent": {
      "kind": "status-update",
      "taskId": "task-456",
      "contextId": "ctx-456",
      "status": {
        "state": "completed"
      },
      "final": true
    }
  }
}

const task = result.summary.continuation?.task
const conversation = result.summary.continuation?.conversation

if (!task) {
  throw new Error("expected a trackable delegated task")
}

if (task.can_watch) {
  // `watch` is valid here.
}

const followUpContext = conversation?.context_id

Continue An Existing Remote Task With task_handle

Resend the persisted continuation subtree:

{
  "action": "send",
  "continuation": {
    "target": {
      "target_url": "https://support.example/",
      "card_path": "/.well-known/agent-card.json",
      "preferred_transports": ["JSONRPC", "HTTP+JSON"],
      "target_alias": "support"
    },
    "task": {
      "task_handle": "rah_0a3ff8c2-4a6d-48cb-a57d-4ae6f3c589d0",
      "task_id": "task-456"
    },
    "conversation": {
      "context_id": "ctx-456",
      "can_send": true
    }
  },
  "parts": [
    {
      "kind": "text",
      "text": "Approved. Continue with the task and finish the reply."
    }
  ]
}

Continue An Existing Remote Task With task_id

Use the persisted continuation without task_handle:

{
  "action": "send",
  "continuation": {
    "target": {
      "target_url": "https://support.example/",
      "card_path": "/.well-known/agent-card.json",
      "preferred_transports": ["JSONRPC", "HTTP+JSON"],
      "target_alias": "support"
    },
    "task": {
      "task_id": "task-456"
    },
    "conversation": {
      "context_id": "ctx-456",
      "can_send": true
    }
  },
  "parts": [
    {
      "kind": "text",
      "text": "Continue the prior conversation and draft the final reply."
    }
  ]
}

Start A New Task In An Existing Conversation

Use summary.continuation.conversation.context_id when only conversation continuity exists:

{
  "action": "send",
  "continuation": {
    "target": {
      "target_url": "https://support.example/",
      "card_path": "/.well-known/agent-card.json",
      "preferred_transports": ["JSONRPC", "HTTP+JSON"],
      "target_alias": "support"
    },
    "conversation": {
      "context_id": "ctx-456",
      "can_send": true
    }
  },
  "parts": [
    {
      "kind": "text",
      "text": "Start a new side task, but keep it in the same conversation."
    }
  ]
}

{
  "ok": true,
  "operation": "remote_agent",
  "action": "send",
  "summary": {
    "target_alias": "support",
    "target_url": "https://support.example/",
    "response_kind": "message",
    "message_text": "Conversation continued. Start the next task when ready.",
    "continuation": {
      "target": {
        "target_url": "https://support.example/",
        "card_path": "/.well-known/agent-card.json",
        "preferred_transports": ["JSONRPC", "HTTP+JSON"],
        "target_alias": "support"
      },
      "conversation": {
        "context_id": "ctx-456",
        "can_send": true
      }
    }
  },
  "raw": {
    "kind": "message"
  }
}

const task = result.summary.continuation?.task
const conversation = result.summary.continuation?.conversation

if (task) {
  throw new Error("expected a context-only continuation")
}

if (conversation) {
  const followUp = {
    action: "send",
    continuation: result.summary.continuation,
    parts: [{ kind: "text", text: "Start the next task in this conversation." }],
  }
}

Conversation continuity is send-only. watch, status, and cancel require summary.continuation.task.

Check Task Status With task_handle

{
  "action": "status",
  "continuation": {
    "target": {
      "target_url": "https://support.example/",
      "card_path": "/.well-known/agent-card.json",
      "preferred_transports": ["JSONRPC", "HTTP+JSON"],
      "target_alias": "support"
    },
    "task": {
      "task_handle": "rah_0a3ff8c2-4a6d-48cb-a57d-4ae6f3c589d0",
      "task_id": "task-456"
    },
    "conversation": {
      "context_id": "ctx-456",
      "can_send": true
    }
  },
  "history_length": 2
}

{
  "ok": true,
  "operation": "remote_agent",
  "action": "status",
  "summary": {
    "target_alias": "support",
    "target_url": "https://support.example/",
    "response_kind": "task",
    "continuation": {
      "target": {
        "target_url": "https://support.example/",
        "card_path": "/.well-known/agent-card.json",
        "preferred_transports": ["JSONRPC", "HTTP+JSON"],
        "target_alias": "support"
      },
      "task": {
        "task_handle": "rah_0a3ff8c2-4a6d-48cb-a57d-4ae6f3c589d0",
        "task_id": "task-456",
        "status": "completed",
        "can_resume_send": false,
        "can_send": false,
        "can_status": true,
        "can_cancel": false,
        "can_watch": false
      },
      "conversation": {
        "context_id": "ctx-456",
        "can_send": true
      }
    }
  },
  "raw": {
    "kind": "task",
    "id": "task-456",
    "status": {
      "state": "completed"
    }
  }
}

const task = result.summary.continuation?.task
const conversation = result.summary.continuation?.conversation

if (!task) {
  throw new Error("status requires summary.continuation.task")
}

const nextStatus = task.task_handle
  ? { action: "status", continuation: result.summary.continuation }
  : { action: "status", continuation: result.summary.continuation }

const nextSend = conversation
  ? { action: "send", continuation: result.summary.continuation }
  : undefined

If summary.continuation.task.task_handle is expired or unavailable, retry with the same persisted continuation:

{
  "action": "status",
  "continuation": {
    "target": {
      "target_url": "https://support.example/",
      "card_path": "/.well-known/agent-card.json",
      "preferred_transports": ["JSONRPC", "HTTP+JSON"],
      "target_alias": "support"
    },
    "task": {
      "task_handle": "rah_0a3ff8c2-4a6d-48cb-a57d-4ae6f3c589d0",
      "task_id": "task-456"
    }
  }
}

watch and cancel require summary.continuation.task from a prior result:

{ "action": "watch", "continuation": { "target": { "target_url": "https://support.example/", "card_path": "/.well-known/agent-card.json", "preferred_transports": ["JSONRPC", "HTTP+JSON"], "target_alias": "support" }, "task": { "task_handle": "rah_0a3ff8c2-4a6d-48cb-a57d-4ae6f3c589d0", "task_id": "task-456" } } }

{ "action": "cancel", "continuation": { "target": { "target_url": "https://support.example/", "card_path": "/.well-known/agent-card.json", "preferred_transports": ["JSONRPC", "HTTP+JSON"], "target_alias": "support" }, "task": { "task_handle": "rah_0a3ff8c2-4a6d-48cb-a57d-4ae6f3c589d0", "task_id": "task-456" } } }

Validation And Actionable Errors

Tool input validation uses Ajv in strict mode. Validation failures use operation: "remote_agent" and include native-style Ajv error objects:

{
  "ok": false,
  "operation": "remote_agent",
  "action": "send",
  "error": {
    "code": "VALIDATION_ERROR",
    "message": "remote_agent input validation failed",
    "details": {
      "source": "ajv",
      "tool": "remote_agent",
      "errors": [
        {
          "keyword": "anyOf",
          "instancePath": "",
          "message": "send requires task_handle, target_alias, target_url, or a configured default target"
        }
      ]
    }
  }
}

Expired handles return an actionable recovery envelope:

{
  "ok": false,
  "operation": "remote_agent",
  "action": "status",
  "error": {
    "code": "EXPIRED_TASK_HANDLE",
    "message": "task handle \"rah_0a3ff8c2-4a6d-48cb-a57d-4ae6f3c589d0\" has expired",
    "details": {
      "taskHandle": "rah_0a3ff8c2-4a6d-48cb-a57d-4ae6f3c589d0",
      "retryHint": "Retry with the same nested continuation so the plugin can fall back to the persisted target plus taskId, or resend the original request after a restart to obtain a new handle.",
      "restartInvalidatesHandles": true,
      "suggested_actions": ["status", "send"],
      "hint": "Retry with the same nested continuation, or use flat target_alias + task_id only as manual compatibility."
    }
  }
}

Development

pnpm build
pnpm test

License

MIT