Multi-Agent Coordination Protocol (MACP) - Task Mode

Document: RFC-MACP-0009 Version: 1.0.0-draft Status: Community Standards Track Updates: RFC-MACP-0002

Abstract

This document defines macp.mode.task.v1, the standards-track MACP primitive for bounded task delegation. Task Mode lets an orchestrator assign one task inside one Session, record assignee responses and progress, and terminate with a single authoritative Commitment that binds success or failure.

1. Purpose

Task Mode is the basic delegation primitive for multi-agent execution. It is intended for one bounded task per Session, not for open-ended job queues or workflow graphs.

2. Identifier and participant model

• Mode identifier: macp.mode.task.v1
• Participant model: orchestrated

The session initiator or a policy-defined coordinator is the requester and default Commitment authority.

3. SessionStart requirements

A Task Mode Session MUST bind:

• participants - requester and eligible assignee participants,
• mode_version - task-mode semantic profile,
• configuration_version - execution profile,
• policy_version - governance or authorization profile,
• ttl_ms - task deadline,
• context - optional task context and constraints.

Base Task Mode v1 assumes exactly one task request per Session.

4. Message types

Task Mode defines the following mode-specific message types:

• TaskRequest - opens the delegated task.
• TaskAccept - assignee accepts responsibility.
• TaskReject - assignee declines responsibility.
• TaskUpdate - non-terminal progress or status update.
• TaskComplete - assignee reports successful completion.
• TaskFail - assignee reports a bounded failure.
• Commitment - authoritative terminal outcome.

5. Validation rules

Implementations MUST enforce the following:

1. A Task Mode v1 Session MUST accept at most one TaskRequest.
2. TaskAccept or TaskReject MUST come from the requested assignee, or from an eligible declared participant if requested_assignee is empty.
3. Only one assignee may become active for the Session in base v1.
4. TaskUpdate, TaskComplete, and TaskFail MUST come from the active assignee.
5. TaskComplete and TaskFail do not resolve the Session on their own. They make the Session eligible for Commitment by the requester or policy authority.

6. Terminal semantics

Task Mode resolves only when an authorized Commitment is accepted.

Implementations SHOULD use CommitmentPayload.action values that make the outcome explicit, for example:

• task.completed
• task.failed

The commitment SHOULD bind the relevant task identifier and the versions that governed execution.

7. Determinism class

Task Mode claims structural-only determinism by default.

The coordination transcript is replay-safe, but task execution may depend on external tools, mutable inputs, or side effects outside the MACP runtime boundary. A deployment MAY define stricter profiles, but those are not part of base Task Mode v1.

8. Security considerations

Implementations MUST address all of the following:

• authenticate requester and assignee identities,
• ensure only authorized assignees accept or complete tasks,
• protect sensitive task inputs and outputs,
• define idempotency keys for any external side effects triggered by task execution,
• reject forged completions and failures from non-assignees.

9. Canonical schemas and examples

Canonical schemas:

• schemas/proto/macp/modes/task/v1/task.proto
• schemas/modes/task.proto

Example transcript:

• examples/task-mode-session.json