macp-sdk-python 0.5.0

Python SDK for the MACP Rust runtime

macp-sdk-python

Python SDK for the MACP Rust runtime.

What this package does

• Connects to the Rust runtime over gRPC
• Provides typed session helpers for all 5 standard coordination modes
• Maintains in-process projections for local state tracking
• Supports envelope builders, retry helpers, and structured logging

Important runtime boundary

This SDK calls the Rust runtime. The runtime does not call into this Python package. If you need runtime-driven business logic, run a Python agent/orchestrator as a separate process and let it communicate with the runtime over MACP transport.

Install

pip install macp-sdk-python

Quick start

Production (Bearer + TLS)

from macp_sdk import AuthConfig, DecisionSession, MacpClient

# TLS is the default; Bearer + expected_sender binds the session to this identity.
client = MacpClient(
    target="runtime.example.com:50051",
    auth=AuthConfig.for_bearer("tok-coord", expected_sender="coordinator"),
)

Local dev (runtime started with MACP_ALLOW_INSECURE=1)

client = MacpClient(
    target="127.0.0.1:50051",
    allow_insecure=True,                                # dev only
    auth=AuthConfig.for_dev_agent("coordinator"),
)

Driving a decision

session = DecisionSession(client)
session.start(
    intent="pick a deployment plan",
    participants=["coordinator", "alice", "bob"],
    ttl_ms=60_000,
)
session.propose("p1", "deploy v2.1", rationale="tests passed")
session.evaluate(
    "p1", "approve", confidence=0.94, reason="low risk",
    sender="alice", auth=AuthConfig.for_dev_agent("alice"),
)
session.vote(
    "p1", "approve", reason="ship it",
    sender="bob", auth=AuthConfig.for_dev_agent("bob"),
)

winner = session.decision_projection.majority_winner()
if winner and not session.decision_projection.has_blocking_objection(winner):
    session.commit(
        action="deployment.approved",
        authority_scope="release-management",
        reason=f"winner={winner}",
    )

Supported modes

Mode	Session Helper	Projection	Example
Decision	DecisionSession	DecisionProjection	examples/decision_smoke.py
Proposal	ProposalSession	ProposalProjection	examples/proposal_negotiation.py
Task	TaskSession	TaskProjection	examples/task_delegation.py
Handoff	HandoffSession	HandoffProjection	examples/handoff_escalation.py
Quorum	QuorumSession	QuorumProjection	examples/quorum_approval.py

Development

# Setup
make setup              # pip install -e ".[dev,docs]"

# Quality
make lint               # ruff check
make fmt                # ruff format
make typecheck          # mypy strict
make test               # unit tests
make test-all           # lint + typecheck + all tests
make coverage           # coverage report

# Build
make build              # sdist + wheel

# Proto definitions (provided by macp-proto package)
make dev-link-protos    # link local proto package for development

For local development against the runtime:

export MACP_ALLOW_INSECURE=1
cargo run   # in the runtime repo

Since runtime v0.5.0, a runtime with no authentication configured (MACP_AUTH_TOKENS_* / MACP_AUTH_ISSUER unset) refuses to start unless MACP_ALLOW_INSECURE=1 is set, and the published Docker image no longer bakes that env in — pass it explicitly for local dev (as above and in the docker run command in CLAUDE.md).

Dev-agent auth rides the standard Authorization: Bearer header — the runtime's dev_authenticate fallback binds the token value verbatim as the sender.

Documentation

Full docs available in docs/ — build with mkdocs serve after make setup.

Architecture boundary

This SDK is a thin typed client library. It provides:

• Typed state models and action builders
• Session helpers (propose(), vote(), commit())
• Local state projections (because GetSession returns metadata only)

Business logic — voting rules, AI decision heuristics, policy enforcement — belongs in the orchestrator/agent layer above the SDK.

Known runtime limitations

• GetSession returns metadata only (not mode state/transcript) — hence the local projection pattern; use StreamSession + send_subscribe for the full transcript
• StreamSession is scoped to one session per stream; use MacpStream.send_subscribe(session_id) (RFC-MACP-0006-A1, since SDK 0.2.3 / macp-proto 0.1.2) to replay accepted history before live broadcast
• For cross-session observability, use MacpClient.list_sessions() and SessionLifecycleWatcher (SDK 0.3.0) to enumerate active sessions and stream CREATED / RESOLVED / EXPIRED / CANCELLED / SUSPENDED / RESUMED lifecycle events
• Pause and cancel sessions with MacpClient.suspend_session() / resume_session() / cancel_session() (SDK 0.4.0 / macp-proto 0.1.3). A suspended session is non-terminal and rejects messages until resumed; an accepted cancel_session() now terminates as CANCELLED (previously surfaced as EXPIRED)
• ListRoots currently returns an empty list and WatchRoots idles — the runtime does not yet populate roots
• Business policy (majority, quorum, veto) belongs in your orchestrator/policy layer