Bicameral MCP

bicameral-mcp is the MCP transport client for the local bicameral-bot daemon. It exposes agent-friendly tools, maps them into canonical ToolRequest envelopes, sends those requests to the daemon, and returns daemon ToolResponse payloads.

MCP is not the Bicameral daemon, Decision Ledger, code graph, dashboard, integration runtime, setup wizard, telemetry sink, or governance engine.

Current Contract

The cutover target is the bot-owned ToolRequest protocol:

MCP tool call
  -> ToolRequest(command + AuthorityContext)
  -> bicameral-bot daemon validation and governance policy
  -> ToolResponse(status + result + governance_result)

MCP performs a daemon capability handshake at startup. It refuses to start when the daemon's ToolRequest protocol version is unsupported. After protocol compatibility is established, individual commands may still return daemon capability errors while bot parity is being implemented.

Related MCP server: Axiom-hub

Configuration

Set the bot daemon endpoint with:

export BICAMERAL_DAEMON_URL=http://127.0.0.1:37373

Optional context:

export BICAMERAL_ACTOR_ID="$(whoami)"
export BICAMERAL_WORKSPACE="$PWD"
export BICAMERAL_POLICY_SCOPE=default

Run the MCP server:

bicameral-mcp

Print supported tool names without contacting the daemon:

bicameral-mcp tools

Supported Tools

MCP exposes only ToolRequest-backed tools:

Product Terminology

bicameral.preflight is the MCP surface for constraint lookup and readiness context before or during implementation. It maps to the bot-owned preflight.run command for historical protocol compatibility, but MCP does not turn lookup output into a governed work gate, compliance decision, signoff, or merge-safety claim.

Use these terms consistently:

• Constraint Lookup: retrieve relevant daemon-authored Decisions, source links, evidence references, and readiness labels.

• Constraint Correction Capture: submit or review proposed corpus corrections.

• Code Grounding: inspect daemon-owned binding and graph evidence.

• Code Compliance: review daemon-owned compliance state when the daemon exposes that capability.

• Governed Work Gate: future policy-controlled blocking/routing behavior; not implied by ordinary lookup or preflight output.

Troubleshooting: Daemon Handshake Failures

MCP stays fail-fast on daemon capability handshake failures. It never starts, installs, upgrades, migrates, or repairs the daemon, and never falls back to legacy MCP-owned handlers. Instead, a failed tool call returns a typed MCP error with an informational recovery payload:

{
  "status": "error",
  "error_code": "daemon_protocol_mismatch",
  "recovery": {
    "error_code": "daemon_protocol_mismatch",
    "category": "setup",
    "retryable": false,
    "mcp_protocol_version": "v2",
    "daemon_protocol_version": "v1",
    "daemon_endpoint": "http://127.0.0.1:37373",
    "requested_tool": "bicameral.preflight",
    "requested_command": "preflight.run",
    "operator_action": "Upgrade bicameral-mcp and bicameral-bot/daemon to matching tags, then retry."
  }
}

When a daemon URL env override is set, the recovery payload adds a daemon_url_override field and calls out the env var in operator_action, so a wrong URL is easy to spot even though it shares the daemon_unavailable transport path.

Remediation such as installing, upgrading, starting, or migrating the daemon is bot-owned or CLI-owned, not MCP-owned.

Prompts And Skills

MCP may expose MCP prompts for generic Bicameral workflows over supported tools, such as constraint lookup, binding, ingest, history, search, and brief.

Repo-local skills are outside MCP. Keep repo/team behavior in repo skills: when to run Bicameral, which ADRs to read, contribution policy, factory attestation, and workflows that span beyond Bicameral MCP.

Retired From MCP

The v0.2 direct MCP payload surface is not preserved. Removed or unsupported legacy behavior includes:

• link_commit

• ratify

• resolve_collision

• remove_decision

• remove_source

• validate_symbols

• get_neighbors

• setup wizard, reset, update, diagnose, usage, feedback, and telemetry

• dashboard hosting

• local ledger/event/graph/source/integration runtimes

Missing bot-backed behavior is intentionally unavailable in MCP rather than emulated locally.

Previous implementation history can be inspected at:

0827444c80d45fe3474f68002166e1fc35708eda

Development

Focused cutover checks:

python -m pytest tests/test_toolrequest_thin_client.py -q
python -m build

Repository boundary

bicameral-mcp is the agent-facing tool surface. It exposes local Bicameral actions to coding agents: ingest, preflight, bind, review-command emission, and local run loops.

It is not the source-specific integration repo, the local bot runtime, or the hosted code graph. See docs/adr/0001-mcp-repository-boundary.md.