Module server 

MCP tool surface for the open-source CPM planner.

PlanServer wraps an Arc<BasicCpmPlanner> and exposes the six Planner trait methods as MCP tools so any MCP-speaking agent (Claude Code, Cursor, custom orchestrator, or the §33 LLM executor) can drive the planner over the standard MCP protocol.

Tool surface

Tool name	Trait method
plan.submit	Planner::submit_plan
plan.acquire_cohort	Planner::acquire_cohort
plan.heartbeat	Planner::heartbeat
plan.mark_status	Planner::mark_status
plan.status	Planner::status
plan.force_release	Planner::force_release

Error mapping

PlannerError variants are surfaced as MCP internal_error responses whose message is the variant’s Display output. The variant prefixes (LOCK_HELD:, LOCK_NOT_HELD:, LOCK_EXPIRED:, OVERLAP_DETECTED:, MISSING_PREREQUISITE:, PLAN_NOT_FOUND:, DELIVERABLE_NOT_FOUND:, INVALID_GRAPH:, BACKEND_ERROR:) are stable machine-parseable signals — see core::plan for the contract. Malformed arguments yield invalid_params with the serde error.

Testing pattern

PlanServer::dispatch_call is the transport-free entry point used by integration tests, mirroring the pattern in mcp-flowgate-mcp-server. The ServerHandler::call_tool impl is a thin wrapper that wraps the result in CallToolResult::structured.

Structs

PlanServer

MCP server façade exposing a BasicCpmPlanner over six tools.

Constants

PLAN_TOOL_NAMES

All six MCP tool names exposed by PlanServer, in declaration order.

TOOL_ACQUIRE_COHORT

TOOL_FORCE_RELEASE

TOOL_HEARTBEAT

TOOL_MARK_STATUS

TOOL_STATUS

TOOL_SUBMIT

SPEC §33 PA4 — tool names. Dot notation plan.<verb> matches the convention used elsewhere in the workspace (flowgate.query, flowgate.command).

Functions

plan_tool_definitions

Build the six Tool definitions advertised in list_tools.