Milestone 5.B.3 — MCP get_memory_lineage Tool

Status: Planned
Goal: Track B — Graph-Aware Retrieval
Phase: 5 — Advanced Retrieval
Estimated effort: 2 days
Track: Track B — Graph-Aware Retrieval

Why This Milestone Exists

Extends the Phase 3.5 MCP surface with a lineage-specific tool for "stateful, auditable read" — the kind of operation MCP excels at. Returns the full supersession/contradiction/specialization chain for a memory.

Orientation (indicative)

Named paths, package layouts, libraries, schemas, env vars, and commands anywhere on this page are rough sketches for orientation — inspiration and a baseline, not a required change list.

During implementation, expect to:

open the live tree and follow existing patterns before inventing new ones
research current constraints (latency, tenancy, deploy shape, libraries) more deeply than this page can
advance the design beyond the sketch where measurement or code reality says so
land work in different filenames, merged packages, deferred docs, or new surfaces when the situation calls for it

Prefer outcomes over matching any particular file tree or command sequence.

Areas that may be involved (situational — not a checklist):

Graph / lineage traversal
Memory service / repositories
MCP server surface

Success signals

Outcome-oriented signals that the milestone is in good shape. Exact filenames, package layouts, and commands may differ from any sketches above.

Reuses same gRPC auth/rate-limit path as existing MCP tools
Traced to ClickHouse identically to other MCP tool calls
ISO-MCP-LINEAGE-01 cross-tenant test: requesting lineage for another org's memory returns not-found

Prerequisites

Milestone 5.B.1 (Graph traversal query layer)
Phase 3.5 MCP tools operational