feat(map): add optional SCC condensation view

[elefthei]

Summary

• Add explicit graft map [dir] --scc / trail map [dir] --scc and MCP graft_repo_map { "scc": true } views. CLI --scc --json serializes the direct { components, edges } result.
• Isolate iterative Tarjan analysis in src/graph/scc.ts, using the existing directed dependency relations and exact node IDs. Include files, isolates, self-recursive singletons, and every inter-component dependency, without transitive reduction or input mutation.
• Retain every member's definition location and every original supporting edge (including bundled links). Mark only count-1 links as candidate abstraction boundaries; counts are stored dependencies, not call sites.
• Reject directory budgets and workspace-parent SCC requests before refresh; workspace children and custom graph directories work through the existing CLI/MCP adapters. Keep the six-tool inventory, ordinary map behavior, core graph algorithms, and main skill/template unchanged. Update README/changelog and the one-line MCP discovery hint.
• Repository import rules required static adapter imports rather than the plan's lazy imports; SCC computation still runs only on a literal explicit opt-in.

Verification

• npm ci: installed missing dev dependencies; prepare/build completed on Node v26.11.1.
• env DO_NOT_TRACK=1 GRAFT_NO_TRAIL_SWITCH=1 node --import tsx --test test/graph-scc.test.ts test/mcp-tools.test.ts: 28/28 passed, no skips. Covers exact partitions/anchors, input reversal and immutability, complete provenance, empty input, a 20,000-node directed path, and real MCP rejected-request/no-refresh then accepted-request/source-edit refresh behavior. The new freshness regression failed before implementation and passed afterward.
• node node_modules/typescript/bin/tsc --noEmit -p tsconfig.json: passed.
• Protected SHA-256 baseline comparison after implementation and smoke: all 12 files unchanged, including the main skill/template, directory map/build/traversal/ranking/types/relations/workspace modules, and MCP server/tool names.
• node --import tsx .scc-smoke.mjs (throwaway script, removed): passed against real commands and actual JSON-lines stdio MCP servers. Exact fixture produced 5 components, 3 links, 2 singleton boundaries; preserved both A→B dependencies and the direct A→c link. Verified complete CLI text/JSON, graft/trail aliases, unchanged ordinary text/JSON and wiring bytes, initialization hint, six schemas with optional boolean, canonical/legacy MCP aliases, scc:false, budget conflicts, missing graphs, custom graph directories, workspace-parent errors without refreshing stale children, child-root CLI/MCP success, and ordinary per-child workspace maps. MCP waited for initialization, collected responses by ID, enforced a 15-second deadline, and terminated children.
• Seeded throwaway smoke: 500 directed graphs matched a mutual-reachability SCC reference and retained all cross-component edge provenance.
• env DO_NOT_TRACK=1 GRAFT_NO_TRAIL_SWITCH=1 npm test: 1,441 passed / 1,448 total; 7 failed, no skips. Full suite is not clean. Failures are outside SCC surfaces: one migration test in graft-to-trail.test.ts, one migration test in hosts-trail.test.ts, three session/note-routing tests in trail-home.test.ts, and stale-cache timing plus migration-nudge tests in upkeep-hooks.test.ts. This run included GRAFT_NO_TRAIL_SWITCH=1, which explicitly disables migration (src/upkeep-run.ts:75); no unrelated code/tests were changed. Scoped SCC/MCP verification above passed afterward.

Closes #632

[trailhq-graft]

🌱 graft blast radius

3 areas changed → 1 area can be affected. 1 dependent symbol, depth 2.
Tests: no test reaches Strongly Connected Components; 1 area updated its tests.
Tag: @anirudhkumar-nanonets — 3 of 4 areas · @shhdwi — 3 of 4 areas

flowchart TB
  A0(("MCP Server<br/>1 symbol"))
  classDef reached fill:#D9EDF3,stroke:#3AA7C9,stroke-width:1.5px,color:#0E313C;
  class A0 reached;

Loading

Can be affected	Symbols	Nearest hop	Reached from
MCP Server	1	src/mcp/server.ts:L73-L155 startMcpServer — calls, depth 1	MCP Tool Integration

Who knows this code — 2 people across 4 areas

Area	Who knows it
MCP Tool Integration · changed	@shhdwi — 15 commits, last 3d ago · @anirudhkumar-nanonets — 9 commits, last 3d ago
Command Line Interface · changed	@anirudhkumar-nanonets — 58 commits, last yesterday · @shhdwi — 26 commits, last yesterday
MCP Server · affected	@anirudhkumar-nanonets — 6 commits, last 3d ago · @shhdwi — 2 commits, last 3mo ago
Strongly Connected Components · changed	only you — nobody else has touched these files

Ownership is git history over each area's own files, weighted towards recent work (120-day half-life). Merge commits and bots are dropped, and you are dropped from your own PR. A name with no @ has no GitHub handle in its commit email — tag them by hand, or add a .mailmap entry. A suggestion from history, not a CODEOWNERS rule.

All 1 dependent symbol, grouped by area

MCP Server — 1 symbol in 1 file

• src/mcp/server.ts:L73-L155 — startMcpServer (calls, depth 1)
  111: instructions: upkeep.length ? `${upkeep.join('\n')}\n\n${mcpInstructions()}` : mcpInstructions(),

Test signal per changed area — 1 ✓ · 1 ✗ · 1 –

Reached = a node under a test path has a resolved edge into the changed symbol. It undercounts anything called indirectly — through a CLI, a spawned process or a dynamic import — so read a low ratio as “look here”, never as a coverage gate.

• ✓ MCP Tool Integration — 1 of 3 reached · 1 test file changed here: test/mcp-tools.test.ts
  • not reached: mcpInstructions, callSingleTool
• – Command Line Interface — no function, method or class changed here
• ✗ Strongly Connected Components — 0 of 2 reached · no test file reaches it
  • not reached: discover, label

4 test suites also reference this code

4 symbols, kept out of the diagram and the table so they cannot crowd out the areas a reviewer has to look at.

• test/graph-follow-submodules.test.ts
• test/graph-load.test.ts
• test/graph-refresh.test.ts
• test/graph-seed.test.ts

⚠️ 2 changed files not in the graph (CHANGELOG.md, README.md) — no parser claims the extension, or the index predates the file.

_{graft blast · origin/main...HEAD · depth 2 · 8 changed files}

Open the interactive graph → — click an area to see its dependent symbols at file:line.