PinchMCP

Find the keystone ticket — the one that, once done, unblocks the most downstream work.

An MCP server between Claude Code and Linear. It reads a project's issues and their blocking relations, fuses them into an in-memory dependency graph, and points you at the leverage — via dominator analysis, not a bare score. Then it goes further: the critical path (CPM), inferred code coupling, cold-start predictions for not-yet-built tickets, and graph hygiene.

Deterministic, read-only, no LLM in the server — it analyzes; you decide.

Status — v0.4.0. Phases I–III shipped (9 tools spanning the explicit dependency graph, inferred code coupling, cold-start prediction, graph hygiene, and feature-decomposition grounding), plus the first Phase IV deliverable — 10 tools in total. Phase IV (Slack + Granola integrations) is on the roadmap — the Granola reconciliation server side has shipped as reconcile_notes; the ingestion/delivery integration remains. See docs/ROADMAP.md for done vs. planned and docs/SECURITY.md for the trust model.

Running locally (quickstart)

There is nothing to deploy. PinchMCP is a stdio MCP server: Claude Code launches it as a local subprocess on demand and talks to it over stdin/stdout. "Running it" just means the built code lives on the machine where you run Claude Code — no port, no daemon, no hosting. Each developer who wants it does this once on their own machine, with their own Linear key.

End to end:

# 1. Get the code and build it (needs Node 22+)
git clone https://github.com/0xdefence/PinchMCP.git
cd PinchMCP
npm install
npm run build

# 2. Get a Linear personal API key
#    Linear → Settings → Security & access → Personal API keys → Create key
#    (copy the lin_api_… value)

# 3. Find the project_id you want to analyze
curl -s https://api.linear.app/graphql \
  -H "Authorization: lin_api_your_key" \
  -H "Content-Type: application/json" \
  -d '{"query":"{ projects(first: 50) { nodes { id name } } }"}'

// 4. Register the server with Claude Code.
//    Create .mcp.json in your project root (or ~/), using the ABSOLUTE path
//    to dist/src/index.js printed by `pwd`:
{
  "mcpServers": {
    "pinch-mcp": {
      "command": "node",
      "args": ["/absolute/path/to/PinchMCP/dist/src/index.js"],
      "env": { "LINEAR_API_KEY": "lin_api_your_key" }
    }
  }
}

5. Restart Claude Code, run /mcp to confirm "pinch-mcp" is connected,
   then ask: "Rank the keystones for Linear project <project_id>."

Each step is expanded in the sections below (Install · API key · project_id · Connect to Claude Code · Use it).

Related MCP server: Linear MCP Server

What it does

Questions teams actually ask, with distinct answers:

• Keystone — "What single ticket, once done, unblocks the most downstream work?" Answered by dominator analysis: a ticket is high-leverage when every path to many downstream tickets must pass through it. This is not the same as "the ticket that touches the most things" — a bottleneck that gatekeeps 5 tickets beats a ticket that merely precedes 20 reachable ones.

• Critical path — "What sets the total timeline?" Answered by CPM over estimates: the longest-duration dependency chain, plus how much slack every other ticket has. Distinct from keystone — max-leverage unlock vs. what sets duration.

• Blockers — "For this one ticket, what must finish first, and what does it unblock?" Answered by a transitive walk up and down the dependency chain.

Explainability is the product. Output says why: "every path to ENG-2, ENG-3 passes through ENG-1," not a bare score.

Tools exposed to Claude Code

Across the analysis tools, project_id accepts a Linear project name, URL slug, or UUID — it's resolved internally, so you can speak in names ("rank keystones for 0xDefence") and PinchMCP maps it to the right project.

Requirements

• Node.js 22 or newer (active LTS; Node 18 is end-of-life). The server uses the global fetch.

• A Linear account and a personal API key.

• Claude Code (or any MCP client that can launch a stdio server).

Install

git clone https://github.com/0xdefence/PinchMCP.git
cd PinchMCP
npm install
npm run build

npm run build compiles TypeScript to dist/. The server entrypoint is dist/src/index.js.

Verify it built and starts (it should wait for stdio input, then exit cleanly on EOF):

LINEAR_API_KEY=dummy node dist/src/index.js < /dev/null && echo "starts OK"

With no key it should fail fast with a clear message:

node dist/src/index.js < /dev/null   # -> Error: LINEAR_API_KEY environment variable is required.

Get a Linear API key

1. Linear → Settings → Security & access → Personal API keys.

2. Create key, give it a name, copy the value (looks like lin_api_…).

The key is passed to the server as the LINEAR_API_KEY environment variable. For local CLI use you can also copy .env.example to .env and set it there.

Never commit your key. .env is gitignored. The key grants access to your Linear workspace.

Fetched project graphs are cached in memory for 5 minutes by default. Set PINCH_CACHE_TTL_MS (a positive integer, in milliseconds) to override the TTL. build_feature_graph always forces a refresh regardless of the cache.

Find your project_id

The analysis tools take a Linear project UUID or the URL slug — not a display name (Linear's project(id:) lookup rejects names). Three ways to get a valid value:

1. Ask Claude Code once the server is connected: "list my Linear projects" runs the list_projects tool and prints every project with its id and slug.

2. From the project URL — linear.app/<workspace>/project/<name>-<slugId>. Paste the whole <name>-<slugId> slug or just the trailing hex; both work.

3. Via curl:

curl -s https://api.linear.app/graphql \
  -H "Authorization: $LINEAR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"query":"{ projects(first: 50) { nodes { id name slugId } } }"}' | jq

Any id or slugId from the output works as project_id.

Connect it to Claude Code

PinchMCP is a stdio MCP server. Point Claude Code at the built entrypoint with your API key in the environment.

Option A — project config file (recommended)

Create .mcp.json in the root of the repo where you want to use it (or your home directory for global use):

{
  "mcpServers": {
    "pinch-mcp": {
      "command": "node",
      "args": ["/absolute/path/to/PinchMCP/dist/src/index.js"],
      "env": { "LINEAR_API_KEY": "lin_api_your_key_here" }
    }
  }
}

Use the absolute path to dist/src/index.js. Restart Claude Code (or reconnect MCP servers) so it picks up the config.

Option B — Claude Code CLI

claude mcp add pinch-mcp \
  -e LINEAR_API_KEY=lin_api_your_key_here \
  -- node /absolute/path/to/PinchMCP/dist/src/index.js

Verify the connection

In Claude Code, run /mcp — you should see pinch-mcp connected with ten tools. If it shows as failed, check: the path is absolute and points at dist/src/index.js, you ran npm run build, and LINEAR_API_KEY is set.

Use it

Once connected, just ask Claude Code in natural language — it will call the tools. Examples:

• "Build the feature graph for project <project_id> and rank the keystones."

• "Which ticket is the biggest bottleneck in <project_id>?"

• "What's blocking ENG-42, and what does it unblock?"

Claude Code decides when to call build_feature_graph, rank_keystones, and explain_blockers, and explains the results using the tool output.

How it works

Claude Code ──tool call──▶ PinchMCP (stdio)
                              │
              config ─▶ LinearGraphQLSource ──GraphQL──▶ api.linear.app
                              │
                         GraphCache (per project_id)
                              │
                       buildFeatureGraph
                       (normalize blocks/blocked_by → canonical edges)
                              │
              ┌───────────────┴───────────────┐
        rankKeystones                   explainBlockers
   (dominator tree, leverage)       (transitive chain walk)
              │                               │
        explainable text ◀── tool handlers ──▶ explainable text

• Linear layer (src/linear/) — a GraphQL client behind an IssueSource interface (the seam where a future MCP-to-MCP client could slot in), plus normalization of raw payloads into domain Issue/Relation types.

• Graph layer (src/graph/) — pure, I/O-free functions:

  • buildFeatureGraph normalizes blocks/blocked_by into one canonical "A unblocks B" edge direction, de-dups, drops out-of-project and self edges, and keeps related/duplicate as side metadata.

  • rankKeystones adds a virtual entry node to all unblocked tickets, computes a dominator tree (Cooper-Harvey-Kennedy), and sets each ticket's leverage to the size of its dominated subtree.

  • explainBlockers walks predecessors/successors transitively.

• Cache (src/cache.ts) — one built graph per project_id; build_feature_graph forces a refresh.

• Tools (src/tools/) — thin formatters turning graph results into human-readable, explainable output.

Why dominators, not reachability

A node's reachable descendants counts everything downstream, including work reachable by other paths too. A dominator is stricter: ticket X dominates ticket Y only if every path to Y passes through X. That's the real "if this slips, everything behind it slips" signal. The test suite includes a bottleneck graph proving these two metrics diverge.

Documentation

• docs/ARCHITECTURE.md — layers, modules, data types, request flow, error handling, design decisions, and extension points.

• docs/KEYSTONE-ALGORITHM.md — the dominator analysis in depth: why dominators beat reachability, the Cooper–Harvey–Kennedy computation, leverage, edge cases, and complexity.

• docs/ROADMAP.md — what's shipped vs. planned across Phase I (explicit graph), Phase II (code grounding), and Phase III (generative scoping).

• docs/DECOMPOSITION-WORKFLOW.md — how to break a free-text feature into grounded Linear tickets using decompose_grounding, Claude Code, and the Linear MCP together.

• docs/RECONCILIATION-WORKFLOW.md — how to reconcile client-extracted meeting-note items against the graph using reconcile_notes, Claude Code, and the Linear MCP together.

• docs/SECURITY.md — trust model: read-only, one local secret (never logged), writes delegated to the Linear MCP, and how integrations keep secrets with their own MCP.

Develop

npm test        # full vitest suite
npm run dev     # run from source via tsx (no build step)
npm run build   # compile to dist/ (emits src only, via tsconfig.build.json)

The graph algorithms are pure functions tested against synthetic fixtures with hand-computed dominator trees; the Linear adapter is tested against a recorded JSON fixture — no live API calls in the test suite.

Roadmap

Phase I (this explicit-graph slice) is shipped. Phase II adds the inferred code-coupling graph + critical_path; Phase III adds generative scoping (break features into tickets, surface gaps). Full status — done vs. not — is tracked in docs/ROADMAP.md.

Known limitations (slice 1)

• Issues are paged at 50 per request to stay under Linear's 10k query-complexity cap (up to 10,000 issues across pages). A single issue's relations beyond the first 50 are fetched via follow-up paginated queries, so no overflow is missed.

• explain_blockers doesn't annotate cycles, though rank_keystones does.

• Inferred direction from code coupling is not here yet — this slice uses only Linear's explicit, human-asserted relations.