Trail-Code MCP Server: Setup for Claude Code, Cursor and Other Apps

• Finds the code that answers a question about your project

  Takes a question in plain words and returns the best-matching functions with file and line numbers and the source included. The README says it is usually the full answer, with no follow-up read needed.

  Try: “Where do we handle failed payment retries?”

  Files · trail_find_code

• Lists every function in a file without the code inside

  Returns the signatures in one file with no function bodies, so the assistant sees what a file offers using about a tenth of the tokens.

  Try: “Show me what src/billing/invoice.ts exposes.”

  Files · trail_file_api

• Shows what calls a function, or what it calls

  Follows the call graph from a symbol, up to a number of levels deep, to show what a change could break. You can also trace what a function depends on.

  Try: “What breaks if I change calculateTax?”

  Files · trail_trace_calls

• Finds every match for a pattern, grouped by function

  Searches the code for a regular expression and groups every hit by the function around it, ranked by how connected that function is.

  Try: “Find every place that reads process.env.STRIPE_KEY.”

  Files · trail_find_all

• Gives a first overview of an unfamiliar repo

  Returns the main folders, the most connected files and the busiest areas of a repo, so the assistant can orient itself.

  Try: “Give me a map of this repo before we start.”

  Files · trail_repo_map

• Checks whether the code map is out of date

  Reports whether the local map has drifted from the current code.

  Try: “Is the code map up to date?”

  Files · trail_check_freshness

Watch out for

• The full CLI changes more than the MCP server

  The init command writes hooks, a statusline and instruction files for your agents. Register only the MCP server by hand if you want just the six tools. github.com

• It sends anonymous usage stats unless you opt out

  The README says the ping carries buckets and fixed labels only, never code, paths or queries. Set DO_NOT_TRACK=1 to turn it off, along with the daily version check. github.com

• Optional deep summaries use a model provider

  The optional deep build sends summaries to the model provider you choose, under your own key. The six MCP tools do not need it. github.com

• Queries refresh a local code map on disk

  Before it answers, the server re-checks the project and rebuilds its local code map if files changed, which writes to the project's graph folder. The README says this refresh is structural and never calls a model. github.com

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