The self-learning context layer for coding agents.
Trail-code gives Claude Code, Cursor, Codex and other coding agents a map of your code, and what your team has learned about it.
| Code map (previously graft) | Learnings |
|---|
| What is it? | An index of your code: every function and who calls it, so your agent sees what a change can break | What you, your agents and your team have learned and decided |
| What does it do for your agent? | Takes it straight to the right files | Lets it pick up where you and your team left off |
| Where does it come from? | Your code, read on your machine | Your conversations, as you work |
46% fewer tool calls, 60% less time, and more real issues solved.
| Cold agent | Agent with the graft map |
|---|
| Tool calls, 162 runs | baseline | 46% fewer |
| Uncached input tokens, 162 runs | baseline | 42% fewer |
| Time, 162 runs | baseline | 60% less |
| SWE-bench Verified, 50 real issues | 27 solved (54%) | 33 solved (66%) |
npm install -g @trailhq/trail-code && trail init
[!NOTE]
Graft is now Trail-code. Graft lives on as the graft map, and every graft command still works. What's new is learnings. What changed
What changes in your agent
| Without Trail-code | With Trail-code |
|---|
| Greps and opens file after file to find the code it needs | Gets the right files and functions with your prompt |
| Re-explores code a teammate already figured out last week | Starts from their learning: what they decided, what they ruled out, what to watch out for |
| Undoes a teammate's decision, because it never knew about it | trail check flags it before the PR, quoting who decided it and why |
| Finds out at merge time that a teammate changed the same code | Says so right after it edits code a teammate's open branch also changes, and whether the two clash |
| Has to be told the same things every session | Starts from what you've told it before: trail init finds what you said more than once in your past sessions |
| You write and update CLAUDE.md by hand | Learnings are saved from your conversations, in files you can read |
Same model, more tasks solved. On SWE-bench Verified (real GitHub issues, graded by the maintainers' own tests), Claude Sonnet 5 solved 33 of 50 issues with the graft map and 27 of 50 without it, using 23% fewer tokens. Details
Cheaper and faster. Across 162 runs of the same agent on the same tasks: 32% lower cost, 42% fewer uncached input tokens, 60% less time, and the same share of correct answers. On PocketBase, 15 real tasks ran 21% cheaper and 14% faster. Details
Contents
How it works
Trail-code has two parts. Both run on your machine.
- The graft map: your code.
trail init parses your repo with tree-sitter into a map of every file, function and who calls what. No model, no API key. It refreshes itself when the code changes, uncommitted edits included. Your agent gets pointers to the matching files and functions with each prompt, and sees what depends on a file right after it edits it.
- Learnings: what you, your agents and your team know. When a session works something out, or you correct how something is done, your agent saves it as a learning. The next session on that code, yours or a teammate's, starts from it instead of digging again. Learnings about the code are committed with the code; learnings about you stay on your machine. On day one,
trail init starts you off with what you told Claude more than once in your past sessions, and what reviewers flagged on more than one of the repo's merged PRs.
The graft map tells your agent where things are. Learnings tell it why they are that way, and how the work gets done here.
Quick start
npm install -g @trailhq/trail-code # install the CLI, once
trail init # in your repo: build the graft map, set up .trail/, wire your agents
[!TIP]
npm install -g says EACCES? Your Node's global folder needs sudo. Skip sudo, or every upgrade will need it too: run mkdir -p ~/.npm-global && npm config set prefix ~/.npm-global, add ~/.npm-global/bin to your PATH, open a new terminal and install again. Trail needs Node 22.3 or newer (20.16 works too).
That is the whole setup. trail init asks which of your coding agents to wire up, builds the graft map from your code, creates .trail/ for the repo's learnings, and adds a statusline and hooks to Claude Code. It also reads your past Claude Code sessions in the repo, once, for what you told Claude more than once, and saves those as learnings. Your own Claude Code does that reading, in about a minute. Then work the way you always do. No daemon, no server, nothing to babysit: it is all files.
This is the beginning of the README. Read the rest at the original. Read the full README ↗
