Trail-Code

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
• Quick start
• Part 1: The graft map, your code
• Part 2: Learnings, what you, your agents and your team know
  • Four kinds, three places · One decision, two teammates · A learning is a file · Your agent does the saving
• Your team
• What stays on your machine
• Benchmark · SWE-bench Verified · Tested on popular repos
• FAQ
• Reference: How the graph gets built · Supported languages · What's in a node · What runs where · Agent integration · CLI · Search & orient · Monorepos · Visualize it · Development

---

How it works

Trail-code has two parts. Both run on your machine.

1. 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.
2. 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

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.

Commit the setup so your teammates get it too. The graft map itself, in graft/, is a local cache like node_modules and is added to .gitignore, so it stays out of the commit:

git add .claude .mcp.json .trail .gitignore .ignore && git commit -m "set up Trail-code"

Team