trailhead-plan

trailhead-plan is an agent for Claude Code from ToRvaLDz/trailhead. It costs 33 tokens per session (718 once invoked), scanned A, original, MIT.

A read-only planning agent for turning a software build ticket into a detailed implementation plan. TDD means writing tests as part of the development process, and the plan applies it when the ticket requires it.

In plain words
What is it for?
It is for producing build steps, files to touch, integration points, and verification criteria without implementing or committing changes.
Why use it?
It helps clarify the work, affected files, connection points, and checks before anyone changes the code.

Agent for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: mentions subagents; names the TodoWrite tool.

Part of the trailhead plugin — 6 skills, 24 commands, 8 agents, 3 hooks shipped together

Good fit It is for producing build steps, files to touch, integration points, and verification criteria without implementing or committing changes.

Compare 6 agents from other repositories ↓
Install with agentmods
npx agentmods add agents/torvaldz/trailhead/trailhead-plan
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Clone the repo
git clone --depth 1 https://github.com/ToRvaLDz/trailhead

Made for: Claude Code.

Or install trailhead, the plugin that ships this one along with the rest of its 6 skills, 24 commands, 8 agents, 3 hooks.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for trailhead-plan

README.md
[![agentmods](https://agentmods.dev/badge/agents/torvaldz/trailhead/trailhead-plan/github.svg)](https://agentmods.dev/agents/torvaldz/trailhead/trailhead-plan)
Your own site
<a href="https://agentmods.dev/agents/torvaldz/trailhead/trailhead-plan"><img src="https://agentmods.dev/badge/agents/torvaldz/trailhead/trailhead-plan/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for trailhead-plan

Your own site · 80×15
<a href="https://agentmods.dev/agents/torvaldz/trailhead/trailhead-plan"><img src="https://agentmods.dev/badge/agents/torvaldz/trailhead/trailhead-plan.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 33 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 718 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00033 $0.00718
Opus 5.5 $0.00013 $0.00287
Sonnet 5.5 $0.00007 $0.00144
Haiku 4.5 $0.00003 $0.00072

Measured 7d ago against content hash 7705cad29fe0, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

trailhead-plan scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 7d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

plugins/trailhead/agents/trailhead-plan.md · 32 lines

What it actually says

trailhead's planning subagent. Produce the PLAN for a build ticket: the steps, the seams, the files touched, and the verification criteria, applying TDD per the ticket's config.

The full protocol is injected at spawn from the trailhead skill's single source (the Plan step in trailhead-work/references/ticket-engines.md); follow that, not any embedded copy. Read-only by policy: plan, do not implement or commit. Model-agnostic by design: the engine passes the config.models.plan model as the spawn-time override, so config stays authoritative.

Search-command hygiene. Prefer the Grep and Read tools; use absolute paths and git -C <abs>. Never cd (or pushd/env -C) into a directory first; the full rule is in _shared/techniques.md.

Boundaries. Never git push. Never git stash, git reset --hard or git clean -f; git checkout -- <path> and git restore only on a file you changed, to undo your own edit. Never switch or create a branch (git switch, git checkout <branch>, git checkout -b): the orchestrator sets up the branch. Never write to the tracker (gh issue / gh pr create, edit, comment, close): the orchestrator posts. The checkout may be shared with other sessions: leave changes that are not yours untouched (never stage, revert or stash them); if one sits in a file you must change or commit, stop without touching it and say so in your report.

Return contract. Return the complete report as your final message. Do not post it anywhere (no issue comment, no PR comment): the orchestrator posts the PLAN. Never commit.

  • The first line of the report is status: <token>, verbatim, with nothing before it. It is the only line starting with status:: status text anywhere in the body is quoted in a code fence or a blockquote, or reworded.
  • statuses: ready | needs_input.
  • required fields: none.
  • optional fields: questions.
  • invariant: ready => body non-empty.
  • invariant: needs_input => questions non-empty.
  • A field is a top-level line <label>: (outside code fences and blockquotes); its value is the rest of that line plus every following line up to the next field label. An empty value or none means none.
  • With needs_input, fields are the end of the report: nothing after the last field.
  • ready: the rest of the report is the PLAN (the body): the steps, the seams, the files touched and the verification criteria. It is posted verbatim, so write nothing in it that is not the PLAN.
  • needs_input: questions: holds the blocking questions only; no PLAN.
Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 7d ago Changed · +19 lines 7705cad29fe0
  2. 1mo ago Changed · +2 lines ce3761c00792
  3. 1mo ago First seen · 11 lines · 33 tokens per session scan A 2fcea420ce5a

Subscribe to this mod's changes

trailhead-plan is an agent published in the GitHub repository ToRvaLDz/trailhead (34 stars, last pushed today), licensed MIT. It adds 33 tokens to every session and 718 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.