tcr-kentbeck

tcr-kentbeck is a skill for Claude Code, Codex from xpepper/tcr-skill. It costs 124 tokens per session (1,130 once invoked), scanned A, original, MIT.

A strict Test && Commit || Revert workflow, often shortened to TCR. After each small code change, tests run; a passing change is committed, while a failing change is discarded.

In plain words
What is it for?
Use it when strict incremental development is required: make a tiny change, run the project’s full test command, commit green results, and revert red ones.
Why use it?
It prevents failing changes from remaining in the working tree or commit history and keeps each committed step validated.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it when strict incremental development is required: make a tiny change, run the project’s full test command, commit green results, and revert red ones.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/xpepper/tcr-skill/tcr-kentbeck
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.

Any agent
npx skills add xpepper/tcr-skill --skill tcr-kentbeck
Clone the repo
git clone --depth 1 https://github.com/xpepper/tcr-skill

Made for: Claude Code, Codex.

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 tcr-kentbeck

README.md
[![agentmods](https://agentmods.dev/badge/skills/xpepper/tcr-skill/tcr-kentbeck/github.svg)](https://agentmods.dev/skills/xpepper/tcr-skill/tcr-kentbeck)
Your own site
<a href="https://agentmods.dev/skills/xpepper/tcr-skill/tcr-kentbeck"><img src="https://agentmods.dev/badge/skills/xpepper/tcr-skill/tcr-kentbeck/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 tcr-kentbeck

Your own site · 80×15
<a href="https://agentmods.dev/skills/xpepper/tcr-skill/tcr-kentbeck"><img src="https://agentmods.dev/badge/skills/xpepper/tcr-skill/tcr-kentbeck.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 124 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,130 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 $0.00124 $0.01130
Opus 5 $0.00062 $0.00565
Sonnet 5 $0.00025 $0.00226
Haiku 4.5 $0.00012 $0.00113

Measured 10d ago against content hash fc9a2b87f8af, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

tcr-kentbeck 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 10d 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.

tcr-kentbeck/SKILL.md · 66 lines

How it starts

The opening of the file, as written. The whole thing — 66 lines — stays where its author put it; the contents beside it link to each section on GitHub.

TCR (Test && Commit || Revert)

Non-negotiables

When this skill applies, treat TCR as mandatory, not optional:

  1. One small step — Prefer the smallest change that could move tests toward green (or add a failing test first in strict TDD, then minimal implementation).

  2. Run tests — Use the project’s real test command (see Detecting the test command). Always run the full suite for that command (same as CI / default project test entrypoint): e.g. pytest with no path arguments, npm test / pnpm test / yarn test, cargo test, go test ./..., make test if that runs everything. Do not narrow to a single file, class, or -k filter unless the user explicitly asks for a scoped run.

  3. Green → commit — If tests pass, commit that step immediately with a message that describes what changed (present tense, imperative).

  4. Red → revert — If tests fail, do not keep the change. Restore the working tree to the last committed state (git restore . / git checkout -- . or revert unstaged edits as appropriate). Then retry with a smaller or different step.

  5. Red → log — After reverting, append an entry to tcr-failure-log.md at the repository root (create it with a short title if missing). Record what went wrong so the failure is not invisible: when (ISO timestamp or equivalent), which test(s) failed and the assertion or error (or a short traceback excerpt), what change was attempted (intent in one or two sentences), and optionally what to try next. This file is append-only; do not delete past entries. Commit this log update with the next green commit if it is part of the same work, or as its own tiny commit if the user prefers a clean separation.

Do not accumulate uncommitted red edits “to fix in the next message.” Red means revert first, then log.

Workflow loop

edit (tiny) → run tests → pass? → git add + git commit
                      ↘ fail? → revert working tree → append tcr-failure-log.md → try again

Read the full file on GitHub · 66 lines

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. 10d ago First seen · 66 lines · 124 tokens per session scan A fc9a2b87f8af

Subscribe to this mod's changes

tcr-kentbeck is a skill published in the GitHub repository xpepper/tcr-skill (2 stars, last pushed 5mo ago), licensed MIT. It adds 124 tokens to every session and 1,130 once invoked, about $0.0006 per session on Opus 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.