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Agent skill

Dev TDD

by hashgraph-online in hashgraph-online/awesome-codex-plugins

Implement scoped behavior changes using meaningful tests before code where practical.

Apache-2.0Auto-check passedTesting & QA

Install Dev TDD

skills CLI
$ npx skills add hashgraph-online/awesome-codex-plugins --skill dev-tdd -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI
$ gh skill install hashgraph-online/awesome-codex-plugins dev-tdd --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy
$ git clone --depth 1 https://github.com/hashgraph-online/awesome-codex-plugins.git skills-src && mkdir -p .claude/skills && cp -r skills-src/plugins/Jason-chen-coder/dev-skills/skills/dev-tdd .claude/skills/dev-tdd && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Facts

Skill name
dev-tdd
GitHub stars
1.2k
Token cost
~1.1k tokens
SKILL.md length
588 words
Files
3 (incl. references)
Skills in repo
686
Repo updated
First seen
Licence
Apache-2.0

At a glance

Implement scoped behavior changes using meaningful tests before code where practical.

  • Works in 4 steps: Run the focused test. For new behavior,… → Implement the smallest coherent behavior… → Run the same test and inspect the… → …
  • Behavior-preserving refactors
  • SKILL.md covers Load baseline, Establish the behavior, Choose the test strategy and Implement and verify, plus 2 more sections
  • Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md

What it does

Dev TDD is an agent skill from hashgraph-online/awesome-codex-plugins. Implement scoped behavior changes using meaningful tests before code where practical. Use for features, behavior-preserving refactors, and direct fixes with a known cause; use dev-fix for bug investigation. Documentation, formatting, and asset-only edits do not need this coding workflow.

Its SKILL.md is about 1.1k tokens, which your agent loads only when the skill is triggered. The skill folder holds 3 other files, including reference files (for example `examples.md` and `references/dev-baseline.md`).

It sits in Testing & QA, covering Test-driven development and Refactoring. The repository describes itself as: A curated list of awesome OpenAI Codex / ChatGPT plugins, skills, and resources. The 1 Codex Marketplace. See live plugins at: https://hol.org/plugins/best-codex-plugins. The licence is Apache-2.0.

When your agent uses it

  • Behavior-preserving refactors
  • Direct fixes with a known cause
  • Use dev-fix for bug investigation

Example prompts

  • “/dev-tdd”

Workflow steps

4 steps, taken from the first numbered list in SKILL.md.

  1. Run the focused test. For new behavior, confirm failure comes from the missing behavior, not a broken fixture, import, or environment. If…
  2. Implement the smallest coherent behavior change. Keep assertions intact unless investigation shows the test contradicts the contract.
  3. Run the same test and inspect the result. Refactor only what the task needs, and rerun affected checks after further edits.
  4. Expand checks according to impact: adjacent paths for a local change, integration and project checks for shared interfaces, persistence…

What it can do on your machine

Read from SKILL.md and the folder at commit 78497e5. It shows what the files ask for, not the result of running them.

  • Tool permissions

    Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

    From allowed-tools in the SKILL.md frontmatter.

  • Runs code

    No scripts in the folder and no shell commands in SKILL.md.

    From the folder's file list and the shell code blocks in SKILL.md.

  • Network

    No URLs in SKILL.md.

    From URLs in SKILL.md, links to its own repository left out.

  • Credentials

    Names no API keys, tokens, secrets or passwords.

    From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Dev TDD loads about 1.1k tokens when it runs, and up to ~2k if it reads all its reference files. Until then it costs about 74 tokens; SKILL.md has 588 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it
~74
When it runs · the whole SKILL.md, loaded when a task matches
~1.1k
With references · SKILL.md plus every file in references/, read only if the agent opens them
~2k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from hashgraph-online/awesome-codex-plugins at commit 78497e5, republished under its Apache-2.0 licence (© hashgraph-online). 588 words, ~1,127 tokens.

Download SKILL.mdSave it as .claude/skills/dev-tdd/SKILL.md (or your agent's skills folder). This skill also uses 2 other files; get the full folder from GitHub.
name
dev-tdd
description
Implement scoped behavior changes using meaningful tests before code where practical. Use for features, behavior-preserving refactors, and direct fixes with a known cause; use dev-fix for bug investigation. Documentation, formatting, and asset-only edits do not need this coding workflow.

Dev TDD

Use tests to establish the behavior being implemented, then make the smallest coherent change. Honor an explicit request for strict TDD; otherwise choose verification proportional to the behavior and risk.

Load baseline

Read references/dev-baseline.md before execution. Resolve paths relative to this skill directory.

Establish the behavior

  • Read the affected implementation, nearby tests, and project test commands before choosing a test boundary.
  • Use the current request and relevant SDD spec/plan as the contract. Existing artifacts may live in .claude/artifacts/designs/ or .claude/artifacts/plans/; read only those connected to this task. The user's latest correction takes precedence over an older artifact.
  • State expected observable behavior briefly. Ask only when a missing decision materially changes the implementation and cannot be inferred from the project.
  • Inspect repository root, branch, working tree, and index before edits. Preserve unrelated changes, partially staged files, and explicit exclusions. A dirty tree alone is not a blocker.

Choose the test strategy

For new behavior or a known regression, prefer a focused test that fails on the unchanged implementation. Exercise the real boundary and assert outputs or state transitions; avoid assertions that mirror implementation details.

For behavior-preserving refactors, passing characterization tests on the original implementation are valid evidence. Add coverage for relevant gaps, then keep those tests passing during the refactor.

Low-impact reversible changes need no new test if it would only restate the edit. Use an existing check or direct inspection where sufficient. Respect a user's request to skip TDD without a second permission exchange; run appropriate remaining checks and state the resulting evidence limit. Never call post-implementation tests a completed red/green cycle.

Implement and verify

  1. Run the focused test. For new behavior, confirm failure comes from the missing behavior, not a broken fixture, import, or environment. If a required symbol does not yet exist, establish that the failure is exactly that missing contract; it does not yet prove runtime behavior.
  2. Implement the smallest coherent behavior change. Keep assertions intact unless investigation shows the test contradicts the contract.
  3. Run the same test and inspect the result. Refactor only what the task needs, and rerun affected checks after further edits.
  4. Expand checks according to impact: adjacent paths for a local change, integration and project checks for shared interfaces, persistence, authentication, or other high-risk behavior. Do not repeat sufficient checks without a new change or unresolved concern.

A second reversal of the fix is optional when the original red result already proves the test detects the defect. If additional mutation testing is needed, isolate it in a temporary copy and preserve the regression test; never use a blanket stash or reset on the shared working tree.

Show full SKILL.md (149 more words)Show less

Completion and handoff

Report the changed behavior, commands and observed results, and material limitations. Map evidence to relevant SDD acceptance criteria when present. Use dev-verify if available for completion evidence and dev-code-review when review is requested or required; their names do not force a new workflow or extra user turn. Without those skills, perform equivalent scoped checks directly. Commit, PR, and branch operations require the corresponding user authorization.

Multi-Agent Profile

Recommended agent_type: worker

Delegate only when permitted and a bounded behavior can be implemented independently. Each worker owns explicit files or modules and reports its source requirement, changed files, test evidence, and limitations. Keep concurrent changes and index state intact. A reviewer or verifier evaluates the resulting implementation in a separate pass without inheriting its conclusions as proof.

When installed from this repository, docs/multi-agent-policy.md provides additional coordination guidance if available. Standalone installations use the ownership and evidence rules above.

© hashgraph-online, Apache-2.0. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 2 other files (references) in plugins/Jason-chen-coder/dev-skills/skills/dev-tdd of hashgraph-online/awesome-codex-plugins.

  • SKILL.md
  • examples.md
  • references/dev-baseline.md

Open the folder on GitHubat commit 78497e5

Compare with similar skills

Dev TDD next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Dev TDD compared with similar skills
SkillStarsUsed inTokensAuto-checkLicenceRepo updated
Dev TDD this skillhashgraph-online/awesome-codex-plugins1.2k—~1.1kAutomated safety check: PassApache-2.0
TDD WorkflowhellangleZ/burn-in-cceverywhere-ralph11211 repos~2.4kAutomated safety check: PassNone
TDD Methodoly Expertthedaviddias/skill-check190—~2.2kAutomated safety check: PassMIT
Implementgenkovich/sdd171—~2.5kAutomated safety check: PassMIT
TDDDanMcInerney/architect-loop626—~730Automated safety check: PassMIT
TDD Workflowaffaan-m/ECC275k1 repos~2.6kAutomated safety check: PassMIT

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Categories

Questions about Dev TDD

What does Dev TDD do?

Implement scoped behavior changes using meaningful tests before code where practical. Dev TDD is an agent skill from hashgraph-online/awesome-codex-plugins. Implement scoped behavior changes using meaningful tests before code where practical.

When should I use Dev TDD?

Dev TDD fits situations like: behavior-preserving refactors; direct fixes with a known cause; use dev-fix for bug investigation.

How do I install Dev TDD in Claude Code?

Run `npx skills add hashgraph-online/awesome-codex-plugins --skill dev-tdd -a claude-code`. Or copy the skill folder (plugins/Jason-chen-coder/dev-skills/skills/dev-tdd in hashgraph-online/awesome-codex-plugins) into .claude/skills/dev-tdd in your project. Claude Code loads it when a task matches its description.

How do I install Dev TDD in Codex?

Run `npx skills add hashgraph-online/awesome-codex-plugins --skill dev-tdd -a codex`. Or copy the skill folder (plugins/Jason-chen-coder/dev-skills/skills/dev-tdd in hashgraph-online/awesome-codex-plugins) into .agents/skills/dev-tdd in your project. Codex loads it when a task matches its description.

Can I use Dev TDD in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add hashgraph-online/awesome-codex-plugins --skill dev-tdd -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/dev-tdd, .gemini/skills/dev-tdd, .github/skills/dev-tdd and .opencode/skills/dev-tdd in your project.

What does Dev TDD need to run?

SKILL.md names no scripts, command-line tools or credentials: Dev TDD is instructions for the agent only.

Does Dev TDD access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is Dev TDD safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Dev TDD use?

Dev TDD is published under the Apache-2.0 licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Dev TDD use?

About 1.1k tokens (SKILL.md is roughly 4.5k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full. Its references folder adds about 893 tokens, read only when the agent opens those files.

What are the alternatives to Dev TDD?

Skills that share tags, products or a category with Dev TDD: TDD Workflow (hellangleZ/burn-in-cceverywhere-ralph, 112 stars), TDD Methodoly Expert (thedaviddias/skill-check, 190 stars), Implement (genkovich/sdd, 171 stars) and TDD (DanMcInerney/architect-loop, 626 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Dev TDD?

hashgraph-online (a GitHub organization) maintains it in hashgraph-online/awesome-codex-plugins, which has 1,242 GitHub stars. The repository holds 686 skills in this directory. The repository was last updated on October 8, 2026.

Source: hashgraph-online/awesome-codex-plugins on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.