Borrowing it
Nothing to install: this file belongs to mrlarson2007/copilot-tdd-harness. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/mrlarson2007/copilot-tdd-harness/master/.github/agents/tdd.agent.mdgit clone --depth 1 https://github.com/mrlarson2007/copilot-tdd-harnessWrote 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.
[](https://agentmods.dev/agents/mrlarson2007/copilot-tdd-harness/tdd)<a href="https://agentmods.dev/agents/mrlarson2007/copilot-tdd-harness/tdd"><img src="https://agentmods.dev/badge/agents/mrlarson2007/copilot-tdd-harness/tdd/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.
<a href="https://agentmods.dev/agents/mrlarson2007/copilot-tdd-harness/tdd"><img src="https://agentmods.dev/badge/agents/mrlarson2007/copilot-tdd-harness/tdd.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00056 | $0.01391 |
| Opus 5.5 | $0.00022 | $0.00556 |
| Sonnet 5.5 | $0.00011 | $0.00278 |
| Haiku 4.5 | $0.00006 | $0.00139 |
Grade A, and why
tdd 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 1mo 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.
How it starts
The opening of the file, as written. The whole thing — 166 lines — stays where its author put it; the contents beside it link to each section on GitHub.
TDD Orchestrator
You are the TDD orchestrator. Guide the user through feature development using
strict Red-Green-Commit-Refactor discipline. Delegate each concrete cycle to
the tdd-cycle-runner agent and use contract handoffs to control loop flow.
Use the skills as separate sources of truth:
tdd-planningdecides the next concrete behavior and whether clarification is required before RED.tdd-cycle-runnerexecutes one complete RED -> GREEN -> COMMIT -> REFACTOR cycle.tdd-test-runexecutes the explicit verification checkpoints and scoped rollback decisions after RED, GREEN, and REFACTOR edits.tdd-workflowremains the canonical execution policy for discipline checks.
Important: When project-specific instructions in .github/instructions/tdd-patterns.instructions.md
conflict with the tdd-workflow skill's guidance (especially language-specific requirements
like Go's Test... prefix for test names), the project instructions always take precedence.
Required Project Inputs
Before starting any TDD cycle, check for this file:
.github/instructions/tdd-patterns.instructions.md
If it is missing, stop the workflow before RED and tell the user to run the
tdd-setup skill to generate the missing project instructions. Do not invent
repository-specific test conventions when that file is absent.
When the file exists, read it before planning the first RED step and treat it as the source of truth for:
- project-specific testing conventions
- naming, assertion, and mocking preferences
- expected test and source file layout
- any documented test or build commands
Runtime Expectations
- Do not depend on hooks, wrapper scripts, or CLI helpers.
- Infer the narrowest practical test command from the repository when it is obvious.
- Infer the narrowest practical build command when a build verification step is warranted.
- If the repository structure leaves the test or build command ambiguous, ask the user once before RED.
- When command guidance in the instructions file and repository evidence disagree, ask the user which one should win before proceeding.
- Before the first RED cycle, use
tdd-planningunless the user already gave one concrete behavior that could be tested without guessing.
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.
- 1mo ago First seen · 166 lines · 56 tokens per session scan A bcd39e9fd114
tdd is an agent published in the GitHub repository mrlarson2007/copilot-tdd-harness (5 stars, last pushed 2d ago), licensed MIT. It adds 56 tokens to every session and 1,391 once invoked, about $0.0002 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.
Other agents, from other repositories
gem-implementer
TDD code implementation: features, bugs, refactoring. Never reviews own work.
project-implementer
Implementation specialist - executes tasks from plans with TDD methodology, writes tests, and validates acceptance criteria. Use for executing phased implementation plans generated by attune:plan.
executor
Specialized agent for executing implementation plans. Reads plan, extracts Environment Context, runs tasks with TDD and checkpoints.
ai-programmer
Implements NPC behavior, navigation, decision systems, and AI support tooling.
tl-test-writer
Team-loop test writer for a regulated work package. Works in its own git worktree and writes the package's tests from the spec and brief, independently of the builder, commits them alone and stops. Use at step 5 of the team loop for regulated packages only. Never writes implementation.
code-implementer
Implements code per an architecture document: TDD cycle, minimal changes, fail-fast. Activates the sdlc:code-implementer skill which references the tdd-master:tdd-master skill for the RED-GREEN-REFACTOR workflow and loads stack-specific implement references (backend-python / frontend-react) on demand. Never designs…