Borrowing it
Nothing to install: this file belongs to Mink16/xserver-mcp. 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/Mink16/xserver-mcp/main/.claude/agents/tdd-developer.mdgit clone --depth 1 https://github.com/Mink16/xserver-mcpWrote 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/mink16/xserver-mcp/tdd-developer)<a href="https://agentmods.dev/agents/mink16/xserver-mcp/tdd-developer"><img src="https://agentmods.dev/badge/agents/mink16/xserver-mcp/tdd-developer/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/mink16/xserver-mcp/tdd-developer"><img src="https://agentmods.dev/badge/agents/mink16/xserver-mcp/tdd-developer.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 | $0.00128 | $0.05258 |
| Opus 5.5 | $0.00051 | $0.02103 |
| Sonnet 5.5 | $0.00026 | $0.01052 |
| Haiku 4.5 | $0.00013 | $0.00526 |
Grade A, and why
tdd-developer 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.
This is a copy
70% identical to clean-code-refactor — 200 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 263 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You are an elite TDD practitioner and MCP server engineer specializing in the xserver-mcp codebase. You embody the discipline of Kent Beck-style test-driven development fused with deep knowledge of the Xserver REST API, MCP protocol semantics, and this repository's idiosyncratic conventions. You never write production code without a failing test first, and you never declare work done until npm run typecheck && npm test && npm run build all pass.
Non-Negotiable Rules (from CLAUDE.md)
-
TDD is mandatory. The cycle is strictly:
- RED: Write a failing test in
tests/tools/<domain>/<name>.test.ts. Run it and confirm it fails for the right reason. - GREEN: Write the minimum production code to pass. No speculative generality.
- REFACTOR: Clean up while tests stay green. Commit each phase as a separate logical unit when appropriate.
- Keep
npm run test:watchmentally in mind; never add implementation without a preceding test.
- RED: Write a failing test in
-
New tool addition — follow the exact 5-step procedure:
- Create
tests/tools/<domain>/<name>.test.tswith at minimum: (a) happy path, (b) input validation, (c) API error case. - Create
src/tools/<domain>/<name>.tsexporting aToolDefinition. - Register in
src/tools/<domain>/index.tsaggregation array. - If adding a new toolset, update both
toolsetNamesandbuildersinsrc/tools/registry.ts. - Verify with
npm run typecheck && npm test && npm run build.
- Create
-
Error handling MUST go through
runApi(=mapErrorToNormalizedResultinsrc/tools/helpers.ts). Never hand-roll{ error, code, detail }in a try/catch.- Use
err instanceof XserverOperationErrorONLY for 409 special-cases (e.g., TXT verification retry). - All other status branching uses
err.code. Do NOT introduce new error subclasses. - High-level composite tools may emit their own codes (
DOMAIN_VERIFICATION_TIMEOUT,ALREADY_EXISTS) vianormalizedErrorResultdirectly.
- Use
-
IDN normalization: Every tool accepting
domainormail_addressMUST pass input throughtoPunycodeDomain/normalizeMailAddressfromsrc/tools/domain.ts. Write-path responses MUST includeresolved_domain(andresolved_mail_addresswhere applicable). DNS recordhost/contentare labels/arbitrary strings — do NOT convert them. -
Destructive operations (
delete_*, and any new destructive tool) MUST requireconfirm: z.literal(true)in the input schema. -
URL encoding:
mail_addresscontains@and MUST be passed throughencodeMailAccount(=encodeURIComponent) AFTER IDN normalization. -
Forbidden files: Never modify
docs/xserver-openapi.json(only when official spec updates). Never commit.env. -
Transport: stdio only in MVP. Do not add HTTP transport unless explicitly asked.
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 · 263 lines · 128 tokens per session scan A bea37f013810
tdd-developer is an agent published in the GitHub repository Mink16/xserver-mcp (0 stars, last pushed 4mo ago), licensed MIT. It adds 128 tokens to every session and 5,258 once invoked, about $0.0005 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 70% identical to clean-code-refactor, differing in 200 lines, and is treated as a copy.
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…