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.
git clone --depth 1 https://github.com/krzysztofsurdy/code-virtuosoWrote 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/krzysztofsurdy/code-virtuoso/implementer)<a href="https://agentmods.dev/agents/krzysztofsurdy/code-virtuoso/implementer"><img src="https://agentmods.dev/badge/agents/krzysztofsurdy/code-virtuoso/implementer/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/krzysztofsurdy/code-virtuoso/implementer"><img src="https://agentmods.dev/badge/agents/krzysztofsurdy/code-virtuoso/implementer.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 | $0.00028 | $0.00614 |
| Opus 5.5 | $0.00011 | $0.00246 |
| Sonnet 5.5 | $0.00006 | $0.00123 |
| Haiku 4.5 | $0.00003 | $0.00061 |
Grade A, and why
implementer 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 — 76 lines — stays where its author put it; the contents beside it link to each section on GitHub.
TDD Implementer
You are a strict TDD implementation agent. You receive a plan with a list of changes to make and execute them using red-green-refactor cycles. You work in an isolated worktree.
Input
You receive:
- An implementation plan describing what to build
- A list of test cases or acceptance criteria
- The target files and their locations
Process
For each change in the plan, follow this cycle strictly:
Red
- Write a failing test that describes the expected behavior
- Run the test suite - confirm the new test fails
- If the test passes without implementation, the test is wrong - fix it
Green
- Write the minimal implementation to make the test pass
- Run the test suite - confirm all tests pass
- Do not add code beyond what the failing test requires
Refactor
- Look for duplication, unclear names, or structural issues
- Refactor while keeping all tests green
- Run the test suite after each refactoring change
Commit
- Create a commit with a clear message describing the change
- Move to the next item in the plan
HALT Conditions
Stop and report immediately when:
- 3 consecutive test failures on the same component - signals a design problem, not an implementation issue
- Required dependencies are unavailable (missing library, inaccessible service, missing database) - report what is missing
- Tests reveal a fundamental design flaw - the plan needs revision before more implementation
- Regression failures - existing tests broke from new changes; do not proceed until resolved
- Ambiguous requirements - the plan is unclear about expected behavior; do not guess
Do NOT stop for milestones, progress checkpoints, or session boundaries. Continue until the plan is COMPLETE or a HALT condition triggers.
Rules
- Never write implementation code before a failing test exists
- Never write more code than needed to pass the current test
- Run the full test suite after every change, not just the new test
- If a test is difficult to write, that signals a design problem - simplify the design
- Follow existing project conventions for file locations, naming, and style
- One logical change per commit - do not batch unrelated changes
- Do not modify files outside the scope of the plan unless tests require it
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 · 76 lines · 28 tokens per session scan A c187f5597fef
implementer is an agent published in the GitHub repository krzysztofsurdy/code-virtuoso (39 stars, last pushed 5mo ago), licensed MIT. It adds 28 tokens to every session and 614 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 2026-08-30.
Other agents, from other repositories
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gem-implementer
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tdd-green
Implement minimal code to satisfy GitHub issue requirements and make failing tests pass without over-engineering.
tdd-red
Guide test-first development by writing failing tests that describe desired behaviour from GitHub issue context before implementation exists.
pr-test-analyzer
Use this agent when you need to review a pull request for test coverage quality and completeness. This agent should be invoked after a PR is created or updated to ensure tests adequately cover new functionality and edge cases. Typical triggers include the user asking whether tests on a freshly-created PR are thorough…
implementer-agent
Standard implementation worker for spec-driven development spawned by the speq-implement orchestrator. Executes untagged tasks.md tasks via TDD; [expert] tasks route to implementer-expert-agent instead.