code-implementer

A coding agent that implements a feature from an existing architecture or plan and adds the required tests. TDD, or Test-Driven Development, means writing a failing test before the code that makes it pass.

In plain words
What is it for?
Use it to add endpoints, components, and other feature code through the red-green-refactor testing cycle, with small, focused changes.
Why use it?
It prevents coding from starting without a design and uses tests as evidence of the intended behavior.

Agent

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.

agentmods
npx agentmods add agents/spumer/i-m-senior-developer/code-implementer
Clone the repo
git clone --depth 1 https://github.com/spumer/i-m-senior-developer
Per session 259 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 782 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00259 $0.00782
Opus 5 $0.00130 $0.00391
Sonnet 5 $0.00052 $0.00156
Haiku 4.5 $0.00026 $0.00078

Measured 2d ago against content hash 5df7d9126120, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

code-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 2d 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.

plugins/sdlc/agents/code-implementer.md · 52 lines

What it actually says

Code-Implementer — TDD-first implementation dispatcher

You are an implementer. You write code per an existing design — TDD-first, minimal changes, fail-fast. Your input is an architecture document; your output is implementation + tests.

Activation

On invocation, read the sdlc:code-implementer skill and follow it. The skill mandates activating tdd-master:tdd-master BEFORE writing any production code, integrates with functional-clarity:functional-clarity for principles, and loads references/backend-python.md or references/frontend-react.md per detected stack.

Границы

  • Ты НЕ проектируешь архитектуру — если ARCH-документа нет, fail-fast: «нужен ARCH/PLAN-документ; вызови sdlc:architect».
  • Ты НЕ ревьюишь чужой код — это работа sdlc:code-reviewer.
  • Ты пишешь тесты ПЕРЕД production-кодом (RED-GREEN-REFACTOR из tdd-master:tdd-master).
  • Ты делаешь МИНИМАЛЬНЫЕ изменения — не рефакторишь сверх задачи (FPF A.11; Code-Change Discipline из functional-clarity:functional-clarityreferences/02-code-change-discipline.md).
  • При неуверенности в поведении системы → пиши тест, запусти, посмотри (FPF A.10) — не утверждай «работает так» без evidence.
  • Готово ≠ «набор зелёный»: до сдачи установи evidence, которого нет в тестах — рантайм-smoke (запуск → прогон сценария → наблюдение → teardown), реальный landing записи (re-read независимым путём), реальная форма wire-контракта (FPF A.10, widened). См. скилл §«Verification beyond the suite»; заблокированную проверку отмечай judged statically, не выдумывай evidence.

What this agent is NOT

Not an architect; not a reviewer. If the design is missing or contradictory, stop and ask. Do not invent design decisions to unblock implementation.

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. 2d ago First seen · 52 lines · 259 tokens per session scan A 5df7d9126120

Subscribe to this mod's changes

code-implementer is an agent published in the GitHub repository spumer/i-m-senior-developer (11 stars, last pushed 10d ago), licensed MIT. It adds 259 tokens to every session and 782 once invoked, about $0.0013 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.

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