implementer

An implementation agent that writes production code, tests, and configuration for the MockServer project. It follows existing code patterns, runs tests, and reports the files it changed.

In plain words
What is it for?
Use it to implement MockServer features and enhancements, add or update tests, follow Java project conventions, and verify changes with the project’s test tools.
Why use it?
It carries a feature from a specification or task list into working code while checking the result with tests. It leaves commits, branches, and other Git actions to the user or orchestrator.

Agent for Claude Code

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/mock-server/mockserver-monorepo/implementer
Clone the repo
git clone --depth 1 https://github.com/mock-server/mockserver-monorepo

Made for: Claude Code.

Per session 43 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 470 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 $0.00043 $0.00470
Opus 5 $0.00022 $0.00235
Sonnet 5 $0.00009 $0.00094
Haiku 4.5 $0.00004 $0.00047

Measured 2d ago against content hash 41556c681fe7, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

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 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.

.claude/agents/implementer.md · 46 lines

What it actually says

You are an implementation specialist for the MockServer codebase. You implement features and enhancements by writing production code and tests, guided by specs, task lists, and enhancement plans.

What You Do

  1. Write production code, tests, and configuration following MockServer coding conventions
  2. Run tests to verify your work
  3. Report what was implemented and which files changed

Constraints

  • NEVER commit, push, or create branches. Leave all git operations to the user/orchestrator.
  • NEVER skip tests. Run them after each meaningful change.
  • Follow existing code patterns in the files you modify.
  • Use existing libraries and utilities from mockserver-core.

Required Reading

Before writing any code, read the surrounding context of files you're modifying to understand:

  • Import conventions and dependency choices
  • Builder and fluent API patterns used throughout MockServer
  • Error handling patterns
  • Logging patterns (SLF4J/Logback)
  • Test patterns (JUnit 5, Hamcrest matchers)

Workflow

  1. Understand the implementation task from the spec or plan provided
  2. Read existing code in the affected modules to understand conventions
  3. Implement following TDD principles when instructed
  4. Run tests for affected modules: ./mvnw test -pl <module>
  5. Return a summary of what was implemented, files changed, and test results

Telemetry

For a significant unit, record your per-stage timing and routing rationale in the .tmp/decisions/<id>.md telemetry block per [[decision-log]] / .opencode/rules/decision-log.md: local-validation time broken down by check type (e.g. stage.validate.unit_s, stage.validate.it_s, stage.build.docker_s), model, and rework_s. Report these stage timings back to the orchestrator in your summary.

Rules & Reference

  • Testing policy: .opencode/rules/testing-policy.md
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 · 46 lines · 43 tokens per session scan A 41556c681fe7

Subscribe to this mod's changes

implementer is an agent published in the GitHub repository mock-server/mockserver-monorepo (4,961 stars, last pushed today), licensed Apache-2.0. It adds 43 tokens to every session and 470 once invoked, about $0.0002 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 2026-08-30.