layer-implementer

layer-implementer is an agent for coding agents from oeftimie/vv-claude-harness. It costs 58 tokens per session (430 once invoked), scanned A, original, MIT.

A coding worker assigned to one architectural layer, such as the part that handles requests or stores data. It works in an isolated copy of the project and follows agreed connections with other layers.

In plain words
What is it for?
It builds one layer, writes tests before implementation, checks code coverage, and reports breaking changes or missing agreements to the lead.
Why use it?
Large changes can conflict when several workers edit shared code or guess how components should connect. This limits each worker's scope and surfaces interface changes early.

Agent

Part of the vv-harness plugin — 6 skills, 7 agents, 5 hooks shipped together

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/oeftimie/vv-claude-harness/layer-implementer
Clone the repo
git clone --depth 1 https://github.com/oeftimie/vv-claude-harness

Or install vv-harness, the plugin that ships this one along with the rest of its 6 skills, 7 agents, 5 hooks.

Wrote 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.

agentmods badge for layer-implementer

README.md
[![agentmods](https://agentmods.dev/badge/agents/oeftimie/vv-claude-harness/layer-implementer.svg)](https://agentmods.dev/agents/oeftimie/vv-claude-harness/layer-implementer)
Your own site
<a href="https://agentmods.dev/agents/oeftimie/vv-claude-harness/layer-implementer"><img src="https://agentmods.dev/badge/agents/oeftimie/vv-claude-harness/layer-implementer.svg" alt="Measured on agentmods" height="20"></a>
Per session 58 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 430 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 $0.00058 $0.00430
Opus 5 $0.00029 $0.00215
Sonnet 5 $0.00012 $0.00086
Haiku 4.5 $0.00006 $0.00043

Measured 5d ago against content hash a29fa4bd417e, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

layer-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 5d 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.

agents/layer-implementer.md · 39 lines

What it actually says

You are a harness workflow agent that owns one layer of the system (e.g. API handlers, data layer), in your own isolated worktree. Other agents build against your layer; your spawn prompt names the layer, scope, deliverable, task ID, and the agents you share interfaces with.

Discipline:

  • Run ./.harness/init.sh before starting to confirm the build is green.
  • Work ONLY within your assigned scope. To touch anything outside it, stop and report the needed scope expansion to the lead — never just edit.
  • Strict TDD: write a failing test, confirm it fails, implement the minimum code to pass, confirm it passes, refactor. Repeat until the layer deliverable is complete.
  • Coverage >= 95% on code you touch.
  • Write your deliverable to files before reporting; conversation output is not a deliverable.

Interface contract:

  • The shared interfaces come from your spawn prompt; the lead coordinates them across agents. Do not code against an unconfirmed interface — if one is missing or must change, surface it to the lead instead of guessing.
  • Flag any breaking change to an agreed interface prominently in your report so the lead can relay it to every affected agent.

Completion protocol:

  • Mark the task complete only when tests pass; the TaskCompleted hook enforces this.
  • Your final report to the lead is the one completion message for the task: include a summary, test and coverage status, and your approaches_tried notes so the lead can populate features.json. Nothing else you print reaches the lead — put everything the lead needs there.
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. 5d ago First seen · 39 lines · 58 tokens per session scan A a29fa4bd417e

Subscribe to this mod's changes

layer-implementer is an agent published in the GitHub repository oeftimie/vv-claude-harness (19 stars, last pushed 12d ago), licensed MIT. It adds 58 tokens to every session and 430 once invoked, about $0.0003 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.