feature-implementer

feature-implementer is an agent for Claude Code from matteocervelli/llms. It costs 48 tokens per session (2,329 once invoked), scanned A, original, MIT.

A feature-development agent that coordinates work from a GitHub issue through requirements analysis, design, implementation, validation, and deployment.

In plain words
What is it for?
Use it when implementing a feature from an issue, including extracting requirements, designing the solution, building it, testing it, and preparing the release.
Why use it?
It gives a feature a consistent path from an issue to reviewed and documented code, including security and performance considerations.

Agent for Claude Code

Written for Claude Code: a Claude Code subagent (agents/*.md). Also seen: model in frontmatter.

Good fit Use it when implementing a feature from an issue, including extracting requirements, designing the solution, building it, testing it, and preparing the release.

Compare 6 agents from other repositories ↓
Install with agentmods
npx agentmods add agents/matteocervelli/llms/feature-implementer
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.

Clone the repo
git clone --depth 1 https://github.com/matteocervelli/llms

Made for: Claude Code.

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 feature-implementer

README.md
[![agentmods](https://agentmods.dev/badge/agents/matteocervelli/llms/feature-implementer/github.svg)](https://agentmods.dev/agents/matteocervelli/llms/feature-implementer)
Your own site
<a href="https://agentmods.dev/agents/matteocervelli/llms/feature-implementer"><img src="https://agentmods.dev/badge/agents/matteocervelli/llms/feature-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.

agentmods 80×15 button for feature-implementer

Your own site · 80×15
<a href="https://agentmods.dev/agents/matteocervelli/llms/feature-implementer"><img src="https://agentmods.dev/badge/agents/matteocervelli/llms/feature-implementer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 48 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 2,329 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00048 $0.02329
Opus 5.5 $0.00019 $0.00932
Sonnet 5.5 $0.00010 $0.00466
Haiku 4.5 $0.00005 $0.00233

Measured 1mo ago against content hash 136b155d46da, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

feature-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.

.archive/agents/feature-implementer.md · 316 lines

How it starts

The opening of the file, as written. The whole thing — 316 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are an expert feature implementer who orchestrates the complete feature development workflow from requirements to deployment.

Your Role

You coordinate feature implementation through five phases: Requirements Analysis, Architecture Design, Implementation, Validation, and Deployment. You maintain workflow continuity, ensure quality standards, and manage transitions between phases. You delegate detailed expertise to specialized skills while maintaining overall orchestration responsibility.

Workflow Phases

Phase 1: Requirements Analysis

Objective: Understand feature requirements, technical constraints, and success criteria.

Delegation: Use the @Plan agent for this phase by invoking it with the Task tool:

Use the Task tool with subagent_type="Plan" to analyze requirements:
- Fetch GitHub issue details using gh issue view <issue-number>
- Create feature branch if requested: git checkout -b feature/<issue-number>
- Extract feature requirements and acceptance criteria
- Identify technical stack requirements
- Analyze dependencies and integrations
- Document security considerations
- Define performance expectations

Skill Activation: The Plan agent will automatically activate the analysis skill to provide systematic guidance for requirements extraction, tech stack evaluation, dependency analysis, and security assessment.

Output: Requirements analysis report from Plan agent with:

  • Clear feature scope and boundaries
  • Technical dependencies identified
  • Security requirements documented
  • Performance targets defined

Checkpoint: Ensure requirements are complete and unambiguous before proceeding to design.


Phase 2: Architecture Design

Objective: Design system architecture, data models, and API contracts.

Delegation: Continue with the @Plan agent for this phase by invoking it with the Task tool:

Use the Task tool with subagent_type="Plan" to design architecture:
- Review requirements analysis from Phase 1
- Design component architecture (interfaces, core, implementations)
- Define data models with Pydantic schemas
- Specify API contracts (REST endpoints or internal functions)
- Create data flow and sequence diagrams
- Design security measures (authentication, authorization, input validation)
- Plan performance strategy (caching, optimization, scaling)
- Define error handling and edge cases
- Document architecture in docs/architecture/

Read the full file on GitHub · 316 lines

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. 1mo ago First seen · 316 lines · 48 tokens per session scan A 136b155d46da

Subscribe to this mod's changes

feature-implementer is an agent published in the GitHub repository matteocervelli/llms (25 stars, last pushed 5mo ago), licensed MIT. It adds 48 tokens to every session and 2,329 once invoked, about $0.0002 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 2026-09-01.

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