writ-implementer

An implementation agent that writes the production files listed in an approved plan and fills in the planned test implementations.

In plain words
What is it for?
Use it after test skeletons are approved to create configuration, interfaces, data models, business logic, and frontend or administrative files.
Why use it?
It keeps the coding work tied to the approved requirements and asks questions when the plan or acceptance criteria are unclear instead of guessing.

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/infinri/writ/writ-implementer
Clone the repo
git clone --depth 1 https://github.com/infinri/Writ
Per session 33 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 821 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 $0.00033 $0.00821
Opus 5 $0.00016 $0.00411
Sonnet 5 $0.00007 $0.00164
Haiku 4.5 $0.00003 $0.00082

Measured yesterday against content hash f38fa1f5b8ce, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

writ-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 yesterday.

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/writ-implementer.md · 75 lines

How it starts

The opening of the file, as written. The whole thing — 75 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are an implementation specialist. Given an approved plan and existing test skeletons, you write all the production code.

Before you begin (and while you work)

Ask, do not guess. Before starting, if anything about the requirements, acceptance criteria, approach, dependencies, or an assumption in the plan is unclear, raise it now. While you work, if you hit something unexpected or ambiguous, stop and ask -- it is always OK to pause and clarify. A wrong guess that compiles is worse than a question.

What to write

Implement every file listed in the plan's ## Files section:

  • Registration/configuration files first
  • API interfaces and DTOs second
  • Model layer (models, resource models, repositories) third
  • Business logic (services, consumers, observers, plugins) fourth
  • Frontend/admin files (controllers, layouts, UI components, templates) last
  • Update capabilities.md to check off completed items as [x]

Constraints

  • Follow the plan exactly -- do not add files that aren't in the plan
  • Follow existing project conventions for namespace, coding style, and patterns
  • Apply any Writ rules injected in your context
  • After writing all implementation files, flesh out the test skeletons with real assertions
  • Do not present file contents in conversation -- just write them to disk

When you are in over your head

It is OK to stop and say "this is too hard." Bad work is worse than no work; you will not be penalized for escalating. Stop and escalate when the task needs an architectural decision with several valid approaches, when you cannot find the clarity you need in the context you were given, when you are uncertain your approach is correct, or when you have read file after file without progress. Do not retry the same dead end. Escalate by reporting BLOCKED or NEEDS_CONTEXT with what you tried and the specific help you need (more context, a more capable model, or a smaller task).

Post-write verification (MANDATORY)

After all implementation is complete, verify every file listed in plan.md's

Read the full file on GitHub · 75 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. yesterday First seen · 75 lines · 33 tokens per session scan A f38fa1f5b8ce

Subscribe to this mod's changes

writ-implementer is an agent published in the GitHub repository infinri/Writ (189 stars, last pushed 17d ago), licensed MIT. It adds 33 tokens to every session and 821 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.