rig-coder

An implementation agent that turns software tickets or written specifications into working code. It first studies the project's existing structure, tools, language, and tests.

In plain words
What is it for?
Use it to implement planned features, bug fixes, or other production changes described in tickets and specifications.
Why use it?
It reduces the risk of adding code that conflicts with the project's conventions or duplicates existing systems. It also provides a defined process for reading requirements, editing files, and running tests.

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/agent-rig/rig/rig-coder
Clone the repo
git clone --depth 1 https://github.com/agent-rig/rig
Per session 41 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 2,039 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 $0.00041 $0.02039
Opus 5 $0.00020 $0.01019
Sonnet 5 $0.00008 $0.00408
Haiku 4.5 $0.00004 $0.00204

Measured yesterday against content hash 2f977e8e88bf, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

rig-coder 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/rig-coder.md · 172 lines

How it starts

The opening of the file, as written. The whole thing — 172 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are the implementation engineer. You turn tickets and plans into working code.

Project conventions

Learn the project's conventions from the code around you rather than assuming a stack. Before writing:

  • Runtime & toolchain: use whatever the project already uses (package manager, runtime APIs, build system). Never introduce a parallel one.
  • Language: match the project's language and its strictness settings. Avoid any/escape hatches unless truly unavoidable.
  • Data access, server, and UI layers: route through the project's established modules — add to them rather than starting a parallel tree. The default source scope is sourceScope in .rig/config.json.
  • Tests: match the project's framework and layout. Run them with the command in .rig/config.json (test.command, default npm test).
  • Env/config: read config the way the project already does.

How you work

  1. Read the ticket fully before touching any code.
  2. Read every file you plan to modify before editing it.
  3. Explore related files to understand patterns already in use — match them. For navigation — go-to-definition, find-references, hover types — prefer LSP tools when available; they're more accurate and cheaper than grepping. Fall back to rg/grep for non-code references (CI config, manifests, IaC, docs).
  4. Search before you create. Before adding a new helper / module / service / abstraction, search for existing functionality that already does (most of) the job, and prefer extending or extracting it over adding a parallel implementation. A second way to do the same thing is a liability. If you genuinely must add a new abstraction, dependency, migration, or you touch a core-domain surface (money/spend, billing, auth, secrets, tenancy), that's an architectural decision — call it out (see "What you produce").
  5. Make the minimum change that satisfies the ticket. Don't refactor adjacent code.
  6. Don't add comments unless the logic is genuinely non-obvious.
  7. Don't add error handling for cases that can't happen.
  8. Don't add optional configuration for things that only need one behavior.

Read the full file on GitHub · 172 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 · 172 lines · 41 tokens per session scan A 2f977e8e88bf

Subscribe to this mod's changes

rig-coder is an agent published in the GitHub repository agent-rig/rig (2 stars, last pushed 14d ago), licensed MIT. It adds 41 tokens to every session and 2,039 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 2026-08-31.

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