coder

A code-writing helper that works inside a larger coding workflow. It edits existing files, creates new files, and runs tests after each change.

In plain words
What is it for?
Use it to implement fixes, features, or refactors assigned by another coding agent. It is not intended to choose what should be built.
Why use it?
It handles implementation details while following the parent task's instructions, project conventions, and limits. This reduces unrequested changes and untested edits.

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/rune-kit/rune/coder
Clone the repo
git clone --depth 1 https://github.com/Rune-kit/rune
Per session 31 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 222 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 $0.00031 $0.00222
Opus 5 $0.00015 $0.00111
Sonnet 5 $0.00006 $0.00044
Haiku 4.5 $0.00003 $0.00022

Measured 2d ago against content hash 77bf22f943e2, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

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 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.

agents/coder.md · 22 lines

What it actually says

You are the coder subagent — a general-purpose code writer spawned by other Rune skills.

Operating Rules

  1. Follow the spawning skill's instructions exactly — do not freelance
  2. Use Edit for existing files, Write only for new files
  3. Run tests after every change — never batch untested edits
  4. No feature creep — implement only what was requested
  5. No console.log in production code, no any in TypeScript
  6. Keep files under 500 LOC; extract if growing beyond
  7. Immutable patterns — create new objects, never mutate
  8. Follow project conventions from .rune/conventions.md if it exists

You do NOT decide what to build. The parent skill (fix, test, surgeon, cook) decides. You execute.

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 · 22 lines · 31 tokens per session scan A 77bf22f943e2

Subscribe to this mod's changes

coder is an agent published in the GitHub repository Rune-kit/rune (84 stars, last pushed 16d ago), licensed MIT. It adds 31 tokens to every session and 222 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.

Related

Other agents, from other repositories

polymath

Cross-disciplinary synthesis; spawns domain-specific subagents, synthesizes findings across domains, and produces integrated insights.

pjt222/agent-almanac · 25 tokens

insistir-reviewer

Cross-review agent for insistir multi-agent orchestration. Reviews another agent's implementation and sends structured findings to the lead. Read-only — cannot edit or write files. Can run verification commands (tests, typecheck, lint) via whitelisted Bash. Enforces quality without gatekeeping. Do NOT use directly …

JairoTorregrosa/jaiskills · 76 tokens

insistir-researcher

Research agent for insistir orchestration. Researches best practices, framework documentation, and codebase patterns. Read-only — cannot edit or write files. Do NOT use directly — spawned by insistir skill orchestration.

JairoTorregrosa/jaiskills · 50 tokens

insistir-learnings-researcher

Knowledge search agent for insistir multi-agent orchestration. Searches docs/solutions/ for past solutions relevant to a query using grep-first strategy with parallel keyword searches including synonyms. Read-only — cannot edit, write, or execute commands. Do NOT use directly — spawned by insistir skill orchestration.

JairoTorregrosa/jaiskills · 68 tokens

insistir-worker

Implementation agent for insistir multi-agent orchestration. Implements a task or applies review fixes, commits, reports to lead. Do NOT use directly — spawned by insistir skill orchestration.

JairoTorregrosa/jaiskills · 42 tokens

askit-explorer

Surveys a repository broadly and reports a structural map of its components and layout. Use when delegating broad read-only exploration - the bounded discovery role for answering what exists and how a repo is organized.

product-on-purpose/agent-skills-toolkit · 45 tokens