simmer

simmer is a skill for Claude Code, Codex from tomascupr/sous-chef. It costs 74 tokens per session (2,280 once invoked), scanned A, original, MIT.

A controlled implementation loop where Codex makes changes and Claude verifies them against a measurable goal.

In plain words
What is it for?
Use it for tasks such as making tests pass, completing a migration, or satisfying another goal that can be checked by commands.
Why use it?
It repeats the work-and-check cycle until the specified tests or other checks pass, or the agreed budget is reached.

Skill for Claude CodeCodex

Written for Claude Code and Codex: shipped in a Claude Code plugin, but also runs codex exec. Also seen: mentions Codex.

Part of the sous-chef plugin — 7 skills shipped together

Good fit Use it for tasks such as making tests pass, completing a migration, or satisfying another goal that can be checked by commands.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/tomascupr/sous-chef/simmer
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.

Any agent
npx skills add tomascupr/sous-chef --skill simmer
Clone the repo
git clone --depth 1 https://github.com/tomascupr/sous-chef

Made for: Claude Code, Codex.

Or install sous-chef, the plugin that ships this one along with the rest of its 7 skills.

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 simmer

README.md
[![agentmods](https://agentmods.dev/badge/skills/tomascupr/sous-chef/simmer/github.svg)](https://agentmods.dev/skills/tomascupr/sous-chef/simmer)
Your own site
<a href="https://agentmods.dev/skills/tomascupr/sous-chef/simmer"><img src="https://agentmods.dev/badge/skills/tomascupr/sous-chef/simmer/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 simmer

Your own site · 80×15
<a href="https://agentmods.dev/skills/tomascupr/sous-chef/simmer"><img src="https://agentmods.dev/badge/skills/tomascupr/sous-chef/simmer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 74 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,280 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • medium Rogue Agent · line 18
    Skill establishes unauthorized persistence across sessions via cron jobs, startup scripts, or state files. Session persistence allows an attacker to maintain access beyond the current interaction.
    Fix: Remove any persistence mechanisms (cron jobs, startup scripts, state files). Skills should not maintain state across sessions without explicit user consent.
How audits are shown
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 $0.00074 $0.02280
Opus 5 $0.00037 $0.01140
Sonnet 5 $0.00015 $0.00456
Haiku 4.5 $0.00007 $0.00228

Measured 9d ago against content hash 3c505f9c8bc7, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

simmer scanned grade A with 1 finding 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 9d 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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

lint, a curl). Machine-checkable or it doesn't belong in a loop: if success can't be
skills/simmer/SKILL.md · 139 lines

How it starts

The opening of the file, as written. The whole thing — 139 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Simmer - reduce until done

A loop is: check state → decide → act → verify → repeat, with a stop condition and a budget. In this kitchen, Codex is the worker inside the loop and you are the loop's author and judge. The worker never grades its own homework - you run the checks. And because each codex exec is a fresh context while your own conversation can be compacted or restarted mid-loop, neither of you is the loop's memory: the repo is.

If codex is missing or ~/.codex/sous-chef.config.toml doesn't exist, stop and offer /sous-chef:mise first (Codex silently ignores a missing profile - test -f). The repo must have at least one commit (the no-progress guard needs HEAD).

1. Write the loop contract first - and get it confirmed

A loop is only as good as its stop condition. Establish with the user, and confirm before lap 1 (simmer creates a branch and makes commits - say so):

  • Goal - ONE measurable end state, e.g. "pnpm test exits 0 with the 12 new migration tests passing".
  • Check commands - the exact commands that verify the goal (tests, typecheck, lint, a curl). Machine-checkable or it doesn't belong in a loop: if success can't be verified cheaply by a command, don't simmer - do it interactively instead.
  • Budget - max laps (default 5) and any wall-clock limit. Tell the user the realistic wall time: each lap is a full Codex run, typically 5–20 minutes at high reasoning effort.
  • Branch - create sous-chef/<task> yourself before lap 1 and tell the user its name up front. Never loop directly on main: a bad run must be a branch delete, not an incident. If the repo or user config has commit hooks/gates (pre-commit reviews, staged-tree checks), resolve how per-lap checkpoints interact with them BEFORE lap 1 - ask the user rather than fighting the gate lap after lap.

2. Loop state - in the repo, out of git

Add .sous-chef/ to $(git rev-parse --git-path info/exclude) if it isn't there yet, then write the contract (goal, check commands, budget, branch with its base commit, and the UTC start time as a started: line - the receipt reads it back for wallclock, same field name as serve's state.md) to .sous-chef/loop.md and create .sous-chef/progress.md. The state survives session restarts because it lives in the repo; the ignore keeps it out of diffs, checkpoint commits, and the no-progress guard.

Read the full file on GitHub · 139 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. 9d ago First seen · 139 lines · 74 tokens per session scan A 3c505f9c8bc7

Subscribe to this mod's changes

simmer is a skill published in the GitHub repository tomascupr/sous-chef (76 stars, last pushed 1mo ago), licensed MIT. It adds 74 tokens to every session and 2,280 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

Related

Other skills, from other repositories