trace-codes

trace-codes is a skill for Claude Code, Codex from Calibre-Labs/reforge-ai-evals. It costs 117 tokens per session (1,894 once invoked), scanned A, original, MIT.

A tool for grouping human notes about AI-agent runs into trace codes. A trace is a record of one agent run; a trace code is a named yes-or-no pattern, such as a specific failure, seen across those records.

In plain words
What is it for?
Use it to cluster annotated traces, describe recurring failure modes, connect them to evaluation criteria, and prepare patterns for later automated checks.
Why use it?
It turns scattered review notes into consistent categories that can be counted and reused. The required notes keep the human's observations separate from automated interpretation.

Skill for Claude CodeCodex

Written for Claude Code and Codex: shipped in a Claude Code plugin, but also agents/openai.yaml present.

Part of the ai-evals plugin — 9 skills, 9 commands shipped together

Good fit Use it to cluster annotated traces, describe recurring failure modes, connect them to evaluation criteria, and prepare patterns for later automated checks.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/calibre-labs/reforge-ai-evals/trace-codes
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 Calibre-Labs/reforge-ai-evals --skill trace-codes
Clone the repo
git clone --depth 1 https://github.com/Calibre-Labs/reforge-ai-evals

Made for: Claude Code, Codex.

Or install ai-evals, the plugin that ships this one along with the rest of its 9 skills, 9 commands.

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 trace-codes

README.md
[![agentmods](https://agentmods.dev/badge/skills/calibre-labs/reforge-ai-evals/trace-codes/github.svg)](https://agentmods.dev/skills/calibre-labs/reforge-ai-evals/trace-codes)
Your own site
<a href="https://agentmods.dev/skills/calibre-labs/reforge-ai-evals/trace-codes"><img src="https://agentmods.dev/badge/skills/calibre-labs/reforge-ai-evals/trace-codes/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 trace-codes

Your own site · 80×15
<a href="https://agentmods.dev/skills/calibre-labs/reforge-ai-evals/trace-codes"><img src="https://agentmods.dev/badge/skills/calibre-labs/reforge-ai-evals/trace-codes.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 117 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,894 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 $0.00117 $0.01894
Opus 5.5 $0.00047 $0.00758
Sonnet 5.5 $0.00023 $0.00379
Haiku 4.5 $0.00012 $0.00189

Measured 7d ago against content hash b7c58caed82a, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

trace-codes 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 7d 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.

skills/trace-codes/SKILL.md · 165 lines

How it starts

The opening of the file, as written. The whole thing — 165 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Trace codes skill

Trace analysis has three steps: build a set of inputs and run the agent, read the traces and write notes, then cluster the notes into codes. A person does the reading. This skill does the clustering and everything that follows from it.

A trace code is a short name for one pattern seen across traces, defined so that anyone can answer yes or no for a single trace. Codes become the vocabulary for the rubric, the backlog and the automated evals.

Do not write the notes yourself. If the user has traces and no notes, tell them to read and annotate at least ten first. Reading is where product judgment comes in, so a person does it. You may help them read faster (summarize a long trace, point at the tool calls) but the observations must be theirs.

Inputs

Input Required Typical form
Notes Yes A CSV or JSON with a trace id and a free-text note per trace, pasted text, or a review page that stores notes (see below).
Traces Helpful The files or folder the notes refer to, so examples can quote what happened
Rubric Helpful The current eval rubric, to map each code to a line
Existing codes If any A previous trace codes file to merge into

Find these in the working folder before asking. If the notes have no trace ids, number them and say so.

Workflow

Step 1. Split notes into observations

One note often contains several observations ("stale revenue number, also no source for the third company, good scoping question"). Split each note into single observations and keep the trace id with each. Keep positive observations too. A code can describe something the agent should keep doing.

Step 2. Cluster into codes

Group observations that describe the same pattern. For each group write:

  • Title: three to six words, descriptive, no jargon the team would not use.
  • Definition: one sentence that can be answered yes or no for a single trace. Start with "The agent ..." or "The output ...".
  • Examples: two or three, each with the trace id and a short paraphrase of what happened. Quote the trace when it is available.
  • Count: how many traces show it, out of how many were annotated.

Read the full file on GitHub · 165 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 7d ago Changed · +25 lines b7c58caed82a
  2. 10d ago First seen · 140 lines · 117 tokens per session scan A a5a3d8e26ee6

Subscribe to this mod's changes

trace-codes is a skill published in the GitHub repository Calibre-Labs/reforge-ai-evals (87 stars, last pushed yesterday), licensed MIT. It adds 117 tokens to every session and 1,894 once invoked, about $0.0005 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 2026-10-17.