agent-eval-cases

agent-eval-cases is a skill for Claude Code, Codex from agentailor/fullstack-langgraph-nextjs-agent. It costs 174 tokens per session (4,724 once invoked), scanned A, original, MIT.

A guide for deciding which behaviors of an AI agent deserve evaluation cases and for writing those cases. An evaluation case gives the agent a task and uses graders to check its answer, tool use, or resulting state.

In plain words
What is it for?
Use it to design or review evaluation suites, choose between fixed checks and an AI judge, and write cases that work across agent frameworks and programming languages.
Why use it?
It helps teams measure agent behavior rather than merely comparing wording with one expected response.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: installed under .agents/ (shared by several agents).

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 skills/agentailor/fullstack-langgraph-nextjs-agent/agent-eval-cases
Any agent
npx skills add agentailor/fullstack-langgraph-nextjs-agent --skill agent-eval-cases
Clone the repo
git clone --depth 1 https://github.com/agentailor/fullstack-langgraph-nextjs-agent

Made for: Claude Code, Codex.

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 agent-eval-cases

README.md
[![agentmods](https://agentmods.dev/badge/skills/agentailor/fullstack-langgraph-nextjs-agent/agent-eval-cases.svg)](https://agentmods.dev/skills/agentailor/fullstack-langgraph-nextjs-agent/agent-eval-cases)
Your own site
<a href="https://agentmods.dev/skills/agentailor/fullstack-langgraph-nextjs-agent/agent-eval-cases"><img src="https://agentmods.dev/badge/skills/agentailor/fullstack-langgraph-nextjs-agent/agent-eval-cases.svg" alt="Measured on agentmods" height="20"></a>
Per session 174 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,724 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 5.1 $0.00174 $0.04724
Opus 5 $0.00087 $0.02362
Sonnet 5 $0.00035 $0.00945
Haiku 4.5 $0.00017 $0.00472

Measured yesterday against content hash 754adf9bf98c, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

agent-eval-cases 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/skills/agent-eval-cases/SKILL.md · 196 lines

How it starts

The opening of the file, as written. The whole thing — 196 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Agent Eval Cases

Overview

A case is one task you give the agent, plus the graders that decide whether what came back was acceptable.

That is the whole shape — and note what it is not. It is not an input paired with an expected output. There is no single correct answer string to compare against, which is why the right-hand side is a list of graders rather than a value. Many frameworks offer an expected / expected_output field; reaching for it by default is the most common way to write a suite that measures phrasing instead of behavior.

Three consequences shape everything below:

  • A grader can assert on what the agent said or on what the agent did — which tools it called, what is in the store afterwards, whether a gate fired. The second kind is usually the stronger one.
  • Graders see only what the run recorded. That record — the final answer, the tool calls, what each returned, what a guardrail stopped — is called the capture here; your harness may have no name for it at all. It bounds every assertion you can write, so find out what is in it before designing a case around one.
  • A case is not passed or failed by a person reading it, so whatever you want to be true has to be expressible as code (or as a rubric a model can apply, or — occasionally — as a human's read).

The hard part is not the format. It is knowing which handful of tasks are worth paying a model to run, repeatedly, forever.

The workflow

Steps 1–3 are the ones that decide whether a suite is worth having. Do not skip to step 5.

Step 0 — Confirm where these will run

A case needs something to run it on. Before writing any, find out what exists.

Look for an existing suite first. Search for an eval/evals/evaluation directory, a case or dataset type, *.eval.* files, or a framework dependency. If one exists, write cases in its idiom — its case type, its grader catalog, its repeat convention — and stop looking. See references/vocabulary.md.

Read the full file on GitHub · 196 lines

Files

What ships with it

4 files 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. yesterday First seen · 196 lines · 174 tokens per session scan A 754adf9bf98c

Subscribe to this mod's changes

agent-eval-cases is a skill published in the GitHub repository agentailor/fullstack-langgraph-nextjs-agent (131 stars, last pushed yesterday), licensed MIT. It adds 174 tokens to every session and 4,724 once invoked, about $0.0009 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 2026-09-05.

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