fixture-new

fixture-new is a skill for Claude Code, Codex from bearded-illirian/trailmark. It costs 122 tokens per session (1,549 once invoked), scanned A, original, MIT.

A process for creating a frozen test case for a skill, including the input it receives and the shape its output must have. It also checks that an empty run fails as expected.

In plain words
What is it for?
It is for adding parity tests, documenting expected artifacts, and checking that a new test does not pass without doing anything.
Why use it?
It helps detect when a skill or runtime stops producing the required kind of work.

Skill for Claude CodeCodex

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

Good fit It is for adding parity tests, documenting expected artifacts, and checking that a new test does not pass without doing anything.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/bearded-illirian/trailmark/fixture-new
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 bearded-illirian/trailmark --skill fixture-new
Clone the repo
git clone --depth 1 https://github.com/bearded-illirian/trailmark

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 fixture-new

README.md
[![agentmods](https://agentmods.dev/badge/skills/bearded-illirian/trailmark/fixture-new.svg)](https://agentmods.dev/skills/bearded-illirian/trailmark/fixture-new)
Your own site
<a href="https://agentmods.dev/skills/bearded-illirian/trailmark/fixture-new"><img src="https://agentmods.dev/badge/skills/bearded-illirian/trailmark/fixture-new.svg" alt="Measured on agentmods" height="20"></a>
Per session 122 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,549 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. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
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 $0.00122 $0.01549
Opus 5 $0.00061 $0.00775
Sonnet 5 $0.00024 $0.00310
Haiku 4.5 $0.00012 $0.00155

Measured 4d ago against content hash 573cf78d6f5f, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

fixture-new 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 4d 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.

adapters/codex/.agents/skills/fixture-new/SKILL.md · 193 lines

How it starts

The opening of the file, as written. The whole thing — 193 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Fixture-New Protocol

Writes one fixture: fixtures/{skill}/{case}/ holding input.md and expect.yml.

A fixture answers "did this runtime produce the same shape of work as the reference one" — never "did it produce the same words". Two agents word an artifact differently, and so does one agent twice.

When to invoke

  • A skill has no fixture and you want the parity suite to reach it
  • An existing fixture covers the happy path and a second case is worth freezing
  • Before claiming a runtime is supported for a skill nothing checks

Input

The name of a shipped skill, a short case name, and knowledge of what that skill's artifact looks like.

Output

Two files under fixtures/{skill}/{case}/, plus a demonstration that the new fixture fails when handed a directory with nothing in it.

Hands off to

$parity-check — the skill that actually runs a fixture end to end.


Step 0 — Locate the workspace root

test -d fixtures && test -d bin && echo "root ok"

Not there → walk up until fixtures/ and bin/ sit side by side.


Step 1 — Name the fixture

Ask for the skill and a case name. Then check both:

ls aihub/.agents/skills/{skill}/SKILL.md      # the skill must exist
ls -d fixtures/{skill}/{case} 2>/dev/null      # the case must not

Skill missing → stop. A fixture for a skill that does not ship tests nothing and will fail forever, which trains people to ignore red.

Case exists → stop and say so. Overwriting someone's fixture silently is how a suite quietly loses coverage.

Case names read as NNN-short-slug: 001-add-endpoint, 002-empty-input. The number orders them; the slug says what is being frozen.


Step 2 — Decide the expected shape

Read the skill's own protocol to see what it writes, then fill these:

Key What to put How to find it
artifact filename glob, e.g. plan-first-*.md the skill's artifact-writing step
artifact_type value in task_artifacts.artifact_type the skill's INSERT statement
sections headings that must be present the skill's artifact template
gate substring proving an approval gate was offered only if the gate lands in the artifact
min_table_rows minimum rows in the first table only when the protocol states a count

Read the full file on GitHub · 193 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. 4d ago First seen · 193 lines · 122 tokens per session scan A 573cf78d6f5f

Subscribe to this mod's changes

fixture-new is a skill published in the GitHub repository bearded-illirian/trailmark (19 stars, last pushed 6d ago), licensed MIT. It adds 122 tokens to every session and 1,549 once invoked, about $0.0006 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 2026-09-04.

Related

Other skills, from other repositories

qa

Run scalable, isolated live QA for nac development. The top-level local orchestrator must parse n (default 4), dispatch one setup worker with this skill, copy its n assignment contracts verbatim into exactly n parallel test workers with this skill, then dispatch one aggregate worker with this skill using all test…

arcee-ai/nac · 100 tokens

chrome-automation

A browser-automation toolkit for controlling Chrome to visit pages, interact with forms, collect data, run tests, and create screenshots or PDFs.

aAAaqwq/AGI-Super-Team · 34 tokens

agent-tester

Test agent: dry-run, unit, integration, compatibility.

aAAaqwq/AGI-Super-Team · 0 tokens

browser-check

Drive a real browser and come back with a MEASUREMENT rather than an impression - console errors and >=400 responses as counts, computed styles as JSON when appearance is disputed. Use when work touches UI, when a review must verify one, or when fidelity-gate asks for its measurement.

jjanczur/tyran · 58 tokens

dos-witness-claim

Route subagent claims through independent read-back before another agent relies on them. Use at parallel, pipeline, or synthesis barriers where shipped phases, files, rows, messages, or other effects must be witnessed.

anthony-chaudhary/dos-kernel · 47 tokens

dos-self-improve

Run the DOS self-improvement loop: propose a candidate, verify it in an isolated worktree, measure suite/truth/metric gates, and keep only confirmed gains. Use for recursive improvement; use dos-enforce-tune for policy knobs.

anthony-chaudhary/dos-kernel · 56 tokens