runtime-verification

A runtime-checking skill that verifies a change by running the actual page, route, command, or background job it affects, not only its unit tests.

In plain words
What is it for?
Use it after changes to user-facing pages, APIs, command-line tools, queues, jobs, or other interfaces to observe the real result.
Why use it?
Passing unit tests does not prove that a page renders, an API responds, a command works, or a job completes correctly.

Skill for Claude CodeCodex

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/ohswedd/praxis/runtime-verification
Any agent
npx skills add Ohswedd/praxis --skill runtime-verification
Clone the repo
git clone --depth 1 https://github.com/Ohswedd/praxis

Made for: Claude Code, Codex.

Per session 157 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,692 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. 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 $0.00157 $0.01692
Opus 5 $0.00078 $0.00846
Sonnet 5 $0.00031 $0.00338
Haiku 4.5 $0.00016 $0.00169

Measured 2d ago against content hash 3a78a01afdb2, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

runtime-verification 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 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.

Makes network callslowCapability

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

| An HTTP route or API | A request against a locally running server (`curl`, `httpie`, the project's client) |
plugins/praxis/skills/runtime-verification/SKILL.md · 131 lines

How it starts

The opening of the file, as written. The whole thing — 131 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Runtime Verification

A green unit suite proves that a function returns what its test expects. It does not prove that the page renders, the route answers, the button submits, the migration applies, or the command exits zero. That gap is where a change passes every check and is still broken for the person who has to use it, and it is why "the tests pass" is the single most common true-but-useless sentence in a handover.

The rule: if a change alters something a person or another system interacts with, run that thing and observe the result before you call the work done.

Step 1: Decide what "running it" means here

Derive it from the project, never from habit. The question is always the same: what is the smallest real execution that would fail if this change were wrong?

The change touches Run
A page, component, or style The app in a browser, on the route that renders it
An HTTP route or API A request against a locally running server (curl, httpie, the project's client)
A CLI command or flag The command itself, including its failure path and its --help
A background job, queue, or cron The job, against a real (local) queue or a fake with the same contract
A migration or schema change The migration forward, then backward, against a scratch database
A build, bundler, or CI change The build, and check the artifact it produced
A library with no runnable surface The test suite is the runtime check; say so rather than inventing one

Step 2: Use the harness the project already has

python3 "${CLAUDE_PLUGIN_ROOT}/scripts/config.py" status reports the end-to-end harness praxis detected, and report.py runs it for you:

python3 "${CLAUDE_PLUGIN_ROOT}/scripts/report.py" record \
  --runtime "npm run e2e" --runtime-timeout 900 --verticals "..."

report.py executes the command and records the real exit code, exactly as it does for the test suite. When the change touches user-facing files and the project has a harness, the run is required and the report is not green without it (gate.require_runtime).

Read the full file on GitHub · 131 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. 2d ago First seen · 131 lines · 157 tokens per session scan A 3a78a01afdb2

Subscribe to this mod's changes

runtime-verification is a skill published in the GitHub repository Ohswedd/praxis (1 stars, last pushed 1mo ago), licensed MIT. It adds 157 tokens to every session and 1,692 once invoked, about $0.0008 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 2026-08-31.

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