principle-prove-it-works

principle-prove-it-works is a skill for Claude Code from chhoumann/t3-pstack. It costs 50 tokens per session (293 once invoked), scanned A, original, MIT.

A verification principle for checking the actual result of a coding task before declaring it complete. It means running the feature, reading the real value, or inspecting the actual change rather than trusting a proxy or a compilation result.

In plain words
What is it for?
Use it after implementing a feature, changing data, or completing a task to inspect the output, run relevant checks, and confirm that each important fact came from the correct project record.
Why use it?
Unverified work has unknown correctness, even when a build succeeds or another process reports success. Direct checks reveal whether the real artifact and the process behind it work as expected.

Skill for Claude Code

Written for Claude Code: disable-model-invocation in frontmatter.

Part of the t3-pstack plugin — 62 skills, 4 agents, 1 hook shipped together

Good fit Use it after implementing a feature, changing data, or completing a task to inspect the output, run relevant checks, and confirm that each important fact came from the correct project record.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/chhoumann/t3-pstack/principle-prove-it-works
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 chhoumann/t3-pstack --skill principle-prove-it-works
Clone the repo
git clone --depth 1 https://github.com/chhoumann/t3-pstack

Made for: Claude Code.

Or install t3-pstack, the plugin that ships this one along with the rest of its 62 skills, 4 agents, 1 hook.

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 principle-prove-it-works

README.md
[![agentmods](https://agentmods.dev/badge/skills/chhoumann/t3-pstack/principle-prove-it-works/github.svg)](https://agentmods.dev/skills/chhoumann/t3-pstack/principle-prove-it-works)
Your own site
<a href="https://agentmods.dev/skills/chhoumann/t3-pstack/principle-prove-it-works"><img src="https://agentmods.dev/badge/skills/chhoumann/t3-pstack/principle-prove-it-works/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 principle-prove-it-works

Your own site · 80×15
<a href="https://agentmods.dev/skills/chhoumann/t3-pstack/principle-prove-it-works"><img src="https://agentmods.dev/badge/skills/chhoumann/t3-pstack/principle-prove-it-works.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 50 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 293 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 $0.00050 $0.00293
Opus 5.5 $0.00020 $0.00117
Sonnet 5.5 $0.00010 $0.00059
Haiku 4.5 $0.00005 $0.00029

Measured yesterday against content hash ec79a15025ba, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

principle-prove-it-works 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.

plugins/pstack/skills/principle-prove-it-works/SKILL.md · 23 lines

What it actually says

Prove It Works

Verify every task output by checking the real thing directly. Do not infer from proxies, self-reports, or "it compiles."

Why: Unverified work has unknown correctness. Indirect verification (file mtimes, output freshness, agent self-reports, cached screenshots) feels cheaper than direct observation. Acting on a wrong inference costs far more than checking the source.

Check the real thing, not a proxy:

  • Check process liveness directly, not indirectly through derived state
  • Read the actual value, not a cached or derived representation
  • When verification fails, suspect the observation method before suspecting the system

Script the check when you can

The strongest proof is a deterministic script that re-runs the same comparison, not a one-time eyeball. Write the script, run it, and keep its output as an artifact a reviewer can re-run instead of trusting your word.

Keep the artifact visible for the human. Commit it only for large or complex work where the trail has to be auditable later, like a big port or migration (the show-me-your-work skill).

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 Changed · -4 lines ec79a15025ba
  2. 3d ago First seen · 27 lines · 50 tokens per session scan A 779a5955bfcf

Subscribe to this mod's changes

principle-prove-it-works is a skill published in the GitHub repository chhoumann/t3-pstack (190 stars, last pushed yesterday), licensed MIT. It adds 50 tokens to every session and 293 once invoked, about $0.0002 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 2026-10-13.

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