opensession: Skill for Claude Code

.agents/skills/pstack-suite/skills/principle-prove-it-works/SKILL.md

principle-prove-it-works is a skill for Claude Code, Codex from tellahq/opensession. It costs 50 tokens per session (439 once invoked), scanned A, original, MIT.

A verification rule for checking the actual feature, output, or change after completing coding work.

In plain words
What is it for?
Use it after implementing features, integrations, or delegated work by running the real path and inspecting the resulting artifact.
Why use it?
It catches failures that a successful build, a status message, or a cached result can hide.

Skill for Claude CodeCodex

Written for Claude Code: disable-model-invocation in frontmatter. Also seen: installed under .agents/ (shared by several agents).

This is tellahq/opensession's own configuration. It tells Claude Code and Codex how to work on opensession itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything opensession configures →

Reuse

Borrowing it

Nothing to install: this file belongs to tellahq/opensession. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/tellahq/opensession/main/.agents/skills/pstack-suite/skills/principle-prove-it-works/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/tellahq/opensession

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 principle-prove-it-works

README.md
[![agentmods](https://agentmods.dev/badge/skills/tellahq/opensession/principle-prove-it-works/github.svg)](https://agentmods.dev/skills/tellahq/opensession/principle-prove-it-works)
Your own site
<a href="https://agentmods.dev/skills/tellahq/opensession/principle-prove-it-works"><img src="https://agentmods.dev/badge/skills/tellahq/opensession/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/tellahq/opensession/principle-prove-it-works"><img src="https://agentmods.dev/badge/skills/tellahq/opensession/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 439 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 $0.00050 $0.00439
Opus 5 $0.00025 $0.00219
Sonnet 5 $0.00010 $0.00088
Haiku 4.5 $0.00005 $0.00044

Measured 5d ago against content hash 9bbe6138505b, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, 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 5d 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.

Origin

Copies of this mod

6 near-identical copies found in the catalogue:

.agents/skills/pstack-suite/skills/principle-prove-it-works/SKILL.md · 34 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.

Pattern: After completing any task, ask: "how do I prove this actually works?"

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

Code and features:

  1. Build it (necessary but not sufficient)
  2. Run it and exercise the actual feature path
  3. Check the full chain: does data flow from input to output?
  4. For integrations, test the full communication path end-to-end

Delegation: trust artifacts, not self-reports. When verifying delegated work, inspect the actual output artifact (git diff, file contents, runtime behavior), not the delegate's summary. Agents report what they intended, not always what happened.

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. A script comparing the old and new compiled output catches what a glance misses.

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). Most work just needs it visible, not committed.

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. 5d ago First seen · 34 lines · 50 tokens per session scan A 9bbe6138505b

Subscribe to this mod's changes

principle-prove-it-works is a skill published in the GitHub repository tellahq/opensession (363 stars, last pushed today), licensed MIT. It adds 50 tokens to every session and 439 once invoked, about $0.0003 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 2026-09-03.

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