principle-sequence-verifiable-units

principle-sequence-verifiable-units is a skill for Claude Code, Codex from painhardcore/pstack. It costs 68 tokens per session (494 once invoked), scanned A, a copy of principle-sequence-verifiable-units, MIT.

A workflow for dividing multi-step development work into small changes that can each be checked. It also applies this ordering to commits and pull requests, with each step leaving the project in a verifiable state.

In plain words
What is it for?
Use it for migrations, large batches of similar edits, multi-step runs, and commit or pull-request sequences that need clear verification.
Why use it?
It makes problems easier to locate because each change is checked close to where it was introduced. Reviewers can follow evidence that a bug first fails and then is fixed.

Skill for Claude CodeCodex

Part of the pstack plugin — 41 skills, 2 agents shipped together

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/painhardcore/pstack/principle-sequence-verifiable-units
Any agent
npx skills add painhardcore/pstack --skill principle-sequence-verifiable-units
Clone the repo
git clone --depth 1 https://github.com/painhardcore/pstack

Made for: Claude Code, Codex.

Or install pstack, the plugin that ships this one along with the rest of its 41 skills, 2 agents.

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-sequence-verifiable-units

README.md
[![agentmods](https://agentmods.dev/badge/skills/painhardcore/pstack/principle-sequence-verifiable-units.svg)](https://agentmods.dev/skills/painhardcore/pstack/principle-sequence-verifiable-units)
Your own site
<a href="https://agentmods.dev/skills/painhardcore/pstack/principle-sequence-verifiable-units"><img src="https://agentmods.dev/badge/skills/painhardcore/pstack/principle-sequence-verifiable-units.svg" alt="Measured on agentmods" height="20"></a>
Per session 68 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 494 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 95% copy Near-identical to another mod 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 $0.00068 $0.00494
Opus 5 $0.00034 $0.00247
Sonnet 5 $0.00014 $0.00099
Haiku 4.5 $0.00007 $0.00049

Measured 4d ago against content hash 40de5b6d82a4, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

principle-sequence-verifiable-units 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.

Origin

This is a copy

95% identical to principle-sequence-verifiable-units — 1 line differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

.opencode/skills/principle-sequence-verifiable-units/SKILL.md · 22 lines

What it actually says

Sequence work into verifiable units

Order work as a sequence of small units, each ending in a state you can check, and don't advance until the current one is green. The same discipline runs at two altitudes, how you execute and how you deliver.

Why: A break caught at the unit that caused it is cheap to localize. A break caught after a batch is buried, and you have already built further on a broken base. Sequencing those same units into a delivery a reviewer can replay turns "trust me" into "watch it go red, then green."

Execution. In a sweep, migration, or any run of similar edits, verify each change before starting the next. Never batch the edits and verify once at the end. Each unit is a before/after bracket: known-good state, one change, run the check, then proceed. Rebase onto clean trunk first so every check measures against the real baseline. When a lever does the edits, the per-unit check is nearly free; run it anyway.

Delivery. Stack commits and PRs in the order that proves the work. The canonical shape is the failing test first, then the fix on top. The first unit shows the bug is real (red), the next shows it resolved (green), so a reviewer sees both the problem and the proof. Other story orders are a subtraction before the reshape, a baseline capture before the treatment, the scaffold before the feature. Each commit lands on its own and the sequence reads as an argument.

Pattern:

  • Pick the smallest unit that ends in a check: an edit plus its test, or a commit that stands alone.
  • Verify before advancing. Red to green per unit, never deferred to a final batch.
  • Order the units so the sequence builds confidence on its own, for you while executing and for a reviewer reading the stack.

The sequencing complement to the prove-it-works principle skill, which keeps each check real, and the build-the-lever principle skill, which makes the per-unit check cheap.

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 · 22 lines · 68 tokens per session scan A 40de5b6d82a4

Subscribe to this mod's changes

principle-sequence-verifiable-units is a skill published in the GitHub repository painhardcore/pstack (1 stars, last pushed 8d ago), licensed MIT. It adds 68 tokens to every session and 494 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. It is 95% identical to principle-sequence-verifiable-units, differing in 1 line, and is treated as a copy.