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.
npx skills add OutlineDriven/odin-claude-plugin --skill universal-invariant-baselinegit clone --depth 1 https://github.com/OutlineDriven/odin-claude-pluginWrote 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.
[](https://agentmods.dev/skills/outlinedriven/odin-claude-plugin/universal-invariant-baseline)<a href="https://agentmods.dev/skills/outlinedriven/odin-claude-plugin/universal-invariant-baseline"><img src="https://agentmods.dev/badge/skills/outlinedriven/odin-claude-plugin/universal-invariant-baseline/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.
<a href="https://agentmods.dev/skills/outlinedriven/odin-claude-plugin/universal-invariant-baseline"><img src="https://agentmods.dev/badge/skills/outlinedriven/odin-claude-plugin/universal-invariant-baseline.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00047 | $0.00837 |
| Opus 5 | $0.00023 | $0.00418 |
| Sonnet 5 | $0.00009 | $0.00167 |
| Haiku 4.5 | $0.00005 | $0.00084 |
Grade A, and why
universal-invariant-baseline 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.
How it starts
The opening of the file, as written. The whole thing — 46 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Universal invariant baseline
Contract
| Field | Bound contract |
|---|---|
| Trigger | User explicitly requests an invariant-first, fail-fast, special-case-eliminating baseline for a named implementation. |
| Authority | Reversible local: writes only the named local artifact; rollback is version control (restore) or undo (file deletion). No remote mutation. |
| Side effect | Replace the target local file with its invariant-first, fail-fast, special-case-eliminating refinement. |
| Done | All named invariant checks pass and no unresolved special-case artifacts remain. |
Inputs
Required:
TARGET: path to the local source file or module to baseline.LANGUAGE: the target's language (e.g.,python,rust,typescript). Required to select correct invariant patterns.
Procedure
- Validate the request. Confirm
TARGETis a concrete, scoped implementation task with a named local path. IfTARGETis absent, empty, or points to a non-local artifact, raiseBLOCKED-INPUTand stop. Done when:TARGETis confirmed as a concrete local path. - Enumerate invariants. For
LANGUAGE, enumerate the language-native invariant patterns that govern correctness: type contracts, ownership/borrow rules, null/void guards, resource lifecycle ordering, and domain-specific preconditions. Write each as a named, executable check with a unique identifier. Done when: every invariant pattern is a named, executable check with a unique identifier. - Insert fail-fast guards. Before every mutable state operation, every external call, and every branching decision, insert the matching invariant check. If any check fails, halt immediately with
INVARIANT-FAIL: <identifier>and the observed violation. The target artifact is unchanged until all checks pass. Done when: every mutable state operation, external call, and branching decision has a matching invariant guard. - Eliminate special cases. Scan the target for:
- Boolean flag arguments or module-level toggles that gate behavior.
- Hardcoded branch paths that duplicate a general case.
- Numeric or string domain constants used as inline guards. For each found artifact, either refactor the boolean branch into a data-driven lookup, merge the special case into the general path, or convert the magic constant into a named constant with a documented invariant. Done when: no boolean flags, hardcoded duplicate branches, or inline magic constants remain.
- Re-validate. Run checks by compiling the target in its language-native build and running the existing test suite scoped to the target. If the project has no compile step, run the test suite alone. If any check fails, halt with
INVARIANT-FAIL: <identifier>listing the specific failure. Record the complete set of removed special-case artifacts as the resolution log. Done when: all invariant checks pass and the resolution log is complete.
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 4d ago Changed · -7 tokens per session 8d880dd6a961
- 6d ago First seen · 46 lines · 54 tokens per session scan A 2dccba997500
universal-invariant-baseline is a skill published in the GitHub repository OutlineDriven/odin-claude-plugin (35 stars, last pushed yesterday), licensed Apache-2.0. It adds 47 tokens to every session and 837 once invoked, about $0.0002 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.
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