axiom-mode

axiom-mode is a skill for Claude Code, Codex from OutlineDriven/odin-claude-plugin. It costs 37 tokens per session (1,146 once invoked), scanned A, original, Apache-2.0.

A response style for compact formal-logic English, using short predicate-like statements and ASCII keywords. It changes how the agent communicates rather than adding a coding tool.

In plain words
What is it for?
Writing responses in axiom mode, formal-logic mode, or another explicitly requested compact form until normal mode is restored.
Why use it?
It provides a stricter, compressed way to express claims when precision or limited space matters.

Skill for Claude CodeCodex

Written for Claude Code and Codex: shipped in a Claude Code plugin, but also agents/openai.yaml present.

Part of the odin-core plugin — 16 skills shipped together

Good fit Writing responses in axiom mode, formal-logic mode, or another explicitly requested compact form until normal mode is restored.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/outlinedriven/odin-claude-plugin/axiom-mode
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 OutlineDriven/odin-claude-plugin --skill axiom-mode
Clone the repo
git clone --depth 1 https://github.com/OutlineDriven/odin-claude-plugin

Made for: Claude Code, Codex.

Or install odin-core, the plugin that ships this one along with the rest of its 16 skills.

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 axiom-mode

README.md
[![agentmods](https://agentmods.dev/badge/skills/outlinedriven/odin-claude-plugin/axiom-mode/github.svg)](https://agentmods.dev/skills/outlinedriven/odin-claude-plugin/axiom-mode)
Your own site
<a href="https://agentmods.dev/skills/outlinedriven/odin-claude-plugin/axiom-mode"><img src="https://agentmods.dev/badge/skills/outlinedriven/odin-claude-plugin/axiom-mode/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 axiom-mode

Your own site · 80×15
<a href="https://agentmods.dev/skills/outlinedriven/odin-claude-plugin/axiom-mode"><img src="https://agentmods.dev/badge/skills/outlinedriven/odin-claude-plugin/axiom-mode.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 37 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,146 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 $0.00037 $0.01146
Opus 5 $0.00018 $0.00573
Sonnet 5 $0.00007 $0.00229
Haiku 4.5 $0.00004 $0.00115

Measured 4d ago against content hash c6252b2514ea, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

axiom-mode 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

Copies of this mod

2 near-identical copies found in the catalogue:

plugins/odin-core/skills/axiom-mode/SKILL.md · 49 lines

How it starts

The opening of the file, as written. The whole thing — 49 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Axiom mode

Contract

Field Bound contract
Trigger User requests axiom, axiom-mode, axiom-compact, formal-logic, or compact form.
Authority Read-only. No file, VCS, credential, paid, published, deployed, or remote mutation. Changes response register only.
Side effect None; response style only.
Done Responses remain in-register without sacrificing structure, then restore after exceptions.

Inputs

No external input required. The user's invocation phrase activates the register; a later "stop axiom-mode" or "normal mode" phrase deactivates it.

Procedure

  1. Activate the Compacted Formal-logic English register. This ASCII-only register uses shortened-English keywords for logical connectives and follows predicate-calculus and Hoare-triple conventions for structural framing. Persist the register for every subsequent response until the user signals "stop axiom-mode" or "normal mode". Done when: the register is active and persists across responses.

  2. Emit only allowed characters: A-Z, a-z, 0-9, hyphens, spaces, slash, underscore, and standard sentence punctuation (period, comma, colon, semicolon, parentheses, brackets, quotes). Do not emit Unicode logic glyphs: universal-quantifier, existential-quantifier, logical-and, logical-or, logical-not, material-implication, biconditional, equivalence, syntactic-turnstile, semantic-turnstile. Done when: the response contains only allowed characters.

  3. Do not use operator shortcuts in prose: fat-arrow, double-ampersand, double-pipe, bang-as-logical-not, less-than-equals-greater-than-equivalence, bang-equals, colon-equals, double-equals. The same characters inside fenced code blocks are exempt; code is preserved verbatim. Done when: prose contains no operator shortcuts (code blocks exempt).

  4. Use the keyword set: IMPLIES, AND, OR, NOT, IFF, XOR, FORALL, EXISTS, THEREFORE, GIVEN, ASSUME, IF, THEN, ELSE, WHEN, UNLESS, PRE, POST, INVARIANT, DEF, LET, WHERE, LEMMA, THEOREM, QED, CASE, MUST, SHALL, MAY, CANNOT, EQUALS, BEFORE. Done when: logical connectives use the keyword set.

Read the full file on GitHub · 49 lines

Files

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.

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 Changed · -24 tokens per session c6252b2514ea
  2. 6d ago Changed · -54 lines · +9 tokens per session 0e23859cadfd
  3. 10d ago First seen · 103 lines · 52 tokens per session scan A f9893d8cdddc

Subscribe to this mod's changes

axiom-mode is a skill published in the GitHub repository OutlineDriven/odin-claude-plugin (35 stars, last pushed yesterday), licensed Apache-2.0. It adds 37 tokens to every session and 1,146 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 2026-08-30.

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