theory-fidelity

theory-fidelity is a skill for Claude Code from haabe/mycelium. It costs 57 tokens per session (2,657 once invoked), scanned A, original, MIT.

An audit guide for checking whether a project genuinely applies the theories and methods it claims to use, rather than merely mentioning them.

In plain words
What is it for?
Use it after adding or changing a theory, when reviewing citations, or during periodic checks of a project's framework and implementation.
Why use it?
It reveals when a theory is implemented in code or process, described only in documentation, distorted, or absent.

Skill for Claude Code

Written for Claude Code: ${CLAUDE_PLUGIN_ROOT} variable. Also seen: mentions subagents.

Runs only inside its plugin — its command needs a path that Claude Code sets for a plugin’s own hooks and for nothing else. Install the plugin, not this.

Part of the mycelium plugin — 61 skills, 6 hooks shipped together

Good fit Use it after adding or changing a theory, when reviewing citations, or during periodic checks of a project's framework and implementation.

Compare 6 skills from other repositories ↓
Install

Getting it into your agent

This one installs as part of its plugin. Adding the marketplace and installing the plugin brings it with everything else the plugin ships.

Claude Code
/plugin marketplace add haabe/mycelium
Claude Code
/plugin install mycelium

Made for: Claude Code.

Or install mycelium, the plugin that ships this one along with the rest of its 61 skills, 6 hooks.

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 theory-fidelity

README.md
[![agentmods](https://agentmods.dev/badge/skills/haabe/mycelium/theory-fidelity/github.svg)](https://agentmods.dev/skills/haabe/mycelium/theory-fidelity)
Your own site
<a href="https://agentmods.dev/skills/haabe/mycelium/theory-fidelity"><img src="https://agentmods.dev/badge/skills/haabe/mycelium/theory-fidelity/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 theory-fidelity

Your own site · 80×15
<a href="https://agentmods.dev/skills/haabe/mycelium/theory-fidelity"><img src="https://agentmods.dev/badge/skills/haabe/mycelium/theory-fidelity.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 57 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,657 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 $0.00057 $0.02657
Opus 5 $0.00028 $0.01328
Sonnet 5 $0.00011 $0.00531
Haiku 4.5 $0.00006 $0.00266

Measured 11d ago against content hash a37a1da2035e, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

theory-fidelity 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 11d 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.

plugins/mycelium/skills/theory-fidelity/SKILL.md · 148 lines

How it starts

The opening of the file, as written. The whole thing — 148 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Theory Fidelity Audit

Most framework checks evaluate process (cycle health, gates) or artifact performance (evals, DORA). None of them ask the question this skill exists for: for every theory a project claims to represent, is the mapped mechanism actually faithful to what the theory says — or is it theatre? This is the audit of the theory→mechanism mapping itself.

The framework's own stated bar (docs/theories.md): "every theory is mechanism-mapped … citations without mechanism-mapping are theatre." This skill holds the project to that bar — including holding the theory doc to it.

When to Use

  • Quarterly, alongside /mycelium:framework-health (process health) — this is the theory-fidelity half.
  • After adding/citing a new theory, or after editing a theory's mechanism (skill/gate/schema).
  • When a citation looks decorative, or when a doc claims a mechanism you suspect doesn't exist.

The Grading Rubric (three axes)

For each claimed theory, record:

  1. RepresentationMechanized (a skill/gate/schema/canvas applies it) · Prose-only (cited + described, no mechanism) · Absent.
  2. Fidelity (only if Mechanized):
    • Faithful — the mechanism matches the theory's real claims.
    • Justified-Adaptation — the mechanism deliberately diverges and the rationale is documented in-repo. Divergence with no documented rationale is Distorted, not Justified.
    • Partial — a faithful subset, with a named gap.
    • Distorted — diverges without rationale, or misrepresents the theory.
    • Over-claim — the theory doc claims more than the mechanism delivers (the project's own "theatre" failure mode).
    • Name-only — cited but not actually mechanized.
  3. Evidence-basissource-grounded (verified against the author's canonical work) · model-knowledge (from the agent's training — provisional / consistency-only).

Workflow

  1. Rule on the PREVIOUS audit's findings — before producing any new ones. Per ${CLAUDE_PLUGIN_ROOT}/engine/canvas-guidance.yml#prior_findings_first.

Read the full file on GitHub · 148 lines

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. 11d ago First seen · 148 lines · 57 tokens per session scan A a37a1da2035e

Subscribe to this mod's changes

theory-fidelity is a skill published in the GitHub repository haabe/mycelium (45 stars, last pushed today), licensed MIT. It adds 57 tokens to every session and 2,657 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 2026-08-30.

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