diagnose

diagnose is a skill for Claude Code from mycelium-hq/ai-brain-starter. It costs 110 tokens per session (2,176 once invoked), scanned B, original, MIT.

A health-check tool for an AI Brain vault, a system that stores notes and working context for an AI assistant. It checks whether key files, hooks, indexes, scripts, and related integrations are working.

In plain words
What is it for?
Use it to inspect the vault after installation problems, updates, crashes, missing journal entries, or broken automatic context loading.
Why use it?
It helps locate common setup or maintenance problems when the assistant ignores instructions, entries are missing, hooks fail, or performance changes.

Skill for Claude Code

Written for Claude Code: argument-hint in frontmatter. Also seen: reads .claude/ paths; mentions CLAUDE.md.

Part of the ai-brain-starter plugin — 38 skills, 17 commands, 3 agents, 1 hook shipped together

Good fit Use it to inspect the vault after installation problems, updates, crashes, missing journal entries, or broken automatic context loading.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/mycelium-hq/ai-brain-starter/diagnose
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 mycelium-hq/ai-brain-starter --skill diagnose
Clone the repo
git clone --depth 1 https://github.com/mycelium-hq/ai-brain-starter

Made for: Claude Code.

Or install ai-brain-starter, the plugin that ships this one along with the rest of its 38 skills, 17 commands, 3 agents, 1 hook.

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 diagnose

README.md
[![agentmods](https://agentmods.dev/badge/skills/mycelium-hq/ai-brain-starter/diagnose/github.svg)](https://agentmods.dev/skills/mycelium-hq/ai-brain-starter/diagnose)
Your own site
<a href="https://agentmods.dev/skills/mycelium-hq/ai-brain-starter/diagnose"><img src="https://agentmods.dev/badge/skills/mycelium-hq/ai-brain-starter/diagnose/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 diagnose

Your own site · 80×15
<a href="https://agentmods.dev/skills/mycelium-hq/ai-brain-starter/diagnose"><img src="https://agentmods.dev/badge/skills/mycelium-hq/ai-brain-starter/diagnose.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 110 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,176 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 1 finding. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • medium Prompt Injection · line 111
    Subtle instructions detected that may alter agent decision-making or introduce hidden biases.
    Fix: Review content for implicit steering or bias. Ensure instructions are explicit and align with the skill's stated purpose.
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 $0.00110 $0.02176
Opus 5 $0.00055 $0.01088
Sonnet 5 $0.00022 $0.00435
Haiku 4.5 $0.00011 $0.00218

Measured 10d ago against content hash e23752950a7a, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade B, and why

diagnose scanned grade B with 1 finding 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 10d 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.

Subtle steeringmediumPrompt injection

Instructions that bias recommendations or shape behaviour without the user noticing.

Do NOT use /diagnose as an email-capture surface. If `~/.claude/.ai-brain-starter-email-on-file` is missing, that is fine and never a finding — the email is optional, and the only places it is ever asked are the setup in
skills/diagnose/SKILL.md · 118 lines

How it starts

The opening of the file, as written. The whole thing — 118 lines — stays where its author put it; the contents beside it link to each section on GitHub.

/diagnose

{SKILL_DIR} = this skill's own folder (locally: the directory this SKILL.md lives in; a served brain substitutes the real absolute path before you read this). Shared starter files live at the repo root two levels up: {SKILL_DIR}/../... If a path does not resolve, name the missing file and stop — never guess another location.

Tells you whether your second brain is healthy.

Why

Most "Claude is broken" reports trace to one of:

  • CLAUDE.md missing or has no Vault Map
  • Hooks not registered, so no auto context-loading
  • journal-index.json stale or malformed, so insights find nothing
  • .ps1 files lost their UTF-8 BOM, so Windows PowerShell crashes
  • ai-brain-starter is many commits behind, so the user is on stale logic

/diagnose checks all of these in ~5 seconds. It writes nothing, sends no network requests beyond a single git fetch, and exits with a status code so it can be wired into CI or cron.

What to do

  1. Find the script: {SKILL_DIR}/../../scripts/diagnose.sh (the starter repo root sits two levels above this skill's folder on every install shape).

  2. Run it. Pick the right one for the platform:

    Mac / Linux:

    bash "{SKILL_DIR}/../../scripts/diagnose.sh"
    # or pass an explicit vault:
    bash "{SKILL_DIR}/../../scripts/diagnose.sh" "/path/to/vault"
    

    Windows:

    pwsh "{SKILL_DIR}/../../scripts/diagnose.ps1"
    # or:
    pwsh "{SKILL_DIR}/../../scripts/diagnose.ps1" -Vault "C:\path\to\vault"
    

    By default it uses $VAULT_PATH if set, else the current directory.

  3. Read the output to the user in plain language. Don't dump the raw report unless they ask. Translate:

    • All green: "Your vault is healthy. Nothing to do."
    • Only WARNs: "Working, but $N things to clean up. Want me to fix them?" Then offer to fix the specific WARNs (re-build journal index, add Vault Map to CLAUDE.md, pull latest ai-brain-starter, etc).
    • At least one FAIL: "Something is broken: [name the FAIL in one sentence]. I can fix it: [propose the fix]." Wait for confirmation, then fix.

Read the full file on GitHub · 118 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. 10d ago First seen · 118 lines · 110 tokens per session scan B e23752950a7a

Subscribe to this mod's changes

diagnose is a skill published in the GitHub repository mycelium-hq/ai-brain-starter (36 stars, last pushed yesterday), licensed MIT. It adds 110 tokens to every session and 2,176 once invoked, about $0.0006 per session on Opus 5. A static security scan graded it B with 1 finding (subtle steering). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

Related

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