diagnose

diagnose is a skill for Claude Code from avibebuilder/claude-prime. It costs 153 tokens per session (995 once invoked), scanned A, original, MIT.

A guide for investigating bugs and unexpected software behavior by separating confirmed facts from possible causes.

In plain words
What is it for?
Use it to examine symptoms, build testable explanations, check logs and code, and identify the most likely cause.
Why use it?
It helps avoid fixing the wrong problem when failures are intermittent, environment-specific, or otherwise hard to explain.

Skill for Claude Code

Written for Claude Code: argument-hint in frontmatter.

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/avibebuilder/claude-prime/diagnose
Any agent
npx skills add avibebuilder/claude-prime --skill diagnose
Clone the repo
git clone --depth 1 https://github.com/avibebuilder/claude-prime

Made for: Claude Code.

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/avibebuilder/claude-prime/diagnose.svg)](https://agentmods.dev/skills/avibebuilder/claude-prime/diagnose)
Your own site
<a href="https://agentmods.dev/skills/avibebuilder/claude-prime/diagnose"><img src="https://agentmods.dev/badge/skills/avibebuilder/claude-prime/diagnose.svg" alt="Measured on agentmods" height="20"></a>
Per session 153 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 995 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00153 $0.00995
Opus 5 $0.00077 $0.00498
Sonnet 5 $0.00031 $0.00199
Haiku 4.5 $0.00015 $0.00100

Measured 6d ago against content hash 5884a816c52c, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-05, from the pricing page.

Security

Grade A, and why

diagnose 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 6d ago.

The scan reads SKILL.md. This mod also ships 2 executable files (scripts/__tests__/diagnose-server.test.js, scripts/diagnose-server.js), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

.claude/skills/diagnose/SKILL.md · 89 lines

How it starts

The opening of the file, as written. The whole thing — 89 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Think harder.

Process

Check conversation context and skip completed steps.

1. Understand the symptom

  • Read the bug report, errors, logs, and surrounding code carefully
  • Clarify reproduction steps, expected behavior, and environment when they are unclear
  • Separate confirmed facts from working assumptions. List them explicitly:
    • Fact (confirmed): the server returns 200
    • Assumption (unconfirmed): the client receives the full HTML body Misidentifying an assumption as a fact is the most common source of wasted investigation.

2. Build hypotheses

  • Form 2-4 plausible root-cause hypotheses that are mechanistically distinct — different failure layers (e.g., server render vs. client hydration vs. network layer), not variations of the same idea

  • Rank them by likelihood

  • For each hypothesis, state both sides:

    • Confirm if: [what observation would prove this is the cause]
    • Eliminate if: [what observation would rule this out]

    A hypothesis you can't falsify in both directions is too vague to test.

3. Choose the lightest evidence method

Start with the cheapest source of truth that can kill hypotheses:

  • existing logs, traces, stack traces, metrics, and error output
  • static code inspection around the suspected path
  • config, environment, deploy, cache, queue, and permissions state that could explain the symptom
  • targeted reproduction in the relevant environment

Only add new instrumentation when existing evidence is insufficient.

  • If you need runtime probes, read diagnose/references/runtime-debugging.md
  • Use #region agent log / #endregion markers for any instrumentation you add
  • Tag each log point with the relevant hypothesisId
  • Log only the minimum fields needed to discriminate between hypotheses; never log secrets, tokens, passwords, cookies, or full sensitive payloads
  • If runtime probes require starting the local debug server, ask the user before launching it
  • For browser/UI bugs, combine with the agent-browser skill when reproduction or inspection needs it

Read the full file on GitHub · 89 lines

Files

What ships with it

4 files 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. 6d ago First seen · 89 lines · 153 tokens per session scan A 5884a816c52c

Subscribe to this mod's changes

diagnose is a skill published in the GitHub repository avibebuilder/claude-prime (119 stars, last pushed 3mo ago), licensed MIT. It adds 153 tokens to every session and 995 once invoked, about $0.0008 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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