investigate

investigate is a skill for Claude Code from adamthewilliam/grepika. It costs 48 tokens per session (748 once invoked), scanned A, original, MIT.

A debugging investigation tool that traces an error or bug through a codebase to find where it starts and how execution reaches it.

In plain words
What is it for?
Use it to search for an error, inspect nearby code, find related functions, and build the path from the starting point to the failure.
Why use it?
It narrows a problem from an error message or description to the responsible code and its callers.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter. Also seen: model in frontmatter.

Part of the grepika plugin — 9 skills, 3 commands, 2 agents shipped together

Good fit Use it to search for an error, inspect nearby code, find related functions, and build the path from the starting point to the failure.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/adamthewilliam/grepika/investigate
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 adamthewilliam/grepika --skill investigate
Clone the repo
git clone --depth 1 https://github.com/adamthewilliam/grepika

Made for: Claude Code.

Or install grepika, the plugin that ships this one along with the rest of its 9 skills, 3 commands, 2 agents.

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 investigate

README.md
[![agentmods](https://agentmods.dev/badge/skills/adamthewilliam/grepika/investigate/github.svg)](https://agentmods.dev/skills/adamthewilliam/grepika/investigate)
Your own site
<a href="https://agentmods.dev/skills/adamthewilliam/grepika/investigate"><img src="https://agentmods.dev/badge/skills/adamthewilliam/grepika/investigate/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 investigate

Your own site · 80×15
<a href="https://agentmods.dev/skills/adamthewilliam/grepika/investigate"><img src="https://agentmods.dev/badge/skills/adamthewilliam/grepika/investigate.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 48 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 748 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 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 Excessive Agency · line 12
    Skill selects an external model or provider that may use a different account or billing plan than the operator expects. Undisclosed model switches can cause unexpected cost or quota consumption.
    Fix: Remove the model/provider override or disclose it prominently and require explicit operator approval before invoking an external coding CLI or billed model.
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 $0.00048 $0.00748
Opus 5 $0.00024 $0.00374
Sonnet 5 $0.00010 $0.00150
Haiku 4.5 $0.00005 $0.00075

Measured 10d ago against content hash d9f54f328125, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

investigate 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 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.

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/grepika/skills/investigate/SKILL.md · 102 lines

How it starts

The opening of the file, as written. The whole thing — 102 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Debug Investigation Skill

You are a debugging investigator. Trace errors and bugs through the codebase to find their origin and call chain.

Input

Query: $ARGUMENTS

If no query provided, ask the user what error or bug they want to investigate.

Pre-check

If any tool returns "No active workspace", call mcp__grepika__add_workspace with the project root first, then retry the tool.

Investigation Workflow

  1. Search for the error/keyword

    • Use mcp__grepika__search with mode: "grep" for exact error message strings (regex patterns)
    • Use mcp__grepika__search with mode: "fts" for natural language variations (e.g., related concepts, similar error descriptions)
    • Use mode: "combined" (default) when you're unsure which approach fits best
  2. Get context around matches

    • Use mcp__grepika__context to see surrounding code for each match
    • Identify which matches are the actual error origin vs error handling
  3. Find references to key functions

    • Use mcp__grepika__refs to trace function calls
    • Build the call chain from entry point to error location
  4. Discover connected files

    • Use mcp__grepika__refs to find connected modules
    • Look for related error handling, logging, or retry logic
  5. Extract file structure

    • Use mcp__grepika__outline on key files to understand their shape
    • Identify relevant functions, classes, and exports

Output Format

Provide a structured investigation report:

## Error Investigation: [query]

### Origin
- **File**: [path:line]
- **Function**: [name]
- **Context**: [what the code does]

### Call Chain
1. [entry point] →
2. [intermediate call] →
3. [error location]

### Related Error Handling
- [list any try/catch, error boundaries, or recovery logic found]

### Investigation Points
- [specific lines/functions to examine further]
- [questions that remain unanswered]

### Suggested Fixes
- [potential approaches based on findings]

Tips

  • Start broad, then narrow down
  • Look for multiple occurrences - the same error may be thrown in different places
  • Check for error handling that might swallow or transform the original error
  • Note any logging that could help reproduce the issue

Read the full file on GitHub · 102 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. 10d ago First seen · 102 lines · 48 tokens per session scan A d9f54f328125

Subscribe to this mod's changes

investigate is a skill published in the GitHub repository adamthewilliam/grepika (135 stars, last pushed 28d ago), licensed MIT. It adds 48 tokens to every session and 748 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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