Bug Investigation

Bug Investigation is a skill for Claude Code, Codex from vinilana/dotcontext. It costs 11 tokens per session (1,485 once invoked), scanned A, original, MIT.

A systematic guide for investigating software bugs and finding their root causes in the @dotcontext/cli tool.

In plain words
What is it for?
Use it to investigate CLI errors, MCP responses, generated files, semantic analysis, workflow transitions, and failed tests.
Why use it?
It replaces guesswork with checks across the relevant code paths when commands crash, output is wrong, or tests and analysis fail.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

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/vinilana/dotcontext/bug-investigation
Any agent
npx skills add vinilana/dotcontext --skill bug-investigation
Clone the repo
git clone --depth 1 https://github.com/vinilana/dotcontext

Made for: Claude Code, Codex.

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 Bug Investigation

README.md
[![agentmods](https://agentmods.dev/badge/skills/vinilana/dotcontext/bug-investigation.svg)](https://agentmods.dev/skills/vinilana/dotcontext/bug-investigation)
Your own site
<a href="https://agentmods.dev/skills/vinilana/dotcontext/bug-investigation"><img src="https://agentmods.dev/badge/skills/vinilana/dotcontext/bug-investigation.svg" alt="Measured on agentmods" height="20"></a>
Per session 11 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,485 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 $0.00011 $0.01485
Opus 5 $0.00005 $0.00743
Sonnet 5 $0.00002 $0.00297
Haiku 4.5 $0.00001 $0.00148

Measured 6d ago against content hash d938e19b67c9, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

Bug Investigation 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.

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.

.context/skills/bug-investigation/SKILL.md · 145 lines

How it starts

The opening of the file, as written. The whole thing — 145 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Bug Investigation

Systematic approach to investigating and fixing bugs in the @dotcontext/cli CLI tool.

When to Use

  • A CLI command (workflow, sync, mcp, etc.) produces incorrect output or crashes
  • An MCP tool returns an error or unexpected response
  • Semantic analysis (tree-sitter / LSP) fails on certain codebases
  • Scaffold generation produces malformed frontmatter or missing content
  • Workflow phase transitions behave incorrectly
  • Tests fail unexpectedly after changes

Project-Specific Investigation Surfaces

Area Key Files Common Issues
CLI commands src/index.ts, src/services/*/index.ts Commander option parsing, missing args
MCP server src/services/mcp/mcpServer.ts, src/services/mcp/gateway/*.ts repoPath resolution, Zod validation failures
Scaffold generation src/generators/*/, src/types/scaffoldFrontmatter.ts Frontmatter parsing, file path resolution
Scaffold fill via MCP src/services/ai/tools/fillScaffoldingTool.ts, src/services/mcp/gateway/context.ts Missing files, stale context, oversized responses
Semantic analysis src/services/semantic/codebaseAnalyzer.ts, src/services/semantic/treeSitter/ tree-sitter optional dep missing, parse failures
Workflow src/workflow/, src/services/workflow/workflowService.ts Phase transition logic, gate checking
i18n src/utils/i18n.ts Missing translation keys, locale detection
Frontmatter src/utils/frontMatter.ts v1 vs v2 format confusion, status detection

Instructions

1. Reproduce the Bug

Run the CLI in dev mode to reproduce:

# Direct execution via tsx
npx tsx src/index.ts workflow --help

# For MCP-related bugs, capture stderr output
npx tsx src/index.ts mcp --verbose 2>mcp-debug.log

For MCP tool bugs, test the gateway handler directly in a script or test file rather than through the full MCP transport.

2. Identify the Service Layer

Trace the call path from the CLI command or MCP tool to the responsible service:

Read the full file on GitHub · 145 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. 6d ago First seen · 145 lines · 11 tokens per session scan A d938e19b67c9

Subscribe to this mod's changes

Bug Investigation is a skill published in the GitHub repository vinilana/dotcontext (565 stars, last pushed 1mo ago), licensed MIT. It adds 11 tokens to every session and 1,485 once invoked, about $0.0001 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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