Compound Engineering Debug
EveryInc/compound-engineering-plugin
Finds the root cause of failing or slow behavior with a hypothesis-driven loop, then fixes it test-first if you choose, or hands back a diagnosis only.
Use early when debugging a medium or hard bug, especially when tests alone may not reveal the real runtime failure.
Install Debugging Difficult Bugs
$ npx skills add mastra-ai/mastra --skill debugging-difficult-bugs -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install mastra-ai/mastra debugging-difficult-bugs --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/mastra-ai/mastra.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.claude/skills/debugging-difficult-bugs .claude/skills/debugging-difficult-bugs && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "debugging-difficult-bugs" agent skill from https://github.com/mastra-ai/mastra/tree/main/.claude/skills/debugging-difficult-bugs into .claude/skills/debugging-difficult-bugs/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "debugging-difficult-bugs", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/mastra-ai/mastra/tree/main/.claude/skills/debugging-difficult-bugsType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add mastra-ai/mastra --skill debugging-difficult-bugs -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install mastra-ai/mastra debugging-difficult-bugs --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/mastra-ai/mastra.git skills-src && mkdir -p .agents/skills && cp -r skills-src/.claude/skills/debugging-difficult-bugs .agents/skills/debugging-difficult-bugs && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "debugging-difficult-bugs" agent skill from https://github.com/mastra-ai/mastra/tree/main/.claude/skills/debugging-difficult-bugs into .agents/skills/debugging-difficult-bugs/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "debugging-difficult-bugs", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add mastra-ai/mastra --skill debugging-difficult-bugs -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install mastra-ai/mastra debugging-difficult-bugs --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/mastra-ai/mastra.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/.claude/skills/debugging-difficult-bugs .cursor/skills/debugging-difficult-bugs && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "debugging-difficult-bugs" agent skill from https://github.com/mastra-ai/mastra/tree/main/.claude/skills/debugging-difficult-bugs into .cursor/skills/debugging-difficult-bugs/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "debugging-difficult-bugs", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/mastra-ai/mastra.git --path .claude/skills/debugging-difficult-bugs--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add mastra-ai/mastra --skill debugging-difficult-bugs -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install mastra-ai/mastra debugging-difficult-bugs --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/mastra-ai/mastra.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/.claude/skills/debugging-difficult-bugs .gemini/skills/debugging-difficult-bugs && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "debugging-difficult-bugs" agent skill from https://github.com/mastra-ai/mastra/tree/main/.claude/skills/debugging-difficult-bugs into .gemini/skills/debugging-difficult-bugs/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "debugging-difficult-bugs", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install mastra-ai/mastra debugging-difficult-bugsInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add mastra-ai/mastra --skill debugging-difficult-bugs -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/mastra-ai/mastra.git skills-src && mkdir -p .github/skills && cp -r skills-src/.claude/skills/debugging-difficult-bugs .github/skills/debugging-difficult-bugs && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "debugging-difficult-bugs" agent skill from https://github.com/mastra-ai/mastra/tree/main/.claude/skills/debugging-difficult-bugs into .github/skills/debugging-difficult-bugs/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "debugging-difficult-bugs", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add mastra-ai/mastra --skill debugging-difficult-bugs -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install mastra-ai/mastra debugging-difficult-bugs --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/mastra-ai/mastra.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/.claude/skills/debugging-difficult-bugs .opencode/skills/debugging-difficult-bugs && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "debugging-difficult-bugs" agent skill from https://github.com/mastra-ai/mastra/tree/main/.claude/skills/debugging-difficult-bugs into .opencode/skills/debugging-difficult-bugs/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "debugging-difficult-bugs", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
- Skill name
debugging-difficult-bugs- GitHub stars
- 29k
- Token cost
- ~1.9k tokens
- SKILL.md length
- 830 words
- Files
- 1
- Skills in repo
- 44
- Repo updated
- First seen
- Licence
- Custom licence
At a glance
Use early when debugging a medium or hard bug, especially when tests alone may not reveal the real runtime failure.
- Works in 6 steps: State the uncertainty → Add temporary unconditional… → Reproduce the real issue → …
- This before extended TDD iteration when a bug involves runtime state
- SKILL.md covers When to Use, Required Approach, JSONL Logging Pattern and What to Log, plus 3 more sections
- Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
What it does
Debugging Difficult Bugs is an agent skill from mastra-ai/mastra. Use early when debugging a medium or hard bug, especially when tests alone may not reveal the real runtime failure. Trigger this before extended TDD iteration when a bug involves runtime state, ordering, persistence, streaming, concurrency, UI/manual reproduction, external services, or when a red or newly passing test may not model the real issue. Skip only when the root cause is already directly proven by a stack trace or deterministic test that exercises the real runtime path.
Its SKILL.md is about 1.9k tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.
It sits in Development, covering Debugging, Test-driven development and Root cause analysis. The repository describes itself as: Mastra is the modern TypeScript framework for AI-powered applications and agents.
When your agent uses it
- This before extended TDD iteration when a bug involves runtime state
- UI/manual reproduction
- External services
- Newly passing test may not model the real issue
Example prompts
- “/debugging-difficult-bugs”
Workflow steps
6 steps, taken from the first numbered list in SKILL.md.
- State the uncertainty
- Add temporary unconditional instrumentation
- Reproduce the real issue
- Analyze the log before fixing
- Clean up instrumentation
- Keep or improve tests
What it can do on your machine
Read from SKILL.md and the folder at commit 647e656. It shows what the files ask for, not the result of running them.
Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
No scripts in the folder and no shell commands in SKILL.md (its code samples are typescript).
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Context cost
Debugging Difficult Bugs loads about 1.9k tokens when it runs. Until then it costs about 127 tokens; SKILL.md has 830 words of instructions outside code blocks.
Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.
Safety
Auto-check passed
The automated check found no risky patterns in SKILL.md.
Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.
SKILL.md
Its licence (Custom licence) doesn't allow us to republish the file, so here is its outline and opening line. It has 830 words (~1,863 tokens).
“Use this skill early for medium or hard bugs where normal TDD may give false confidence because the test does not fully capture the real bug.”
- name
- debugging-difficult-bugs
Files
Just SKILL.md in .claude/skills/debugging-difficult-bugs of mastra-ai/mastra.
Open the folder on GitHubat commit 647e656
Compare with similar skills
Debugging Difficult Bugs next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| Debugging Difficult Bugs this skillmastra-ai/mastra | 29k | — | ~1.9k | Automated safety check: Pass | Custom licence | |
| Compound Engineering DebugEveryInc/compound-engineering-plugin | 25k | — | ~4.2k | Automated safety check: Pass | MIT | |
| Golang Troubleshootingsamber/cc-skills-golang | 3.4k | — | ~3.3k | Automated safety check: Pass | MIT | |
| Systematic Debuggingtmdgusya/engineering-discipline | 125 | — | ~2k | Automated safety check: Pass | None | |
| Triage Issuesoftspark/ai-toolkit | 179 | — | ~1.3k | Automated safety check: Notes | Apache-2.0 | |
| Nw BugfixnWave-ai/nWave | 617 | — | ~1.5k | Automated safety check: Pass | MIT |
Similar skills
Golang Troubleshooting
samber/cc-skills-golang
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Systematic Debugging
tmdgusya/engineering-discipline
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Triage Issue
softspark/ai-toolkit
Bug triage: explores codebase for root cause, files GitHub issue with TDD fix plan.
Nw Bugfix
nWave-ai/nWave
Bug fix workflow: root cause analysis → user review → regression test + fix via TDD
Foreman Debug
VisionForge-OU/foreman
Headless root-cause debugging loop for a Foreman worker whose tests, build, or acceptance check are failing — especially on a retry.
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Related
Categories
Questions about Debugging Difficult Bugs
What does Debugging Difficult Bugs do?
Use early when debugging a medium or hard bug, especially when tests alone may not reveal the real runtime failure. Debugging Difficult Bugs is an agent skill from mastra-ai/mastra. Use early when debugging a medium or hard bug, especially when tests alone may not reveal the real runtime failure.
When should I use Debugging Difficult Bugs?
Debugging Difficult Bugs fits situations like: this before extended TDD iteration when a bug involves runtime state; UI/manual reproduction; external services; newly passing test may not model the real issue.
How do I install Debugging Difficult Bugs in Claude Code?
Run `npx skills add mastra-ai/mastra --skill debugging-difficult-bugs -a claude-code`. Or copy the skill folder (.claude/skills/debugging-difficult-bugs in mastra-ai/mastra) into .claude/skills/debugging-difficult-bugs in your project. Claude Code loads it when a task matches its description.
How do I install Debugging Difficult Bugs in Codex?
Run `npx skills add mastra-ai/mastra --skill debugging-difficult-bugs -a codex`. Or copy the skill folder (.claude/skills/debugging-difficult-bugs in mastra-ai/mastra) into .agents/skills/debugging-difficult-bugs in your project. Codex loads it when a task matches its description.
Can I use Debugging Difficult Bugs in Cursor, Gemini CLI or GitHub Copilot?
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add mastra-ai/mastra --skill debugging-difficult-bugs -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/debugging-difficult-bugs, .gemini/skills/debugging-difficult-bugs, .github/skills/debugging-difficult-bugs and .opencode/skills/debugging-difficult-bugs in your project.
What does Debugging Difficult Bugs need to run?
SKILL.md names no scripts, command-line tools or credentials: Debugging Difficult Bugs is instructions for the agent only.
Does Debugging Difficult Bugs access the network?
SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.
Is Debugging Difficult Bugs safe to install?
Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.
What licence does Debugging Difficult Bugs use?
Debugging Difficult Bugs has a licence file (the repository's licence) that doesn't match a standard licence. Read it on GitHub before reusing the skill.
How many tokens does Debugging Difficult Bugs use?
About 1.9k tokens (SKILL.md is roughly 7.5k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.
What are the alternatives to Debugging Difficult Bugs?
Skills that share tags, products or a category with Debugging Difficult Bugs: Compound Engineering Debug (EveryInc/compound-engineering-plugin, 25k stars), Golang Troubleshooting (samber/cc-skills-golang, 3.4k stars), Systematic Debugging (tmdgusya/engineering-discipline, 125 stars) and Triage Issue (softspark/ai-toolkit, 179 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Debugging Difficult Bugs?
mastra-ai (a GitHub organization) maintains it in mastra-ai/mastra, which has 28,610 GitHub stars. The repository holds 44 skills in this directory. The repository was last updated on October 7, 2026.
Source: mastra-ai/mastra on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.