Agent skill

Fix Bug

Debug and fix bugs in Syncpack using scientific debugging methodology.

MITAuto-check passedDevelopment

Install Fix Bug

skills CLI

$ npx skills add JamieMason/syncpack --skill fix-bug -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI

$ gh skill install JamieMason/syncpack fix-bug --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy

$ git clone --depth 1 https://github.com/JamieMason/syncpack.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.claude/skills/fix-bug .claude/skills/fix-bug && rm -rf skills-src

Use ~/.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/

Paste into Claude Code

Install the "fix-bug" agent skill from https://github.com/JamieMason/syncpack/tree/main/.claude/skills/fix-bug into .claude/skills/fix-bug/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "fix-bug", 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

$skill-installer install https://github.com/JamieMason/syncpack/tree/main/.claude/skills/fix-bug

Type 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.

skills CLI

$ npx skills add JamieMason/syncpack --skill fix-bug -a codex

Project install goes to .agents/skills/; add -g for ~/.codex/skills/.

GitHub CLI

$ gh skill install JamieMason/syncpack fix-bug --agent codex

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/JamieMason/syncpack.git skills-src && mkdir -p .agents/skills && cp -r skills-src/.claude/skills/fix-bug .agents/skills/fix-bug && rm -rf skills-src

Use ~/.agents/skills/ instead of .agents/skills for a personal install.

Codex skills documentation · loads skills from .agents/skills/

Paste into Codex

Install the "fix-bug" agent skill from https://github.com/JamieMason/syncpack/tree/main/.claude/skills/fix-bug into .agents/skills/fix-bug/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "fix-bug", 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.

skills CLI

$ npx skills add JamieMason/syncpack --skill fix-bug -a cursor

Project install goes to .agents/skills/; add -g for ~/.cursor/skills/.

GitHub CLI

$ gh skill install JamieMason/syncpack fix-bug --agent cursor

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/JamieMason/syncpack.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/.claude/skills/fix-bug .cursor/skills/fix-bug && rm -rf skills-src

Use ~/.cursor/skills/ instead of .cursor/skills for a personal install.

Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/

Paste into Cursor

Install the "fix-bug" agent skill from https://github.com/JamieMason/syncpack/tree/main/.claude/skills/fix-bug into .cursor/skills/fix-bug/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "fix-bug", 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

$ gemini skills install https://github.com/JamieMason/syncpack.git --path .claude/skills/fix-bug

--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.

skills CLI

$ npx skills add JamieMason/syncpack --skill fix-bug -a gemini-cli

Project install goes to .agents/skills/; add -g for ~/.gemini/skills/.

GitHub CLI

$ gh skill install JamieMason/syncpack fix-bug --agent gemini-cli

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/JamieMason/syncpack.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/.claude/skills/fix-bug .gemini/skills/fix-bug && rm -rf skills-src

Use ~/.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/

Paste into Gemini CLI

Install the "fix-bug" agent skill from https://github.com/JamieMason/syncpack/tree/main/.claude/skills/fix-bug into .gemini/skills/fix-bug/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "fix-bug", 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.

GitHub CLI

$ gh skill install JamieMason/syncpack fix-bug

Installs 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).

skills CLI

$ npx skills add JamieMason/syncpack --skill fix-bug -a github-copilot

Project install goes to .agents/skills/; add -g for ~/.copilot/skills/.

Manual copy

$ git clone --depth 1 https://github.com/JamieMason/syncpack.git skills-src && mkdir -p .github/skills && cp -r skills-src/.claude/skills/fix-bug .github/skills/fix-bug && rm -rf skills-src

Use ~/.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/

Paste into GitHub Copilot

Install the "fix-bug" agent skill from https://github.com/JamieMason/syncpack/tree/main/.claude/skills/fix-bug into .github/skills/fix-bug/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "fix-bug", 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.

skills CLI

$ npx skills add JamieMason/syncpack --skill fix-bug -a opencode

OpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.

GitHub CLI

$ gh skill install JamieMason/syncpack fix-bug --agent opencode

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/JamieMason/syncpack.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/.claude/skills/fix-bug .opencode/skills/fix-bug && rm -rf skills-src

Use ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.

OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/

Paste into OpenCode

Install the "fix-bug" agent skill from https://github.com/JamieMason/syncpack/tree/main/.claude/skills/fix-bug into .opencode/skills/fix-bug/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "fix-bug", 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: fix-bug
GitHub stars: 2.1k
Token cost: ~1.2k tokens
SKILL.md length: 364 words
Files: 1
Skills in repo: 11
Repo updated: Sep 26, 2026
First seen: Oct 7, 2026
Licence: MIT

At a glance

Debug and fix bugs in Syncpack using scientific debugging methodology.

Works in 5 steps: Observe → Hypothesise → Experiment → …
A test is failing
SKILL.md covers Scientific Debugging Workflow, Step 1: Observe, Step 2: Hypothesise and Step 3: Experiment, plus 6 more sections
Calls cargo and just

What it does

Fix Bug is an agent skill from JamieMason/syncpack. Debug and fix bugs in Syncpack using scientific debugging methodology. Use when a test is failing, unexpected behaviour occurs, or investigating issues. Covers hypothesis-driven debugging and TDD-based fixes.

Its SKILL.md is about 1.2k 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. It works with npm. The repository describes itself as: Consistent dependency versions in large JavaScript Monorepos. The licence is MIT.

When your agent uses it

A test is failing
Unexpected behaviour occurs
Investigating issues

Example prompts

“/fix-bug”

Workflow steps

5 steps, taken from the step headings in SKILL.md.

Observe
Hypothesise
Experiment
Validate
Verify

What it can do on your machine

Read from SKILL.md and the folder at commit 958d306. 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
Shell commands in SKILL.md call:
- cargo
- just
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

Fix Bug loads about 1.2k tokens when it runs. Until then it costs about 54 tokens; SKILL.md has 364 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it: ~54
When it runs · the whole SKILL.md, loaded when a task matches: ~1.2k

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

The full file from JamieMason/syncpack at commit 958d306, republished under its MIT licence (© JamieMason). 364 words, ~1,151 tokens.

Download SKILL.mdSave it as .claude/skills/fix-bug/SKILL.md (or your agent's skills folder).

name: fix-bug
description: Debug and fix bugs in Syncpack using scientific debugging methodology. Use when a test is failing, unexpected behaviour occurs, or investigating issues. Covers hypothesis-driven debugging and TDD-based fixes.

Fix Bug

Guide for debugging and fixing bugs in Syncpack.

Scientific Debugging Workflow

Observe — Understand the symptom precisely
Hypothesise — Form a theory about the root cause
Experiment — Test the hypothesis with targeted changes
Validate — Confirm the fix with tests
Verify — Run full test suite

Step 1: Observe

Gather information before changing code:

bash

# Run the failing test with output
cargo test test_name -- --nocapture

# Run with backtrace
RUST_BACKTRACE=1 cargo test test_name

# Test against fixture
cd fixtures/fluid-framework
cargo run -- lint

Questions to answer:

What is the exact error message?
What input triggers it?
What is the expected vs actual behaviour?

Step 2: Hypothesise

Common root causes by symptom:

Symptom	Likely Cause
State is `Unknown`	`visit_packages` not called or instance skipped
Wrong state assigned	Validation logic order, earlier check overriding
Instance not found	Package/dependency name mismatch, location format
Command not running	Missing registration in cli.rs, main.rs, or commands.rs
Panic/unwrap failure	Unexpected None or Err value

Step 3: Experiment

Add targeted debug output:

rust

use log::debug;

debug!("Instance: {:#?}", instance);
debug!("State before: {:?}", instance.state.borrow());

Search for related code:

bash

# Find where state is assigned
ast-grep -p 'InstanceState::fixable' src/visit_packages/

# Find similar patterns
ast-grep -p 'PATTERN' src/

Step 4: Validate

Write a failing test FIRST (TDD):

rust

#[test]
fn reproduces_the_bug() {
    let ctx = TestBuilder::new()
        .with_packages(vec![/* minimal reproduction */])
        .build_and_visit_packages();

    // Assert expected behaviour (will fail initially)
}

Then fix the code until the test passes.

Step 5: Verify

bash

just test        # All tests pass
cargo clippy     # No warnings

Where to Look

By component

Issue with...	Check...
CLI parsing	`src/cli.rs`
Config loading	`src/config.rs`, `src/rcfile.rs`
Package reading	`src/packages.rs`, `src/package_json.rs`
State assignment	`src/visit_packages/*.rs`
Command output	`src/commands/*.rs`, `src/commands/ui/`
Version parsing	`src/specifier/*.rs`

By phase

Phase	What happens	Files
Create	Read config, packages, collect instances	`context.rs`, `packages.rs`
Inspect	Assign InstanceState	`visit_packages.rs`, `visit_packages/*.rs`
Run	Process instances, output/write	`commands/*.rs`

Common Fixes

Show full SKILL.md (147 more words)Show less

Instance state not being assigned

Check:

Is the instance's version group variant handled in visit_packages.rs?
Is there an early return skipping this instance?
Is another validation assigning a state first?

Test assertion failing

Check:

Is build_and_visit_packages() called (not just build())?
Is the location string format correct? ("{dep} in {location} of {package}")
Are there multiple instances of the same dependency?

Command not found

Verify registration in all three places:

src/cli.rs — Subcommand enum
src/main.rs — match arm
src/commands.rs — module declaration

Debugging Tips

Isolate — Create minimal reproduction
Binary search — Comment out code to narrow down
Print early — Add debug output before suspected area
Check order — Validation order matters (first match wins)
Read tests — Existing tests show expected behaviour

Anti-Patterns

❌ Changing code without understanding the cause ❌ Removing code just to make tests pass ❌ Fixing symptoms instead of root cause ❌ Skipping the test-first step

Files

Just SKILL.md in .claude/skills/fix-bug of JamieMason/syncpack.

Open the folder on GitHubat commit 958d306

Compare with similar skills

Fix Bug 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.

Fix Bug compared with similar skills
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Fix Bug this skillJamieMason/syncpack	2.1k	—	~1.2k	Automated safety check: Pass	MIT	11 days ago
AO Desktop App LauncherOrchestratorInc/agent-orchestrator	13k	—	~2.4k	Automated safety check: Pass	Apache-2.0	today
Debugging and Error Recoveryaddyosmani/agent-skills	102k	1 repos	~2.6k	Automated safety check: Pass	MIT	4 days ago
EasyEDA Pro API Bridgeeasyeda/easyeda-api-skill	855	—	~7.8k	Automated safety check: Pass	MIT	5 days ago
Qwen Code Memory Leak DebuggerQwenLM/qwen-code	28k	—	~1.3k	Automated safety check: Pass	Apache-2.0	today
Plugin BuilderAIDotNet/NextCoWork	638	—	~2.4k	Automated safety check: Pass	Apache-2.0	5 days ago

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Questions about Fix Bug

What does Fix Bug do?

Debug and fix bugs in Syncpack using scientific debugging methodology. Fix Bug is an agent skill from JamieMason/syncpack. Debug and fix bugs in Syncpack using scientific debugging methodology.

When should I use Fix Bug?

Fix Bug fits situations like: A test is failing; unexpected behaviour occurs; investigating issues.

How do I install Fix Bug in Claude Code?

Run `npx skills add JamieMason/syncpack --skill fix-bug -a claude-code`. Or copy the skill folder (.claude/skills/fix-bug in JamieMason/syncpack) into .claude/skills/fix-bug in your project. Claude Code loads it when a task matches its description.

How do I install Fix Bug in Codex?

Run `npx skills add JamieMason/syncpack --skill fix-bug -a codex`. Or copy the skill folder (.claude/skills/fix-bug in JamieMason/syncpack) into .agents/skills/fix-bug in your project. Codex loads it when a task matches its description.

Can I use Fix Bug 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 JamieMason/syncpack --skill fix-bug -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/fix-bug, .gemini/skills/fix-bug, .github/skills/fix-bug and .opencode/skills/fix-bug in your project.

What does Fix Bug need to run?

Going by SKILL.md and its folder, Fix Bug needs the command-line tools its instructions call (cargo and just).

Does Fix Bug 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 Fix Bug 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 Fix Bug use?

Fix Bug is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Fix Bug use?

About 1.2k tokens (SKILL.md is roughly 4.6k 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 Fix Bug?

Skills that share tags, products or a category with Fix Bug: AO Desktop App Launcher (OrchestratorInc/agent-orchestrator, 13k stars), Debugging and Error Recovery (addyosmani/agent-skills, 102k stars), EasyEDA Pro API Bridge (easyeda/easyeda-api-skill, 855 stars) and Qwen Code Memory Leak Debugger (QwenLM/qwen-code, 28k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Fix Bug?

JamieMason (a GitHub user) maintains it in JamieMason/syncpack, which has 2,099 GitHub stars. The repository holds 11 skills in this directory. The repository was last updated on September 26, 2026.

Source: JamieMason/syncpack on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.

Install Fix Bug

Facts

At a glance

What it does

When your agent uses it

Example prompts

Workflow steps

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Context cost

Safety

SKILL.md

Fix Bug

Scientific Debugging Workflow

Step 1: Observe

Step 2: Hypothesise

Step 3: Experiment

Step 4: Validate

Step 5: Verify

Where to Look

By component

By phase

Common Fixes

Instance state not being assigned

Test assertion failing

Command not found

Debugging Tips

Anti-Patterns

Files

Compare with similar skills

Similar skills

More from JamieMason/syncpack

Related

Questions about Fix Bug