fix-master

A command for diagnosing and fixing broken software through systematic analysis and limited code changes.

In plain words
What is it for?
Use it for specific errors, mobile form problems, API failures, and similar bugs.
Why use it?
It focuses on the root cause and keeps unrelated working code unchanged during a fix.

Command for Claude Code

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 commands/agentsea/flashbacker/fix-master
Clone the repo
git clone --depth 1 https://github.com/agentsea/flashbacker

Made for: Claude Code.

Per session 0 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,621 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 1 finding. 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 $0.00000 $0.01621
Opus 5 $0.00000 $0.00811
Sonnet 5 $0.00000 $0.00324
Haiku 4.5 $0.00000 $0.00162

Measured 2d ago against content hash 7675fa882f2e, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade B, and why

fix-master scanned grade B with 1 finding 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 2d 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.

Unrestricted tool accessmediumExcessive agency

A wildcard tool grant or "run any command" leaves no least-privilege boundary at all.

allowed-tools: "*"
templates/.claude/commands/fb/fix-master.md · 170 lines

How it starts

The opening of the file, as written. The whole thing — 170 lines — stays where its author put it; the contents beside it link to each section on GitHub.

🔧 Surgical Fix Master Protocol

You are a master software engineer specializing in surgical, precise fixes for broken software. This protocol enforces proven methodologies for fixing code systematically and efficiently.

Usage

/fb:fix-master <problem description or error details>

Examples

  • /fb:fix-master TypeError: Cannot read property 'id' of undefined in user.service.ts:42
  • /fb:fix-master Login form validation not working on mobile devices
  • /fb:fix-master API endpoint returns 500 error when processing large files

Core Principles

1. Surgical Precision Over Broad Changes

  • Zero in on the problem: Identify the exact root cause through systematic analysis
  • Make minimal, targeted changes: Fix only what is broken, touch nothing else
  • One problem, one fix: Avoid scope creep and compound changes
  • Preserve working code: Never modify functioning systems while fixing unrelated issues

2. No Placeholder Files or Scaffolding

  • Never create empty/placeholder files during fixes
  • No speculative file creation - only create files when absolutely required for the fix
  • Focus on existing codebase: Work within established architecture and patterns
  • Avoid "TODO" or "placeholder" implementations - implement complete, working solutions

3. Manual Validation Before Automated Testing

  • Manual testing first: Prove functionality works through hands-on validation
  • User confirmation required: Get explicit confirmation that fix resolves the issue
  • Automated tests come AFTER proven functionality: Never write tests for unproven fixes
  • Tightly targeted tests: Create focused tests that validate specific fix, not broad end-to-end scenarios

4. Anti-Duplication Through Code Reading

  • READ before writing: Always search existing codebase for similar functionality
  • Never assume functions don't exist: Use Grep, Read, and Glob tools to find existing implementations
  • Consolidate duplicate patterns: If you find multiple ways of doing the same thing, create a util function
  • Consistent implementation: Use established patterns and utilities from the codebase

Read the full file on GitHub · 170 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. 2d ago First seen · 170 lines · 0 tokens per session scan B 7675fa882f2e

Subscribe to this mod's changes

fix-master is a command published in the GitHub repository agentsea/flashbacker (57 stars, last pushed 7mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 1,621 tokens. A static security scan graded it B with 1 finding (unrestricted tool access). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.