fix

A coding command for finding the cause of a software bug and applying a focused fix without unrelated changes.

In plain words
What is it for?
Use it to collect reproduction details, trace the failing path, compare working and broken behavior, and update tests when possible.
Why use it?
It helps move from symptoms to the underlying failure, while reducing the risk of introducing new problems.

Command for Cursor

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/duongductrong/cursor-kit/fix
Clone the repo
git clone --depth 1 https://github.com/duongductrong/cursor-kit

Made for: Cursor.

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 468 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 $0.00000 $0.00468
Opus 5 $0.00000 $0.00234
Sonnet 5 $0.00000 $0.00094
Haiku 4.5 $0.00000 $0.00047

Measured 2d ago against content hash e59824e7bb9b, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

fix 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 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.

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.

.cursor/commands/fix.md · 67 lines

How it starts

The opening of the file, as written. The whole thing — 67 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Before answering:

  • Use toc.mdc to identify the most relevant Skills and Rules for this task.
  • Skills are comprehensive guides (e.g. frontend-development, ui-styling, backend-development).
  • Rules are concise best practices (e.g. git.mdc, coding-style.mdc).
  • Apply ONLY the selected skills/rules that match the task context.
  • If no skill or rule clearly matches, ignore all and answer normally.

Purpose

Act as an expert bug fixer. Find the root cause, apply a safe fix, and avoid regressions.

Principles

  • Understand the problem before editing code.
  • Fix causes, not symptoms.
  • Keep scope narrow to the reported issue.
  • Avoid unrelated refactors in the same change.
  • Explain what broke and why.
  • Add or adjust tests when possible.

Process

1. Understand

Gather:

  • Expected vs actual behavior.
  • Steps to reproduce.
  • Errors, logs, stack traces (if any).
  • Related files/components and dependencies.
  • Recent changes in the affected area.
  • Existing tests or similar working code.

2. Diagnose

  • Isolate: smallest reproducible case.
  • Trace: follow data/control flow to the failure point.
  • Compare: working vs broken paths or states.
  • Classify likely root cause: logic, state, type, integration, environment.

3. Fix

Before coding:

  • Confirm the root cause.
  • Note possible side effects and why this was not caught earlier.

When coding, describe:

LOCATION: [file:line]
ROOT CAUSE: [one clear sentence]
FIX: [what you changed and why]

After coding:

  • Change addresses the root cause only.
  • No unrelated refactors.
  • Existing expected behavior still works.

4. Verify

Check:

  • Bug is no longer reproducible.
  • Related flows still work.
  • Edge cases are covered.
  • No obvious performance regression.
  • Propose at least one test that would have caught this bug.

Output format

Return:

DIAGNOSIS: symptom, root cause, location
FIX: explanation and relevant code snippet(s)
VERIFICATION: what you tested
PREVENTION: how to avoid similar bugs in the future.

Read the full file on GitHub · 67 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 · 67 lines · 0 tokens per session scan A e59824e7bb9b

Subscribe to this mod's changes

fix is a command published in the GitHub repository duongductrong/cursor-kit (21 stars, last pushed 5mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 468 tokens. 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.