What is bug_fix_detection?

A rule that recognises when a user is reporting a software defect, error, broken feature, or failing test.

Use it when a request includes bug reports, error messages, stack traces, regressions, or test failures.

It helps an agent start the appropriate bug-fixing process and gather details such as affected files, symptoms, and reproduction steps.

bug_fix_detection — Cursor rule for Cursor by markmhendrickson

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.

Clone the repo

git clone --depth 1 https://github.com/markmhendrickson/foundation

Made for: Cursor.

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.

README.md

[![agentmods](https://agentmods.dev/badge/rules/markmhendrickson/foundation/bug_fix_detection/github.svg)](https://agentmods.dev/rules/markmhendrickson/foundation/bug_fix_detection)

Your own site

<a href="https://agentmods.dev/rules/markmhendrickson/foundation/bug_fix_detection"><img src="https://agentmods.dev/badge/rules/markmhendrickson/foundation/bug_fix_detection/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/rules/markmhendrickson/foundation/bug_fix_detection"><img src="https://agentmods.dev/badge/rules/markmhendrickson/foundation/bug_fix_detection.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 27 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.

When invoked 1,130 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

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.

Model	Per session	Once invoked
Fable 5.1	$0.00027	$0.01130
Opus 5.5	$0.00011	$0.00452
Sonnet 5.5	$0.00005	$0.00226
Haiku 4.5	$0.00003	$0.00113

Measured 1mo ago against content hash c71906ed271a, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

bug_fix_detection 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 1mo 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/rules/bug_fix_detection.mdc · 143 lines

How it starts

The opening of the file, as written. The whole thing — 143 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Bug Fix Detection Rule

Reference: Skill fix-feature-bug — Bug fix workflow (.cursor/skills/fix-feature-bug/SKILL.md or foundation/agent_instructions/cursor_skills/fix-feature-bug/SKILL.md)

Configuration is read from foundation-config.yaml.

Trigger Patterns

When a user mentions any of the following patterns, automatically detect bug fix intent:

"bug"
"error"
"fix"
"broken"
"not working"
"failing"
"issue" (in context of problems)
"problem" (in context of code/functionality)
Error messages or stack traces
Test failures
"regression"
"broken feature"
"doesn't work"

Agent Actions

Step 1: Detection and Confirmation

If context suggests a bug (mentions "bug", "error", "fix", "broken", error messages, etc.):

Extract bug information from context:
- Error messages or stack traces (if provided)
- Feature/module ID (if mentioned or can be inferred from path/context)
- Description of the problem
- Steps to reproduce (if mentioned)
Identify affected feature/module:
- Check error messages for file paths
- Check context for feature mentions
- Check open files for feature references
- If cannot identify → ask user: "Which feature/module is affected? (identifier or 'unknown')"

Ask for confirmation:

I see you're reporting a bug. Should I fix this using the bug fix workflow? 
Feature/Module: {identifier} (or 'unknown' if not identified)
(yes/no)

Exception handling:
- If user says "no" → do not proceed with bug fix workflow
- If user says "just document it" → document the bug instead

Step 2: Execute Bug Fix Workflow

If user confirms (yes):

Load configuration:
- Read foundation-config.yaml to get bug fix workflow settings
- Check if error classification is configured
- Determine feature unit directory (if feature units enabled)
Load required documents:
- Skill fix-feature-bug (.cursor/skills/fix-feature-bug/SKILL.md or foundation/agent_instructions/cursor_skills/fix-feature-bug/SKILL.md)
- Repository navigation guide (if configured)
- Feature spec and manifest (if feature units enabled and identifier provided)
- Error classification documentation (if configured)
- Relevant subsystem/module docs (if configured)

Read the full file on GitHub · 143 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.

1mo ago First seen · 143 lines · 27 tokens per session scan A c71906ed271a

Subscribe to this mod's changes

bug_fix_detection is a cursor rule published in the GitHub repository markmhendrickson/foundation (2 stars, last pushed 2mo ago), licensed MIT. It adds 27 tokens to every session and 1,130 once invoked, about $0.0001 per session on Opus 5.5. 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 2026-08-31.

Debugging

error-handling-and-validation

A code-quality guide for handling errors, invalid inputs, edge cases, preconditions, logging, and user-friendly error messages.

holtwood/awesome-cursorrules-zh · 185 tokens

css-render-blocking-diagnosis

Cursor rule "css-render-blocking-diagnosis" from adobecom/da-express-milo, covering css render-blocking diagnosis & resolution, critical learning from 98 pagespeed achievement, primary diagnostic protocol, step 1: css blocking symptom recognition and step 2: css loading sequence audit.

adobecom/da-express-milo · 1,102 tokens

bug_fix_detection