Senior Root Cause And Safe Fix

What it does

This prompt instructs the AI to act as a staff-level Node.js debugging engineer who, given a Node.js stack trace and the relevant source code (plus optional context), produces a production-ready incident-style report: it determines the root cause and precise failure location, proposes the smallest safe code change to fix the bug without altering intended behavior, and supplies a Jest/Vitest regression test that would have failed before the fix and passed after, with clear structure and explicit assumptions when details are ambiguous.

For more installation instructions go to https://raw.githubusercontent.com/BetterPromptme/skills/refs/heads/main/betterprompt/SKILL.md to check out this skill.

Inputs

textInputs

Pass each text input using --input <key>=<value> flags.

Models and options

This skill's modality is: text.

To discover which model values you can use (and which options keys/values are valid for each model), run:

betterprompt resources --models-only --json

Then filter the returned JSON array to entries where modality is "text".

How to run

Step 1: Collect inputs

First, run betterprompt resources --models-only --json and filter to modality: "text" to discover valid models and available options:

betterprompt resources --models-only --json

Use only the models and option values that appear in the filtered results.

Then collect all inputs from the human:

• Optional text inputs (use defaults if not provided by the human):
  • CONTEXT (default: - Environment: Production - Recent change: Migrated from custom auth middleware to JWT-based middleware. - Reports: Errors only appear for some routes, not all authenticated endpoints.)
  • STACK_TRACE (default: TypeError: Cannot read properties of undefined (reading 'id') at getUserProfile (/src/user/service.js:42:22) at processRequest (/src/api/handler.js:18:11) at Layer.handle [as handle_request] (/node_modules/express/lib/router/layer.js:95:5) at next (/node_modules/express/lib/router/route.js:144:13) at Route.dispatch (/node_modules/express/lib/router/route.js:114:3) at Layer.handle [as handle_request] (/node_modules/express/lib/router/layer.js:95:5) at /node_modules/express/lib/router/index.js:284:15)
  • CODE_SNIPPET (default: // /src/user/service.js async function getUserProfile(req) { const userId = req.user.id; // line 42 const user = await db.users.findById(userId); return user.profile; } module.exports = { getUserProfile };)
• Optional: model and options.
  • Present the human with the default model gpt-5.1 and its available options. Look up gpt-5.1 in the betterprompt resources output (filtered to modality "text") and show its availableOptions as: key: val1, val2 (default), val3 | key2: .... Mark a value (default) if it matches these defaults: {"reasoningEffort":"low"}.
  • If the human does not specify, defaults are used: model gpt-5.1, options {"reasoningEffort":"low"}. Other models from the resources call are also available.

Step 2: Run via BetterPrompt CLI

Use the frontmatter's name as the positional argument (for this skill, use senior-root-cause-and-safe-fix).

Command form:

betterprompt generate senior-root-cause-and-safe-fix \
  [--input <key>=<value>] \
  [--model <model>] \
  [--options <options JSON>] \
  [--json]

Notes:

• Pass each text input as a separate --input <key>=<value> flag.
• If the human does not mention a model, omit --model and BetterPrompt will use the default model: gpt-5.1.
• If the human does not mention options, omit --options and BetterPrompt will use the default options: {"reasoningEffort":"low"}.
• If the run times out, the response will include a runId you can use to fetch the result later.

Example (using defaults shown above):

betterprompt generate senior-root-cause-and-safe-fix \
  --input 'CONTEXT=- Environment: Production - Recent change: Migrated from custom auth middleware to JWT-based middleware. - Reports: Errors only appear for some routes, not all authenticated endpoints.' \
  --input 'STACK_TRACE=TypeError: Cannot read properties of undefined (reading 'id')     at getUserProfile (/src/user/service.js:42:22)     at processRequest (/src/api/handler.js:18:11)     at Layer.handle [as handle_request] (/node_modules/express/lib/router/layer.js:95:5)     at next (/node_modules/express/lib/router/route.js:144:13)     at Route.dispatch (/node_modules/express/lib/router/route.js:114:3)     at Layer.handle [as handle_request] (/node_modules/express/lib/router/layer.js:95:5)     at /node_modules/express/lib/router/index.js:284:15' \
  --input 'CODE_SNIPPET=// /src/user/service.js async function getUserProfile(req) {   const userId = req.user.id; // line 42   const user = await db.users.findById(userId);   return user.profile; }  module.exports = { getUserProfile };' \
  --model gpt-5.1 \
  --options '{"reasoningEffort":"low"}'