Root Cause Analysis Assistant — Diagnose the Bug Instead of Guessing at Fixes
Turn an error, stack trace, and logs into a structured root-cause diagnosis — reconstructed failure, ranked hypotheses with evidence, the most likely cause, and the cheapest next diagnostic or fix. The disciplined pass a senior engineer runs, instead of scattershot guess-and-check.
- Identify the origin of an error from a complex multi-frame stack trace.
- Rank debugging hypotheses based on recent code changes and environment info.
- Determine the single most effective log or test to isolate a bug.
$14
· or 70 creditsSecure checkout via Stripe
Included in download
- Identify the origin of an error from a complex multi-frame stack trace.
- Rank debugging hypotheses based on recent code changes and environment info.
- file_read, file_write automation included
- Ready for including Claude Code
PubsProToolkit builds rigor-first skills for AI agents — they write your docs and content properly, then adversarially r…
Media gallery
See it in action
You say
I'm getting a NullPointerException in UserService.java:142 after today's deploy. It only happens for new signups. Here is the stack trace and the diff for the user creation logic.
Your agent does
What happened
NPE at UserService.java:142 during profile lookup. Scope is limited to new signups since today's deploy, specifically when Address records are not yet persisted.
Most likely root cause
The new ProfileMapper assumes User.getAddress() is non-null, but your diff shows the registration flow now delays address creation until onboarding.
Next step
Check if user.getAddress() is null at line 142. Fix by adding an optional check or reverting the mapper's dependency on the address object during initial signup.
Root Cause Analysis Assistant — Diagnose the Bug Instead of Guessing at Fixes
Turn an error, stack trace, and logs into a structured root-cause diagnosis — reconstructed failure, ranked hypotheses with evidence, the most likely cause, and the cheapest next diagnostic or fix. The disciplined pass a senior engineer runs, instead of scattershot guess-and-check.
$14
· or 70 creditsSecure checkout via Stripe
Included in download
- Identify the origin of an error from a complex multi-frame stack trace.
- Rank debugging hypotheses based on recent code changes and environment info.
- file_read, file_write automation included
- Ready for including Claude Code
- Instant install
Media gallery
See it in action
You say
I'm getting a NullPointerException in UserService.java:142 after today's deploy. It only happens for new signups. Here is the stack trace and the diff for the user creation logic.
Your agent does
What happened
NPE at UserService.java:142 during profile lookup. Scope is limited to new signups since today's deploy, specifically when Address records are not yet persisted.
Most likely root cause
The new ProfileMapper assumes User.getAddress() is non-null, but your diff shows the registration flow now delays address creation until onboarding.
Next step
Check if user.getAddress() is null at line 142. Fix by adding an optional check or reverting the mapper's dependency on the address object during initial signup.
About This Skill
Most debugging with an AI turns into guess-and-check: it proposes a fix, you try it, it proposes another, and three rounds later the real cause is still untouched. Systematic debugging is a discipline. Root Cause Analysis Assistant runs it on your error. Give it the symptom, the stack trace, the logs, the scope (always or intermittent, one environment or all), and what recently changed, and it reconstructs what actually happened — reading the trace to the real origin, not just the top frame — separates the symptom location from where the bad state originated, forms ranked hypotheses using the common failure patterns (a recent change, a null from upstream, an edge input, an environment or config difference, a race, an external dependency, a wrong assumption about the data), and recommends the single cheapest diagnostic that eliminates the most possibilities rather than a shotgun of speculative fixes. It names the most likely root cause with the evidence, gives the fix and how to confirm it addresses the cause rather than silencing the symptom, and offers a fallback hypothesis if the top one is wrong. The download includes three reference files: the diagnosis worksheet, a common-root-cause pattern guide, and a worked sample diagnosis. It reasons from what you provide — it doesn't run your code, reproduce the bug, or access your system, so its diagnosis is a ranked hypothesis to verify. Works with Claude Code, Cursor, Codex CLI, Gemini CLI, and any SKILL.md agent.
Use Cases
- Identify the origin of an error from a complex multi-frame stack trace.
- Rank debugging hypotheses based on recent code changes and environment info.
- Determine the single most effective log or test to isolate a bug.
- Separate surface-level symptoms from underlying logical or data flaws.
Known Limitations
Reasons from the error, stack trace, logs, and context you provide — it does not run or reproduce your code, attach a debugger, access your repository, or connect to live logs, APM, or any external service. Because it doesn't execute anything, its output is a ranked hypothesis to verify, not a confirmed fix, and accuracy drops when the scope, recent changes, or relevant logs are omitted. It assists debugging and does not guarantee it will pinpoint every bug; the cheapest-diagnostic step is meant to be run by you to confirm or rule out the top hypothesis.
How to install
Drop the file into your AI tool. Works with Claude, Cursor, ChatGPT, and 20+ more.
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Security Scanned
Passed automated security review
Permissions
File Scopes
Read Files: to read the error, stack trace, logs, and context you provide, plus the three bundled reference files (references/**). Write Files: to write the diagnosis report (reconstructed failure, ranked hypotheses, most likely cause, and next step). The skill does not use a terminal, run or reproduce your code, access the network, browse, or read environment variables — it reasons from what you provide.
Tags
Works with any SKILL.md-compatible agent, including Claude Code, Cursor, Codex CLI, Gemini CLI, and VS Code Copilot. No runtime, debugger, or system access required — you paste the error, stack trace, logs, scope, and recent changes, and the skill returns a reasoned diagnosis. Language- and stack-agnostic; reasons about traces and logs from any language.
Creator
PubsProToolkit builds rigor-first skills for AI agents — they write your docs and content properly, then adversarially review them to catch what's wrong before it ships. The result: cleaner output and a hard quality gate in one toolkit. Built by a CMPP-certified, PhD medical writer who brings regulated-industry standards to developer docs, content, compliance, and research integrity.
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