Stack Trace Root Cause Classifier

How Stack Trace Root Cause Classifier works

Press Load model once: your browser downloads Gemma 4 E2B instruction-tuned (web build) (2.0 GB) from this site and keeps it in its cache. Then add your text and press Classify locally. The model runs on this device using your graphics card, so nothing you enter is sent to a server. Until the model is loaded, or if your device cannot run it, the tool falls back to a simple keyword check and labels the result as the fallback.

Gemma 4 E2B instruction-tuned (web build) is a small open language model from Google. The tool sends it the instruction below plus your text, asks for a JSON answer with fixed fields, and shows each field as a card. It runs at temperature 0, so the same input gives the same answer on the same device, though different graphics cards can word it slightly differently.

Inputs longer than 6,000 characters are cut to that length before they reach the model, and the result says so. The model only sees what you paste: it does not look anything up.

The instruction the model gets

You read a stack trace or error report and classify the most likely root-cause category: null or undefined access, type or schema mismatch, missing module or dependency, configuration or environment, network or timeout, permission or auth, resource exhaustion (memory, disk, connections), concurrency or race, data or input validation, or unclear. Point to the first frame in the application's own code, not framework or library frames. Quote function names, files and line numbers exactly as written and do not invent code you cannot see.

What it returns

• Root-cause category: The category, followed by a short reason.
• First app frame: The first application frame (file, function, line) as written, or 'not in trace'.
• Evidence: Lines or phrases from the trace, quoted, that support the category.
• What to check: Checks or fixes to try, based only on what the trace shows.

Worked example

The model's output for the built-in sample, recorded on a desktop browser. Your run may word things slightly differently.

Stack trace: TypeError cannot read properties of undefined reading customer.id at createInvoice, after optional billingAddress refactor. Fails only for guest checkout with PayPal.

Root-cause category

null or undefined access

First app frame

createInvoice

Evidence

TypeError cannot read properties of undefined reading customer.id

What to check

Check if 'customer' is defined before accessing 'customer.id' in createInvoice. Ensure that the guest checkout flow correctly populates the 'customer' object.

The model

The files are served from this site, versioned so a cached copy is never stale. Nothing is fetched from a third party while you use the tool.

Limitations

• Small language models make mistakes: they can miss an item, merge two, or state something more confidently than the text supports. Check the result against your input before you rely on it.
• It needs WebGPU and about 8 GB of memory, so it is offered on desktops and laptops, not on phones and tablets. Devices that cannot run it get the keyword fallback, clearly labelled.
• Results describe the input you gave, not the real-world situation behind it. Review them yourself before acting.

Good uses

• Triage developer workflow notes before deeper review
• Prepare consistent labels for repeat workflows
• Reduce manual sorting on small batches
• Keep sensitive drafts in the browser preview