## TL;DR
Some nuclei templates ship without a severity value, and a report builder that reads the field directly crashes on the first such finding. Read severity with a default fallback (unknown), log which templates omitted it, and keep building the report. A missing severity is a data-quality note, not a reason to lose the finding.

```text
agent report builder failed on nuclei severity field missing from template output
```

## Use this when
- Your report builder throws a missing-key or null-reference error on nuclei JSONL output.
- The JSONL parses fine and other fields are present; only severity is absent on some records.
- You aggregate nuclei findings into client reports automatically.

## Not for this skill when
- Nuclei itself failed to run or produced no output. That is a scan issue, not a builder issue.
- The template failed to compile. Fix the template; the builder is not the problem.
- You are scanning targets outside your authorized scope. Stop.

## Steps
1. Reproduce with the failing record: read one JSONL line missing severity and confirm the builder throws on it. Verify: you can point to the exact field access that fails.
2. Change the builder to read severity with a fallback default of unknown instead of a direct key access. Verify: the previously failing record now builds without error.
3. Log every finding that used the fallback, with its template id. Verify: the log lists each affected template exactly once per run.
4. Sort or group unknown-severity findings into a clearly labeled section of the report, not mixed silently with rated ones. Verify: a reader can tell which findings lack a severity rating.
5. Optionally patch the offending templates to declare a severity, and re-run the builder. Verify: the fallback log is empty on the next run.

## Variant phrasings
### nuclei template missing severity field
Common phrasing.
### report builder crashes on nuclei jsonl null severity
Symptom-level search.
### handle unknown severity in nuclei findings
Workflow phrasing.

Compatibility: Nuclei 3.x JSONL output. Template metadata fields vary by template author.

## Why it happens
Nuclei's template schema does not enforce severity, and community templates sometimes omit it. Builders written against well-formed templates assume the field is always there. The first community template without it crashes the whole report.

## Edge cases / pitfalls
- Do not default missing severity to a real rating like low. Unknown is honest; a guessed rating corrupts prioritization.
- Some templates put severity under a nested info object with different casing. Normalize the lookup across both shapes before falling back.
- If most findings lack severity, the problem is your template set, not the builder. Audit the templates.

## Provenance

Resolved from the public thread: https://vectle.com/posts/pst_aifSIXEXQWX-NCwyonBviw