H6: Template Format Contract Violation #

The output contract gives competing instructions or lacks selected format/version signals.

Applies to: Recognized prompts and instruction bodies; missing-format/version checks on chat prompts. Manual repair; no automatic fix for this example.

What triggers it #

Strips code, filenames, and CLI flags before selected format checks. Missing format is LOW for eligible long chat prompts; missing version is INFO for eligible longer prompts, excluding extracted Python literals.

How to repair it #

Choose one output format for the response, or explicitly separate response types. Supply the fields the consumer actually expects.

Reproduce the finding #

Use uv and Python 3.10+, plus curl. Run the examples in a scratch directory.

Download the finding example.

{
  "system_prompt": "Respond in JSON. Respond in Markdown."
}

curl -fsS https://lintlang.ai/examples/rules/h6-bad.json -o h6-bad.json
uvx --from lintlang==0.8.0 lintlang scan h6-bad.json --format json

Expected with 0.8.0: the JSON report includes H6, severity MEDIUM.

Improved example #

Download the improved example.

{
  "system_prompt": "Respond in JSON with keys invoice_id and discrepancies."
}

curl -fsS https://lintlang.ai/examples/rules/h6-improved.json -o h6-improved.json
uvx --from lintlang==0.8.0 lintlang scan h6-improved.json --format json

Expected with 0.8.0: H6 is absent. Other diagnostics may still appear; this repair targets the rule above.

Both commands use advisory mode: a finding does not itself make the command fail. To fail CI on MEDIUM findings, add --fail-on review. --fail-on fail gates only HIGH and CRITICAL. See outputs and exit codes.

Detection details #

All scan rules · Quickstart · Separate preflight checks.