> For the complete documentation index, see [llms.txt](https://docs.heeler.com/mrecEO40m5D6bt7Pq5pE/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.heeler.com/mrecEO40m5D6bt7Pq5pE/prevent/pr-guardrails/guardrail-types/sast-guardrails.md).

# SAST Guardrails

Gate a pull request on new source-code findings the branch introduces.

SAST guardrails gate a PR on **new source-code findings the branch introduces**. Heeler compares the branch's SAST results against the repository's **default-branch baseline**, so only findings the change actually adds can fire — your existing backlog never blocks a PR.

SAST uses the `Code` entity, so a SAST guardrail is **dedicated** — it can't be combined with dependency or hygiene rules.

## Conditions

Match the findings you care about with any combination of:

| Filter         | Values                                                                                                                                      |
| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------- |
| **Severity**   | Critical, High, Medium, Low, Info                                                                                                           |
| **Confidence** | High, Medium, Low                                                                                                                           |
| **Category**   | Injection, Cross-Site Attacks, Cryptography, Access Control, Data Exposure, Deserialization, AI/LLM Security, Supply Chain, Availability, … |
| **Rule ID**    | Target specific detections                                                                                                                  |

{% hint style="warning" %}
**Baseline required.** A SAST guardrail needs a completed SAST scan of the repository's **default branch** to establish the baseline before it can enforce. It's evaluated once per repository (not per code root).
{% endhint %}

{% hint style="info" %}
**On GitLab, a CI pipeline is required.** Heeler waits for a CI pipeline to run on the commit before it scans a merge request. A repository with **no pipeline** won't be evaluated — a minimal `.gitlab-ci.yml` is enough to enable scanning.
{% endhint %}

## What developers see on the PR

When a SAST guardrail matches, the findings render **inline on the pull request** — each with its severity, rule, and message, a **source → sink data-flow summary** and flow path, the **suggested fix**, and **CWE/OWASP** references. Findings that share the same source are **grouped** into one entry that lists all the sinks, so a single tainted input doesn't spam the PR with duplicates.

Actions and scope work the same as every guardrail — **Observe / Warn / Block** across the standard [scope model](/mrecEO40m5D6bt7Pq5pE/prevent/pr-guardrails.md#scope-where-each-guardrail-applies).

## Auto-fix on the pull request

Beyond the suggested fix, an eligible SAST guardrail violation can be **auto-fixed on the pull request**: Heeler applies a targeted source-code change — for example parameterizing a query, escaping output, allowlisting input, or normalizing a path — to the PR's own branch, runs build validation, and re-evaluates the guardrail, all on the pull request. The **guardrail summary shows how many matched SAST findings are auto-fixable**, and each qualifying finding carries an **Auto-Fixable** marker.

Unlike dependency auto-fix (a version upgrade), a SAST auto-fix is a code transform gated on a high-confidence, deterministic fix; findings without one are routed to manual review. See [Guardrail Auto-Fix](/mrecEO40m5D6bt7Pq5pE/prevent/pr-guardrails/guardrail-auto-fix.md) and [SAST Auto-Fix](/mrecEO40m5D6bt7Pq5pE/fix/sast-auto-fix.md).

## Related

* [Guardrail Types](/mrecEO40m5D6bt7Pq5pE/prevent/pr-guardrails/guardrail-types.md) — the other rule families and the shared scope model.
* [Code Security (SAST)](/mrecEO40m5D6bt7Pq5pE/findings/code-security-sast.md) — how these findings are detected and scored.
* [SAST Auto-Fix](/mrecEO40m5D6bt7Pq5pE/fix/sast-auto-fix.md) — the code change Heeler generates for a finding.


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