> 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/overview/three-layers-one-model.md).

# Prevent, Fix and Operate

What the Prevent, Fix and Operate layers each do, the surfaces in each, and the model all three read from.

{% columns %}
{% column %}
Heeler's capabilities are grouped into three layers. They are concurrent, not sequential stages: Prevent runs on every change, Operate runs continuously against the whole estate, and Fix is available for any open finding. All three read from the same [context model](/mrecEO40m5D6bt7Pq5pE/overview/the-context-model.md).
{% endcolumn %}

{% column %}
{% hint style="info" %}
Prevent gates new risk. Fix resolves what is already open. Operate detects, routes and confirms closure.
{% endhint %}
{% endcolumn %}
{% endcolumns %}

```mermaid
%%{init: {'theme':'base','themeVariables':{'lineColor':'#9aa0b5','primaryColor':'#eef1f8','primaryTextColor':'#10163a','primaryBorderColor':'#c2c7de','fontSize':'14px'}}}%%
flowchart TB
    CE["Context model · ProductDNA<br/>code, cloud and runtime"]:::anchor
    CE --> P["Prevent<br/>checks before merge"]
    CE --> F["Fix<br/>validated pull requests"]
    CE --> O["Operate<br/>detect, route, verify"]
    classDef anchor fill:#5A3FFF,color:#ffffff,stroke:#3a2ad0,stroke-width:1px;
```

## Prevent

Your policy, approved versions, service tier and exposure data are applied at four points in the development cycle:

<table><thead><tr><th width="230">Surface</th><th>Where it runs</th></tr></thead><tbody><tr><td><a href="/mrecEO40m5D6bt7Pq5pE/prevent/mcp.md"><strong>MCP Server</strong></a> <strong>and</strong> <a href="/mrecEO40m5D6bt7Pq5pE/prevent/agent-skills.md"><strong>Agent Skills</strong></a></td><td>Inside the coding agent, at code generation.</td></tr><tr><td><a href="/mrecEO40m5D6bt7Pq5pE/prevent/cli.md"><strong>CLI</strong></a></td><td>At the keyboard, before commit, and as a CI gate.</td></tr><tr><td><a href="/mrecEO40m5D6bt7Pq5pE/prevent/pr-guardrails.md"><strong>PR Guardrails</strong></a></td><td>On the pull request, as a native status check.</td></tr><tr><td><a href="/mrecEO40m5D6bt7Pq5pE/operate/workflows.md"><strong>Workflows</strong></a></td><td>After merge, on every push.</td></tr></tbody></table>

## Fix

Heeler generates the change for a finding, validates it, and opens a pull request. Two domains are covered:

* [**SCA Auto-Fix**](/mrecEO40m5D6bt7Pq5pE/fix/sca-auto-fix.md) (dependencies) — the lowest version that clears the CVEs without introducing new ones, validated in CI.
* [**SAST Auto-Fix**](/mrecEO40m5D6bt7Pq5pE/fix/sast-auto-fix.md) (code) — a specific source change that closes the weakness, with a named strategy and a confidence rating.

Every fix follows the same path: [**Prioritize**](/mrecEO40m5D6bt7Pq5pE/fix/prioritize-heeler-risk.md) **→ Calculate →** [**Validate**](/mrecEO40m5D6bt7Pq5pE/fix/validate-and-merge-ready.md) **→ merge-ready.**

## Operate

Heeler's own analysis engines run on every commit, and [workflows](/mrecEO40m5D6bt7Pq5pE/operate/workflows.md) act on what they produce:

<table><thead><tr><th width="180">Engine</th><th>What it does</th></tr></thead><tbody><tr><td><a href="/mrecEO40m5D6bt7Pq5pE/findings/open-source-sca.md"><strong>SCA</strong></a></td><td>Reachability and runtime analysis, first-party correlation, and supply-chain checks.</td></tr><tr><td><a href="/mrecEO40m5D6bt7Pq5pE/findings/code-security-sast.md"><strong>SAST</strong></a></td><td>Cross-function taint analysis from source to sink, with API endpoint and auth analysis.</td></tr><tr><td><a href="/mrecEO40m5D6bt7Pq5pE/findings/secrets.md"><strong>Secrets</strong></a></td><td>Detection on every push, with provider validation of each credential.</td></tr><tr><td><a href="/mrecEO40m5D6bt7Pq5pE/findings/agentic-supply-chain-agent-files.md"><strong>Agent Files</strong></a></td><td>Inventory and analysis of agent instruction files.</td></tr><tr><td><a href="/mrecEO40m5D6bt7Pq5pE/operate/workflows.md"><strong>Workflows</strong></a></td><td>Assignment, ticketing, routing, messaging and SLO changes.</td></tr></tbody></table>

## The shared model

All three layers read the same model of your code, dependencies, endpoints, deployments and cloud resources. A guardrail can therefore evaluate a pull request using the exposure of the affected service, a fix can be validated against the way the repository actually builds, and a finding can be closed only once the fix appears in a running deployment.

## Related

* [Get Started](/mrecEO40m5D6bt7Pq5pE/get-started.md) — connect your first repository.
* [Prevent](/mrecEO40m5D6bt7Pq5pE/prevent.md) · [Fix](/mrecEO40m5D6bt7Pq5pE/fix.md) · [Operate](/mrecEO40m5D6bt7Pq5pE/operate.md) — each layer in detail.


---

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