---
title: Migration playbook: legacy profiles.yaml to runtime registry YAML
description: Legacy profile-map migration has been removed after the StepSettingsPatch hard cut.
doc_version: 1
last_updated: 2026-07-02
---


# Migration playbook: legacy profiles.yaml to runtime registry YAML

Automatic migration of legacy `profiles.yaml` maps has been removed.

Why:

- legacy profile maps only described engine-setting overlays,
- `runtime.step_settings_patch` no longer exists,
- applications now own final `StepSettings` and provider credentials outside the profile registry.

What to do instead:

1. Create a new single-registry YAML file.
2. Rebuild each profile around `runtime.system_prompt`, `runtime.tools`, and `runtime.middlewares`.
3. Move model/provider/client settings into app config, env, or explicit `fromConfig(...)` calls.

Minimal example:

```yaml
slug: default
profiles:
  analyst:
    slug: analyst
    runtime:
      system_prompt: You are an analyst.
      tools:
        - calculator
```