Model Configuration

Manage the reusable model presets used for Agent Zero's main, utility, and embedding models.

Model Presets

• Default is always present, appears first, and cannot be renamed or deleted.
• Every runtime configuration resolves from a preset. There is no separate durable model configuration layer.
• Preset definitions are global and live in usr/plugins/_model_config/presets.yaml. Plugin defaults in mode_presets_fallback.yaml are used only when a saved collection cannot be initialized.
• Non-default presets may omit advanced fields or model slots; omitted values resolve from Default, while provider-specific kwargs are replaced or cleared instead of leaking between providers.
• API keys remain in the approved environment/settings flow and are never written into preset YAML.

Scoped Selection

Global, project, project/profile, and agent-profile scopes store only a preset name in their standard plugin config.json:

{"model_preset": "Balance"}

For example, a project selection is stored at:

/a0/usr/projects/<project>/.a0proj/plugins/_model_config/config.json

The normal plugin resolution order selects the most specific available reference. A missing or deleted reference safely resolves to Default. Chats may store an explicit preset reference in chat_model_override; clearing it returns the chat to its scoped selection.

User Interfaces

• Agent Settings shows the global selection, its three resolved models, and actions for preset editing, API keys, and per-project/agent settings.
• The full plugin settings modal uses the generic scope selector and stores only the chosen preset at that scope.
• The closed chat switcher shows the effective preset plus the main model's short name; its menu supports a chat-only selection or returning to the scoped preset.
• The preset editor exposes the shared API key for each selected provider and saves key changes separately from secret-free preset definitions.
• Project Settings selects from the same global preset definitions.

Initial Presets And Migration

The startup migration converts the prior global full model configuration into Default, preserves existing global presets, promotes distinct scoped full configurations and legacy project presets into uniquely named global presets, and rewrites scoped config files to selection-only JSON. Original files receive a .pre-unified-presets.bak backup before replacement; the migration is idempotent.

At every startup, legacy migration runs first. If usr/plugins/_model_config/presets.yaml then exists, initialization returns immediately without network access. Otherwise the plugin makes one bounded request for agent0ai/a0-presets/model_presets.yaml, validates the whole collection, removes secret fields, and saves it locally. A download, parse, or validation failure processes and saves plugin-local mode_presets_fallback.yaml through the same validation path, so initialization remains usable offline.

Key Files

• helpers/model_config.py owns preset validation, resolution, compatibility config shapes, and runtime model construction.
• api/model_presets.py owns global preset editing, scoped selection, and reference repair after rename/delete/reset.
• extensions/python/startup_migration/_10_migrate_model_config.py owns legacy conversion.
• extensions/python/startup_migration/_20_bootstrap_model_presets.py owns missing-collection initialization and plugin-local fallback.
• webui/preset-overview.html is the shared Settings/plugin-settings summary widget.
• webui/main.html is the preset editor.

Plugin Metadata

• Name: _model_config
• Settings section: agent
• Per-project config: true
• Per-agent config: true
• Always enabled: true

Source: plugins/_model_config/README.md