## ADDED Requirements

### Requirement: API can spawn a tool instance
The system SHALL provide an endpoint to create and start a tool instance.

#### Scenario: Spawn code-server
- **WHEN** a POST request is made to /api/v1/tool-instances with tool_id and project_id
- **THEN** the system creates a ToolInstance record
- **AND** generates a Docker Compose service definition
- **AND** starts the container via Docker Compose API
- **AND** returns the tool instance with status "creating"

#### Scenario: Spawn with config overrides
- **WHEN** a spawn request includes config overrides
- **THEN** the overrides are merged with scope-resolved configs
- **AND** applied to the container environment

### Requirement: Spawn validates prerequisites
The system SHALL validate prerequisites before spawning.

#### Scenario: Valid project
- **WHEN** the spawn request references a project
- **THEN** the project must exist and belong to the user
- **AND** the tool definition must exist in the registry

#### Scenario: Duplicate spawn prevention
- **WHEN** a spawn request is made for an already-running instance
- **THEN** the system returns the existing instance
- **AND** does not create a duplicate container