## ADDED Requirements

### Requirement: Tool instance status is tracked
The system SHALL track the lifecycle status of tool instances.

#### Scenario: Status transitions
- **WHEN** a tool instance is created
- **THEN** its status is "creating"
- **AND** when the container starts, status becomes "running"
- **AND** when stopped, status becomes "stopped"
- **AND** on error, status becomes "error"

#### Scenario: Status polling
- **WHEN** the user views a tool instance
- **THEN** the frontend polls the status endpoint
- **AND** updates the UI when status changes

### Requirement: Tool instances can be stopped and restarted
The system SHALL allow stopping and restarting tool instances.

#### Scenario: Stop instance
- **WHEN** the user clicks "Stop" on a running instance
- **THEN** the system stops the Docker container
- **AND** updates the status to "stopped"

#### Scenario: Restart instance
- **WHEN** the user clicks "Start" on a stopped instance
- **THEN** the system starts the existing container
- **AND** updates the status to "running"