## MODIFIED Requirements

### Requirement: Status Monitoring
The system SHALL track tool status with startup and health states.

#### Scenario: Status check with health details
- **GIVEN** a tool instance
- **WHEN** status is queried
- **THEN** the real-time container status is returned:
  - `pending`: Instance created, container not yet started
  - `starting`: Container is running, readiness probe in progress
  - `running`: Container is running and probe passed (or terminal tool)
  - `unhealthy`: Container is running but probe failed/timed out
  - `stopped`: Container was stopped by user
  - `error`: Container failed to start or crashed

## ADDED Requirements

### Requirement: Health check endpoint enhancement
The system SHALL provide detailed health information through the health check endpoint.

#### Scenario: Health check with container and tunnel status
- **GIVEN** a running instance
- **WHEN** `GET /instances/{id}/health` is called
- **THEN** the response includes:
  - `healthy`: boolean - overall health
  - `container_status`: "running", "exited", "restarting", or "not_found"
  - `tunnel_status`: "healthy", "unreachable", "error_response", or "not_applicable"
  - `tunnel_status_code`: HTTP status code or null
  - `probe_status`: "passed", "failed", "pending", or "not_configured"
  - `last_probe_output`: string or null

### Requirement: Smart tunnel recreation
The system SHALL only allow tunnel recreation when the tunnel itself is broken.

#### Scenario: Recreate tunnel for unreachable tunnel
- **GIVEN** an instance with `tunnel_status: "unreachable"`
- **WHEN** the recreate tunnel endpoint is called
- **THEN** the tunnel is recreated
- **AND** the new URL is returned

#### Scenario: Block recreation for application errors
- **GIVEN** an instance with `tunnel_status: "error_response"` (e.g., HTTP 502)
- **WHEN** the recreate tunnel endpoint is called
- **THEN** the request is rejected with 400 Bad Request
- **AND** the error message explains the tunnel is working but the application is returning errors

## REMOVED Requirements

None.