# Server Mode Enforcer
Singleton that manages server mode configuration with strict precedence rules.
## Files
- `ServerModeEnforcer.ts` - Main singleton implementation
- `index.ts` - Re-exports
## Server Modes
```typescript
type ServerMode = 'DYNAMIC_TOOL_DISCOVERY' | 'STATIC_TOOL_SETS' | 'ALL_TOOLS';
```
| Mode | Behavior |
|------|----------|
| `DYNAMIC_TOOL_DISCOVERY` | Client discovers/activates tool sets at runtime |
| `STATIC_TOOL_SETS` | Fixed tool sets loaded at startup |
| `ALL_TOOLS` | All 253+ tools loaded immediately (default) |
## Configuration Precedence
**CLI arguments take highest priority, then env vars:**
```
1. CLI args (highest)
--dynamic-tool-discovery → DYNAMIC_TOOL_DISCOVERY mode
--fmp-tool-sets=a,b,c → STATIC_TOOL_SETS mode with specified sets
--tool-sets=a,b,c → alias for --fmp-tool-sets
2. Environment variables
DYNAMIC_TOOL_DISCOVERY=true → DYNAMIC_TOOL_DISCOVERY mode
FMP_TOOL_SETS=a,b,c → STATIC_TOOL_SETS mode
3. Default (lowest)
No override → ALL_TOOLS mode
```
## Singleton Pattern
```typescript
// Initialize once at startup (required before getInstance)
ServerModeEnforcer.initialize(process.env, minimist(process.argv.slice(2)));
// Get instance anywhere in code
const enforcer = ServerModeEnforcer.getInstance();
const mode = enforcer.serverModeOverride; // ServerMode | null
const toolSets = enforcer.toolSets; // ToolSet[] (copy)
```
## Critical Behaviors
### Fail-Fast Validation
Invalid tool set names cause immediate process termination:
```typescript
// If user specifies invalid tool set
FMP_TOOL_SETS=search,INVALID,company
// → Logs error and calls process.exit(1)
```
### Immutability Protection
`toolSets` getter returns a copy to prevent external mutation:
```typescript
public get toolSets(): ToolSet[] {
return [...this._toolSets]; // New array each call
}
```
### Single Initialization
```typescript
ServerModeEnforcer.initialize(env, args); // OK
ServerModeEnforcer.initialize(env, args); // Logs warning, ignored
```
### Instance Requirement
```typescript
ServerModeEnforcer.getInstance(); // Throws if initialize() not called
```
## Validation Rules
- Tool set names: case-sensitive, lowercase only
- Whitespace trimmed: `" search "` → `"search"`
- Comma-separated parsing: `"search,company,quotes"`
- Empty strings ignored: `"search,,company"` → `["search", "company"]`
## Testing
```typescript
ServerModeEnforcer.reset(); // Clears singleton for test isolation
```
## Integration Point
Used by `ModeConfigMapper` to translate enforcer state into Toolception configuration.
