Implement AI tool execution and validation

[apermo]

Summary

Implement server-side execution and validation of AI tool calls. The AI proposes actions, the backend validates and executes them safely.

Tool Definitions

update_exercise

Update weight, sets, reps, or rest time.

• Validate exercise exists
• Validate reasonable ranges (weight ±20%, reps 1-100, etc.)
• Log change to audit

skip_exercise

Mark exercise to skip for a date.

• Create date override
• Require reason

add_exercise

Add new exercise to a day.

• Validate day exists
• Validate exercise type
• Set sort_order

create_override

Create one-time schedule change.

• Validate date format
• Validate override type

get_exercise_history

Read-only: get recent feedback.

• Return last N feedback entries
• Used by AI to understand patterns

get_schedule

Read-only: get schedule for date.

• Used by AI to understand current program

Validation Rules

class ToolValidator {
    public function validateUpdateExercise(array $params): ValidationResult {
        // Weight change max ±20%
        // Sets 1-10
        // Reps 1-100
        // Rest 10-300 seconds
    }
}

Audit Logging

CREATE TABLE ai_actions (
    id INT AUTO_INCREMENT PRIMARY KEY,
    conversation_id VARCHAR(36),
    tool_name VARCHAR(50) NOT NULL,
    params JSON NOT NULL,
    result JSON,
    status ENUM('success', 'rejected', 'error') NOT NULL,
    rejection_reason TEXT,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

Part of

Phase 2: AI Proxy