Single tool with critical definition gaps. Tool name 'commit_state_checkpoint' lacks action verb clarity (should be 'create_state_checkpoint' or 'save_state_checkpoint'). Description is present (67 chars) but generic, does not explain WHEN to use it, what prerequisites exist, or what 'rollback transaction support' means operationally. Input schema visible in code but parameters lack descriptions entirely: 'session_id', 'step_name', 'current_state_payload' have no guidance on format, constraints, or dependencies. Output schema not documented, LLM cannot predict response structure. No error handling guidance. Tool definition is hardcoded in mcp_server.py with no explicit schema registration visible.

• Rename tool to 'create_state_checkpoint' or 'save_workflow_checkpoint' to signal the action verb clearly.
• Add parameter descriptions: session_id (format: 'sess_<alphanumeric>', required), step_name (enum or pattern of valid workflow steps), current_state_payload (JSON object with required keys: cart_id, customer_email, sku, quantity, inventory_held_lock, payment_status, step_completed).
• Document output schema in tool description: returns object with checkpoint_id (string), session_id (string), state_hash (string, 16-char hex), total_checkpoints_in_session (integer), safe_rollback_target (string or 'GENESIS_STATE').
• Expand tool description to 150-200 chars: explain that this tool saves workflow state at each step, enables rollback to prior checkpoints, and should be called after each critical workflow transition (e.g., after inventory lock, after payment capture).
• Add error handling: document that invalid session_id returns 'Session not found' with guidance to create_session first; malformed state_payload returns 'Invalid state structure' with required field list; return per-error recovery hints.