Server has 3 tools with complete input schemas and tool annotations present. Descriptions are adequate (100-200 chars) but lack actionable guidance on when/why to use each tool. Parameter descriptions are minimal. run_secure_query and unmask_text have good naming (verb_noun), but add_to_roster is vague about scope and side effects. No output schema documentation. Error handling returns basic messages without recovery guidance. Tool composition is reasonable but lacks chaining context (e.g., unmask_text should document that it requires prior run_secure_query calls).

• Document output schema for run_secure_query: 'Returns array of objects with masked PII fields. Each PII value replaced with placeholder like __PERSON_1__, __EMAIL_2__. Placeholders cached in session for unmask_text.'
• Enhance sql_query parameter description: 'Read-only SELECT query only. No INSERT/UPDATE/DELETE/DROP. Max 1000 rows returned. Supports WHERE, JOIN, GROUP BY. Example: SELECT name, email FROM users WHERE active=true LIMIT 10'
• Add format constraint to masked_text: 'Text containing PII placeholders (format: __TYPE_N__, e.g. __PERSON_1__, __EMAIL_2__). Placeholders must match those from prior run_secure_query call in this session.'
• Rename add_to_roster to add_session_roster_names and clarify: 'Register names for regex-based PII detection in this session only. Does not persist across sessions. Affects all subsequent run_secure_query calls. Example: ["John Smith", "Jane Doe"]'
• Add recovery guidance to error responses: Catch SQL syntax errors and return 'Invalid SQL syntax. Only SELECT queries allowed. Example: SELECT name, email FROM contacts WHERE id > 100 LIMIT 5'. Catch unmask failures and return 'Placeholder __PERSON_99__ not found in session cache. Run run_secure_query first to populate cache.'