Server has 8 tools with complete input schemas and descriptions in Chinese. Naming follows verb_noun pattern (list_, search_, read_, send_, summarize_, draft_, compose_, translate_). Schemas are well-structured with type constraints, min/max bounds, and format declarations. However, descriptions are in Chinese (non-English), limiting LLM comprehension in English-first contexts. Parameter descriptions are present but terse. Output schemas are not documented. Error handling and recovery guidance are absent. No tool annotations (readOnlyHint/destructiveHint) despite clear risk levels. Missing idempotency support on write operations.

• Translate all tool descriptions and parameter descriptions to English. Use clear, concise descriptions (50-200 chars) that explain WHAT the tool does, WHEN to use it, and any prerequisites. Example: 'Search emails by keyword, sender, folder, or date range. Returns up to 50 matching messages with IDs, subjects, and senders. Use this to find relevant emails before reading or replying.'
• Document output schemas for all tools. Specify what fields are returned, their types, and which fields are required for chaining to other tools. Example: search_mail should return [{id, subject, sender, date, hasAttachment}] so agents can pass id to read_mail.
• Add tool annotations: mark send_mail with destructiveHint=true (irreversible), mark read_mail and search_mail with readOnlyHint=true. This enables agents to distinguish safe operations from risky ones.
• Add explicit error handling and recovery guidance. For send_mail, document: 'If recipient is invalid, error will include the invalid email. Verify the email format and retry. If the account lacks send permissions, contact the administrator.' For search_mail, document: 'If no results found, try broadening the date range or removing filters.'
• Document idempotencyKey usage in send_mail: 'To safely retry a failed send, include the same idempotencyKey. The server will return the original result without sending a duplicate email. Key must be 8-200 alphanumeric characters with optional . _ : - separators.'