GSuite MCP provides 20 tools with complete input schemas and descriptions. Tool naming follows verb_noun convention consistently (gmail_list_messages, calendar_create_event, etc.). Descriptions are present but vary in quality, most are 20-60 characters, which is acceptable but below the 50-200 char ideal for LLM comprehension. All parameters include type definitions and descriptions. However, descriptions lack actionable guidance (e.g., 'When to use this', recovery hints, prerequisites). Output schemas are not documented, responses are inferred from the code but not declared in tool definitions. Error handling is basic; no recovery guidance visible. Parameter relationships (e.g., account aliases and their valid values) are undocumented. The 'account' parameter is present across nearly all tools but lacks enum constraints for valid aliases. Tool composition is sound (single responsibility per tool, good chaining via IDs), but parameter validation guidance is minimal.
Tools (20)
auth_completewriteauthsource verified75/100
Complete OAuth authentication by providing the authorization code
Output schemas not documented. Tool descriptions do not specify what fields the response will contain. LLMs cannot plan downstream calls or extract specific data without knowing response structure.
'account' parameter appears across 19 tools but lacks enum constraint. No documentation of valid account aliases (work, personal, default). Agents must guess or fail on invalid values. Should declare allowed values or link to configuration discovery.
Add output schema documentation to each tool. Specify fields in the response (e.g., gmail_list_messages returns [{id, from, subject, snippet, date}]) so LLMs know what data is available for downstream use.
Convert gmail_manage_labels into separate tools: gmail_list_labels, gmail_get_label, gmail_create_label, gmail_update_label, gmail_delete_label. Each should have a single, clear responsibility.
Add enum constraints to the 'account' parameter across all tools. Document valid aliases in descriptions: 'Account alias (e.g., work, personal, default). Uses default if not specified. Valid values: [work, personal, default]' or link to a discovery endpoint.
Enhance tool descriptions with dependency hints and prerequisites. Example for gmail_send_message: 'Send an email. If replying, use in_reply_to to auto-fetch threading headers. Requires prior authentication via auth_init/auth_complete.' Example for calendar_create_event: 'Create a new event. start_time and end_time must be ISO 8601 (RFC 3339). Attendees are invited automatically.'
Add structured error responses with recovery guidance. When a tool fails, return: {error, reason, recovery_action}. Example: {error: 'Invalid recipient', reason: 'john@example.com not found in Contacts', recovery_action: 'Try people_search_contacts to find the correct email.'}
Document pagination. For list tools (gmail_list_messages, calendar_list_events), specify: 'Returns up to max_results (default 100). To fetch the next page, use the nextPageToken (if present) as the pageToken parameter in the next call.' Or clarify if pagination is not supported.
Descriptions lack actionable context. No indication of WHEN to use a tool vs. a similar one, WHAT prerequisites exist, or HOW to handle errors. Example: 'List Gmail messages' doesn't explain when to hydrate=true vs. false or how to handle no results.
Destructive/write operations (delete, send, modify) lack error recovery guidance. No indication of whether failures are retryable, what caused them, or what the agent should do. Example: gmail_send_message fails but doesn't indicate if it's a transient network issue or invalid recipient.
gmail_manage_labels uses a generic 'action' parameter (list, get, create, update, delete) bundling 5 operations into one tool. Per pattern:tool, each action should be a separate tool (gmail_list_labels, gmail_create_label, gmail_delete_label, etc.) so the LLM can reason about them independently.
Pagination support unclear. calendar_list_events and gmail_list_messages accept max_results but no documentation of pagination mechanism (offset, cursor, continuation token). Large result sets could exhaust context window.
No indication that tools require prior authentication (auth_init + auth_complete). If an agent calls gmail_list_messages without first authenticating, the error message may not guide it to run auth_init first.
Parameter descriptions do not specify valid formats or constraints. Example: 'start_time' and 'end_time' say 'RFC 3339 format' in description but should also validate and return clear error 'start_time must be ISO 8601 (RFC 3339), e.g. 2024-01-15T10:30:00Z'.
Add human-friendly parameter variants. calendar_create_event currently accepts start_time/end_time as strings. Consider also accepting natural-language inputs like 'tomorrow at 2pm' or 'next Monday', with internal parsing.
Clarify retry semantics for write operations. For gmail_send_message, tasks_delete_task, etc., document: 'This operation is [idempotent | non-idempotent]. If the call fails, retrying is [safe | unsafe].' This guides the agent's retry strategy.
Add examples to descriptions where they clarify intent without introducing literal values. Instead of 'e.g., from:me is:unread', write 'Gmail search query syntax (see https://support.google.com/mail/answer/7190?hl=en for operators).' This avoids LLMs reusing example values literally.
Document max_results constraints. Add min/max bounds: 'max_results (integer, 1-1000, default 100). API may return fewer results if limit is exceeded or insufficient data available.'