send_gmail_message

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries full burden for behavioral disclosure. It states the action (sends an email) and return value (confirmation with message ID), but doesn't mention authentication requirements, rate limits, error conditions, whether it's synchronous/asynchronous, or what happens if sending fails. For a mutation tool with zero annotation coverage, this is insufficient.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Well-structured with clear sections (purpose, args, returns). The description is appropriately sized - every sentence serves a purpose. Could be slightly more concise by integrating the parameter descriptions more naturally rather than as a separate 'Args' section.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a mutation tool with 5 parameters, no annotations, and no output schema, the description is incomplete. It doesn't explain authentication requirements, error handling, rate limits, or the purpose of the undocumented 'service' parameter. The return value description is helpful but doesn't substitute for a proper output schema.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 60% (3 of 5 parameters have descriptions in schema). The description adds parameter documentation for 'to', 'subject', 'body', and 'user_google_email', but doesn't mention the 'service' parameter at all. It provides some additional context about 'user_google_email' being required, but doesn't fully compensate for the undocumented 'service' parameter.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states 'Sends an email using the user's Gmail account' - a specific verb (send) and resource (email via Gmail). It distinguishes from sibling 'draft_gmail_message' by specifying sending rather than drafting, but doesn't explicitly contrast with 'send_message' which appears to be a different messaging system.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance on when to use this tool versus alternatives like 'draft_gmail_message' or 'send_message'. The description doesn't mention prerequisites, authentication requirements, or any context about when this specific Gmail sending tool is appropriate versus other messaging options.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.