Gmail MCP Server

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

With no annotations provided, the description carries the full burden and does so effectively. It discloses key behavioral traits: the draft is saved but not sent automatically, user confirmation is required, and it returns specific fields (draft_id, confirmation_required). However, it doesn't mention potential errors, rate limits, or authentication details beyond prerequisites.

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?

The description is appropriately front-loaded with the core purpose, but it includes extensive procedural details (7-step example) and repetitive warnings about user confirmation. While helpful, this makes it longer than necessary; some information could be condensed without losing clarity.

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?

Given no annotations and no output schema, the description provides strong contextual completeness: it explains prerequisites, parameters, return values, and usage flow. However, it lacks explicit error handling information and doesn't fully detail the output structure beyond the listed fields, leaving some gaps for a mutation tool.

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 0%, so the description must compensate. It adds meaningful context for all three parameters: email_id (obtained from list_emails() or search_emails()), reply_text (text of the reply), and include_original (whether to include original email, with default True). This goes beyond the bare schema, though it doesn't detail format constraints for email_id or reply_text.

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 the specific action ('create a draft reply') and resource ('to an email'), distinguishing it from siblings like 'confirm_send_email' (which sends) and 'prepare_email_reply' (which prepares context). It explicitly notes the draft is saved but not sent, which differentiates it from actual sending tools.

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?

The description provides explicit guidance on when to use this tool, including prerequisites (authentication, obtaining email ID, using prepare_email_reply first) and clear alternatives (e.g., using list_emails() or search_emails() to get email IDs). It also specifies when NOT to use it (never assume automatic sending) and the subsequent step (confirm_send_email).

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