Email SMTP/IMAP MCP Server

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 mentions HTML support and file attachments, but fails to address critical aspects like authentication requirements (account_name parameter), rate limits, delivery guarantees, error handling, or whether this is a synchronous or asynchronous operation. For a mutation tool with significant impact, this is inadequate.

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 concise with two sentences. The first sentence states the core functionality, and the second provides usage examples. There's no unnecessary repetition or fluff. However, it could be slightly more front-loaded with key behavioral information.

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 an 8-parameter mutation tool with no annotations and no output schema, the description is incomplete. It doesn't explain what happens after sending (success/failure indicators, message IDs), doesn't address authentication or permission requirements, and provides minimal guidance on when to use alternatives. The schema does heavy lifting, but the description should compensate for missing behavioral context.

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 100%, so the schema already documents all 8 parameters thoroughly. The description adds minimal value beyond the schema - it mentions HTML support (implied by body_type enum) and file attachments (covered in schema). No additional syntax, format, or constraint details are provided beyond what's in the structured fields.

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 tool's purpose: 'Send a new email with HTML support and file attachments.' It specifies the verb ('send') and resource ('email'), and distinguishes it from siblings like email_respond (reply) and emails_modify (edit). However, it doesn't explicitly differentiate from emails_find (search) beyond the 'new' qualifier.

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 implied usage guidance: 'Use this to send messages, project updates, or any new email conversation.' This suggests it's for initiating conversations rather than replying (email_respond) or modifying existing emails (emails_modify). However, it lacks explicit when-not-to-use instructions or clear alternatives for edge cases.

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