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 the full burden of behavioral disclosure. While it mentions the core action (reply/forward), it doesn't describe important behavioral traits like whether this sends the email immediately, requires specific permissions, has rate limits, or what happens on failure. For a mutation tool with 9 parameters, this leaves significant gaps in understanding how the tool behaves beyond basic functionality.

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 perfectly concise with two sentences that each earn their place. The first sentence states the core functionality, and the second provides usage context. There's no wasted text, and the information is front-loaded with the essential action.

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 the tool's complexity (9 parameters, mutation operation) and lack of both annotations and output schema, the description is minimally adequate. It covers the basic purpose and usage context but doesn't address behavioral aspects, error conditions, or return values. For a tool that modifies email state, more completeness would be expected to help an agent use it correctly.

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?

The schema description coverage is 100%, so the schema already documents all 9 parameters thoroughly. The description doesn't add any parameter-specific information beyond what's in the schema, but it does provide context about the overall purpose which helps frame parameter usage. This meets the baseline expectation when schema coverage is complete.

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 ('Reply to or forward an existing email') and resource ('email'), distinguishing it from sibling tools like 'email_send' (new emails) and 'emails_modify' (general modifications). It explicitly mentions continuing conversations, responding, and forwarding, which provides comprehensive purpose coverage.

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 clear context for when to use this tool ('to continue email conversations, respond to messages, or forward information to others'), but it doesn't explicitly state when NOT to use it or mention alternatives like 'email_send' for new emails. The guidance is helpful but lacks explicit exclusions or sibling tool comparisons.

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