MCP Email Service

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. It mentions that 'Returned UIDs must be used with the same account', which is valuable context about data consistency requirements. However, it doesn't address important behavioral aspects like whether this is a read-only operation, potential rate limits, authentication requirements, or what happens when no results are found.

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 that convey essential information. The first sentence states the core purpose, and the second provides important behavioral context about UIDs and account targeting. There's no wasted verbiage, though it could be slightly more structured for 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?

For a search tool with 10 parameters and no output schema, the description provides basic operational context but lacks details about return format, error conditions, or result structure. The absence of annotations means the description should do more to explain the tool's behavior, especially regarding what the search returns and any limitations. It's minimally adequate but has clear gaps.

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 input schema has 100% description coverage, so all parameters are well-documented in the schema itself. The description adds some semantic context about 'account_id for precise targeting' and the general scope of searching, but doesn't provide additional parameter meaning beyond what's already in the comprehensive schema descriptions. This meets the baseline for high schema coverage.

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 as 'Search emails with various criteria across all accounts or specific account', which is a specific verb+resource combination. However, it doesn't explicitly differentiate from sibling tools like 'list_emails' or 'get_recent_activity', which might offer similar functionality with different scopes or approaches.

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 some context about when to use the tool ('specify account_id for precise targeting') and mentions the scope ('across all accounts or specific account'), but doesn't explicitly guide when to choose this tool over alternatives like 'list_emails' or 'get_recent_activity'. It offers implied usage guidance rather than explicit comparisons.

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