Apple Mail 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. It successfully discloses prerequisites (package dependencies, client compatibility) and error conditions ('error message if UI is unavailable'), but does not explicitly state safety characteristics (read-only nature) or rate limits that would help an agent assess invocation risks.

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 well-structured with the purpose front-loaded, followed by bulleted feature details, technical requirements, and return value documentation. While slightly verbose, every sentence provides necessary context about the UI resource nature or technical prerequisites.

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 absence of an output schema, the description comprehensively documents the return value (UIResource with specific URI and HTML content) and error states. For a zero-parameter tool, this level of detail regarding the UI package requirements provides complete contextual coverage.

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 contains zero parameters, which establishes a baseline score of 4 per the evaluation rules. The description correctly offers no parameter details since none exist, avoiding unnecessary elaboration.

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 opens with the specific action 'Get' and resource 'interactive dashboard view of your email inbox.' It clearly distinguishes itself from data-fetching siblings (like get_inbox_overview or list_inbox_emails) by emphasizing the UIResource return type and interactive visualization aspects.

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 about requirements ('Requires mcp-ui-server package and a compatible MCP client') and implies usage for visual interaction rather than data retrieval. However, it lacks explicit guidance on when to choose this over get_inbox_overview for users wanting non-UI data.

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