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 and successfully discloses the matching algorithm (subject matching + same recipient check). This is crucial behavioral context that defines what 'awaiting reply' means. Minor gap: doesn't explicitly state it's read-only or describe performance characteristics.

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?

Uses Google-style docstring format with Args/Returns sections. Front-loaded with the value proposition in the first sentence, followed by implementation details, use case, and structured parameter documentation. No redundant or wasted text.

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?

Comprehensive for a 4-parameter tool with cross-referencing logic. Documents all inputs and summarizes return values (subject, recipient, date) despite the existence of an output schema. Minor gap: doesn't mention error conditions (e.g., invalid account name).

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?

Despite 0% schema description coverage (titles only), the Args section provides complete semantic documentation for all 4 parameters including examples (account), units (days_back), and business logic (exclude_noreply). Fully compensates for the schema's lack of descriptions.

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 a specific action ('Find sent emails that haven't received a reply yet') and immediately clarifies the unique implementation (cross-referencing Sent with Inbox using subject matching). This distinguishes it from generic search tools like 'search_emails' or overview tools like 'get_inbox_overview'.

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?

Provides clear context ('Useful for follow-up tracking') indicating when to use the tool. However, it lacks explicit guidance on when NOT to use it (e.g., 'use search_emails instead for content-based searching') or comparisons to sibling 'get_needs_response'.

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