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 disclosure burden. It documents the return value ('Confirmation message...') and default mailbox value, but omits critical behavioral details: what happens if subject_keyword matches multiple emails, zero emails, or partial matches. No mention of whether this creates a sent item or modifies the original.

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 structured Args/Returns format that efficiently conveys information without prose bloat. Every line provides specific constraints or examples. Slightly mechanical format but appropriate given the need to compensate for empty schema descriptions.

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?

Documents all input parameters and acknowledges the output schema (confirmation message), satisfying basic requirements. However, for a complex search-and-forward operation with 7 parameters, it lacks edge case documentation and ambiguity resolution (e.g., multiple matches) that would make it complete.

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?

Excellent compensation for 0% schema description coverage. The Args section documents all 7 parameters with precise semantics: account examples ('Gmail', 'Work'), subject_keyword purpose ('search for in email subjects'), format guidance for email fields ('comma-separated for multiple'), and optionality markers ('Optional').

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 opening sentence 'Forward an email to one or more recipients' states the core action but fails to mention the critical search mechanism (via subject_keyword) used to locate the email. It reads as if forwarding a specific known email, when actually it searches first. No differentiation from sibling tools like reply_to_email.

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?

No guidance on when to use this versus compose_email or reply_to_email. No mention of prerequisites like knowing the exact subject keyword or handling multiple matches. The user must infer usage solely from the parameter list.

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