icloud-mcp

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries the full burden and succeeds in disclosing key behavioral traits: the special formatting for calendar extraction, the presence of _dateAnchor for date resolution, and the 'No API key required' authentication detail. Minor gap: does not explicitly declare read-only status (though implied by 'Fetch').

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?

Three sentences, zero waste. Front-loaded with purpose ('Fetch an email...'), followed by workflow instructions, and ending with authentication note. Every clause earns its place.

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 lack of output schema, the description adequately compensates by explaining the return value's purpose (formatted for extraction) and highlighting the critical _dateAnchor field. It also names the follow-up tool (create_event). Could be improved by specifying the return format type (JSON vs text), but sufficient for agent operation.

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?

Schema description coverage is 100% (uid and mailbox are fully documented with types and descriptions). The description does not add parameter-specific semantics beyond what the schema already provides, which is appropriate given the complete 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 opens with a specific verb ('Fetch') and resource ('email'), and immediately distinguishes this from sibling tools like get_email by specifying the content is 'formatted for calendar event extraction.' This clearly defines the unique scope and intent of the tool.

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 explicit procedural guidance: extract fields from the returned content, pay attention to _dateAnchor for relative dates, present to user for confirmation, then call create_event. This establishes a clear workflow and implicitly distinguishes when to use this (calendar extraction workflow) versus standard email retrieval.

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