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. It discloses the From address constraint and multipart format behavior, but fails to mention that this is an irreversible external action (sending email), potential rate limits, or error handling. Critical safety context for a destructive-by-nature operation is missing.

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?

Two sentences, zero waste. First sentence establishes core function and transport mechanism; second covers sender constraint and format support. Every clause provides essential information not redundant with structured fields.

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 7-parameter email sending tool with no output schema and no annotations, the description covers format options and sender identity but omits discussion of delivery status, failure modes, or irreversibility. Adequate but lacks critical behavioral warnings expected for external-communication tools.

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 has 100% coverage (baseline 3). The description adds value by explaining the implicit From constraint (not in schema) and summarizing the body/html multipart relationship. It clarifies that body serves as fallback when html is provided, adding semantic context beyond individual field 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?

Description clearly states 'Compose and send a new email via iCloud SMTP' - specific verbs (compose, send), resource (email), and mechanism (iCloud SMTP). It distinguishes from sibling tools like reply_to_email and forward_email by specifying 'new email' and the SMTP transport method.

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 implies usage through 'new email' but does not explicitly state when to use this versus similar siblings like reply_to_email or forward_email. No explicit 'when-not-to-use' or alternatives are named, though the tool name provides strong implicit guidance.

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