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

Annotations cover safety (readOnly=false, destructive=false, idempotent=false, openWorld=true), and the description adds genuinely non-obvious behavior: Matt reads and replies personally, no automated reply is sent, and only user-authorized content with real name/email may be sent. It stops short of covering failure modes, retries, or whether duplicates result from re-sending (relevant given idempotentHint=false).

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?

Front-loads the purpose, then when-to-use, then content constraints, then the routing alternative. Each sentence carries weight; the closing routing sentence slightly restates the 'not book a call yet' clause, but with specific tool names that add actionable precision.

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?

With no output schema, the description supplies the expected outcome (personal email reply, no automated response) and the identity/content constraints an agent needs to form a valid call. Nothing material is missing for a 5-parameter, fully documented send tool.

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 coverage is 100%, so baseline is 3; the description still adds meaning by constraining identity fields ('with their real name and email') beyond the schema's neutral 'The user's name'/'The user's own email'. It leaves topic and company semantics entirely to the schema.

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?

States a specific verb and resource ('Send a message to Matt Turley (Continuum) on the user's behalf') and anchors it with a concrete analogue ('like the contact form on uxcontinuum.com'). It is clearly distinguishable from the scheduling siblings (book_call, get_availability) without opening any schema.

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?

Gives explicit when-to-use ('when the user wants to ask Matt something or describe a project but not book a call yet') and names the alternative path for the excluded case ('For a time to talk, use get_availability and book_call instead'). Both the selecting and the excluding conditions are spelled out.

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