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

Adds meaningful behavior beyond annotations: merge semantics (partial update, not replace), token-based authorization instead of email, and a concrete idempotency signal ('A repeat with nothing new returns already: true'). Consistent with idempotentHint and destructiveHint=false, with no contradictions.

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 dense, front-loaded sentences: operation, authorization, and optionality/field semantics. Every sentence adds a distinct fact with no redundancy or filler.

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?

Covers the critical call-time facts (auth, idempotency, optional fields) and relies on schema/annotations for the rest. Could have mentioned the successful merge return value or consent field, but these are either in the schema or not essential for correct invocation.

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?

Description supplements the 67% schema coverage by listing the optional detail fields and giving glosses for context, why, and question. It doesn't define name/role/company beyond optionality, but those are self-explanatory and the schema already covers required parameters.

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 action ('Merges follow-up details') and resource ('existing waitlist record'), with the title reinforcing it. Distinguishes this from sibling join_waitlist by emphasizing 'existing' and the edit token, making the purpose immediately unambiguous.

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?

Explicitly names the prerequisite (edit_token from join_waitlist) and states when not to rely on it ('email alone never authorizes a merge'). Also tells the agent that detail fields are optional, clarifying when this tool is appropriate to call.

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