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

Annotations already declare readOnlyHint=true, destructiveHint=false, openWorldHint=true. The description adds meaningful context beyond them: the auth requirement ('Needs the user's Cotlet API key with access to this app') and the fields returned. It omits pagination/limit behavior, but the schema covers the limit param.

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?

The opening two sentences are near-duplicates ('Search clients by name, email or phone; returns contact details, tags and last visit' vs 'Searches your customers by name, email or phone and returns contact details and tags'), wasting space and even disagreeing on whether 'last visit' is returned. The useful routing and auth sentences are buried at the end.

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 does describe returned fields, and it covers the auth prerequisite and downstream ID usage. It is complete enough to call correctly; only pagination behavior and the redundant/mismatched return-field statements are gaps.

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% and both parameters are already documented there, so the baseline is 3. The description's 'name, email or phone' adds slight interpretive value for the query field but largely restates 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 (find/search) and resource (clients), plus the match keys (name, email, phone) and return fields (contact details, tags, last visit). It is readily distinguishable from siblings like vagaro_list_appointments or vagaro_search_availability.

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 routes the agent: 'Use client_id in book_appointment and add_to_waitlist' and explains why this tool exists ('The official API needs a customer ID up front; this finds the ID'). It gives clear context but no when-not-to-use or alternative search tool guidance.

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