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

Annotations declare readOnlyHint=true, so the agent already knows it's a safe read. The description adds critical behavioral context: quote_id is valid for 15 minutes, the price is locked, and pickup_date must be dd/mm/yyyy. No contradiction with annotations.

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: purpose+returns, usage workflow, format warning. Each sentence earns its place, front-loads the core purpose.

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?

Despite no output schema, the description tells the agent exactly what is returned (prices for all vehicles, quote_id) and how to use it downstream. With an 8-parameter schema fully covered, this is complete for successful 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?

Schema description coverage is 100%, so the baseline is 3. The description only repeats the dd/mm/yyyy format already in the schema, adding no new parameter semantics beyond that.

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 uses the verb 'Calculate' with a specific resource 'exact price for a private chauffeur transfer' and states it returns prices for all available vehicles and a quote_id. It clearly differentiates from book_ride (which consumes the quote_id) and get_vehicles (which lists vehicles).

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 states 'Always call this before book_ride and pass the quote_id to book_ride', defining the exact pre-condition and workflow. It also explains the benefit (locks price, prevents drift), giving the agent clear guidance on when to invoke.

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