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

Annotations already declare readOnlyHint=false, idempotentHint=false, destructiveHint=false, openWorldHint=true, so the safety profile is covered. The description adds a genuinely non-obvious behavioral trait: the result is a draft awaiting customer approval, not a committed booking, which materially changes how an agent should treat the response.

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 dense sentences, front-loaded with what the tool does and immediately followed by the outcome (draft). No 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?

For a mutation tool with no output schema, the description usefully discloses the return (a draft pending approval), which is the key completeness win. However, gaps remain: the required slug/customer inputs and any failure modes (slot taken, service-area mismatch) are unaddressed, and 40% schema coverage leaves required fields under-explained.

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 40% across 5 params, so the schema undersells several fields. The description indirectly clarifies slot_start ('slot from get_availability') and loosely maps service_sku to the flat-rate service, but slug and the required customer fields get no meaning beyond the schema's own partial description. It helps but doesn't fully compensate.

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 ('Book a flat-rate service') and scopes it to fixed-price/services contrasted against siblings like request_quote and place_order. The parenthetical example ('e.g. drain cleaning') makes the service class concrete without opening the 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?

Explicitly ties slot_start to 'from get_availability', routing the agent through the sibling prerequisite, which is real when-to-use guidance. It doesn't state when NOT to use it (e.g. vs place_service_request or request_quote), so it stops short of the top band.

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