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

Annotations only declare readOnly=false, idempotent=true, destructive=false. The description adds substantial context beyond them: the WhatsApp confirmation card, the 60-minute decision window, that nothing is booked until the customer taps 'Yes', that the slot is not held while they decide, and the payment-link flow. These are exactly the behavioral traits an agent needs and cannot get from the schema.

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 core purpose and then layers workflow, caveat, return reference, alternative tool, and the customer-consent warning. Each sentence carries a distinct fact, though the middle section is dense and could be split for easier scanning.

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 9-parameter mutation tool with no output schema, the description supplies the missing pieces: what happens after the call, what the return reference is for, and which tool follows up. Nothing an agent needs to invoke it correctly is absent.

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 reiterates 'use a start time from find_times' and {'Cleaning only'} for hours/frequency, but those facts are already present in the schema field descriptions, so it adds little semantic value beyond what is structured.

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 ('Ask HomeMaster to book a home clean for the customer') and immediately separates itself from the sibling 'start_booking' by restricting scope to cleaning ('for aircon use start_booking'). An agent can identify the tool 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?

Gives explicit preconditions (use a start time from find_times; ask the customer before sending because it messages their phone) and names the alternative for a different service. Both when-to-use and when-not-to-use are covered.

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