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

Annotations already declare readOnlyHint=true and openWorldHint=false, consistent with a pure local calculation, so the description needn't restate safety. It adds real value beyond that by clarifying the VAT base (on the commission, not the property) and by declaring currency-agnostic behavior, which an agent could otherwise get wrong.

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?

A single front-loaded sentence that names the computation first and then the outputs, closed with a short scope note on currency. No filler, no repetition of the title, and every clause carries information.

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?

There is no output schema, so the description correctly carries the burden of describing what is returned by naming all four computed values, and it covers the two optional percentage inputs implicitly through the split/agent-share framing. Minor gaps remain around rounding/precision behavior and what happens when optional inputs are omitted, but nothing an agent needs in order to call it correctly is missing.

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% and each parameter already carries its own description, including the VAT example and the '100 if no co-broker' default for share. The description reinforces the conceptual relationship (VAT on commission; split with co-broker office; agent's share) but introduces no new syntax, defaults, or constraints beyond the schema, so baseline 3 applies.

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 (computes a broker's commission on a deal) and enumerates exactly what is produced: commission, VAT on the commission, co-broker split, and agent share. None of the siblings (fal_license_check, lease_agreement, property_listing_writer, publish_listing_page) overlap with a pure calculation, so no differentiation is needed.

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?

Usage is implied by the domain framing — an agent can infer this is for calculating deal commissions — but there is no explicit when-to-use, when-not-to-use, or routing guidance relative to any alternative. No prerequisites or edge-case conditions (e.g. missing co-broker, zero VAT) are stated.

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