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

Annotations declare readOnly/idempotent/non-destructive, but the description adds substantial context beyond them: it discloses the return shape ("original issued URL and browser-agent steps"), states what is NOT done ("No merchant request, cart, order or payment"), and warns that agreement to preparation is not payment authority. This is exactly the behavioral disclosure an agent needs.

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-loaded with the core purpose and constraints, and each sentence carries a distinct rule (requirements, return shape, payment-authority caveat, scope limits). Dense but no filler, though the run-on phrasing could be tightened.

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 readOnly annotations covering safety and the description covering return values in lieu of an output schema, an agent has enough to call it correctly. The conditional US/region rule is stated, though the per-field semantics rely on the schema's inline text.

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 only 40%, so the description must compensate, and it does partially by specifying required fields (items, destinationCountry, conditional destinationRegion) and preservation rules (variant, quantity, budget, benefits). The nested fields also carry rich inline schema descriptions, so the remaining gap is minor.

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 states a specific verb and resource ("Prepare an exact buyer-selected purchase handoff") and clarifies the output is a URL plus browser-agent steps. It implicitly distinguishes itself from the discovery siblings (find_*, get_product) by being the preparation step, though it never names them explicitly.

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?

It gives concrete prerequisites ("Requires items and actual destinationCountry; US requires destinationRegion") and a clear post-condition workflow ("verify merchant final quote then obtain specific buyer approval"). It lacks an explicit statement of when to use a sibling instead, which keeps it from a 5.

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