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

With no annotations, the description carries the behavioral disclosure burden. It adds valuable traits: the call is free, prices are indicative rather than final, and the quote operation is what fixes them. It does not mention pagination or return format, but 'browse' sufficiently implies a read-only listing operation.

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?

The description is two sentences with no filler. It front-loads the core purpose and offer-type enumeration, then adds the free cost and indicative-price caveat concisely. Every sentence earns its place.

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 read-only browse tool, the description plus schema covers the offer categories, country filtering, pagination semantics, and the key pricing caveat. No output schema exists, but the offset parameter's schema description already references next_offset. A minor gap is the lack of an explicit return format, but it is not critical for calling this tool.

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 80%, so the schema already documents most parameters. The description mirrors the type enum by listing categories but adds little beyond it, and the undocumented 'brand' parameter is not clarified in the description either. Baseline 3 is appropriate because the schema does most of the work.

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 a specific verb ('Browse') with a clear resource ('purchasable offers') and enumerates the four offer categories: mobile top-ups, travel eSIMs, prepaid bills, and international payment corridors. It also distinguishes itself from transactional siblings by noting that shown prices are indicative and that the quote tool fixes them.

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?

The description implies the tool is for discovery before a purchase/quote and notes the call is free, but it never explicitly names alternatives or states when not to use this tool. The contrast with quote is only implicit through 'the quote fixes them,' so the agent must infer the routing decision.

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