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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered; the description goes further by disclosing the exact cost ($0.002 USDC per successful call), the x402 payment rails (Base, Solana, Arc), and that failed calls are not charged. That payment/auth detail is exactly the kind of context annotations cannot express. Rate limits and result-cap behavior are not mentioned, keeping it off a 5.

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 naming the resource, geography and returned fields, followed by two short notes on default ordering and cost. Dense but every clause carries information, and the commercial terms are placed last where they belong.

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 an output schema present, the long returned-field enumeration is partly redundant, but the description still supplies the essential missing context: supported countries, default sort, and pricing model. An agent can call it correctly from this plus the schema.

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 all seven parameters (sort, limit, offset, country, min/maxPrice, query) are already documented with defaults and ranges. The description only reinforces 'newest first by default', adding essentially nothing beyond the schema, so the 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 ('OLX classified listings search') and enumerates the seven supported country markets, which lets an agent tell it apart from generic marketplace siblings like social_facebook_marketplace. It stops short of explicitly naming a sibling alternative, so it lands just below the top mark.

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 field list and the 'newest first by default' note, but the description never says when to choose this over the other regional/marketplace search tools in the sibling set, nor any exclusions. Adequate but with a clear gap.

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