x402_news

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

No annotations are provided, so the description carries full responsibility for behavioral disclosure. It discloses the cost per call ($0.01 USDC), which is a useful behavioral trait (pricing), but it does not mention side effects, rate limits, authentication requirements, or what the response contains. For a tool with no annotation safety hints, this is insufficient.

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 a single sentence that front-loads the purpose and includes cost information. It is concise with no wasted words. However, it could be slightly more structured by separating purpose from cost, but for its brevity it is efficient and earns its place by adding the cost detail.

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?

Given the simplicity of the tool (one string parameter, no output schema), the description still lacks key context. It does not mention return format, pagination, or how the 'q' query affects results. It also doesn't explain how it differs from other content-fetching siblings (e.g., x402_read, x402_rss). The cost is the only extra context beyond the schema, which is insufficient for an agent to fully understand the tool's behavior.

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% – the parameter 'q' has a description 'News query' in the schema. The description adds no additional meaning beyond that. According to the rubric, baseline is 3 when schema covers parameters; the description does not compensate or elaborate beyond the schema, so a 3 is appropriate.

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 the tool returns 'latest news headlines' which clearly indicates a news query tool. It is specific enough to distinguish from siblings like x402_weather or x402_crypto, though it could be more explicit about whether it returns full articles or just headlines. The verb 'get' is implied but not stated; still, the resource 'news headlines' is clear.

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?

There is no guidance on when to use this tool versus alternatives. It does not mention when not to use it, nor does it reference any sibling tools. The only contextual hint is the cost, which is not a usage guideline. The agent is left to infer that it is for news queries from the resource name.

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