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

The description discloses important behavioral details beyond annotations: payment requirement (0.001 USDC per call), the need for X-PAYMENT header, and alternative auth methods (X-API-Key, X-Owner-Key, Bearer token). It also notes the HTTP endpoint. These are meaningful disclosures not present in the minimal annotations.

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 concise but packs technical payment details into the main paragraph, making it slightly dense. The HTTP and payment info could be separated for readability. Still, every sentence adds value, but not as clean as the best examples.

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 simple list tool with no output schema, the description covers purpose, parameters, payment, and HTTP equivalent. It lacks explicit return format, but 'headlines' is self-explanatory. The security/payment details add necessary context for successful invocation.

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?

The input schema is empty, but the description adds 'limit?: int' as an optional parameter, providing meaning beyond the schema. This compensates for the schema's lack of parameter definitions. However, the parameter is not formally documented in the schema, which is a minor inconsistency.

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 clearly states the resource: 'Crypto news headlines from public RSS (CoinDesk + Bitcoin Magazine)'. It's clear the tool returns crypto headlines, though it lacks an explicit verb like 'get' or 'fetch'. It differentiates from general news tools like 'news_headlines' by specifying crypto and sources.

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 provides no guidance on when to use this tool versus alternatives. It mentions the HTTP equivalent and payment, but does not explain when to prefer this over other news or crypto tools, nor any exclusions. No alternative tools are named.

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