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

With no annotations, the description must carry the full transparency burden. It discloses a useful behavioral trait: '300s cache' (caching behavior), and implies a read-only news analysis operation. However, it does not explicitly state whether this operation has side effects, requires authentication, or what the response structure looks like. For a news query tool, the absence of side-effect warnings is acceptable, but the description could add more detail about the output or pagination if any.

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 extremely concise and front-loaded. Each sentence serves a clear purpose: the first defines what the tool does, the second frames the use case, and the third notes caching behavior. There is no redundant or fluff content, making it easy to parse quickly.

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 tool with only one optional parameter and no output schema, the description is nearly complete. It explains what the tool returns (most-mentioned FX pairs with sentiment), why it is useful, and mentions the cache. The main gap is that it does not describe the return format or what 'sentiment tilt' concretely looks like, but given the simplicity of the tool and the presence of a schema-driven parameter, the description is adequately comprehensive.

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 schema has one parameter, date_range, with an enum of today/last7days/last30days, but the description's schema coverage is 0% - it never mentions the parameter name, allowed values, or how it maps to the 'window' concept. The phrase 'over a window' is vague and does not inform the agent about the available date range options. Since the schema already provides the enum, the description adds no real semantic value for the parameter.

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 identifies the tool as returning the most-mentioned FX pairs over a time window with sentiment tilt. It uses 'fx-news' as a domain prefix, then explicitly states the resource (FX pairs), scope (most-mentioned, over a window), and an extra attribute (sentiment tilt). The phrase 'what is the FX market talking about?' reinforces the tool's role, distinguishing it from other news tools by emphasizing top mentions for FX specifically.

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 gives a clear use case: 'High-leverage what is the FX market talking about? single call.' This tells an agent when to use it (for a quick, comprehensive view of FX market sentiment). However, it does not explicitly mention when not to use it or provide comparisons to alternative tools like the forex trending or summary tools, so it lacks explicit exclusions or alternative recommendations.

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