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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the description's job is to add context beyond those. It does mention a rate limit ('max 20 queries/session') and a cost ('0.01 USDC/query'), but then contradicts itself by saying 'FREE preview — no key, no payment.' This creates confusion about whether the tool incurs cost. It also does not describe what happens when called, such as output format or side effects, beyond what annotations already indicate.

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 overly verbose and marketing-heavy, using emojis, repeated emphasis on 'free' and 'no key', and sample questions that occupy space without clarifying the tool's function. It is not front-loaded with the purpose; instead it leads with a call to action ('call this now'). The length and informal tone detract from clarity and structured communication.

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 two optional parameters and no required ones, the description should still explain what the preview returns and how to interpret it. It gives sample questions but no indication of the response structure or whether it returns metadata, news items, or something else. The absence of an output schema raises the need for the description to explain the result, but it does not. The description is not complete enough for an agent to know what to expect.

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 already has 100% description coverage, so the baseline is 3. The description provides sample questions and mentions the listing slug, but does not add new semantic meaning beyond the schema. It implies the 'question' parameter is free-text via examples, and the 'slug' relates to a listing, but it does not clarify how these parameters affect the preview output. The description adds marginal value but does not compensate for any gap since the schema is complete.

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 reads as a sales pitch rather than a clear functional statement. It says 'FREE preview' and 'Try one of the sample questions now' but never states what the preview returns or what the tool does beyond being a 'taste of a listing'. It mentions the listing name and sample questions, but the core purpose—e.g., 'returns public metadata and sample query results for a listing'—is absent. It does not distinguish itself from siblings like data_session_query or data_session_open.

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?

No guidance on when to use this tool versus alternatives is provided. It says 'call this now' and emphasizes no API key, but does not mention when to choose this over data_session_open or data_session_query, nor when not to use it. There is no context about prerequisites, session flow, or limitations relative to siblings.

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