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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds useful behavioral context beyond that: no API key required, a price of 0.01 USDC/query, a 20-query session limit, and that it is a free preview. This gives the agent a realistic sense of cost and access constraints that annotations alone do not convey.

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 repetitive and marketing-heavy: 'No API key needed' and 'FREE preview — no key, no payment' say the same thing twice, and the emphatic '✅' and exclamation points add noise. It is not efficiently structured; the core purpose is buried under promotional phrases rather than front-loaded as a clean function statement.

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 tool with two optional parameters and no output schema, the description covers access, cost, and usage examples. It does not, however, describe what the return value looks like or when to choose this over the paid data_session_query tool, which would be helpful for an agent deciding among siblings. It is adequate but leaves some gaps.

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 both parameters (slug and question) are fully documented. The description contributes sample questions that map to the question parameter but does not add new semantic meaning beyond what the schema already states. Baseline 3 is appropriate when the schema carries the parameter documentation burden.

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 a free preview action for a specific listing ('scinews'), and the schema description adds 'Free, guest-callable taste of a listing (public metadata only)'. This makes the tool's purpose understandable, though it relies on the schema description to provide the clean verb+resource framing and does not explicitly distinguish itself from sibling tools like data_session_query.

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 strongly encourages immediate use ('call this now', 'Try one of the sample questions now') and states no API key is needed, implying it is meant for quick, free trials. However, it provides no explicit guidance on when NOT to use it or when to prefer alternatives such as data_session_query, leaving the routing decision to inference.

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