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

The description adds useful context beyond the readOnly/idempotent annotations: no API key needed, no payment, a 20-query session cap, and public metadata only. However, 'Price 0.01 USDC/query' followed by 'FREE preview' is internally ambiguous, and the sample questions imply the tool answers them even though the schema says the question is only echoed back.

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 padded with repetitive calls to action like 'call this now' and 'Try one of the sample questions now', plus redundant no-key/no-payment statements. The useful information could be conveyed in one or two clean sentences.

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?

The tool is simple, has no required parameters, and the schema covers the inputs, so an agent can likely invoke it. Still, the description itself does not explain what is returned, and the cost/free ambiguity plus lack of alternative routing makes the full selection context incomplete.

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 coverage is 100%, so the schema already documents both slug and question parameters. The description's sample questions illustrate possible question values but add no new parameter semantics beyond what the schema provides.

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 a free preview of a data listing and gives a concrete example listing with sample questions. It is not a tautology, but it does not explicitly contrast itself with sibling session/query tools, so it lacks clear sibling differentiation.

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 implies this is the low-commitment, no-key entry point for trying a listing, which gives some usage context. However, it never names alternatives like data_session_open or data_session_query, nor does it state when not to use this tool.

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