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

The description adds valuable behavioral context beyond the annotations: each query costs 0.01 USDC, there is a max of 20 queries per session, and the flow is prepaid. This is important cost and quota information that annotations do not provide. It does not describe what a successful response looks like or failure modes, but the financial and sequencing behavior is well disclosed.

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 compact and information-dense, with the key monetization detail front-loaded. Each sentence adds useful context: cost, quota, alternative preview tool, and required call sequence. There is no wasted wording.

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 description covers pricing, quota, listing content, and the required session sequence, which is helpful. However, with no output schema and five parameters, it leaves important gaps: how to formulate 'query', what 'k' controls, what the response contains, and what happens on insufficient funds or invalid receipts. It is adequate for basic routing but not fully complete for confident 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?

Schema description coverage is only 40%, and the description does little to explain the parameters. It mentions 'per-query' and 'session' at a high level, but does not clarify the meaning of the 'query' string, the 'k' integer, or how delivery_receipt and sandbox_receipt interact with the paid flow. The schema provides some descriptions, but the tool description does not compensate for the coverage gap.

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 the final step in a paid data-access flow: 'Buy per-query access to live data listings' and 'Sequence: data_session_open → data_session_fund → data_session_query.' It also names the specific listing being queried. It does not use the exact phrase 'run a query,' so the purpose is slightly indirect, but the title and sequence make it clear.

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 sequence data_session_open → data_session_fund → data_session_query explicitly states when this tool should be invoked relative to its siblings. It also points to data_preview as the free alternative for a first taste. It lacks an explicit 'when not to use' statement, but the context is strong enough for an agent to route correctly.

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