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

The description discloses the paid nature, the per-query cost, the 20-query session cap, and the requirement that the session be funded/open. This adds valuable behavioral context beyond the sparse annotations, which only mark it as non-read-only and non-idempotent.

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 front-loads the core purpose before pricing and sequence. The specific listing example adds concrete context without bloating the text, though the schema-level detail 'REST body + session id' is not carried into the description.

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 core lifecycle, pricing, and required session state are clear, but optional parameters remain under-specified and there is no output schema to clarify what the query returns. An agent could likely invoke the tool correctly with the required fields, but not confidently use optional fields.

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 only 40%, and the description does not explain key parameters like k or delivery_receipt. It focuses on pricing and workflow rather than the meaning or effect of optional inputs, leaving the agent to guess how k limits results or how delivery_receipt interacts with sandbox_receipt.

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 states a specific action: buying/executing per-query access to live data listings, and explicitly distinguishes it from data_preview. The sequence data_session_open → data_session_fund → data_session_query makes the tool's role in the workflow unmistakable.

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?

It names data_preview as the free alternative and gives an explicit required sequence of sibling operations before this tool should be used. This tells an agent when to call it and what must happen first.

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