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

With all annotation hints false and minimal guidance, the description carries the disclosure burden. It reveals that each query costs 0.01 USDC, is capped at 20 queries per session, and depends on a prior open-and-fund sequence. This is meaningful behavioral context beyond the annotations, though it does not describe response behavior or failure modes.

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 — three short clauses that front-load the core purpose, pricing, cap, and sequence. Every sentence earns its place without filler, making it easy to parse quickly.

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 paid, multi-step tool with five parameters and no output schema, the description covers the economic model, query cap, and prerequisite flow. However, it omits how optional parameters (k, delivery_receipt) behave and what the response contains, leaving an agent with partial information to invoke the tool correctly.

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%, covering session_id and sandbox_receipt, while query, k, and delivery_receipt are undocumented in the schema. The description does not compensate: it mentions 'per-query access' (implying query) and the session sequence, but says nothing about k or delivery_receipt. The description adds little meaning for most parameters.

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 the tool provides 'per-query access to live data listings' and names the specific listing, price, and query cap. The sequence 'data_session_open → data_session_fund → data_session_query' distinguishes it from sibling tools. However, the verb 'Buy' is slightly misleading because the schema says the tool actually 'Run[s] a prepaid query' rather than performing a purchase.

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 explicitly points to data_preview for a free alternative ('first taste free via data_preview') and gives the required sequence of open → fund → query. This clearly implies the tool should be used only after a session is opened and funded, and that data_preview is the choice for sampling. It does not explicitly state exclusions, but the sequencing covers typical usage.

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