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

Annotations are all false, so the description carries the burden of behavioral disclosure. It adds meaningful beyond-schema context: the operation costs 0.01 USDC per query, consumes a per-session quota, and depends on a prior open/fund flow. It does not describe failure modes or response shape, but the paid/quota/sequence behavior is useful and non-obvious.

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-loaded with the purpose, then pricing/quota, then the required sequence. The listing-specific detail is useful context rather than fluff. It could be slightly tighter, but every sentence earns its place.

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 basic invocation, the description gives sufficient orientation: have a funded session, send a query, pay per call. However, with no output schema and only 40% parameter coverage, the definition leaves optional parameters (k, delivery_receipt) and return/error behavior unaddressed. It is adequate but has clear 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 only 40%, and the main description provides no parameter-level meaning. The schema covers session_id and sandbox_receipt, but k, query, and delivery_receipt remain effectively undocumented. With low coverage, the description was expected to compensate, and it does not.

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 conveys a specific commercial action — buying per-query access to live data listings — and references the exact sequence data_session_open → data_session_fund → data_session_query. It does not explicitly say 'run a query' in the main description, and the schema description is needed to make that fully explicit, so it stops just short of a 5.

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 ('first taste free via data_preview') and gives the explicit prerequisite sequence data_session_open → data_session_fund → data_session_query. It also communicates a hard usage bound: max 20 queries/session. This is clear when-to-use guidance against the sibling tools.

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