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

Discloses the financial side effect (per-query purchase), auth requirements, sandbox receipt behavior, and return contents (attested hits plus purchase receipt). Annotations only flag non-readonly/non-idempotent, and the description enriches this with cost and receipt details without contradicting them.

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?

Four dense sentences with no filler; each adds auth, prerequisite, behavior, or endpoint detail. Slightly front-loaded with the marketing-like 'Buy per-query access' phrasing, but still efficient.

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?

Covers auth, prerequisite, sandbox behavior, REST endpoint, and return summary, which is strong for a 5-param tool with no output schema. The optional k and delivery_receipt parameters and the exact return shape remain unresolved, so it is not fully complete.

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%, so the description needed to clarify k and delivery_receipt, but it only re-emphasizes session_id and sandbox_receipt. 'Run a prepaid query' gives no detail on query syntax, and k's meaning remains undocumented.

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?

States a specific action (run a prepaid query against a funded data session) and resource (live data listings / data session), and differentiates from siblings like data_session_open and data_preview by focusing on paid querying. The name and description align clearly.

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?

Explicitly names the free alternative (data_preview), states the prerequisite funded data session, requires an agent API key, and notes it is not guest-callable. This gives an agent clear when-to-use and when-not-to-use guidance.

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