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

Annotations already indicate this is not read-only, not destructive, and idempotent. The description adds that the platform 'executes funding' and mentions a per-query price, which is useful. However, it does not explain what happens financially, whether funds are committed immediately, or any failure-related behavior, so transparency is only partial.

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 short, front-loads the core purpose, and avoids repetitive filler. The listing-specific pricing detail is relevant, and the reference to data_preview and data_session_query adds orientation without bloating 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?

For a single-parameter tool with a well-documented schema, the description covers the main action and outcome. Still, it omits explicit prerequisites such as having an open session and does not clarify how this relates to data_session_funding_package or data_session_attach_escrow, leaving some context 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 100%, with the session_id parameter already documented as 'UUID of a data session you opened (from data_session_open).' The tool description adds no parameter-level detail beyond this, so the baseline of 3 applies.

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 concrete action — 'Buy per-query access to live data listings' — and names the outcome: platform-executed funding that enables data_session_query. However, it does not explicitly differentiate itself from sibling data_session_funding_package, so it is clear but not fully distinguished.

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 gives useful context: try the free data_preview first, then fund so you can query. But it never explicitly says when to choose this over data_session_funding_package or data_session_attach_escrow, so usage guidance is implied rather than explicit.

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