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

The description implies a financial action ('Buy per-query access', 'Platform-executes funding') and that it prepares for querying. The idempotentHint annotation is consistent, and no contradictions appear. It could be more explicit about the irreversible spending of funds, but it is generally transparent.

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 concise (two sentences) and efficiently conveys the purpose, pricing, and linkage to other tools. No fluff or redundancy.

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 simple funding tool with one parameter and no output schema, the description covers the core purpose and references the free preview and downstream query tool. It lacks differentiation from the sibling funding_package tool, which would make the context more complete, but overall it's adequate.

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?

The single required parameter session_id is well-described in the schema as 'UUID of a data session you opened (from data_session_open),' providing clear provenance. The tool description doesn't add extra context, but the schema coverage is complete, so this is sufficient.

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 clearly states the action: buying per-query access to live data listings, with a specific listing example and cost. It distinguishes from data_preview (free taste) and ties to data_session_query, making the tool's purpose unambiguous.

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 mentions data_preview as a free alternative and indicates this tool is for paid access, but it does not differentiate from the sibling data_session_funding_package or data_session_attach_escrow. Guidance on when to choose this over those alternatives is missing.

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