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

Annotations already mark the operation as non-read-only and non-destructive, and the description adds meaningful behavioral facts beyond that: each query costs 0.01 USDC, there is a 20-query session cap, and the query must be prepaid against a funded session. This gives the agent practical expectations about side effects and limits, with no contradiction of the annotations.

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 core purpose, then the pricing/limit detail, then the workflow sequence. Every sentence carries useful information, though the phrasing 'first taste free' is slightly promotional rather than purely instructional.

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?

The workflow, pricing, and session limit are covered well, which is important given the multi-step sibling sequence. However, there is no output schema and the description does not explain the expected query format or the returned result shape, leaving a meaningful gap for an agent deciding how to form a valid request.

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 tool description does not compensate: it never explains what 'query' should contain, what 'k' controls, or how 'delivery_receipt' / 'sandbox_receipt' should be used. The schema provides descriptions only for session_id and sandbox_receipt, leaving key parameters underspecified for an agent trying to invoke the tool correctly.

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 specific action ('Buy per-query access to live data listings') and names the concrete listing ('googleblogwatch'), making the tool's function unmistakable. It also distinguishes itself from data_preview by positioning preview as the free first taste, and the sequence clarifies how it fits with data_session_open and data_session_fund.

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?

The description gives an explicit call sequence — data_session_open → data_session_fund → data_session_query — which tells the agent when this tool is appropriate. It also names data_preview as the alternative for a free first taste, though it does not enumerate explicit 'when not to use' conditions such as lacking a funded session.

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