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

The description discloses that this opens a prepaid session and may involve payment at 0.01 USDC/query with a 20-query session cap. Annotations indicate a non-destructive, non-idempotent side-effecting operation, which aligns with creating a session, though the exact state changes and failure modes are not detailed.

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 and readable, packing price, limits, and workflow into a few lines. The promotional phrasing and hardcoded listing example add flavor but are not overly verbose.

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 description explains the high-level workflow: open, fund, query. However, it does not mention what the function returns, how the optional parameters interact at a deeper level, or what errors or prerequisites exist beyond the basic listing and wallet hints.

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 descriptions cover listing_id, listing_slug, and buyer_address, but max_queries, open_tx_hash, and proof_escrow_id are left unexplained. The overall description mentions the 20-query cap but does not clarify the transaction hash or escrow parameters, leaving significant gaps.

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 tool's purpose: 'Buy per-query access to live data listings' and 'Open a prepaid session, then fund and query.' It also distinguishes itself from the free preview tool by mentioning 'first taste free via data_preview.'

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 implies usage context: use data_preview for free sampling, open a session here, then fund and query. It names the follow-up actions and the pricing, but does not explicitly contrast with all sibling session tools such as data_session_attach_escrow.

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