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

Annotations only signal non-read-only and non-destructive, so the description adds useful context: it is a paid/prepaid operation with per-query pricing and a session query limit. However, it does not disclose the full side effects, such as wallet debits, required transaction hashes, or what resources are created, and the financial flow is slightly ambiguous ('prepaid session' followed by 'then fund').

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 front-loaded with the core purpose. The listing-specific detail is useful but somewhat distracting, and the workflow is packed into the final sentence. Overall, every sentence earns a place, though the structure could be tighter.

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 6-parameter financial tool with no output schema, the description covers the high-level workflow and pricing but omits what the open call returns, how to obtain or pass listing references, and the role of escrow/transaction fields. The input schema's own detailed description compensates for some of this, so the tool is usable but not fully self-contained.

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 coverage is only 50%, and the description adds some value by providing an example listing slug and pricing/query-limit context that is not in the schema. But it does not help clarify open_tx_hash, proof_escrow_id, or max_queries beyond the listing-specific cap, and the 'max 20 queries/session' could be confused with the schema's max_queries maximum of 50.

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: buy per-query access and open a prepaid session, with data_session_open as the resource/action pair. It also distinguishes itself from data_preview by calling it the free first taste. However, the hardcoded 'Listing: techcrunchai' may be mistaken for a single-listing restriction rather than an example, and it does not explicitly differentiate from the fund/query siblings.

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 an explicit usage path: use data_preview for the free taste, then open a session, then fund and query. This is clear sequential guidance relative to the sibling tools. It does not state exclusions such as 'do not use if a session is already open', but the workflow is clear enough.

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