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

No standard MCP annotations are present, so the description must carry the behavioral burden. It discloses auth requirements, network restriction, execution mode, and the operation sequence (approve + createEscrowWithProof + attach). It does not explicitly state irreversibility or what a successful call returns, but 'Buy' and 'funding' do convey the financial side effect.

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 a compact, dense block where every clause adds a distinct prerequisite, constraint, or alternative. The main purpose is front-loaded, and there is no filler or redundant repetition of schema information.

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 one-parameter operation with no output schema, it covers auth, network, wallet type, sibling routing, and invocation prerequisites. The main gap is the lack of a return/error description, but an agent can correctly invoke the tool with the information given.

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 100% and the single session_id parameter is already documented as a UUID from data_session_open. The tool description does not add session_id-specific semantics beyond what the schema provides, so the baseline score of 3 is appropriate.

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 opens with 'Buy per-query access to live data listings', which names a concrete action and a specific resource. It further clarifies the mechanics with 'platform-execute funding' and explicitly distinguishes this tool from data_session_funding_package, so an agent can tell it apart from a closely related sibling.

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 explicit routing guidance: use data_preview for a free first taste, use data_session_funding_package for user-supplied wallets, and use this tool when platform-executing funding for a testnet sandbox wallet. It also states hard constraints such as requiring an agent API key, testnet-only availability, not guest-callable, and no REST analogue.

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