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

The description states authentication requirements and explicitly says the tool returns calldata, implying it does not execute the escrow creation itself. This aligns with the readOnlyHint annotation and adds auth-related behavioral detail beyond 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 concise and front-loaded with the core purpose. The marketing phrase 'first taste free via data_preview' adds slight ambiguity but does not significantly detract from clarity.

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?

With no output schema, the description helpfully explains the return value (funding instructions and createEscrow calldata) and includes auth requirements. It omits potential error conditions but is sufficient for the tool's low complexity.

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 100% for the single session_id parameter, including the note that it comes from data_session_open. The tool description repeats this context but does not add new semantic information beyond the schema.

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 function: buying per-query access to live data listings and returning funding instructions plus createEscrow calldata for an opened session. It distinguishes itself from sibling tools like data_session_fund and data_session_attach_escrow by specifying this is the funding-package retrieval step.

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 provides concrete usage context: requires an agent API key, is not guest-callable, and applies to an opened data session. It does not explicitly contrast with sibling funding tools, but the endpoint and prerequisites make the intended usage clear.

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