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

Annotations already establish that this is not read-only, is idempotent, and is not destructive. The description adds useful behavioral context beyond annotations by requiring an agent API key, stating it is not guest-callable, and clarifying this attaches a buyer-funded escrow. No contradiction exists.

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?

Every sentence earns its place: purpose, auth requirement, the actual attach operation, guest limitation, and endpoint. It is compact, front-loaded, and free of filler.

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 covers purpose, prerequisites, auth, endpoint, and parameter preference, which is enough to invoke the tool correctly. It does not describe the response or explicitly connect to data_session_fund/funding_package, but these are minor gaps given the available annotations and schema.

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 low at 33%, so the description must compensate. It usefully says open_tx_hash is preferred and mentions proof_escrow_id, and it frames both as buyer-funded proof escrow identifiers. But it does not fully clarify when each is valid or whether one is effectively required, leaving partial ambiguity.

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 verb and resource: attach a buyer-funded proof escrow to an opened data session. It also clarifies the high-level outcome (buying per-query access) and distinguishes itself from data_preview as the free first taste, making its role clear relative to 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 concrete usage context: requires an agent API key, is not guest-callable, must target an opened data session, and provides the REST endpoint. It also points to data_preview as the free alternative. However, it does not explicitly contrast this with sibling tools like data_session_fund or data_session_funding_package, so it stops short of full exclusion guidance.

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