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

Beyond the readOnlyHint=false annotation, the description discloses authentication requirements, the guest-call restriction, the REST endpoint, and the preference for open_tx_hash over proof_escrow_id. This adds meaningful behavioral context without contradicting the idempotentHint or destructiveHint 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 three sentences, front-loaded with the core purpose, followed by auth requirements, prerequisites, and the endpoint. Every sentence contributes practical information with no 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?

For a tool with no output schema and modest complexity, the description covers purpose, prerequisite session, auth, guest restriction, REST endpoint, and the two escrow identifier options. The main gap is that it does not explicitly state that at least one of open_tx_hash or proof_escrow_id must be supplied, despite the schema listing only session_id as required.

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 only 33%, so the description must add meaning. It does by explaining that open_tx_hash and proof_escrow_id refer to the buyer-funded proof escrow and by indicating that open_tx_hash is preferred. It could clarify format and whether one is strictly required, but it adds value 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 states a specific verb and resource: attach a buyer-funded proof escrow to an opened data session. It also explains the broader purpose (buy per-query access to live data listings) and distinguishes itself from the free data_preview path, making the tool's role clear even among 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 provides clear usage context: use this after opening a data session, requires an agent API key, and is not guest-callable. It also mentions data_preview as the free first taste, giving an alternative. It does not explicitly enumerate when not to use related funding tools, but the guidance is sufficient for basic routing.

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