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

Annotations already provide idempotent and non-destructive hints, and the description adds useful behavioral context: authorization via Bearer or X-API-Key, guest exclusion, and the preference for open_tx_hash over proof_escrow_id. It does not describe post-attach effects or failure modes, but the added context goes beyond the structured metadata.

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 dense sentences with no filler. It front-loads the core purpose, then adds auth, guest restriction, and the REST endpoint, all of which earn their place. It does not restate input schema details.

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 three-parameter action, the description includes the endpoint, auth requirement, guest restriction, and parameter preference, which is a solid basis for invocation. There is no output schema, but the absence of return-value documentation is a minor gap. It could be more complete by explicitly stating whether exactly one escrow identifier must be supplied and what happens after attachment.

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%, with session_id documented and open_tx_hash/proof_escrow_id left undocumented. The description partially compensates by explaining the roles and preference of these parameters, saying open_tx_hash is preferred or proof_escrow_id. Still, it leaves ambiguity about whether one of them is required and does not explain open_tx_hash formatting beyond schema constraints.

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 (open_tx_hash or proof_escrow_id) to an opened data session, and frames it as buying per-query access. This clearly distinguishes it from sibling tools like data_session_open, data_session_query, and data_session_fund. The REST path further reinforces the exact operation.

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 clear prerequisites: an opened data session, an agent API key, and a buyer-funded escrow, and explicitly says 'Not guest-callable.' It also points to data_preview as the free alternative for a first taste. However, it does not explicitly contrast with data_session_fund or state when attaching escrow is preferred over other funding flows.

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