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

Annotations already cover readOnly, destructive, and idempotent hints. The description adds useful behavioral context: API-key authentication via Bearer or X-API-Key, guest-call restriction, and the preference for open_tx_hash over proof_escrow_id. Nothing in the description contradicts 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 compact and front-loaded with the value proposition, followed by auth, mechanics, and endpoint. Every sentence contributes information, though 'Not guest-callable' and the API-key requirement are mildly overlapping.

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 payment/escrow attach operation with no output schema, the description covers the main invocation facts: endpoint, required session context, escrow identifier choice, and auth. It does not explain how the buyer-funded escrow is created or what a successful response returns, but annotations supply the idempotency/safety profile.

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 compensate for open_tx_hash and proof_escrow_id. It does this by identifying them as alternative escrow references and stating that open_tx_hash is preferred, which is not inferable from the bare schema. It could go further by saying where these ids come from, but the core semantic is present.

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 the operation explicitly: 'Attach a buyer-funded proof escrow ... to an opened data session,' and gives the REST endpoint. It also positions the tool against free access via data_preview, making its role in the data-session workflow clear.

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 establishes a clear precondition: the data session must already be open, and the escrow must be buyer-funded. It also directs free first tastes to data_preview and notes that guest calls are not allowed. It does not explicitly contrast with the sibling data_session_fund tool, so a small usage gap remains.

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