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

Annotations already indicate this is a mutating, idempotent, non-destructive operation. The description adds useful behavioral context: required auth headers, non-guest restriction, preference for open_tx_hash over proof_escrow_id, and the exact REST method and path. No contradiction with 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 a bit dense with five sentences, but each adds useful information: business context, auth requirements, the attach action, guest restriction, and REST endpoint. The core action appears near the end rather than front-loaded, so it is slightly less crisp than ideal.

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 simple three-parameter tool with no output schema, the description covers auth, prerequisites, parameter preference, and the REST call. Missing details like response shape and the exact behavior when both escrow identifiers are omitted would help, but the current description is adequate for an agent to make the call.

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%, and the description partially compensates by explaining that open_tx_hash is preferred and proof_escrow_id is an alternative, both tied to a buyer-funded escrow. However, it does not fully define the relationship between the two, when one is required, or what happens if both are absent.

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 action and resource: attach a buyer-funded proof escrow to an opened data session. It clearly differentiates this from sibling tools by naming the exact mechanism (open_tx_hash or proof_escrow_id) and the REST endpoint.

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 gives clear context: it is the paid step after a free preview, requires an agent API key, requires an already-opened session, and is not guest-callable. It does not explicitly compare with sibling tools like data_session_fund, but the conditions for use are clear enough.

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