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

Annotations already cover readOnly, destructive, and idempotent hints. The description adds authentication requirements, the financial implication of 'buy per-query access', and the REST method, enriching the behavioral context beyond the structured fields without contradicting them.

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 dense but well-organized, starting with the high-level purpose, then auth, then the core action, and ending with the REST endpoint. Every sentence adds value, though it could be slightly tighter by merging the auth and endpoint 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 tool with 3 params and no output schema, the description covers the essential calling context: authentication, the required session, the two escrow identifiers, and the endpoint. It omits response details but that's acceptable given no output schema, and idempotency is already annotated.

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 coverage is only 33%, so the description must compensate. It explicitly mentions open_tx_hash and proof_escrow_id as alternatives with a preference for open_tx_hash, giving meaning to both parameters. It also clarifies that session_id refers to a session opened via data_session_open.

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 clearly states the action: attaching a buyer-funded proof escrow to an opened data session. It distinguishes from siblings by naming data_preview as a free alternative and specifying the REST endpoint, making its role unambiguous.

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 explicit usage context: requires an agent API key, not guest-callable, and should follow data_session_open. It also points to data_preview as a free alternative, giving clear when-to-use guidance, though it doesn't enumerate all non-use cases relative to other funding tools.

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