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

The annotations already cover read-only, destructive, and idempotency hints. The description adds valuable operational context: API-key auth, guest-call restriction, REST method/path, and the preferred escrow identifier. It could further disclose what happens if both open_tx_hash and proof_escrow_id are provided, which keeps it from a 5.

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: purpose, auth requirement, core action with parameter preference, caller restriction, and REST endpoint. Every sentence contributes distinct value with no repetition or 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 3-parameter tool with no output schema, the description supplies the key invocation details: prerequisites, authentication, endpoint, alternatives, and parameter preference. It is nearly complete but would benefit from an explicit statement about required escrow input and post-attach behavior.

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. It does meaningfully by naming both optional escrow parameters, marking open_tx_hash as preferred, and tying session_id to an already-opened session. However, it does not explicitly state that at least one escrow identifier is expected or define behavior when both are supplied, so minor ambiguity remains.

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 names a precise action — attaching a buyer-funded escrow to an opened data session — and clearly connects it to buying per-query access. It also distinguishes itself from data_preview by positioning that tool as the free first taste, so the resource and intent are 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 gives a clear precondition (an opened data session), names data_preview as the free alternative, and states explicit exclusions: requires an agent API key and is not guest-callable. It does not explicitly contrast with data_session_fund or data_session_funding_package, so the when-not-to-use guidance is slightly incomplete.

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