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

Annotations already declare idempotentHint=true, destructiveHint=false and openWorldHint=true, and the description goes well beyond them: it states the tool 'never sends, signs or authorizes payment' and that the receipt's policy is UNKNOWN (no agent identity, wallet ownership, provider identity or service-delivery claim). That last disclosure is indispensable for correctly interpreting the returned evidence and is not available from any structured field.

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?

Four tight sentences, front-loaded with the usage trigger, then the non-authorization guarantee, the scope limitation and the retry rule. No sentence is filler; minor jargon ('OCD receipt') is the only friction.

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?

With only two fully documented parameters, no output schema and annotations covering the safety profile, the description supplies everything else an agent needs: timing, non-authorization, the limits of what the receipt proves, and retry semantics. Nothing material is missing.

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 100%, so the baseline is 3. The description adds the useful qualifier that the network and transaction reference must be the 'exact' observed values, reinforcing what the schema already documents (EVM hash / Solana signature, no credentials).

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: independently observe a completed payment's network/transaction reference and 'create or return a signed OCD receipt.' The pre-condition ('after a supported payment has occurred') sharply separates it from get_receipt, inspect_payment and verify_receipt, but none of those siblings is named explicitly, so an agent must infer the routing.

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 tells the agent exactly when to call it ('after a supported payment has occurred') and how to recover ('Pending requests must be retried with the same reference, not another payment'). It does not name an alternative tool or state a when-not condition, so sibling selection is left implicit.

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