Free for a PAID check: add a callback (https) that receives signed events when requiredLevel is reached, when the answer changes, when it becomes final, or when checking gives up. The service re-checks on its own.
| Name | Required | Description | Default |
|---|---|---|---|
| checkId | Yes | ||
| callbackUrl | Yes | ||
| requiredLevel | No | Proof level you need before releasing money (Base: tee_attested < zk_proven < resolved; Ethereum: finalized; XRPL: unl_quorum). The answer then says whether it is releasable. |
Changes observed during successful MCP inspections.
Input schema / properties / requiredLevel / descriptionPrevious value: -"Proof level you need before releasing money (Base: tee_attested < zk_proven < resolved; Ethereum: finalized). The answer then says whether it is releasable."New value: +"Proof level you need before releasing money (Base: tee_attested < zk_proven < resolved; Ethereum: finalized; XRPL: unl_quorum). The answer then says whether it is releasable."Input schema / properties / requiredLevel / enumPrevious value: -[
- "tee_attested",
- "zk_proven",
- "resolved",
- "finalized"
-]New value: +[
+ "tee_attested",
+ "zk_proven",
+ "resolved",
+ "finalized",
+ "unl_quorum"
+]Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations exist, so the description carries the full burden. It does disclose useful behavior: the payload is signed, the feature is free for a paid check, re-checking is automatic, and the four event triggers. However, it omits re-registration semantics, retry/failure behavior, and any permission requirements.
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?
Two tight sentences with no padding, and the event list is front-loaded. The opening 'Free for a PAID check:' is slightly cryptic and delays the actual action, which keeps it from a 5.
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 webhook-registration tool with no annotations, no output schema, and a partially documented schema, the description covers triggers, cost, and payload signing. It still leaves gaps around checkId usage, lifecycle of an existing watch, and error behavior, so it is adequate but not complete.
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 33%: only requiredLevel is documented in the schema, and its enum is well explained with per-chain ordering. The description adds that callbackUrl must be https, which compensates partially, but checkId is never explained and callbackUrl semantics beyond https remain unclear.
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 on a specific resource: registering an https callback for a verification check to receive signed events. It is clearly distinguishable in spirit from polling siblings like get_verification, but it never names or contrasts them explicitly, so it falls short of a 5.
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?
Usage is only implied: 'The service re-checks on its own' suggests this is the push-based alternative to polling, and the event list hints at when the callback fires. There is no explicit when-to-use statement, no condition for choosing this over get_verification or try_verify_payment, and no prerequisites.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.