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

With only openWorldHint in annotations, the description adds the cost signal ('Free') and the enum of watch kinds, which is genuinely useful. It does not disclose what happens after creation (delivery semantics, webhook retry, whether watches can duplicate) or any permission requirements beyond the API key.

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 short sentences, all front-loaded, no filler; the kind enumeration and the conditional event/token rules are stated compactly. Every sentence carries information an agent needs to invoke the tool.

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 an 8-parameter creation tool with no output schema, the description covers the tricky conditional parameters well and signals cost. Remaining gaps (chain semantics, label format, post-creation behavior) are minor given the schema carries chain as an enum.

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 low (38%) and the description compensates substantially: it defines the kind enum values, states that event requires a signature or topic0 for kind=event, and explains that token is wallet-kind-only while label is optional. It still leaves chain and label unelaborated, but it adds real meaning beyond the schema.

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 opens with a specific verb+resource ('Start watching an address') and the title clarifies the webhook-alert effect, so an agent knows this creates a subscription. It is distinguishable from delete_watch/list_watches/test_watch by the 'Start' framing, though it never names them explicitly.

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 conditional parameter guidance ('For kind=event pass event as a signature...', 'wallet kind: only this ERC-20') which implies when each mode applies. However, there is no explicit when-to-use-this-vs-alternatives guidance, e.g. no mention of when to call test_watch first or how this relates to list_watches.

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