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

Goes well beyond the annotations: it discloses that Toll POSTs signed JSON to the caller's https URL, names the signature header and algorithm (x-toll-signature: sha256=<hex HMAC-SHA256(secret, raw body)>), warns that the signing secret is returned only 'the first time', and states a Toll key is required with per-tier watch caps (3/20/50/100). These are exactly the non-obvious operational facts an agent needs and none are in the annotations.

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?

Front-loaded with purpose and dense with substance – quota, auth, secret handling, and follow-up tool all earn their place, and no sentence is filler. The cost is a long run-on opener and one garbled clause ('receives a token whose Toll check is against'), which slightly hurts parseability.

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 two-parameter webhook registration with no output schema, it covers everything material: what fires the events, what the payload identity looks like (watch id plus one-time secret), the auth requirement, the quota, and the follow-up revoke path. Remaining gaps such as delivery retries are secondary for a tool this simple.

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 already 100%, but the description still adds meaning: the address is a wallet on Robinhood Chain that may be the agent's own or a counterparty, and the url is the destination that receives POSTed signed JSON events rather than a passive reference. That framing helps an agent decide what to pass, though it adds no format details beyond the schema's regex and maxLength.

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?

States a concrete verb and resource ('Watch one Robinhood Chain wallet') and immediately enumerates the exact triggering events (new ERC-20/NFT/Permit2 approval with spender and unlimited flag, EIP-7702 delegation signing, incoming token with a Toll check). An agent can separate this from watch_coin, my_watches, and unwatch_wallet without opening any schema.

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?

Gives clear usage context ('its own wallet, or one it trades with') and routes the follow-up action to wallet_approvals for revoking what an alert finds, plus a pointer to the watch cap. It does not explicitly say when to prefer watch_coin over this, nor how to undo the watch (unwatch_wallet is never named), so the exclusion/routing picture is incomplete but the positive guidance is solid.

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