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

No annotations are supplied, so the description carries the full burden and does a solid job: it discloses the 24h cooldown for human developer keys, the requirement of a funding-wallet signature under an agent GOVERN key, and immediate approval in that path. It stops short of saying whether the address is usable during the cooldown or what the call returns, but the operational conditions are well surfaced.

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 sentences, front-loaded with the action and then branching by key type in a readable parallel structure. Dense but no wasted wording; the only friction is unexplained shorthand such as 'DA' and 'Assist passkey'.

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 six-parameter mutation tool with no annotations and no output schema, the definition covers the important operational facts: the cooldown, the signature requirement, and the differing approval timing per key type. Minor gaps remain around post-add state and the two-call challenge handshake, but the essential calling context is present.

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 100%, so address, chainId, challengeId, fromWalletId and walletSignature are already documented in the schema, including the challenge-then-signature sequence. The description adds the governance framing around the signature but no format or validation detail beyond what the schema states, so baseline 3 applies.

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 first sentence names a specific verb and resource: 'Add a payout address to the allowlist.' That is unambiguous and lets an agent distinguish this from list_recipients or remove_recipient. It does not explicitly distinguish itself from the close sibling approve_recipient, which is the one plausible confusion point.

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?

The description explains which credential type triggers which path (human developer key vs agent key), which effectively tells the caller when each flow applies. However, it never says when to use this tool versus approve_recipient or propose_recipient_manifest, so tool selection is only implied.

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