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

Annotations only carry readOnlyHint=true; the description adds substantial behavior beyond that: it enumerates the exact checks performed (challenge/dApp-definition/origin signature, ledger owner_keys vs derived virtual address) and states that it 'Reports the reason for every failure'. It also discloses the anti-replay security requirement, which is critical operational context.

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, then input alternatives, then the security warning last, so the most important routing and safety information lands first. It is dense rather than padded, though the single long opening sentence carries several clauses that could be split for readability.

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 read-only verification tool with no output schema, the description covers what an agent needs: what it verifies, the two ways to supply proofs, the origin/dApp-definition linkage, that failures report reasons, and the replay caveat. Nothing material is left undefined.

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, but the description adds real meaning: it clarifies that proofs and wallet_response are alternate input forms ('every proof in it is found') and explains the security-relevant semantics of the challenge parameter. It stops short of field-level detail, which the schema already owns.

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 specific verb+resource ('Server-side ROLA verification of the signed challenge proofs') and frames the exact trust decision a dApp backend must make. It is clearly distinguishable from siblings like build_wallet_request (which produces the challenge) and check_signing_request, and spells out the two things checked: signature over challenge + dApp definition + origin, and key-controls-entity via owner_keys or virtual address.

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?

Explicitly states the two input routes ('Pass EITHER the raw wallet response ... OR proofs in the {type, address, proof} format') and names build_wallet_request as the source of the challenge. It also gives a strong when-not condition: never verify against the challenge inside the response, since that would accept a replayed answer.

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