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

readOnlyHint=false already tells the agent this is a write, and the description adds meaning beyond that: the SIWx challenge/signature auth requirement, that signing must use the referrer wallet, and the reassurance that no payment is authorized. It omits rate limits, idempotency, and side effects of accepting a version.

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 the action and its payoff, then the argument source, then the calling sequence; every sentence carries information. It is dense and slightly clipped (the 'arguments:' fragment), but there is no filler.

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 nested-object tool with no output schema and 0% parameter coverage, the description covers the challenge/response flow and the no-payment caveat well but leaves new_proof and the object shapes unexplained, so an agent could still mis-invoke it.

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 0% for three object parameters, so the description must compensate. It explains that arguments carries terms_version and terms_digest from referral_program, and implies proof is the signed challenge, but new_proof is never explained and the structure of these objects is left undocumented.

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States a specific verb and resource (accept a newer version of the referral terms) plus the motive (to keep earning), which is far beyond a restatement of the name. It references referral_program as the source of terms_version/terms_digest, giving useful lineage, though it does not explicitly distinguish itself from sibling tools like referral_acknowledge.

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 an explicit two-step calling procedure: call without proof to obtain a SIWx challenge, sign it with the referrer wallet, then call again with proof. This is strong how-to guidance, but it never states when to prefer this tool over siblings such as referral_acknowledge or referral_register.

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