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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety and external-scope are covered. The description adds real behavioral context beyond that: the not-found case returns verified=false rather than erroring, and multiple addresses collapse into a single batch request. Missing only secondary traits like rate limits or cost of large batches.

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 one-line answer to the core question, then usage, then sibling differentiation. Slightly verbose with the rhetorical opener and the parenthetical field list, but every sentence carries usable information; nothing is wasted on 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?

With an output schema present, return-value documentation is not needed, and the description covers purpose, triggers, alternatives, the negative case, and batch behavior. For a one-parameter read tool this is close to complete; only limits on batch size/rate behavior remain unstated.

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% and the single parameter is fully documented (format, count, mixed chains, example), which sets a baseline of 3. The description adds batching semantics not present in the schema — that several addresses count as one batch request — which is meaningful for planning multi-address calls.

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 ('Who owns a wallet? Returns the CabalSpy ID user who proved ownership') and enumerates the identifying payload (X handle, KOL badge, verified chains) plus the verified=false fallback. It explicitly distinguishes itself from the sibling lookup_wallet, so an agent can route without opening either 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?

Names concrete use cases ('user pastes an address and asks who is behind it', 'find verified traders among a token's holders') and names the alternative tool (lookup_wallet for CabalSpy's own labels), making the when-to-use and when-to-prefer-the-sibling explicit.

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