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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, open-world), so the bar is lower. The description still adds real context beyond them by flagging the balance as 'best-effort', which tells the agent that the USD figure may be incomplete and should not be trusted as authoritative.

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?

The core capability is front-loaded in one sentence, with the example appended as optional illustration. The example repeats the schema's own examples and the literal placeholder 'your-nansen-key' is filler, keeping it just short of a 5.

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, non-destructive profiler with no output schema, the description says what comes back (labels plus balance) and hints at fidelity limits. It stops short of noting rate limits, credit consumption per call beyond the schema's key note, or how 'chain: all' aggregates, but nothing critical is missing for correct invocation.

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 schema already documents chain (default 'ethereum', 'all' spans chains), address, and the _apiKey cost note. The description's worked example adds convenience but no semantic detail that isn't already in the structured fields — 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?

States the specific verb and resource — returns Nansen labels ("Smart Money", "Fund", exchange tags) plus a best-effort USD balance summary for a wallet — and implicitly distinguishes it from the aggregate nansen_smart_money_holdings/netflow siblings, which cover cohorts rather than one 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?

Usage is only implied: the example invocation shows the intended call shape, but nothing states when to choose this over nansen_smart_money_holdings/netflow or entity_profile/resolve_entity. An agent can infer 'single-wallet lookup' but has no explicit routing guidance or exclusions.

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