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

Annotations only cover readOnly/idempotent/closed-world; the description adds substantial behavioral context beyond them: source_quality semantics (primary = confirmed at source, secondary = reported but unconfirmed), the mandatory CoinGecko attribution and source_terms, the per-answer data_contract, and the bounded 'one question, one answer' server policy. This is real disclosure an agent needs to interpret results.

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 and return shape in the first two sentences, with filters and examples after. It is dense but nearly every clause carries information; the attribution/legal boilerplate is the only mildly padded portion, though it is genuinely operationally relevant.

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?

There is no output schema, so the description correctly carries the full burden by enumerating the return envelope and per-row fields (country_name, holdings_btc, tier, source_quality, etc.). Combined with the filter behavior and bulk-data escape hatch, an agent has everything needed to call and interpret this tool.

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 the baseline is 3, but the description adds usable examples for both parameters and states the default behavior of calling with {} (full ranking), which the schema does not convey. It does not add filtering syntax or multi-value semantics beyond that.

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 resource and scope: 'Nation-state Bitcoin holdings, ranked largest first.' The nation-state qualifier implicitly distinguishes it from the sibling get_treasury_holdings and from sovereign_diff, and the return-shape enumeration confirms exactly what an agent gets back.

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 concrete invocation examples ({"country": "US"}, {"tier": 1}, {} for full ranking) and an explicit out-of-scope route ('for bulk, history, backfills and scheduled pulls use the CSVs and datapackage.json'), plus the 'one question, one answer' framing. It never names a sibling tool as the alternative, so the routing to sovereign_diff or get_treasury_holdings is left to inference.

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