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

Annotations already declare read-only/non-destructive, and the description adds substantial context beyond them: CC0 licensing, 404-on-no-match behavior (uncharged), failure calls free, per-call pricing and payment routes, and an explicit reconciliation of why repeats are not free despite being a pure read. That last point usefully explains the idempotentHint=false, which would otherwise look odd for a read-only tool.

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 useful field list, but the tail is dense and partly redundant: price and 'failed calls free' appear in one sentence, then 'each call is charged, so repeats are not free' restates the billing point. Payment-rail detail (x402 USDC, /credits key) is relevant to cost but crowds out structure in a single undifferentiated paragraph.

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 only two optional parameters, no nested objects, no output schema, and near-zero complexity, the description covers everything needed: the returned fields are enumerated, error behavior and cost are stated, and the read-only nature is explicit. Nothing an agent needs before calling is missing.

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 both parameters are self-documented ('Wikidata item ID such as Q689141, instead of name'; 'give name or id'). The description restates the either/or choice and adds one worked example (name=Spotify), which is mildly helpful but adds no format or disambiguation rules beyond the schema. 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 a specific resource (company facts) with explicit input modes (name or Wikidata ID) and enumerates the exact fields returned: website, founding date, HQ, industries, CEO, founders, parent, employees, tickers, LEI, and external links. An agent can immediately distinguish this from siblings like domain, sec_filings, or check_counterparty without opening the 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?

Gives concrete use cases (enrich leads, vendors, counterparties; ground an answer about a company) plus a scoping constraint ('best for established and listed companies'), which implies when NOT to use it. It stops short of naming which sibling to use for private/early-stage companies or for financial filings, so it is clear context without explicit alternatives.

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