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

Annotations already declare readOnlyHint and openWorldHint, yet the description adds material context beyond them: the data source and cadence, one-year coverage, newest-first ordering, a delta versus the prior report, and a per-call payment model ($0.002 USDC via x402 on Base/Solana/Arc with failed calls free). That payment and freshness detail is exactly what an agent needs and is not encoded anywhere else.

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?

Three sentences, each carrying distinct payload: what the data is, ordering/coverage, source scope, and pricing. Purpose is front-loaded and nothing is repeated from the title or schema.

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, the description needn't explain return values, and it covers everything else an agent would wonder about: ordering, freshness, source compatibility, and cost/charging behavior. Nothing material is missing for a read-only, paid data lookup.

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 schema already documents both parameters, including the 1–24 limit range and example tickers. The description only indirectly enriches semantics by noting 'about one year of reports', which explains why the limit caps at 24, but adds no explicit parameter guidance. Baseline 3 is appropriate.

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: 'Short interest history for a Nasdaq-listed stock from Nasdaq.com'. The parenthetical names the underlying data (FINRA twice-monthly settlement data), and no sibling tool covers short interest, so the agent can place it immediately.

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?

Explicitly scopes applicability with 'Only Nasdaq-listed symbols are supported by the source', which is a real exclusion rule an agent must respect. It does not name a sibling alternative, but no direct alternative exists in the sibling list, so the guidance is adequate.

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