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

Beyond the readOnlyHint and idempotentHint annotations, the description discloses key interpretive cautions: a filing event 'does not prove securities were sold or quantify remaining shelf or ATM capacity', and an empty result is scoped to the requested years. This is valuable behavioral context that prevents misuse.

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?

Two information-dense sentences. The first front-loads the action and scope, the second lists answerable questions and caveats. No fluff, and every clause serves a purpose.

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?

The tool has no output schema, but the description fully compensates by listing filing types, the strategic questions it answers, and critical limitations regarding shelf capacity and year scoping. This is complete enough for an agent to choose and invoke the tool correctly.

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 all parameters are documented. The description adds semantic richness to the 'years' parameter by explaining that an empty result only covers the years requested, and the 'company' parameter is flexible (ticker/name/CIK) in the schema. This goes slightly beyond the baseline.

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?

The description opens with a specific verb+resource+scope: 'List recent SEC capital-markets filings for a company', then enumerates exact filing types (S-1, S-3, 424, etc.). This level of detail clearly distinguishes it from broader siblings like search_filings or get_company_facts.

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?

The description explicitly lists the questions it answers ('has this company filed a shelf', 'what has it registered recently', 'is there an active ATM programme on file'), providing clear use-case context. It also warns about the 'empty result covers only the years requested' limitation, but does not explicitly name alternative tools for other filing types.

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