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

Annotations already declare readOnly/idempotent/openWorld/non-destructive, and the description adds context annotations cannot carry: it is free while the follow-up call is paid, results are newest-first, up to 50 per call, coverage reaches back to 2001, and the endpoint is rate-limited per client. That is meaningful behavioral disclosure beyond structured fields.

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 key differentiator ('Free, no payment needed') and densely packed with useful facts, but it is a long, semicolon-chained block that mixes return-shape, usage, and limits in one breath. Slightly long, though nearly every clause earns its place.

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 no output schema, the description carries the burden of describing returns and does so thoroughly: filing date, fiscal year/period, sec.gov link, extractable sections, 8-K event items, and the `next_call` object with arguments and price. 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 genuine meaning the schema lacks: filtering is 'back to 2001', the per-call cap is framed as 50, and lookup is by ticker OR CIK. It does not explain how form/date filters interact, but it does more than restate the schema.

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 states a specific verb (lists) and resource (SEC filings from EDGAR) and enumerates exactly which forms (10-K, 10-Q, 8-K) with what fields are returned. It also distinguishes itself from the sibling sec_filing_section by framing itself as the free discovery step that returns `next_call` for the paid extraction tool.

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?

It gives explicit when-to-use guidance: 'check what exists before paying, to find a specific year or event, or to track new filings,' and implicitly routes paid text retrieval to sec_filing_section via the `next_call` field. The free-vs-paid boundary is stated up front so the agent knows why to pick this over the sibling.

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