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

Annotations already cover read-only and idempotency, but the description adds material context the annotations lack: a 20/min rate limit, free-of-charge access, and the upstream source (SEC EDGAR, public domain). The 'extractive only' note also signals that output is verbatim metadata rather than analysis.

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 resource and its returned fields, followed by operational facts (cost, rate limit). A meaningful share of the tail is boilerplate disclaimer text ('not investment advice', 'Verify at source; as-is, no warranty') that does not help an agent invoke the tool correctly.

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 well-documented parameters and no output schema, the field enumeration plus source, cost, and rate-limit notes give an agent nearly everything needed to call it. Missing only a note on what an empty result means (no filings vs. invalid ticker).

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 description coverage is 100%, with 'days' explicitly documented as default 90 / max 365 and 'ticker' given examples. The description only echoes the day-window semantics ('in the last N days') and adds no syntax, edge-case, or format detail beyond 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?

States a specific verb+resource ('Form 8-K filings for a ticker') and enumerates the returned fields (form, accession number, report date, Item numbers/titles, EDGAR URL). Siblings (get_insider_trades, get_ownership_stakes) cover different filing types, so the resource itself differentiates, but the description never names or contrasts them explicitly.

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?

'Extractive only' and 'in the last N days' imply intended use (retrieving raw filing metadata for a recent window) and warn against expecting summaries. There is no explicit when-to-use/when-not guidance or pointer to any alternative tool for other filing types or time ranges.

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