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

Annotations cover the read-only/idempotent profile, and the description adds substantial context on top: other forms are listed only, text access is restricted to periodic filings, unknown identifiers produce a repairable error with up to five resolve_company candidates, and ticker variants are normalized with resolvedTicker echoed.

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?

The purpose is front-loaded and nearly every sentence carries operational information. It is a dense single block, though, and the valuation-conclusion instruction sits slightly apart from what the tool itself does.

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 and does so: it spells out the periodic response structure (headline, tl;dr, highlights, changes, watch items, per-section bullets and (part, sectionId) address) and states the exclusion of raw text explicitly.

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 real meaning beyond the schema — that accession must come from list_company_filings and what omitting it does, plus concrete ticker-variant normalization behavior. It says nothing about resultPath/resultOffset beyond the schema's own overflow notes.

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 names the exact resource (8-K/6-K event summary, DEF 14A proxy extraction, 10-K/10-Q/20-F summary) and enumerates the returned fields, so an agent knows precisely what it gets. It also distinguishes itself from read_filing_section by stating full text lives there, not here.

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?

Explicit branching: supply an accession from list_company_filings for events/proxies, omit it for the latest periodic filing, and use read_filing_section for raw text. It names the prerequisite sibling and the alternative in the same breath, leaving nothing to inference.

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