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

Annotations already declare readOnly/idempotent/openWorld, so the bar is low, yet the description adds substantial behavior beyond them: relevance ranking, facets by form type and year, excerpt inclusion conditioned on limit<=10, pagination via page=, and a coverage_note in the response. Nothing important about the call's behavior is left implicit.

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 what it does, then return shape, then routing, then coverage, then args — a logical order with no filler. The Args block restates some of the body (e.g. limit/excerpts) and the support email adds a little bulk, but the redundancy is mild and aids scanning.

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?

Covers query semantics, filtering, result shape, excerpt behavior, pagination, and coverage boundaries, and an output schema exists so return values need no further explanation. Complete enough for an agent to call it correctly on the first try.

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 0%, so the description must compensate and does: it documents all six parameters with examples, including the critical cik-vs-company-name guidance with a worked example and the limit/excerpt interaction that the schema cannot express. This is exactly what a low-coverage schema needs.

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 ('Full-text search across all SEC filing content') and immediately differentiates from siblings: search_document for exhaustive occurrences in one document, get_filings for older filings. An agent can route correctly without opening another schema.

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 routing rules: use search_document for every occurrence in one document, get_filings + get_document for pre-2020 filings, and a concrete exclusion list of forms not covered. Also states the non-obvious failure mode (a search for an earlier year returns nothing).

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