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

Annotations already establish read-only, idempotent, and non-destructive behavior, so the description's duty is lighter. It adds meaningful context by stating the requirement for a free EDINET Subscription-Key via _apiKey and noting the data scope (formats, filer, document type). It does not contradict annotations and gives an example call. The added key requirement and scope are useful behavioral details beyond the annotations, so 4 is warranted.

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 description is a single, information-dense sentence followed by a short requirement note and an example. It front-loads the core purpose and enumerates document types, then covers filtering, key requirement, and a call example. It earns each sentence, though slightly verbose; a trim could tighten it, but it is well-structured and readable.

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?

Given the tool's complexity (7 parameters, no output schema), the description covers the primary use case thoroughly: what it returns, how to filter, required key, and an example. It does not describe pagination (handled by limit param) or return format, but these are not necessary for correct invocation given the schema and annotations. The description is complete enough for an agent to call the tool appropriately.

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%, so the baseline is 3. The description mentions the date and limit in an example and summarizes the filter options, but it does not add substantive semantic meaning beyond what each parameter description already provides. It adds value mainly by framing the tool's typical invocation, not by enriching parameter understanding, so the baseline 3 stands.

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 clearly states a specific verb ('list filings'), a resource (EDINET), and a time scope ('on one day'), enumerating document types and data fields. It distinguishes itself from sibling tools like edinet_company_filings by emphasizing the daily, all-filings scope, making the tool's purpose immediately unambiguous.

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 provides concrete usage context: it is for listing all filings on a given day, with optional filters for filer or document type. It does not explicitly name alternatives or state when not to use it, but the 'every disclosure document' phrasing implies the broad retrieval use case, and the one-liner about filtering gives clear guidance on how to narrow results. No exclusions are mentioned, so a 4 is appropriate.

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