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

Annotations already declare readOnlyHint=true and idempotentHint=true, but the description adds valuable behavioral context: it returns `total_filings` and `returned` so a filtered view cannot be mistaken for the whole day, it does not rank results, and it provides measured payload sizes (112 KB unfiltered, 73 KB with listed_only, ~10 KB with doc_type_code). These details go beyond generic annotations and inform the agent about response characteristics and data volume.

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 front-loaded with the core purpose and then elaborates with relevant details. It is longer than minimal, but every sentence earns its place: upstream comparison, field list, filtering behavior, size measurements, and return fields. The structure is logical, moving from general purpose to specifics. A slightly tighter wording could improve it, but it remains efficient.

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?

The description is thorough for an agent to invoke correctly. It explains the filtering semantics, the return fields (`filings`, `total_filings`, `returned`), the relationship to the upstream tool, and the date format. Since an output schema exists, it need not detail return structure. Nothing critical is missing; the description covers all necessary operational details.

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% (no descriptions in the schema), so the description must fully explain parameters. It does: `date` is YYYY-MM-DD, `listed_only=true` keeps filings with a secCode (~two thirds of a day), and `doc_type_code` matches exactly with concrete examples (120, 140, 160, 350). This gives the agent complete semantic understanding of all three parameters, far exceeding what the schema provides.

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 and resource: 'One day of Japanese EDINET filings as a scannable list, with the filtering upstream lacks.' It clearly identifies the tool's function and differentiates it from the sibling `get_edinet_documents` by highlighting the filtering capability. The mention of six fields and the explicit contrast with the upstream tool leaves no ambiguity about what this tool does.

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 names the sibling `get_edinet_documents` and contrasts it: the upstream has no filter parameters and returns raw fourteen-field records, while this tool provides filtered six-field records. It also states 'It does NOT rank or select beyond your filters,' clarifying scope. However, it does not explicitly say 'use this when you need filtered results, use the upstream when you need full records,' leaving the decision slightly implicit.

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