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

Annotations already declare readOnlyHint=true, openWorldHint=false and destructiveHint=false, so safety is covered. The description adds a genuinely useful behavior — a 200-result cap — but does not say what happens on overflow (silent truncation? ordering of which 200?), which materially affects how the agent should scope queries.

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?

Three short sentences, no redundancy: purpose first, then optional narrowing, then the result-count limit. Every sentence carries operational information.

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 6 parameters and no output schema, the definition should clarify the return shape (a list of dates with which conditions matched?) and default ordering; it does not. Also silent on the default match=any behavior, which changes result semantics considerably.

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 baseline is 3. The description does add one constraint absent from the schema — the start–end span must be ≤366 days — but leaves the match (any/all) parameter and the kinds vocabulary entirely to 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 (探す) and resource (吉日/六曜条件に合う日), with the 366-day scope and matching criteria spelled out. It doesn't name or contrast any sibling (e.g. find_dates, check_business_day), so an agent must infer differentiation from the criteria list alone.

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?

Usage is implied by the criteria description (rokuyo + lucky-day kinds, optional weekday narrowing, excluding 不成就日), but there is no explicit when-to-use vs. when-not guidance and no pointer to which sibling to use for a single-date lookup or a non-lucky search.

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