applicable_rule

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

The description reveals that it returns 'candidate' rules (implying possible multiple matches) and always notifies that revision date and effective date may differ. It also mentions the change summary behavior when compare_with_current is true, going beyond the basic read-only and idempotent annotations.

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 concise, front-loaded with the main purpose, followed by use cases and a note. It does not contain redundant information and is well-structured for quick understanding.

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 presence of an output schema (not shown here) and the thorough parameter explanations, the description is complete for an agent to use the tool. It covers all necessary aspects: what it does, when to use it, key caveats, and the primary alternative.

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?

All six parameters are described with meaningful context beyond the schema: date format, the relationship between law_id and rule_keyword, specific article examples, max_changes default and limit, and the boolean compare_with_current. The description also explains that date can be used without knowing HISTORY_ID, adding semantic clarity.

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 that the tool returns candidate rules revised before a base date, along with the text at that time and a summary of changes. It also explicitly distinguishes from lookup_dongguk_rule for latest rules, making its purpose distinct among siblings.

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?

It provides specific use cases (retroactive work, audit responses, checking past payment standards) and states when not to use it (for latest rules, use lookup_dongguk_rule). However, it does not mention other alternatives like compare_rule_versions or list_rule_history, but the primary scenarios are well covered.

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