Analyze two-person compatibility

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so this is clearly a safe, non-mutating analysis. The description adds a minor behavioral constraint ('Requires both people's birth data') but no additional side-effect or runtime behavior disclosure is necessary.

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 one tightly scoped sentence that front-loads the trigger phrases, with no filler or repeated schema information. Every word contributes to routing the agent correctly.

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 tool has a complex nested schema with 8 parameters, and the description only covers identification and a high-level data requirement. It does not clarify how the agent should phrase or compose the question, whether missing birth info should trigger follow-up questions, or why some optional parameters matter. The output schema helps fill the return-value gap, but the overall guidance remains thin for a tool of this complexity.

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 only 50%, and the description does little to compensate. It names the requirement for both birth datasets but adds no explanation of the question, lifeEvents, targetDate, detailLevel, or outputMode parameters. The schema does some of the work, but the description should surface more about the two required nested birth objects.

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 names precise trigger scenarios (궁합, 결혼 가능성, relationship compatibility) and the comparison of two birth charts, which clearly distinguishes this from single-person tools like legend_saju_read_fortune or legend_saju_analyze_name. The verb and resource are specific and recoverable from context.

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 explicitly says when to use the tool and even provides example Korean intent. The requirement that both birth datasets are needed is a useful precondition. However, it does not mention when not to use it or explicitly name alternative tools for relationship-related queries.

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