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

With no annotations, the description carries the full burden and does disclose the key behavioral trait: it returns a country list or a filtered treaty list with effective dates. It wisely uses '반환한다' (returns), implying a read-only operation, though it does not discuss edge cases, ordering, or data freshness.

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 compact sentence that front-loads the main purpose and then cleanly explains the conditional behavior. Every phrase conveys useful information with no redundancy or filler.

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?

For a tool with one optional parameter and no output schema, the description is nearly complete: it covers both invocation modes and names the returned treaty list and effective dates. It could go slightly further by specifying output shape or sort order, but the high-level return behavior is sufficient for reliable tool selection.

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?

The input schema already documents the optional country parameter, its expected Korean-name format, and the behavior when omitted, with 100% schema description coverage. The description restates the parameter's effect but does not add meaningful new semantics beyond the schema, so the baseline of 3 is appropriate.

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 identifies a specific resource (tax treaties concluded by Korea) and describes the two distinct output behaviors based on the country parameter. However, it does not explicitly differentiate this tool from sibling tools like search_treaties, so it misses the top tier.

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 clear usage context by specifying what happens when country is omitted versus supplied. It does not mention alternatives or exclusion conditions, but for this simple list tool the two calling modes are effectively practical guidance.

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