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

Annotations already cover the safety profile (readOnlyHint=true, idempotentHint=true, destructiveHint=false), so the bar is lower. The description adds genuine context the annotations do not: it enumerates what the comparison surfaces (category, operational status, popularity, intro), which is valuable given there is no output schema. It stops short of describing invalid-slug behavior, so a 4 rather than 5.

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?

A single front-loaded sentence naming the source ('saaskr 한국 SaaS 디렉토리') before the action and the compared dimensions. No wasted text, though quite terse for the amount it must carry.

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 read-only, two-parameter comparison tool with no output schema, the description compensates by listing the comparison dimensions the agent will receive. Nothing essential to invoking it correctly is missing, though error/edge behavior on unknown slugs is unaddressed.

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% for both slug parameters, so the schema already documents them fully. The description adds no format, source, or lookup guidance beyond naming the two items being compared. Baseline 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?

States a specific verb ('비교한다'/compares) and resource (two Korean SaaS) plus the dimensions compared, which separates it from single-item siblings like get_korean_saas. Sibling differentiation is implicit through the 'two, side by side' scope rather than an explicit contrast, so it falls just short of a 5.

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 two-SaaS comparison framing implies when to reach for this over get_korean_saas or search_korean_saas, but no explicit when-to-use, prerequisites, or exclusions are stated. Usage is inferable but not spelled out.

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