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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is known. The description adds that the tool returns a similarity result and notes a cost of 5 points per call. It discloses that the tool accesses and analyzes the two pages, which is consistent with the openWorldHint. No contradictions.

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 two short sentences plus a cost note. The core action is stated first in English, with Korean repetition adding detail. There is no wasted text, and the length is appropriate for the tool's simplicity.

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 description covers purpose, use case, and cost. However, there is no output schema, and the description only vaguely states 'returns similarity results' without specifying the output format (e.g., score, boolean, category). This is a minor gap for an otherwise simple tool, given annotations cover safety.

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?

Both parameters (url1, url2) are fully described in the schema with the same meaning as the tool's purpose. The description does not add parameter-level details or constraints. With 100% schema coverage, a baseline score 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 states 'Compare two web pages and judge how similar they are' in English, with Korean elaboration. It names the specific verb (compare), resource (two web pages), and outcome (similarity). The mention of phishing/duplicate detection further clarifies its use case and distinguishes it from sibling tools like url_screenshot or google_search.

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 a concrete use case: '피싱·복제 사이트 판별 등에 활용할 수 있습니다' (can be used for phishing/duplicate site detection). It does not explicitly name alternatives or state when not to use it, but the tool's unique function among siblings makes the context clear. This earns a 4 rather than 5 because exclusions/alternatives are absent.

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