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 covered. The description adds two useful pieces beyond that: it is limited to *public* profile data, and it discloses a per-call cost of 20 points, which is real operational context. However it omits auth requirements, error behavior for invalid/nonexistent handles, and rate-limit details.

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?

Front-loads the resource and returned fields, with the cost tag placed at the end where it is easy to scan. The content is duplicated verbatim in English and Korean, which is redundant for a monolingual reader but clearly intentional for the bilingual audience, so it is not penalized heavily.

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?

With no output schema, the description carries the burden of describing return values and does so by enumerating the fields returned. Combined with the cost disclosure and annotation-covered safety profile, an agent has enough to invoke it correctly, though error/failure cases are 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 coverage is 100%, so both url and username are already documented in the schema, including the 'username or url required' constraint. The description adds no syntax or format guidance beyond the schema, so the baseline 3 applies.

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?

Names a specific verb (조회/retrieve) and resource (X public profile) and enumerates the exact data returned: followers, following, post count, bio, verification, and recent posts with engagement. The platform-qualified resource ('X (Twitter) public profile') lets an agent distinguish it from instagram_profile/tiktok_profile, though it never explicitly contrasts with the sibling x_post (single post) tool.

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?

Usage is only implied by the resource name; there is no explicit when-to-use statement, no condition for choosing between url and username inputs, and no exclusions (e.g., private vs public accounts). An agent can infer the purpose but gets no routing guidance against profile-fetching siblings.

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