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 genuinely useful behavioral context beyond that: 40-60 second processing time and a 20-point cost per call, which an agent needs to budget correctly.

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 front-loaded with the return payload first, then latency and cost. It is efficient, though the Korean sentence largely restates the English one rather than adding information, which inflates length slightly.

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 well by listing the fields. Combined with timing and cost, an agent has enough to call it correctly, though error/private-account behavior 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% and both url and username are documented in the schema, including the 'username or url required' constraint. The description adds nothing to parameter meaning, 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?

The description names a specific resource (Instagram public profile) and enumerates exact fields returned: followers, following, posts count, bio, verification, and 12 latest posts. It is clearly distinct from instagram_post by resource type, though it never explicitly names the sibling to differentiate.

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 qualifier 'public profile' implies the tool only works on public accounts, which is a useful usage constraint, and the cost/latency note helps a caller judge invocation. However, there is no explicit when-to-use vs instagram_post or tiktok_profile, nor a statement of when-not to use it.

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