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

Beyond readOnlyHint and openWorldHint, the description adds two pieces of real operational context: results are compact and each item carries a url citation, and the call requires a prepaid API key. It omits failure behavior (unknown handle, missing profile) and does not mention rate limits, keeping it short of a 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?

Three short sentences, front-loaded with what is returned, then output shape, then prerequisites. Minor waste in re-listing the ten platforms that the enum already provides verbatim.

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 two-parameter read tool with no output schema, the description covers the resource contents, output shape (cited items with urls), supported platforms, and the auth requirement. Only error/edge-case behavior is absent, which is a small gap relative to the tool's simplicity.

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% and the username parameter already documents the optional leading @, so the schema does the heavy lifting. The description only restates the platform set that the enum already enumerates, adding no new semantics for either parameter.

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 the resource and its contents precisely ("A public account: name, bio and counts"), so an agent knows exactly what it retrieves. It does not, however, distinguish itself from siblings such as get_account or get_user_posts, which look dangerously similar in name and are left for the agent to infer.

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: an agent can infer this fetches a profile given platform plus username. There is no explicit when-to-use versus get_account or get_user_posts, and no statement of when-not to call it (e.g. for private accounts or per-post data).

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