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

Annotations already declare readOnlyHint and non-destructive, so the trailing 'Read-only' adds nothing. The valuable disclosure is the per-platform coverage map (Instagram/Threads country/age/gender/city, LinkedIn page seniority/function/industry/size/location) and the explicit statement of what is not available, which the annotations cannot express.

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 sentences: questions first to aid matching, then exact coverage, then the negative case. Every sentence adds information and nothing is repeated from structured fields.

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 does enough by enumerating the dimension names returned per platform, so an agent can anticipate the response shape. It leaves out things like empty-result behavior for platforms with partial reporting or whether LinkedIn page vs. member distinction requires a separate account selection, minor gaps only.

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 the description says nothing about period, start_date/end_date, or the platform enum. The schema carries the full parameter burden, 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 opens with the user questions it answers and names the exact resource (follower demographics) and dimensions returned per platform. It is clearly distinguishable from siblings like get_follower_history (counts) or get_analytics_summary (performance) without needing their schemas.

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?

It gives an explicit when-not condition: other platforms and LinkedIn member profiles don't expose this data, which prevents wasted calls. It does not name the alternative tool to use for follower counts or audience growth, so the routing advice is one-directional rather than complete.

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