get_realtime_visitors

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

With no annotations, the description carries the full burden; 'Get' implies a read-only operation but that is never stated outright. It does add genuinely useful behavioral context by explaining the token fallback to the PLAUSIBLE_API_KEY environment variable, though it says nothing about rate limits, error behavior, or whether the count is a point-in-time snapshot.

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?

One front-loaded sentence states the purpose, followed by a tight Args block covering both parameters. No redundancy or filler, and each line adds information.

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?

An output schema exists, so return-value explanation is not needed, and the auth model is covered via the token fallback note. What's left out is minor operational context (snapshot semantics, failure modes), which is acceptable for a simple single-count read.

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 0%, so the description must compensate, and it does: site_id is documented with a concrete format example ('surendranb.com') and token is documented with its fallback behavior. Only minor gaps remain, such as whether site_id must match an exact registered domain.

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?

States a specific verb and resource ('Get the current count of active real-time visitors') with the scope qualifier 'right now', which cleanly separates it from historical siblings like get_aggregate_stats and get_timeseries. It doesn't name a sibling explicitly, so it stops just short of a 5.

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 phrase 'right now' implies the tool is for live/current monitoring rather than historical analysis, and the sibling names make the contrast inferable. However, the description never states when to prefer this over get_aggregate_stats or what happens for sites with no recent traffic, leaving usage to inference.

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