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

Adds substantial behavior beyond the readOnlyHint and openWorldHint annotations: plan gating (refused on Free with an upgrade path), a permission prerequisite, a polling rate limit with its own separate budget, and the caveat that bots are only classified at visit end so an unrecognised robot may appear as a person. This is exactly the operational context annotations cannot carry.

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-loaded with the core purpose, followed by a compact sequence of operational facts, each of which earns its place. The narrative phrasing ('your human's site', 'its current reading of them') is slightly wordy but there is no filler sentence.

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 an output schema present, the description need not explain return shape, and it still names the returned fields. Combined with plan, permission, rate-limit and bot-classification caveats, an agent has everything needed to call it correctly.

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%, so the schema already documents both siteId and population (including the enum). The description adds no syntax or format detail for these parameters, 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?

States a specific verb/resource ('Who is on your human's site right now') and enumerates exactly what is returned: each visitor's pages so far, what the agent showed them, and its current reading. It is plainly distinguishable from the history-oriented siblings like cromanion_visits without opening any schema.

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?

Gives clear operational context: it is a real-time/current view implicitly contrasted with 'the history tools', requires the visits permission, is gated to paid plans, and should be polled at most once a minute. It stops short of naming a specific alternative sibling tool to route to, but the when-to-use conditions and constraints are explicit.

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