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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), so the description adds real value beyond them by disclosing the five-minute activity window and the API plan requirement, neither of which is in structured fields. It stops short of describing the response shape or any rate limits.

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 the core operation and scope, then filters, then the plan gate. No wasted text.

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 single-filter read tool with full annotations, the description covers scope, filter behavior, and an access prerequisite. The return value (a visitor count) is implied but not stated, which is a minor gap given there is no output schema.

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?

The schema describes each nested filter property as an 'exact-match filter,' and the description reinforces this by saying it supports the same exact-match filters as get_analytics. That cross-reference is helpful context but doesn't enumerate or add syntax detail, so it sits at the baseline for schema-documented params.

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 with a precise scope: 'Read the number of visitors active on the connected blog within the last five minutes.' This clearly separates it from historical analytics siblings, though it names get_analytics only to borrow its filter semantics rather than to draw a purpose distinction.

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?

Use is implied by the real-time five-minute window, and the 'Requires an eligible API plan' prerequisite is useful. However, it never states when to choose this over get_analytics or which plan tiers qualify, leaving selection logic to inference.

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