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

No annotations exist, so the description carries the full burden of behavioral disclosure. 'Funnel counters' implies a read-only operation, but the description does not state whether results are current totals, period-specific, whether they are reset, or whether the operation is expensive or has side effects.

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?

The description is highly concise and free of filler. It communicates the tool's core purpose in a single short phrase, which is appropriate for a no-parameter stats counter, though it could be more structured with a complete 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?

Given the tool has no parameters and a simple counter purpose, the description is minimally viable. However, with no output schema and no annotations, it leaves ambiguity about the return format, time range, and whether these counters are cumulative or resettable. An agent could invoke it safely, but the interpretation of results would be uncertain.

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 tool has zero parameters and an empty input schema, so there is nothing to document. The baseline for a no-parameter tool is 4, and the description adds no conflicting or redundant parameter information.

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 a specific resource, 'Funnel counters', and enumerates the exact metrics: page views, snapshots run, paid registrations. It is not a tautology and is clear enough that an agent can tell this is a stats/read tool, although it does not explicitly differentiate itself from siblings like pw_health or pw_watch_status.

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?

There is no guidance on when to use this tool versus the sibling tools, no prerequisite context, and no mention of whether this is the right tool for current counts, historical counts, or health monitoring. The usage context is left entirely to inference.

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