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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds meaningful behavioral context by specifying that the data is 'public aggregate' and not 'private Observatory data,' which goes beyond the annotations. It does not describe the exact structure of the return value, but given the annotations, this additional scoping is valuable and not redundant.

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 a single, focused sentence that leads with the primary action and resource, and immediately clarifies scope with the 'no private data' clause. Every word earns its place; there is no filler or repetition. It is optimally concise and front-loaded.

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?

The tool has no output schema, so the description should convey what the agent can expect in return. It mentions 'traffic and activity counters' but does not enumerate specific counters, their format, or any aggregation details. While the simplicity of the tool suggests the description is mostly adequate, the lack of any structural or example info leaves some uncertainty. Given that annotations already cover safety and there are no parameters, the description could be slightly richer on the return anatomy.

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?

With 0 parameters, the schema itself provides 100% coverage (vacuously). The baseline for 0 params is 4, and the description does not need to add parameter information since none exist. The description does not impair parameter understanding, so the baseline score holds.

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 clearly states a specific action ('Return') and resource ('public aggregate AgentWorld traffic and activity counters'). It also differentiates from private data by explicitly saying 'No private Observatory data is exposed,' which helps distinguish it from any tool that might access private data. This makes the purpose unambiguous and distinct from siblings.

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 description provides clear context about what the tool does (public stats) and what it does not do (expose private data), but it does not explicitly mention alternative tools or when to use them. The exclusion of private data implies a scenario where public data is needed, but there is no direct comparison to siblings like list_activities or discover_agentworld. This is clear enough for an agent to infer usage, but lacks explicit guidance.

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