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

Annotations already mark it read-only, idempotent, and non-destructive, and the description adds substantive behavioral rules: 'Never invent events' and 'Do not speak UUIDs aloud — counts + kinds only unless they ask for detail.' These go beyond the annotations and matter for agent output behavior.

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 three compact sentences with front-loaded action and scope, followed by usage context and two high-value cautions. No wasted words or repeated schema details.

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 read-only list tool with no required parameters and full schema coverage, the description provides all essential context: scope, event types, purpose, and behavioral constraints. No output schema exists, but return details are not necessary for this simple listing tool.

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 carries the parameter documentation. The description's parenthetical event names align with the kind filter examples but do not add meaning beyond what the schema already states; baseline 3 is appropriate.

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?

Description opens with a specific verb and resource: 'List THIS operator's recent CoS telemetry,' and enumerates the exact event categories (open/speech/close, host_push, card_decide/confused/buggy). The 'THIS operator's' scope and the downstream reference to propose_cos_content_atoms set it apart from other list_/get_ 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?

Gives two concrete use cases: 'verify dogfood soak' and 'before propose_cos_content_atoms.' The safety cautions ('Never invent events') reinforce when it is appropriate to trust the data, though it does not explicitly state when not to use it or name an alternative tool.

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