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

Annotations already cover the safety profile (readOnlyHint=true, openWorldHint=true), so the bar is lower, yet the description adds genuinely non-structured context: the call is free and does not consume rate limit. That is a real behavioral fact an agent would otherwise have to guess, though it does not describe latency, caching, or failure 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?

Two sentences, zero waste, purpose front-loaded and the cost/rate-limit caveat placed last as a secondary qualifier. Every clause carries information.

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?

An output schema exists, so the description is not obligated to explain return values, and the read-only annotations cover safety. For a zero-parameter diagnostic tool this is essentially complete; only the absence of any usage routing keeps it from a 5.

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 takes zero parameters, which is the baseline-4 case; there is nothing for the description to disambiguate and it correctly does not invent parameter guidance.

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 (Report) and resource (service and beacon health) and enumerates the concrete data points returned: drand quicknet round, relay, rate-limiter mode, noise status. It is clearly distinguishable in kind from the sibling tools random_int/random_int_signed, though it never names them or explicitly contrasts itself.

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?

Usage is implied rather than stated: an agent can infer this is a pre-flight/diagnostic check, but the description gives no explicit when-to-use trigger, no when-not-to-use, and does not point to the siblings as alternatives for actually obtaining randomness.

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