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

Annotations already declare readOnlyHint=true and idempotentHint=false, so the agent knows this is a safe, non-idempotent read. The description adds return-content context ('with dates and block heights') but does not disclose behavioral traits such as pagination, ordering, rate limits, or authentication needs. With annotations covering the safety profile, this is adequate but minimal.

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, front-loaded sentence with no wasted words. It immediately states the action and the returned data. Nothing is superfluous.

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 low-complexity, zero-parameter, read-only endpoint with no output schema, the description gives enough to understand the return content: churn event history with dates and block heights. It does not cover ordering, pagination, or the exact shape of a churn event, but those omissions are minor given the tool's simplicity.

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, so there are no parameter semantics to document. Per the rubric, a zero-parameter schema earns a baseline of 4. The description does not need to compensate for missing parameter details.

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 states a specific verb ('Returns') and resource ('churn event history') and adds the key returned fields (dates and block heights). It is clear and not tautological. No sibling tool covers churn events, so explicit differentiation is unnecessary, but the description could still be more precise about what a churn event represents.

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 alternatives, no prerequisites, and no exclusions. The description only says what it returns, leaving the agent to infer that it is the appropriate call whenever churn history is needed. For a simple getter this is somewhat obvious, but the definition provides no explicit usage context.

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