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

Goes well beyond the annotations: enumerates what is unaffected (listings, claims, declarations, ranking, the free coarse demand table), states the deferred effective date, names the required auth scheme (Bearer hodds_...), and predicts the exact failure mode (token_required). That is exactly the extra context annotations cannot carry.

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?

Three tight sentences, front-loaded with the effect and its timing, then scope-of-impact, then the auth prerequisite. The 'Contract 0.3.1' fragment is minor noise that doesn't help an agent decide or invoke.

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 return values needn't be explained. For a zero-param, destructive, idempotent cancellation the description covers effect, timing, side-effect boundaries, and auth failure — nothing an agent needs to call it safely is missing.

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?

Zero parameters, so the baseline is 4; the schema has nothing to document. The description adds the non-schema prerequisite that an organization token must be supplied in the Authorization header, which is genuinely useful invocation context.

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 and effect: 'Stops the subscription at the end of the paid period,' which tells an agent exactly what happens and when. The gap is sibling differentiation: `cancel_plan` exists and the description never says how this differs from it, nor does it use the word 'creator' anywhere in the body despite the title carrying it.

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 end-of-period timing implies when this is appropriate (deferred cancellation rather than immediate termination), which is useful context for selecting the tool. However, there is no explicit when-to-use/when-not guidance and no naming of `cancel_plan` as the alternative, leaving the sibling choice to inference.

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