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

Annotations already supply destructiveHint=true, and the description is consistent with that mutation semantics. It adds the useful context that expiry lapses without renewal, but does not disclose what the renewal overwrites, whether the original expiry is replaced or extended cumulatively, or any auth/rate-limit constraints. Adequate but not rich beyond the annotation.

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, zero filler: purpose first, rationale second, endpoint reference last. Every sentence earns its place and nothing is buried.

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 one-parameter mutation with an annotation covering the safety profile and no output schema, the description gives enough to invoke correctly. It could say a bit more about what a successful renewal returns or the new expiry window, but the essentials are present.

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?

Single parameter with 100% schema description coverage, so the schema already documents subscription_id fully. The description adds only the framing that the ID refers to the subscription being extended, which is marginal over the schema. Baseline 3 when structured fields carry the parameter burden.

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 (renew/extend) and resource (webhook subscription's expiry), and even names the exact API endpoint PUT /v2/webhook/subscription/renew/{id}. An agent can distinguish this from create/delete/get/list subscription siblings without opening any schema.

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 a clear condition for use: subscriptions lapse if not renewed, so this keeps a live integration alive. That tells the agent when this tool matters, but it never explicitly contrasts with the create/delete subscription siblings or states what happens if renewal is skipped entirely (e.g., subscription dies).

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