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

Annotations already declare destructiveHint=true, idempotentHint=true, and readOnlyHint=false, so the safety profile is known. The description adds real value beyond that: what actually stops (future charges and shipments), the customer-facing side effect (Seal's cancellation email), and that the action is reversible. It does not address permissions, active-state prerequisites, or effect on pending billing attempts, so it falls short of a 5.

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?

Four short clauses, front-loaded with the WRITE marker and the core effect, then alternatives, then endpoint. Every sentence carries information an agent needs; no filler.

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 rich annotations and no output schema, the description covers effects, side effects, and alternatives well. Minor gap: no indication of what is returned or how the cancellation interacts with in-flight billing attempts, though neither is essential to invoke it correctly.

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 single parameter is fully documented in the schema (100% coverage), including the useful distinction between `id` and `internal_id`, so the schema does the heavy lifting. The description adds no parameter-level guidance, which is the expected baseline-3 outcome at full coverage.

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+resource ("Cancel a subscription") and immediately scopes it with "now", which distinguishes it from the sibling sealsubscriptions_schedule_cancellation. The "WRITE:" prefix and endpoint (PUT /subscription action=cancel) make the operation unambiguous.

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?

Explicitly routes to alternatives: "It can be brought back with sealsubscriptions_reactivate_subscription" and "For a later cancellation use sealsubscriptions_schedule_cancellation." Both the undo path and the timing-based alternative are named, leaving nothing to inference.

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