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

Annotations already indicate this is not read-only and not destructive, and the description adds valuable nuance: it stops new signups but does not interrupt live subscriptions. This clarifies the actual behavioral effect beyond the annotation flags.

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?

One sentence, front-loaded with the key action, and the parenthetical adds critical behavioral detail without waste. Every word earns its place.

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 single-required-parameter tool with clear annotations and a fully documented schema, the description provides enough context to select and invoke the tool correctly. No output schema is present, but the operation's outcome is sufficiently described.

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 schema already fully documents plan_id as 'The plan to archive' with 100% coverage, so the description adds no new parameter-level detail. Baseline of 3 is appropriate.

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 ('Stop') and a specific resource ('new signups for a plan'), immediately distinguishing it from cancellation or deletion. The parenthetical clarifies that existing live subscriptions are unaffected, which is a meaningful scope distinction from siblings like cancelSubscription.

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 description clearly implies when to use it: when you want to halt new signups while preserving ongoing renewals. It does not explicitly name sibling tools or exclusions, but the contrast with cancelSubscription is strongly implied.

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