ncloud_cm2_extend_subscription

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

With no annotations, the description carries the full burden and does well: it discloses the HTTP 403 failure mode with Sub Account keys and the public-zone restriction. It does not state whether the extension is reversible, billable, or what happens on failure, so it is strong but not exhaustive.

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?

Core purpose is front-loaded in the first sentence, followed by scope and auth caveats. The provenance tail ('confirmed by Ncloud support; verified 2026-10-02 with NCP_ADMINISTRATOR') is somewhat verbose, but the overall structure is efficient and readable.

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 2-parameter, no-annotation, no-output-schema mutation tool, the description supplies the critical missing context: credential requirements and zone restriction. Only the mutation's effects (reversibility, billing, post-extension state) are unaddressed, which is a minor residual gap.

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?

Schema coverage is 100%, so the enum values and orderId are already fully documented. The description's '1, 2 or 3 years' merely restates the subscriptionPeriod enum without adding format or constraint detail beyond the schema, so baseline 3 applies.

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 precise verb and resource — extend the subscription period of an Advanced certificate order — and scopes it to Certificate Manager 2.0. This clearly separates it from CM2 siblings like ncloud_cm2_reissue_certificate or ncloud_cm2_set_renewal_status, which do different things to a certificate.

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 concrete applicability conditions: 'Public zone only' and the main-account key requirement, which function as when-to-use/when-not signals. It does not, however, name or contrast against a sibling (e.g. renewal-status vs. extension), so routing among CM2 certificate tools is still partly left to inference.

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