Patch Subscription

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

With no annotations, the description carries the behavioral disclosure burden. It does disclose that the operation is a partial update and that it is unavailable in read-only mode, which is useful context. However, it does not mention side effects, required permissions, error behavior, or whether changes are reversible.

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?

Two sentences with zero filler. The core operation is front-loaded, and the read-only restriction is stated separately. Every word contributes meaningful information.

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 mutation tool with no annotations and many closely related siblings, this description is too thin. It does not explain what fields can be updated, how update_mask interacts with the subscription body, which package/product prerequisites apply, or what distinguishes updating a subscription product from updating an offer. The schema covers parameters, but the operational context 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?

Schema description coverage is 100%, so the input schema already documents all parameters including regions_version and update_mask. The description adds no extra parameter semantics, but none are needed beyond the schema for invocation.

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?

The description states a specific verb and resource: 'Partially update an existing subscription product.' It clearly distinguishes this tool from siblings like patch_subscription_offer by specifying the subscription product resource, and from create_subscription/delete_subscription by phrasing the update as partial.

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?

No guidance is provided about when to use this tool versus alternatives. The 'Disabled in read-only mode' note is a mode restriction, not a decision rule. An agent must infer usage from the tool name and siblings, which is insufficient given the large family of subscription-related tools.

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