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

Annotations already indicate non-read-only, non-destructive, non-open-world behavior. The description adds that a specific 'confirm' value is required, which provides some context. However, it does not fully disclose what state changes occur or the impact of a successful confirmation.

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?

The description is concise with two sentences, efficiently conveying the core purpose and a key requirement. However, it could be better structured to separate the confirmation requirement from the main action.

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?

Given the tool has 5 parameters (2 required), no output schema, and no parameter descriptions, the description is insufficient. It fails to explain the role of 'confirmType', 'signupToken', and other optional parameters, leaving the agent with incomplete guidance for invocation.

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 0%, so the description must compensate. It adds meaning for the 'confirm' parameter (must be set to CONFIRM_TIER_CHANGE), but this is misleading because 'confirm' is not required in the schema. Other parameters (signupToken, confirmType, metadata, paymentMethodId) are left unexplained.

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 clearly states the tool's purpose: 'Confirm a signed plan tier change.' This distinguishes it from siblings like 'change_plan_tier' (which likely initiates the change) and 'confirm_plan_payment' (a different confirmation). The verb 'confirm' and resource 'plan tier change' are specific.

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 implies usage after a plan tier change is signed, but it does not explicitly state when to use this tool or when to avoid it. No alternatives or exclusions are mentioned, though siblings provide context.

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