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

Annotations already declare the mutation is non-destructive and idempotent, but the description adds important context beyond them: a paid Stripe subscription is updated, optional interval/currency select a specific price with a default fallback, and failures are atomic ('without changing anything'). This is rich behavioral disclosure for a billing mutation.

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 front-loaded with the core action and scope, then proceeds through side effects, usage, arguments, error behavior, and integration guidance. Every sentence carries useful information for correctly invoking or understanding the tool.

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 complex billing mutation with no output schema, the description covers arguments, side effects, atomic failure modes, and usage well. It stops short of describing what a successful call returns, which is a minor but real gap when no output schema exists.

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%, establishing a baseline of 3. The description still adds meaning by clarifying that plan is the plan KEY, that interval and currency select among the plan's prices, and that the first price is used by default; only the optional app parameter is left to the schema.

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: 'Move a tenant (workspace) to another plan.' It also clarifies the scope and equivalent dashboard action, making it easy to distinguish from siblings like update_tenant or delete_plan.

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?

It gives explicit when-to-use guidance: 'Use it to clear a plan before delete_plan, or to put a customer on a plan by hand.' It also names a prerequisite alternative tool, get_integration_guide, for app-code consumers, leaving little to inference.

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