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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so safety is covered. The description adds value beyond that with the Stripe connection dependency and the important unit caveat that amounts are in the smallest currency unit, which prevents misreading of returned values.

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?

Three short sentences with zero filler: what it returns, what it requires, and how to read the numbers. The most important content leads, and nothing is repeated from the schema or annotations.

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?

With no output schema, the description carries the burden of describing return contents, and it does so by naming the key fields plus the currency-unit convention. The only soft spot is the vague "recent payments" window and no mention of behavior when Stripe is not connected.

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?

There is only one parameter and schema coverage is 100%; the schema already explains that user_id is the app id (preferred) or the VibeAdmin id from list_users. The description adds no further meaning about the identifier, so the baseline of 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?

The description names a specific resource (Stripe subscription state for one user) and enumerates the returned fields: plan, MRR, lifetime value, recent payments. It is clearly distinct from generic siblings like get_user or get_user_activity, though it never explicitly names an alternative tool to disambiguate against.

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?

"Needs Stripe connected" gives a concrete prerequisite that determines whether the tool is usable at all, which is real usage context. It stops short of stating when-not to use it or pointing to sibling tools for billing-adjacent questions, so it does not reach the top of the scale.

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