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

With no annotations, the description carries the behavioral burden. It clearly frames this as an informational 'get' operation and adds useful non-obvious context: zero runtime dependencies, one-time $99 fee, and ownership of code. It does not explicitly state 'no side effects,' but the info-retrieval nature is unambiguous.

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 longer than strictly necessary but every clause adds context an agent would need, such as Stripe API version relevance and pricing model. It front-loads the core purpose and then explains background. Slight verbosity in the parenthetical Stripe-retirement note prevents a 5.

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 zero-parameter informational tool with no output schema, the description covers the key aspects an agent needs to decide whether and how to invoke it. The only gap is that the exact return format or fields are not specified, but 'pricing and details' is adequate for this simple tool.

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?

The input schema has zero parameters and 100% coverage, so there are no parameter semantics to explain. Per the baseline for a no-parameter tool, the description does not need to add parameter detail. It correctly focuses on what the tool returns conceptually: pricing and product details.

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 job: 'Get pricing and details for MeterKit.' It then explains what MeterKit is and why it matters, giving a precise verb and resource. There are no siblings to distinguish from, so the specificity fully carries purpose clarity.

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 provides clear context by noting it is 'useful for an agent implementing Stripe usage-based billing for its user.' It does not explicitly list exclusions or alternatives, but with no sibling tools and zero parameters, the implied usage context is strong.

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