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

Annotations already mark read-only, idempotent, non-destructive. Description adds value: ownership requirement, 'confirmed billing does not prove activation' caveat, and explicit statement that it never mutates checkout/provisioning state. No contradictions with annotations.

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 tight sentences, front-loaded with the core read operation, then prerequisites, caveat, and side-effect disclaimer. No filler or repetition of schema/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?

Covers ownership requirement, parameter provenance, semantic caveat about what billing does not prove, and explicit non-creation/non-retry behavior. Output schema exists, so return values need no elaboration.

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 has 0% description coverage)Skip, so description must carry the semantic weight. It explains that both parameters are required, business_id is the owned business, and session_id comes from checkout. Could specify formats/sources further, but enough for an agent to invoke correctly.

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?

Clear verb ('Read') + specific object ('Stripe-verified subscription checkout receipt') + ownership scoping ('for a business you own'), and immediately distinguishes itself from get_activation_status. No ambiguity about what this tool does.

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?

Explicitly names prerequisites ('business_id and session_id from checkout'), states what the result does NOT prove, points to the correct alternative tool (get_activation_status), and clarifies out-of-scope behavior ('never creates checkout or retries provisioning').

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