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

With no annotations, the description carries the burden of behavioral disclosure. It states that the tool is a status check ('Check the status') and describes the return values ('pending or complete', 'api_key on completion after signup'). However, it omits potential error behavior, authentication requirements, or whether it can be called repeatedly. This is adequate, not rich.

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 two sentences, front-loaded with the core action, and every sentence contributes value. It is highly concise without padding.

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 simple one-parameter polling tool, the description is quite complete. It tells what it returns (pending/complete and api_key on completion after signup) and when to call it. However, it does not cover error cases (e.g., invalid session_id) or whether there are side effects, which prevents a perfect score.

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 schema description for session_id already states it is 'The session_id returned by create_account_card or top_up_card', and the tool description repeats this. With 100% schema coverage, baseline is 3; the description adds no additional meaning beyond 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 clearly states the specific purpose: 'Check the status of a Stripe card payment. Returns pending or complete.' It also adds a distinguishing detail by mentioning the return of api_key on completion after signup. This distinguishes it from sibling tools like check_action or quick_check, which likely serve different purposes.

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?

Provides explicit usage context: 'Call this after create_account_card or top_up_card once the user has paid.' This tells when to use the tool, with clear prerequisites. It does not explicitly mention alternatives or when not to use it, so it falls short of a 5, but the context is strong.

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