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

The description adds significant value beyond annotations: it reveals that PANs are never returned because they are not persisted, and specifies returned fields (last4, funded amount, status, expiry). This complements the readOnlyHint and idempotentHint 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 sentences with no wasted words: purpose stated first, then critical caveat about PANs, then use case. The structure is front-loaded and efficient.

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?

Given no parameters and an output schema that presumably documents return fields, the description covers all necessary context: what the tool does, its behavioral constraints, and a concrete use case. It is complete for a simple list view.

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?

No parameters exist, so schema coverage is 100%. The description does not need to add parameter information, but it provides meaningful context about the return fields, which is incidental to parameter semantics. A baseline of 4 is appropriate.

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 it is an audit view of test cards minted by the account, using specific verb 'list' and resource 'test cards'. It distinguishes from sibling tools like provision_test_card (create) and freeze_test_card (modify) by focusing on read-only listing.

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 states the tool is 'useful for reconciling Stripe Issuing balance against TMV spend', providing clear when-to-use guidance. While it does not explicitly mention alternatives, the context of sibling tools makes its usage context clear.

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