get_credential

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

With no annotations provided, the description carries full burden. It discloses that returned fields are filtered by the agent's access policy and that raw secrets are only returned if policy allows 'read'. This is key behavioral information for a sensitive read operation, but it could mention error behavior (e.g., if service not found or insufficient permissions).

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?

Two concise, front-loaded sentences. Every sentence adds essential information: purpose and security behavior. No fluff or repetition.

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 credential retrieval tool, it covers purpose, parameter usage with policy, and security constraints. The absence of an output schema is mitigated by describing what is returned. Could mention response format or example for completeness, but overall adequate.

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 100% description coverage, but the description adds value by explaining how the 'fields' parameter interacts with access policy (only returns permitted fields). This extra context elevates the parameter understanding beyond the bare schema definitions.

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?

Clearly states 'Retrieve a credential from the Auth Box vault', specifying a verb and resource. It distinguishes from sibling 'list_available_services' by focusing on actual credential retrieval, and from 'proxy_authenticated_request' which is for making requests, not retrieving stored credentials.

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 clear context on when to use the tool—to retrieve a credential—and includes a critical security caveat about access policy and 'read' action. However, it does not explicitly state when not to use it or compare with alternatives, though the sibling distinction is implicit.

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