NEXO Brain

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It states the tool performs deletion, which implies a destructive mutation, but doesn't clarify whether this is reversible, what permissions are required, or what happens to associated data. The conditional behavior ('If no key, deletes all for the service') is useful context, but overall behavioral details are sparse for a destructive operation.

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 efficiently structured with a clear purpose statement followed by parameter explanations. Both sentences earn their place by providing essential information. It could be slightly more front-loaded by integrating the parameter behavior into the first sentence, but overall it's well-organized and avoids redundancy.

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 that this is a destructive mutation tool with no annotations, the description does an adequate job explaining the basic functionality and parameter semantics. However, it lacks important contextual details like authentication requirements, error conditions, or what the output schema contains. The presence of an output schema means the description doesn't need to explain return values, but other behavioral aspects remain under-specified.

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 description adds significant value beyond the input schema, which has 0% description coverage. It explains the purpose of both parameters: 'service' as the service name and 'key' as a specific credential key, and clarifies the critical conditional behavior where an empty 'key' results in deleting all credentials for that service. This compensates fully for the schema's lack of descriptions.

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 action ('Delete credential(s)') and resource ('credential(s)'), making the purpose immediately understandable. It distinguishes from sibling tools like nexo_credential_get and nexo_credential_list by specifying deletion rather than retrieval. However, it doesn't explicitly differentiate from nexo_credential_update or nexo_credential_create beyond the verb.

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 some usage context by explaining the conditional behavior based on the 'key' parameter ('If no key, deletes all for the service'). However, it doesn't offer guidance on when to use this tool versus alternatives like nexo_credential_update or nexo_credential_get, nor does it mention prerequisites or warn about destructive consequences beyond what's implied by 'Delete'.

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