NEXO Brain

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

No annotations are provided, so the description carries the full burden. It states the tool retrieves credential values, implying a read-only operation, but doesn't disclose critical behavioral traits like whether it requires specific permissions, if it handles sensitive data, rate limits, or error conditions. The description adds minimal context beyond the basic action, leaving significant gaps for a credential-related tool.

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 appropriately sized and front-loaded: the first sentence states the purpose, followed by a structured 'Args' section explaining parameters. Every sentence earns its place by providing essential information without redundancy. However, the formatting with 'Args:' could be slightly more integrated into the flow.

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 the tool's moderate complexity (2 parameters, no annotations, but with an output schema), the description is reasonably complete. It covers purpose and parameter usage adequately. Since an output schema exists, the description doesn't need to explain return values. However, for a credential tool, more behavioral context (e.g., security implications) would enhance completeness.

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?

With 0% schema description coverage, the description must compensate, which it does effectively. It explains that 'service' is the service name with examples (e.g., google-ads, meta-ads, shopify) and that 'key' is optional, returning all credentials if empty or a specific one if provided. This adds meaningful semantics beyond the bare schema, though it doesn't detail data formats or constraints.

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 verb ('Get') and resource ('credential value(s) for a service'), making the purpose evident. It distinguishes from siblings like nexo_credential_create, nexo_credential_delete, nexo_credential_list, and nexo_credential_update by specifying retrieval rather than creation, deletion, listing, or modification. However, it doesn't explicitly differentiate from nexo_credential_list, which might also retrieve credential information.

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 implies usage through the optional 'key' parameter explanation: use without key to get all credentials for a service, or with key for a specific one. However, it lacks explicit guidance on when to choose this tool over alternatives like nexo_credential_list, which might list credentials without values, or prerequisites such as authentication needs. The context is clear but incomplete for optimal agent decision-making.

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