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 of behavioral disclosure. It states the tool lists credentials with limited data ('names and notes only, no values'), which implies it's a read-only operation, but doesn't explicitly confirm safety (e.g., non-destructive), discuss permissions, rate limits, or output format. The description adds some context but leaves key behavioral traits unspecified for a tool that likely accesses sensitive credential data.

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 core purpose, and the second explains the parameter concisely. There's zero waste—every sentence earns its place by adding essential information without redundancy or fluff.

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 low complexity (1 optional parameter), no annotations, and the presence of an output schema (which handles return values), the description is reasonably complete. It covers the purpose, parameter semantics, and data scope. However, for a credential-related tool, it could benefit from more behavioral context (e.g., security implications), but the output schema reduces the need for return value explanation.

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 1 parameter with 0% description coverage, so the description must compensate. It adds meaningful semantics: 'service: Filter by service (optional). If empty, shows all.' This clarifies the parameter's purpose, optionality, and default behavior, effectively documenting what the schema lacks. Since there's only one parameter, the description fully covers it, earning a high score.

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 tool's purpose: 'List credentials (names and notes only, no values).' It specifies the verb ('List'), resource ('credentials'), and scope ('names and notes only, no values'), which is specific and actionable. However, it doesn't explicitly differentiate from sibling tools like 'nexo_credential_get' or 'nexo_credential_create', which would require mentioning it's a read-only listing operation versus retrieval or mutation.

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 implied usage guidance through the optional 'service' parameter filter, suggesting it can be used to list all credentials or filter by service. However, it lacks explicit when-to-use guidance, such as when to choose this over 'nexo_credential_get' (which likely retrieves full credential details) or other credential-related siblings. No exclusions or alternatives are mentioned.

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