NEXO Brain

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

With no annotations provided, the description carries full burden but only states it 'stores' a credential without clarifying behavioral aspects. It doesn't mention whether this requires authentication, what happens if a credential already exists for the same service/key, whether values are encrypted, or any rate limits. This is inadequate for a tool that handles sensitive 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 well-structured with a clear purpose statement followed by a formatted parameter section. Every sentence earns its place, though the formatting with 'Args:' could be slightly more integrated with the main description text.

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 storage tool with no annotations and 4 parameters, the description covers parameter semantics well but lacks critical behavioral context about security, idempotency, and error conditions. The existence of an output schema helps, but the description doesn't reference it or explain what success/failure looks like.

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 provides clear semantic explanations for all 4 parameters with examples (e.g., 'service: Service name (e.g., google-ads, cloudflare)'), which is excellent given the 0% schema description coverage. It clarifies that 'notes' is optional and what each parameter represents, adding significant value beyond the bare schema.

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 ('Store a new credential') and identifies the resource ('credential'), making the purpose immediately understandable. However, it doesn't explicitly differentiate from sibling tools like 'nexo_credential_update' or 'nexo_credential_get', which would be needed for a perfect score.

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?

No guidance is provided about when to use this tool versus alternatives like 'nexo_credential_update' for modifying existing credentials or 'nexo_credential_list' for viewing stored credentials. The description assumes the user already knows this is for creating new credentials only.

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