NEXO Brain

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

No annotations are provided, so the description carries full burden. It states the tool 'creates or updates', indicating a mutation operation, but lacks details on permissions required, side effects, error conditions, or what the output contains. This is inadequate for a mutation tool with zero annotation coverage.

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 extremely concise—a single phrase with a clarifying parenthetical. Every word earns its place, and it's front-loaded with the core action. No wasted verbiage.

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 it's a mutation tool with 3 parameters (0% schema coverage), no annotations, but has an output schema, the description is minimally complete. The output schema may cover return values, but the description lacks behavioral context and parameter guidance needed for safe and effective use.

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?

Schema description coverage is 0%, so the description must compensate. It mentions 'preference' but doesn't explain what 'key', 'value', or 'category' parameters represent, their formats, or examples. The description adds no meaningful parameter semantics 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 'Set a preference (creates or updates)' clearly states the action (set) and resource (preference), with the parenthetical clarifying it can create or update. It distinguishes from siblings like 'nexo_preference_delete' and 'nexo_preference_get', but doesn't explicitly differentiate from them in the description text.

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 on when to use this tool versus alternatives like 'nexo_preference_get' or 'nexo_preference_delete'. The description implies it's for setting preferences, but offers no context about prerequisites, timing, or specific use cases.

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