NEXO Brain

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

With no annotations provided, the description carries full burden. It mentions 'fire-and-forget' (implying no delivery confirmation or response), which is useful behavioral context. However, it lacks critical details: required permissions, rate limits, message size limits, whether sessions must be active, or what happens if the target session doesn't exist. For a messaging tool with zero annotation coverage, this leaves significant behavioral gaps.

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 brief purpose statement followed by parameter explanations. Every sentence adds value, and there's no redundant information. It could be slightly more front-loaded with key behavioral details, but overall it's appropriately concise for a simple messaging tool.

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 (messaging with broadcast capability), no annotations, and an output schema (which presumably handles return values), the description is partially complete. It covers basic purpose and parameters but misses important contextual details: authentication needs, error handling, broadcast implications, and relationship to sibling tools. The output schema reduces the need to describe returns, but behavioral gaps remain significant.

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 provides clear semantic explanations for all three parameters: 'from_sid' as 'Your session ID', 'to_sid' as 'Target session ID, or 'all' for broadcast', and 'text' as 'Message content'. This adds meaningful context beyond the bare schema types, though it doesn't specify format constraints (e.g., session ID structure, text encoding).

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 ('send') and resource ('fire-and-forget message'), specifying it goes to another session or broadcast. It distinguishes from siblings like nexo_ask/nexo_answer (which involve queries/responses) but doesn't explicitly contrast with all messaging-related tools. The purpose is specific but could more directly differentiate from similar tools.

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 for sending messages (point-to-point or broadcast) but provides no explicit guidance on when to use this versus alternatives like nexo_ask (which expects a response) or nexo_answer (which responds to queries). There's no mention of prerequisites, error conditions, or typical use cases, leaving usage context somewhat vague.

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