nacos_list_instances

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

With no annotations, the description carries the full burden. It correctly implies a read-only operation by listing instance details. However, it does not disclose potential behaviors like pagination, limits, or error responses (e.g., what if service is missing). The description is honest but lacks depth.

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 two sentences, front-loading the goal and intended use. Every word contributes; no fluff or repetition.

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 simplicity and absence of an output schema, the description covers the main points: what is returned (IP, port, health) and when to use it. It lacks mention of pagination or ordering, but for a basic list tool, this is adequate.

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 coverage is 100% for three parameters, so baseline is 3. The description adds no additional meaning beyond what the schema already provides (e.g., it doesn't explain that 'service_name' must match exactly, or discuss default groups). No value added.

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 it lists online instances with specific fields (IP, port, health) for a single service, and provides a concrete usage example ('is service X up / why is it offline'). This effectively distinguishes it from sibling tools like nacos_list_services (which lists services, not instances) and config-related 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 explicitly states when to use the tool: for service health/offline questions. It does not mention when not to use or alternative tools, but the context is clear enough given the sibling list and the specific instance focus.

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