list_instances

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

Since no annotations are provided, the description carries the full burden of disclosing behavior. It explicitly mentions the port scan range and the API, and lists the returned information. It does not mention side effects (none expected for a listing operation) or potential pitfalls, but it is transparent about how it works and what it returns.

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 three sentences, with the core purpose first, the mechanism second, and usage guidance third. Every sentence adds distinct value with no redundancy or filler. It is appropriately sized and front-loaded.

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 discovery tool with zero parameters and an output schema that presumably documents the return structure, the description is complete. It tells the agent what it returns (port, project name, version) and how to use the port. There is nothing missing that an agent needs to call or use it correctly.

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 tool has zero parameters, so there is nothing to document beyond the schema. The description adds the context that the port value from the output is used elsewhere, which is helpful, but with no parameters the baseline of 4 applies. The description does not need to add parameter detail.

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 opens with a specific verb and resource: 'Find all running Archicad instances.' It also explains the scanning mechanism and the return fields, making it distinct from siblings like execute_script or get_docs, which operate on a specific instance rather than discovering them.

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 clear guidance on how the output is used: 'Use the port value in other tools to target a specific instance.' This implicitly tells the agent when to call this tool (before other instance-specific tools) but does not explicitly state when not to use it or compare directly with siblings. It is clear enough but could be more explicit.

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