List controllers

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

Annotations already declare readOnlyHint and idempotentHint, so the description doesn't need to restate safety. It adds useful behavioral details: readings are null while offline, the tent/ambient distinction, and the special case of an off-mode port with power > 0 indicating an automation. This goes beyond annotations without contradicting them.

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 the core purpose in the first sentence, then a concise breakdown of sensor types and a note about the automation edge case. Every sentence adds value, and the information is front-loaded. It's slightly longer than the high example but still well-organized.

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 that an output schema exists (has_output_schema: true), the description doesn't need to enumerate return fields. It explains the nuanced semantics of tent vs. ambient, offline behavior, and the automation condition, which an agent needs to interpret the results correctly. No critical gaps are apparent.

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 the baseline is 4. The description correctly focuses on output semantics rather than parameter details, which is appropriate. No parameter information is needed, and the description doesn't attempt to invent any.

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 states a clear verb+resource: 'List all AC Infinity controllers on the account with current readings and port status.' It also distinguishes the tool from siblings by specifying it returns a full overview of controllers, rather than individual settings like get_port_settings or get_device_settings. The added explanation of tent vs. ambient sensors further clarifies the scope.

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 gives concrete usage context: it says to use the tent reading 'when the user asks how the tent is doing' and advises calling list_automations when a port shows mode 'Off' but power > 0. However, it doesn't explicitly state when NOT to use this tool or name alternatives for specific tasks, leaving some inference to the agent.

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