list_zones

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the description does not need to restate safety. The description adds value by detailing the output structure: each zone summary includes zone_detail (with fields listed) and zone_state. This goes beyond annotations to inform the agent of what to expect.

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: one summary sentence, then a bullet-like list of return fields, then clear Args list. No extraneous words. It is front-loaded with the core purpose. Every sentence earns its place.

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?

The tool is relatively simple (list zones). The description covers purpose, return structure, and all parameters. Annotations provide safety/behavioral context. Output schema exists (but not shown) and the description already explains the return format. A minor gap: no mention of pagination or handling large numbers of zones, but typical controllers have few zones, so this is acceptable.

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 fully compensates. It provides clear explanations for each parameter: device_id is 'Controller UUID (must be a CONTROLLER_GEN* device)', include_extra 'Ask the server to populate extra diagnostic fields', and include_moisture 'Include per-zone moisture data.' This adds meaning beyond the parameter names.

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 tool's purpose: 'List all zones configured on a controller.' It uses a specific verb (list) and resource (zones), with a clear scope (on a controller). This distinguishes it from sibling tools like get_zone (single zone) or start_zones (action) without needing explicit comparison.

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 that this tool is for obtaining an overview of all zones, but it does not explicitly state when to use it vs alternatives like get_zone. It provides a usage constraint: device_id must be a CONTROLLER_GEN* device. No comparisons or exclusion guidance is given.

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