List desktops (Spaces)

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

The readOnlyHint and idempotentHint annotations already signal safety, and the description adds useful edge-case behavior: fullscreen app spaces have no position, while user desktops use a 1-based position matching Ctrl+N shortcuts. This goes beyond what annotations alone provide.

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?

Two tightly written sentences front-load the main purpose and then clarify an important semantic detail. Every sentence earns its place with no redundant filler.

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 zero-parameter, read-only listing tool with strong annotations, this description is complete: it states the resource, scope across screens, key output fields, current-space indicator, and the position edge case. No output schema exists, but the description sufficiently explains what the caller needs to know.

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?

This tool has zero parameters, so the baseline is 4. The description does not need to explain parameter semantics since the input schema is empty and schema coverage is 100%.

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: 'List macOS Spaces across all screens'. It clearly identifies output fields (id, type, current) and distinguishes Spaces from sibling tools like hs_list_windows and hs_screens.

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 clear context about when to use this tool: whenever you need to enumerate macOS Spaces, identify the current space, or resolve the meaning of 'desktop 2'. It does not explicitly name alternatives or exclusions, so it falls short of full alternative guidance.

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