pointer_position

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

Beyond the readOnlyHint annotation, the description adds meaningful behavioral detail: it may answer from the compositor or from the last server-set position, it explicitly says which source was used, and it never guesses from X due to staleness over Wayland surfaces. This is rich, non-obvious behavior disclosure.

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 short sentences, front-loaded with the core purpose, and every sentence adds necessary caveats about source reliability and staleness. There is no filler or redundant restatement of the tool name.

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 getter with no output schema, the description covers the key behavioral context: data source, fallback, and reliability. It could explicitly state the coordinate system or return format, but the semantics of 'pointer position' are sufficiently clear for safe invocation.

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 and an empty input schema, so there are no parameter semantics for the description to clarify. The baseline of 4 applies because there is no parameter surface to document.

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 identifies the tool as a pointer-position getter ('Where the pointer is'), which distinguishes it from pointer-mutation siblings like pointer_move and pointer_drag. It lacks an explicit verb like 'get' or 'read,' but the meaning is unambiguous.

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 explains when the compositor source is used and when the server-derived last position is used, which gives useful selection context. It does not name alternative tools or state when not to use it, but for a zero-parameter read-only getter the context is sufficient.

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