session_click_xy

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

Annotations only contain a title, so the description carries the full burden. It discloses the event sequence (pointerdown/mousedown, pointerup/mouseup, then click) and the click_count behavior, which adds value beyond the schema. It does not mention side effects like navigation or page state, but the core behavior is well covered.

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 sentences with zero filler. The core action and event sequence are front-loaded, the use case is stated clearly, and click_count behavior is appended without unnecessary detail.

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 coordinate-based click tool with no output schema and moderate parameter count, the description covers purpose, event behavior, and primary use case. It doesn't address error conditions or prerequisites like page loaded state, but these are not essential for a simple click operation. The distinction from element-based clicking is implied, not fully elaborated.

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 100%, so baseline is 3. The description adds semantics for click_count ('2 adds dblclick') and reinforces x/y as viewport coordinates, but it does not add meaning for button or session_id beyond what the schema already provides.

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?

States a specific verb and resource ('Click at viewport coordinates'), explains the real mouse event sequence, and explicitly scopes to canvas/map surfaces with no DOM element to index. This clearly differentiates it from sibling click/session_click tools.

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?

Provides clear context for when to use: 'For canvas/map surfaces with no DOM element to index.' It implies the alternative (element-based clicking) but does not name specific sibling tools or explicitly say 'use session_click instead', so it falls short of a 5.

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