Make Selection

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

Annotations indicate mutation (readOnlyHint=false) but no destructive behavior. The description adds context on post-selection actions but does not disclose additional behavioral traits like whether the selection replaces or adds to existing selections. No contradiction with annotations.

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, front-loaded with the main purpose. Every sentence provides useful information without redundancy.

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 the tool's complexity (3 params, nested bounds, enum, no output schema), the description is complete enough to guide use. It explains type options and bounds requirement, though the feather parameter is not mentioned (but schema covers it).

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 coverage is 100%, and the description adds marginal value by explaining the meaning of 'all', 'rect', and 'ellipse' types and when bounds are required. However, the schema already describes these well, so the description does not significantly enhance understanding.

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 'Create a pixel selection region in the active document,' using a specific verb and resource. It distinguishes from siblings like clear_selection and fill_selection by mentioning them as subsequent actions.

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 guidance on when to use the tool and what to do after creating a selection (fill or clear). However, it does not explicitly state when not to use it or alternatives for different selection shapes beyond the types listed.

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