Read Screen

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

Annotations already declare readOnlyHint=true, and the description adds meaningful behavioral detail beyond that: it captures a screenshot, extracts complete UI structure, and notes platform limitations (Pharo and Squeak for World morphs, Pharo only for Spec/Roassal). This is consistent with the annotations and adds useful context.

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 only two sentences, front-loads the tool's purpose, and each sentence adds necessary information. There is no filler or redundant restatement of the title.

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 that the tool has an output schema, read-only annotations, only two self-describing parameters, and a concise description covering supported UI types and platform constraints, nothing essential is missing for an agent to invoke it correctly.

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 input schema already provides 100% coverage with clear descriptions for both parameters, including the target_type choices and their Pharo-only restrictions. The description reinforces these semantics but does not add substantial new parameter information beyond what the schema states.

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 states a specific verb and resource: it reads the UI screen by capturing a screenshot and extracting UI structure. It also enumerates the supported UI types (World morphs, Spec presenters, Roassal visualizations), making it clearly distinct from sibling source/package/eval 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?

The description clearly frames the tool as being 'for debugging Smalltalk interfaces', giving an agent a strong context for when to use it. It does not explicitly name alternatives or state when not to use it, but among siblings it is the only UI inspection tool, so the usage context is sufficient.

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