Screenshot Apply Layout

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

Annotations already declare readOnlyHint=false, idempotentHint=true and destructiveHint=false, so the safety and repeatability profile is covered. The description usefully names the exact target file that gets modified, but does not explain merge semantics (overwrite vs. deep merge of existing keys) or what happens if the design file is missing.

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?

Three tight sentences, front-loaded with the action, followed by the when-condition and the return shape. No filler or restated 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?

With an output schema present, the description needn't explain return values, and the brief 'Returns' line is a bonus rather than a necessity. It covers purpose, sequencing and output well; only the merge semantics and error behavior are absent.

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?

Only one parameter (app_dir) and schema description coverage is 100%, so the schema fully documents it. The description adds no meaning beyond the schema about how app_dir is used, which is the expected baseline when the schema does the heavy lifting.

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 (Merge) and both resources by path: the design store layout into the screenshots config. The reference to screenshot_brand in the 'Use when' clause gives implicit sibling differentiation, though it doesn't explicitly say what this tool does that screenshot_sync or screenshot_capture do not.

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?

'Use when: before screenshot_brand so every locale renders the approved layout' gives a clear ordering context and the reason for it, which is more than most siblings offer. It stops short of stating when-not to use it or naming an alternative for a different situation.

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