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

Annotations already declare readOnlyHint=false, idempotentHint=false, destructiveHint=false and openWorldHint=false, so the agent knows this is a mutating, non-idempotent, non-destructive action. The description adds only the trigger context ('after a visible change') and does not disclose whether screenshots are replaced, whether the operation is async, or how long it takes.

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?

A single short, front-loaded sentence with no wasted clauses. Slightly vague wording ('now', 'for example') keeps it from being maximally sharp, but it is well-sized.

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 one-parameter tool with no output schema, the description is minimally adequate but omits useful context such as whether this overwrites existing screenshots, whether it is asynchronous, or what happens on failure. It leaves the agent able to invoke the tool but not fully informed.

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?

There is a single parameter with 100% schema description coverage ('Product id from list_products'), so the schema fully documents the input. The description adds no additional meaning about productId, making the baseline 3 appropriate.

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+resource ('take the app's screenshots again'), which is distinct from the read-only sibling get_app_screenshots and the config sibling update_app_screenshots. It is clear what the tool does, though it never names those siblings explicitly to remove ambiguity.

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?

'for example after a visible change' implies a trigger condition, giving some when-to-use signal. However, it offers no when-not guidance, no prerequisites, and does not contrast against get_app_screenshots or update_app_screenshots.

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