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

Annotations already flag destructiveHint=true and openWorldHint=true; the description goes further by specifying exactly what is destroyed (that language's screenshots for this device size are replaced), that it never submits for review, and that an external App Store Connect connection is required. That is real context beyond the structured hints.

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?

Four sentences, each carrying distinct load: action and scope first, exclusion second, scope limit third, prerequisites fourth. No restating of the title or filler.

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 destructive, open-world mutation with no output schema, the description covers action, scope, exclusion, prerequisites, and the create_version fallback path. It doesn't say what a successful or partial upload returns (screenshot counts, failures), which would help an agent interpret the result.

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 only 33%, so the description must compensate. It explains create_version behaviorally (only after asking the user and finding no editable version) and implies locale via 'that language's screenshots'; set_id is covered by the schema itself. Locale's default and matching rules remain slightly underspecified.

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: uploads the unlocked set into the app's editable App Store Connect version, replacing that locale's screenshots for the current device size. It also names the case it is not for (iPhone Duo -> export_set), so an agent can separate it from export_set without opening any schema.

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?

Gives explicit preconditions (user must have connected App Store Connect), a branch instruction (if no editable version, ask the user then retry with create_version=true), and one exclusion (not iPhone Duo). It does not clarify its relationship to the sibling upload_screenshots, so the boundary against every alternative isn't fully drawn.

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