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

Goes beyond the annotations in two useful ways: it explains that a caller-supplied folderId makes retries reuse the same folder (a concrete idempotency mitigation not conveyed by idempotentHint=false), and it states the blast radius — storage paths and saved designs are unchanged. What's missing is failure behavior (what happens on a second call with the same folderId, or a duplicate name), which matters for a mutation tool.

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 short sentences, front-loaded with the action and scope, followed by the retry contract and the non-effect statement. Every sentence carries distinct information and nothing is repeated from the schema or annotations.

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 non-destructive create with an output schema (so no return-value explanation needed) and annotations covering the safety profile, this is nearly complete. The remaining gap is the failure/duplicate path for folderId and name, which an agent calling a create tool would want before retrying.

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 description coverage is 0%, so the description must carry parameter meaning; it explains folderId's purpose as a caller-supplied retry key and clarifies locale is optional, which the schema does not. However projectId, name (1–60 chars), and deviceType are never explained, and the interaction between deviceType and platform is left to the enums.

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 (creates), a specific resource (screenshot folder), and its scoping dimensions (device, platform, optional locale). No sibling competes for the same resource — the other folder tools are list/rename/delete/set_locale — so the resource name alone differentiates it. It stops short of explicitly naming an alternative, hence 4 not 5.

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?

Usage is implied rather than stated: the agent can infer this is the setup step before uploading or listing screenshots in a folder, but no sentence says when to use this versus prepare_asset_upload/upload_screenshots or list_asset_folders. No prerequisites (does projectId need to exist first? must name be unique within the project?) and no when-not guidance are given.

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