export_icon_sizes

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

With no annotations, the description carries the burden well: it enumerates the exact output artifacts per platform, states defaults for platform/format/source index, and discloses the return shape {exported, count, platform}. It omits whether existing files in output_dir are overwritten, whether the directory is created, and what happens on failure, which keeps it out of 5 territory.

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?

Front-loaded one-line summary followed by a compact size table and a parameter/return block; the size enumeration is long but earns its place by telling the agent exactly what files result. No filler sentences.

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 filesystem-writing tool with no annotations and no output schema, the definition covers purpose, all parameters, defaults, and the response shape. The remaining gaps are operational (overwrite policy, directory creation, error cases), which are real but secondary.

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 supply meaning, and it documents all four parameters including the enum-like values for platform (android/ios) and the indexing semantics of source_image_index. The format parameter only says "png" (default), leaving open whether other values are accepted.

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 (export an image as a complete icon set) and narrows scope to Android/iOS with exact pixel size lists, which separates it from generic siblings like export_image, batch_export, and export_web_optimized.

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 makes the use case clear (producing platform icon sets) and gives defaults, but never says when not to use it or names an alternative such as export_image or batch_export for non-icon output. Usage is implied rather than routed.

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