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

With no annotations, the description carries the full burden and adds meaningful behavior: size limits per media type, accepted formats, base64 encoding, content_type matching, ownership requirement, and sequencing after publish_app. It does not cover auth mechanics beyond the schema's api_key field, rate limits, or exact overwrite/return behavior, so it is strong but not exhaustive.

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?

The description is three short sentences, front-loaded with the core action and constraints, and follows with the sequencing instruction. Every sentence adds actionable information with no waste.

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?

Given no annotations and no output schema, the description covers the main operational requirements: ownership, media slot names, size limits, accepted formats, encoding, content_type matching, and when to call it. It does not explain failure modes or authentication in prose, but the schema's api_key description partially covers auth.

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 80%, so the schema already documents most parameters. The description still adds useful meaning beyond the schema: specific size limits for icon versus screenshots, content_type must match content, and the base64 payload encoding requirement.

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 specific verbs and resources: add or replace an icon or a screenshot of an app you own. It names the allowed media slots (icon, shot-1 to shot-5) and size limits, so an agent can distinguish this from sibling tools like publish_app or update_app without opening the 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?

It gives a clear prerequisite and sequencing instruction: call it after publish_app, and only for an app you own. It does not name alternative tools or when-not-to-use conditions, but the context is explicit and actionable.

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