Get App Icon

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

Annotations already declare the tool as readOnlyHint=true, openWorldHint=true, idempotentHint=true, destructiveHint=false. The description adds only the return format (data URL/base64), which is useful but does not disclose new behavioral traits beyond what annotations provide. It is consistent with annotations.

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 sentence with no wasted words. It is front-loaded and efficiently conveys the core action, resource, dimensions, and output format.

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?

The tool is simple with few parameters and no output schema. The description covers the basic purpose but omits context like what a 'channel' is or whether the icon is device-specific. It is minimally adequate but could benefit from clarifying the meaning of appId and the nature of the icon.

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 50%: only 'device' has a description. 'appId' lacks any schema description, and the description does not clarify its meaning or usage. The description hints at 'channel' but does not fully explain parameters, failing to compensate for the low schema coverage.

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 clearly states the verb 'Fetch', the resource '336x210 app icon' for a channel on a device, and the return format (data URL/base64). This unambiguously identifies the tool's function and distinguishes it from sibling tools like 'launch_app' or 'sideload'.

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 implies usage for fetching an app icon but provides no explicit guidance on when to use this tool versus alternatives, nor any conditions or exclusions. The tool's purpose is clear, but the description lacks when-to-use or when-not-to-use context.

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