download_image

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

With no annotations, the description carries the full behavioral burden. It correctly communicates a non-mutating download action and optional cropping, but it does not disclose details such as whether an existing out_file is overwritten, how missing or invalid media_id values are handled, or other runtime side effects.

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 a single, front-loaded sentence that states the action, the resource scope, and the optional crop capability. No wasted words and no unnecessary repetition of schema-provided details.

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 combination of description and rich schema covers the necessary invocation path: media_id identifies the image, out_file defines the destination, and size/fit/background control cropping. It is missing only minor behavioral caveats about failures and overwriting, but those are not essential to correct invocation.

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 80%, and most parameters already have substantive descriptions such as 'WIDTHxHEIGHT format' and 'The extension decides the format.' The description adds minor semantic value by mentioning 'optional cropping to an exact size,' but the schema does the heavy lifting.

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 uses a specific verb and resource: 'Download an image that already exists in Flow by its media id.' This clearly distinguishes it from siblings such as generate_image or generate_batch, which create images, and from flow_status or list_library, which inspect state.

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 phrase 'already exists in Flow' and 'by its media id' signal that this is the retrieval step after generation, not a generation tool. It does not explicitly name alternatives or exclusions, but an agent can infer the appropriate context without ambiguity.

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