Create or edit images with Google Flow

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

With no annotations, the description carries the behavioral burden and does well: it discloses that the agent may rewrite the prompt, may generate several images by default, returns what the agent said, uses no Flow credits, and takes 30-120 seconds. It does not cover authentication or rights-confirmation requirements, but the schema handles the latter.

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 front-loaded with the core action, then moves through editing, agent behavior, output, cost, and latency. Every sentence adds operational value with no filler.

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 nine-parameter tool with no output schema and no annotations, it is largely complete: it covers creation, editing, agent nondeterminism, result content, cost, and latency. It could be stronger by mentioning that local paths are returned or by naming which sibling tool handles non-agent image generation.

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 100%, so the baseline is 3, but the description adds meaningful usage semantics for editing: it explains how attachments and media_ids differ, and that in the same project you can just name the image. It also adds prompt-steering advice for controlling output count, which is not captured by the schema.

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 a specific verb and resource: it asks the Flow agent for images and saves them locally, and it also covers editing existing images. However, it never distinguishes this tool from the sibling generate_images tool, leaving an agent unsure which image-generation path to choose.

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 useful in-context guidance for editing, such as attaching an image via attachments or media_ids, or naming an existing project image. It does not say when to use this tool instead of generate_images or generate_video, so the usage context is implied but not explicitly routed.

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