generate_image

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

With no annotations, the description carries the burden and does substantial work: it discloses that the call creates a durable (async) job, that the prompt is passed verbatim (no rewriting), that output is post-processed with watermark removal, and that delivery is local. It omits authentication/session requirements and does not say how the job's results are retrieved.

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?

Two sentences, front-loaded with the action and resource, no filler. The trailing 'watermark removal and local delivery' clause is slightly promotional but carries genuine behavioral information.

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 an 8-parameter generation tool with no output schema and no annotations, the description explains what is produced but not what is returned (a job handle) or that it must be polled via get_flow_status before assets appear locally. That lifecycle gap is the main missing piece.

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 baseline would be 3, but the description adds real semantics beyond the schema: it clarifies the prompt goes to Flow verbatim as the visual instruction (i.e. no model-side augmentation), which meaningfully affects how an agent should write the prompt.

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 names a specific verb and resource: 'Create a durable Google Flow IMAGE job' with 'still renders'. Capitalized IMAGE and 'still' separate it from the video-oriented siblings like generate_video and flow_browser_generate_video, though it never names that alternative outright.

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?

Usage is only implied by the word IMAGE and by the aspect-ratio framing; there is no explicit 'use this for static images instead of generate_video' statement, no prerequisites (e.g. flow_browser_login/session) and no when-not-to-use guidance.

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