flow_capabilities

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

With no annotations provided, the description carries the burden and does so: it declares the operation read-only and scopes it to static reference content, so there is no ambiguity about mutation or side effects. It does not say whether the call is instantaneous/cached or whether it touches the Flow session, which would fully close the gap.

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 identity of the tool and followed by the single actionable usage rule. The content enumeration is dense but every item is a real capability category a caller might ask about.

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?

Enumerating the sheet's contents largely substitutes for the absent output schema, so an agent knows what it will get back. The only unstated detail is the shape of the response (structured data vs. a formatted text sheet), which matters slightly given no output schema exists.

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?

The tool takes zero parameters, so there is nothing to disambiguate and the baseline applies. The description correctly makes no parameter claims that the empty schema would contradict.

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?

States a specific verb+resource ("Read-only capability sheet for Google Flow") and enumerates the exact contents: modes, aspect ratios, durations, models, output counts, watermark-removal engine, and delivery locations. This clearly separates it from siblings like list_flows (enumerates instances) and video_system_health (operational status).

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?

"Consult it whenever a caller asks what Flow can do or which sizes/ratios are available" gives a concrete trigger condition. It lacks explicit exclusions naming the sibling to use instead (e.g., use list_flows for existing flows), so it stops short of a 5.

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