list_supported_modes

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

With no annotations provided, the description carries the behavioral burden and discloses that the tool is instant, read-only, and takes no input. These are meaningful traits beyond the empty input schema, though it does not describe pagination, authentication needs, or the exact return shape.

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 two sentences, front-loads the core purpose, and adds the usage suggestion without unnecessary wording. Every clause contributes either scope, behavior, or invocation guidance.

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 zero-parameter, read-only lookup tool with no output schema, the description is complete enough: it says what will be listed, which sibling's options are included, and when to call it. No additional detail is necessary for an agent to invoke it correctly.

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 has zero parameters, so parameter semantics are minimal by design. The description reinforces this by stating it takes no input, which aligns with the empty schema and gives the agent baseline clarity.

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 ('List') and resource ('options the other tools accept'), then enumerates the option categories such as content modes, caption styles, voice-over engines, aspect ratios, and sound-effect presets. It also ties content modes to the sibling tool generate_short, making the tool's scope clear without needing to inspect any schema.

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 explicitly says to call it first when unsure which value to pass, which gives clear usage context and positions it as a prerequisite lookup tool. It does not state when not to use it or name every sibling that benefits from it, but the guidance is sufficient for the intended workflow.

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