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

Annotations include readOnlyHint: true, so the agent already knows this is a safe read operation. The description adds valuable detail about the return content: per-model capability flags, exact IDs, durations, aspect ratios, and image model specifics. This goes beyond the annotation without contradicting it.

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 moderately long but every sentence adds value. It front-loads the core purpose, then details the output structure, then provides usage directives. The use of dashes and line breaks aids readability. It could be slightly more concise, but it is well-structured and not bloated.

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 parameterless tool with no output schema, this description is exceptionally complete. It tells the agent what it will receive (model capabilities, IDs, etc.), how to use it (pass exact IDs to media_forge_generate), and when to use alternative tools. Nothing an agent needs to call this correctly is missing.

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 the schema covers 100% trivially. The description doesn't need to explain any parameters, and the baseline for 0 params is 4. The description's focus on output and usage is appropriate.

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 the verb 'List' and the resource 'ALL Media Forge models', and specifies exactly what it returns (capabilities, IDs, durations, aspect ratios per model type). It also differentiates from sibling video_editor_* tools by explicitly saying to use them for reference-image + dialogue scenarios.

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 description provides explicit when-to-use guidance: 'ALWAYS call this and pass an exact id... to media_forge_generate' and never hand-build a model_id. It also states when not to use it: 'For reference-image + dialogue together, use the video_editor_* tools instead.' This is crystal clear.

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