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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds the useful behavioral constraint that it 'does not generate video,' but it does not disclose any other runtime behavior such as return handling or dependencies; with annotations present, this is adequate but not rich.

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 short sentences, no filler. The first sentence states the action and scope, the second adds the key exclusion for video generation. Every word earns its place.

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 two-parameter tool with a rich output schema and annotations covering safety, the description is nearly complete. It could have explicitly pointed to list_free_tools as the source of valid slugs, but that is already encoded in the schema parameter description, so the overall tool definition is sufficient.

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 description coverage is 100%, so the schema already documents the slug and input object sufficiently. The description reinforces the slug's meaning by mentioning 'hooks, scripts, briefs' but adds no new parameter-level guidance beyond what the schema provides.

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 states a specific verb ('Run') and a concrete resource class ('public free tool'), further narrowed by the parenthetical types 'hooks, scripts, briefs.' It also explicitly excludes video generation, which cleanly differentiates it from the many generate_video_lab-like siblings.

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 gives a clear signal that this tool is for free tools and not for video generation, which is useful for excluding generate_* siblings. However, it does not name specific alternative tools or explicitly say when to prefer run_free_tool over them; usage guidance is implied rather than stated.

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