Move the playhead

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

Annotations already indicate readOnlyHint=false, so the description need not restate that it is not read-only. The description adds value by disclosing the side effect on ae_save_frame, clarifying that this changes the playhead position which influences subsequent saves. No contradictions with annotations are present, and the effect on save_frame is a meaningful behavioral trait.

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 just two sentences, each earning its place: the first states the core action and target, the second highlights the important downstream effect. There is no redundancy, filler, or unnecessary detail, making it an ideal length.

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 simple two-parameter tool with no output schema and full parameter documentation, the description gives the essential context—including the tie to ae_save_frame. It doesn't mention result values, but the tool's purpose is pure side-effect; the omission is acceptable. The description is complete enough for an agent to invoke 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?

Schema coverage is 100%, so the comp and time parameters are already well-documented. The description doesn't go beyond the schema for parameter meaning—it just restates the operation. According to the rubric, with high schema coverage the baseline is 3, and there is no additional semantic nuance provided here.

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 'Set the current time in a composition' clearly specifies the verb and resource, while 'Affects what ae_save_frame captures' ties it to a concrete downstream effect. This distinguishes it from siblings like ae_save_frame, ae_render, and ae_set_comp_settings without ambiguity.

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 phrase 'Affects what ae_save_frame captures' implies the primary use case: set the playhead before calling ae_save_frame to control the captured frame. It gives clear context for when to use the tool, though it does not explicitly state when not to use it (e.g., when manipulating layers instead). This lack of exclusion is minor for such a specific operation.

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