timeline_set

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

Annotations declare readOnlyHint=false and destructiveHint=false, so the agent knows this is a non-destructive mutation; the description adds a genuinely useful side effect that 'frame_rate' resamples keyframes. However, it does not disclose what happens when no parameters are supplied, whether 'time' and 'frame' conflict, or any reset/clamping behavior — meaningful gaps for a mutating tool.

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?

A single semicolon-delimited sentence that front-loads the core action and packs every controllable facet without filler. It borders on dense list-reading, but no sentence is wasted.

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?

An output schema exists, so return values need no explanation, and the description covers all eight parameters. What is missing is the semantics of an all-optional mutation tool: what a no-argument call does, and how mutually exclusive time/frame inputs are resolved.

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 0%, so the description carries the full burden, and it largely does: time/frame, total_frames, frame_rate, playback_speed, play, and 'selection range' (mapping to selection_start/selection_end) are all named. The gap is that it never clarifies precedence between 'time' and 'frame' or the units/coordinate basis of selection bounds.

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 ('Set the timeline') and enumerates the exact facets it controls: time, frame, total frames, frame rate, selection range, playback speed, play state. It is clearly distinct from the sibling timeline_get by name and function, though it never says so explicitly.

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?

Usage is implied by the field list and by 'play=true/false starts or stops playback', which tells the agent how to trigger playback. There is no explicit when-to-use guidance, no statement about the relationship to timeline_get (read vs. write), and no note on how to combine partial updates.

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