Play, stop, rewind or seek a timecode show and observe it

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

No annotations are provided, so the description carries the burden. It documents the side effect that a play-started playback keeps running unless switch_off is off, and it explains the post-action observation window and verification logic (dispatching vs observing, matching crossed events to observed cue changes). This is rich behavioural context, but it does not cover permissions, failure modes, or what happens if the cursor is outside the timecode range.

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 single dense paragraph front-loads the actions but then runs on through observation mechanics and conditionals ('unless switch_off is off', 'for play', 'goto -> that cue...') that could be structured as a short list. It is information-dense rather than wasteful, but readability suffers.

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 mutation tool with no annotations, no output schema, and 0% schema description coverage, the description does more than minimum but still leaves key parameters unexplained. It covers the action semantics and observation model well, yet an agent still lacks enough to call it confidently with the undocumented fps/interval_ms/timecode parameters.

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 must compensate. It adds meaning for to (a time as in gma3_build_timecode) and observe_seconds (default 5 for play), but leaves fps, interval_ms, and the interaction between timecode and to undocumented. Six parameters with only 2 described is a meaningful gap.

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 and resource – play/stop/rewind/seek a timecode show – and details the underlying command sent for each action (Go Timecode N, Off, Top, cursor write). It is clearly a transport control tool, distinguishable from gma3_timecodes and gma3_build_timecode. It loses a point because the outcome of each action (what transport state results) is described in internal MA2/MA3 syntax rather than operationally.

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?

Explicitly notes that recording is not offered and names the cursor-writing behaviour for seek. It also explains when the time source comes from the cursor vs a timecode slot, which guides correct use. What remains missing is when to prefer this tool over a plain gma3_command or gma3_playback call.

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