play_timeline

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

Annotations provide little (readOnlyHint=false, destructiveHint=false). Description adds 'Uses QE DOM' but does not disclose behavior on failure, side effects, or state changes. For a mutation tool, more transparency is needed.

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 waste, key action first. Perfectly concise and structured.

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 0-param tool, the description is adequate but could mention prerequisites like needing an active sequence or behavior if already playing. No output schema, but return value not needed. Still minimal gaps.

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?

No parameters exist; baseline is 4 per rubric. Description adds no parameter info, but schema already covers 100% of parameters (none).

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 it starts playback of the active timeline (verb+resource). It distinguishes from sibling stop_playback, but does not explicitly differentiate from play_source_monitor or other playback tools, so lacking full sibling differentiation.

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?

No guidance on when to use or not use this tool. No mention of prerequisites (e.g., must have an active sequence), nor alternatives. The agent has to infer from context.

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