timeline_play

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

No annotations are present, so the description carries the full burden for behavioral disclosure. It states the intended state change but does not mention idempotency (what happens if already playing), whether playback requires an initialized timeline, or any error/return behavior.

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?

At three words, the description is extremely concise and front-loaded. Every word carries meaning, and there is no filler or redundant restatement of the schema.

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?

Given zero parameters, the agent can invoke the tool without inputs, so the description is nearly sufficient. However, it leaves unspecified behavior on repeat calls and the expected return value or success indication, which matters for a stateful playback action with no output schema.

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?

The tool has zero parameters and the schema is trivially complete, so there is no parameter information the description needs to add. This is the baseline for a parameterless tool.

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 names a specific action ('Start') and a specific resource ('timeline playback'), which clearly distinguishes it from siblings like timeline_pause, timeline_get, and timeline_set. Even without naming those alternatives, the verb and object leave no doubt about the tool's role.

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 usage is implied by the description: call this to start timeline playback. However, it does not explicitly state when to use it instead of timeline_pause or timeline_set, nor does it mention prerequisites such as an open or loaded timeline.

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