start_playback

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

With no annotations, the description carries the full burden of disclosing behavior, but it only states the action. It does not mention side effects (e.g., whether it resumes from current position), preconditions (e.g., an open session), or behavior if already playing. This is a significant gap.

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 a single, short sentence that is immediately informative. Every word earns its place, and it is front-loaded with the action and target. No redundant or extraneous text.

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 transport control, the description gives the core function, but it lacks context about session state or how it differs from 'fire_clip'. Since there are no annotations and no output schema, the description should provide more behavioral context to be fully sufficient, yet the tool's simplicity keeps it from being inadequate.

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 input schema has zero parameters, so there is nothing to explain. According to rubric, a 0-parameter tool gets a baseline of 4. The description adds no parameter-specific information, but it doesn't need to.

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 uses a specific verb ('Start') and a clear resource ('Ableton session'), making the tool's function unambiguous. It naturally distinguishes itself from siblings like 'stop_playback' and 'fire_clip' by referring to the session-level transport.

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 is provided on when to use this tool instead of related tools such as 'fire_clip' or 'stop_playback'. The expected context is implied by the name but not explicitly stated, offering no exclusions or alternative recommendations.

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