start_playback

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

Beyond the annotations (destructiveHint: false), the description discloses the critical behavioral quirk that the response reflects the state before the command, which could be misleading. This transparency helps the agent avoid misinterpretation and correctly verify the state.

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 extremely concise—two sentences with no unnecessary words. The first sentence states the purpose, and the second adds a crucial note. It is front-loaded and efficient, earning a top score.

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 the tool has no parameters and an output schema exists (context signal), the description covers the essential functionality and provides an important caveat. It could mention behavior if playback is already active, but overall it is sufficient for a simple command.

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?

There are no parameters, so schema coverage is 100% by default. The description adds no parameter details, but none are needed. A score of 4 (baseline for zero parameters) is appropriate.

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 the action ('Start Arrangement playback') and specifies the starting point ('from the current song time'). It distinguishes this from related tools like 'continue_playing' by implying it starts fresh from the current time, not resuming a paused state.

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 description provides explicit guidance about the pre-command state reporting and recommends confirming with 'get_session_info'. This helps the agent understand how to interpret the response and take follow-up actions. It does not, however, discuss when not to use this tool (e.g., if already playing) or compare to 'continue_playing'.

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