skip_previous

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

No annotations are present, so the description carries the full burden of behavioral disclosure. It states the action and scope clearly, but it does not disclose what happens when there is no active device or when already at the start of the queue. These are common failure or no-op conditions for a skip control, and the description leaves them unaddressed.

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 entire description is a single, front-loaded sentence that communicates the action, target, and scope without any wasted words. It is optimally concise for the tool's simplicity.

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 parameterless action that returns void (inferred from the output schema), the description gives the essential context: what it does and where it applies. It omits edge-case behavior like no active device or queue boundary conditions, which are minor but could be relevant to an agent. The presence of an output schema means return values need no explanation.

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 input schema is an empty object with 100% coverage. There is no parameter information to document, and the description correctly avoids inventing any. The baseline of 4 for zero-parameter tools applies.

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 states a specific verb and resource ('Skip to the previous track') and clearly differentiates from the sibling 'skip_next' by direction. It also names the target scope ('active Spotify device'), leaving no ambiguity about the operation.

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 action itself: use when the user wants to go to the previous track. However, there is no explicit guidance about when not to use it (e.g., when no track is available) or how it compares to alternatives like seek. The 'active device' hint provides minimal context but no direct routing.

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