skip_backwards

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

No annotations are provided, so the description carries the burden of behavioral disclosure. It indicates that the action occurs on the active device or a specified device, but does not disclose what happens if no active device exists, if the device_id is invalid, or any prerequisites (e.g., premium). It is not misleading, but lacks depth for a mutation tool.

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, well-structured sentence that directly communicates the tool's purpose and key parameter. No unnecessary words or redundant information.

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 simplicity of the tool (one optional parameter) and the presence of an output schema, the description is fairly complete. It covers the main context: targeting the active device or a specific device_id. However, it omits edge cases like error handling or behavior when no device is active, which would make it fully complete.

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 covers device_id as optional with a null default, but the description only reiterates that it is optional without adding meaningful detail (e.g., how to obtain a device ID, valid formats, or behavior when omitted). With 0% schema description coverage, the description does not adequately compensate for the lack of parameter semantics.

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 ('skip to the previous track') and the target resource ('active Spotify device or an optional device ID'). It is specific and distinguishes from the sibling tool skip_forward, which moves to the next track.

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 clear context on when to use the tool: to go to the previous track. It mentions the optional device_id targeting, implying that without it the active device is used. However, it does not explicitly contrast with alternatives or state exclusions, so it misses a 5.

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