play

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

With no annotations, the description carries full responsibility for disclosing behavioral traits. It only mentions resuming playback and targeting a device, but does not state what happens if no active device exists, whether it errors, or if it requires an active session. This is insufficient for a mutation tool without annotation support.

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, concise sentence that front-loads the primary action ('Resume playback') and then notes the optional device targeting. There is no wasted content, and it is appropriately sized for a simple tool.

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 tool with one parameter and an output schema, the description is minimally viable but lacks critical contextual details such as error handling when no active device is available. It does not explain whether the tool resumes from the current position or starts anew, but given the presence of an output schema, return values may be documented elsewhere. This leaves a clear gap.

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 schema has one parameter, device_id, which is optional and nullable. The description explicitly mentions 'optional device ID', adding meaning by indicating that this parameter specifies the target device. Since schema coverage is 0%, the description partially compensates by clarifying the parameter's purpose, though it could detail how to specify the ID (e.g., Spotify URI).

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 tool resumes playback on a Spotify device, which is a specific action on a specific resource. It distinguishes itself from sibling tools like pause, skip_forward, and skip_backwards by focusing on resuming rather than stopping or skipping. The optional device ID is also mentioned, providing scope.

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 implies usage when the user wants to resume playback after a pause or start playing on a selected device. It gives clear context about targeting the active device or a specified device ID, though it does not explicitly mention alternatives or when not to use it. This is more than mere implication but lacks explicit exclusions.

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