adjustVolume

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

With no annotations, the description carries the full burden of behavioral disclosure. It does reveal the relative adjustment semantics and the premium requirement, but it omits other behavioral traits such as volume clamping at 0 or 100, behavior if no device is active, or whether the adjustment applies to a specific device. For a mutation tool, these gaps are significant.

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 two sentences long and front-loaded with the core action. The second sentence clarifies sign conventions and a prerequisite, without any fluff or redundancy. Every sentence contributes essential 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?

For a simple two-parameter tool, the description covers the main purpose and prerequisite. However, as a mutating tool without annotations, it lacks context about potential side effects, failure conditions (e.g., no active playback), and device selection nuances. The schema and output schema do not compensate because there is no output schema and the schema only documents parameter names. The description is adequate but not fully complete for safe invocation.

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 provides 100% coverage with descriptions for both deviceId and adjustment. The description's explanation of positive/negative values adds no new meaning beyond the schema's own description for adjustment. It does not elaborate on deviceId's optionality or selection behavior, which is already stated in the schema. Thus, the description provides no additional 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 tool's action: 'Adjust the playback volume up or down by a relative amount.' This specific verb-resource pairing (adjust volume) with the 'relative' qualifier distinguishes it from sibling tool setVolume, which adjusts to an absolute level. The purpose is unambiguous and specific.

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 by indicating the relative nature of adjustment and the requirement for Spotify Premium. However, it does not explicitly name alternatives or exclusions, such as mentioning setVolume for absolute adjustments. The premium requirement gives a usage condition, but there is no explicit 'when not to use' guidance. This is more than implied usage but less than explicit alternative comparison.

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