plan_volume_level_across_devices

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

With no annotations provided, the description carries the full behavioral burden. It explicitly discloses that the tool is read-only, does not execute anything, and returns exact per-device PUT calls. This is a strong, accurate disclosure of the side-effect-free behavior and prevents the agent from expecting actual volume changes.

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 sentence with the core action front-loaded—'Plan setting every (volume-capable) Spotify device...'—followed by the critical execution boundary. The length is appropriate and nearly every clause adds value; the slight redundancy of 'without executing anything' and 'Read-only planner' is acceptable reinforcement rather than bloat.

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 read-only planning tool with no output schema, the description clearly states what the caller will receive ('exact per-device PUT calls'), so the absence of an output schema does not leave the agent guessing about return values. Combined with the fully documented input schema, the description is complete enough for confident invocation and interpretation.

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 already has 100% parameter coverage with descriptions for volume, device_ids, and response_format. The description does add helpful context about 'volume-capable' devices and 'per-device PUT calls', but it does not need to re-explain each parameter. Baseline 3 is appropriate because the schema carries the parameter-semantic load.

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 identifies the verb ('Plan'), the resource ('every volume-capable Spotify device'), and the action (setting one target volume level). It also distinguishes itself from execution tools by explicitly stating it returns PUT calls 'without executing anything' and calling itself a 'Read-only planner.' This is specific enough for an agent to separate it from siblings like apply_volume_plan or set_volume.

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 gives clear context: use this tool when you want to plan/preview per-device volume changes without applying them. It does not explicitly name alternative tools or state when-not-to-use criteria, but 'without executing anything' and 'Read-only planner' make the usage boundary evident enough for an agent to select it correctly.

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