play

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

No annotations are provided, so the description carries the full burden. It discloses the resume-vs-play mode distinction, which is real behavioral information, but says nothing about prerequisites (e.g., Spotify Premium), what happens with no active device, whether starting playback interrupts current audio, or failure behavior.

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?

Five short sentences, zero filler, and the primary behavior ('Play or resume') is front-loaded ahead of the per-argument branches. Every clause maps to a distinct callable mode.

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?

With no annotations and no output schema, the description covers the core question of which argument to pass for which content. It leaves gaps around device targeting rules and error/edge conditions (no active device, non-Premium account), but is sufficient for an agent to invoke correctly in the common case.

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?

Schema coverage is already 100% (baseline 3), but the description adds routing value the schema does not: it maps each URI-style parameter to the content type it accepts (track vs. album/playlist/artist vs. user playlist). It omits device_id entirely, though the schema documents it as optional.

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?

States a concrete verb+resource ('Play or resume music') and then enumerates the four invocation modes, each keyed to a different argument. The no-argument-resumes case is a distinguishing behavior that separates it from siblings like pause and play_liked without needing their schemas.

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?

Effectively a routing guide: no args = resume, a track = uri, an album/playlist/artist = context_uri, user playlist = playlist, and a pointer to search for URI sourcing. It gives clear context for choosing parameters but names no exclusions or alternatives (e.g., play_liked, add_to_queue, pause).

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