dj_play_for_me

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

With no annotations, the description carries full burden. It discloses the composition behavior and the meaning of the discovery blend, which is real value, but is silent on important side effects: whether it replaces or appends to the current queue, whether playback starts immediately, and any auth/subscription requirements.

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?

Two tight sentences, purpose front-loaded, and the parameter clarification attached at the end where it is most useful. No filler.

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?

An output schema exists so return values need no explanation, and the blending behavior is well captured. The remaining gap is queue-replacement and playback-start semantics for an unannotated mutating tool, plus the undocumented size parameter.

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 0%, so the description must compensate. It does well on discovery ('share of new-to-them songs (0 to 1)'), clarifying the range and intent, but 'size' (default 20) is never mentioned and must be guessed as queue length from the purpose sentence.

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 specific verb+resource: 'Builds and plays a personal queue from the user's taste,' with concrete composition logic (recent favourites + YouTube Mix similar songs). It implicitly contrasts with siblings like play_favorites or start_radio by describing the blend, but never names an alternative, so differentiation is inferential.

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?

Usage is implied by the personalization framing — an agent can infer this is for a curated mix rather than a plain playlist — but there is no explicit 'use this when…' or exclusion against play_favorites, start_radio, or play_songs, all of which overlap heavily.

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