quick_save_now

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

With no annotations, the description carries the full burden and does substantial work: it discloses that the tool performs "1 player read + 1 library write" (a mutation), that dry_run previews without writing (and dry_run defaults to true in the schema), and that recent plays are only a fallback when nothing is currently playing. Missing are idempotency behavior (already-saved tracks) and auth requirements, but the core mutation and dry-run safety traits are clearly disclosed.

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?

Four short sentences, each earning its place: primary purpose, collapsed pipeline, operation cost (1 read + 1 write), and dry_run behavior. The purpose is front-loaded in the first sentence and there is zero 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?

For a simple 4-optional-param tool with no output schema, the description covers purpose, fallback behavior, the composed pipeline, the mutation cost, and dry_run safety. Gaps are the return-value details of the three response formats and idempotency semantics, but against a sibling list of 500+ tools, the explicit naming of the collapsed pipeline provides strong disambiguation.

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 description coverage is 100%, so the baseline is 3; all four parameters (market, recent, dry_run, response_format) are already documented in the schema. The description adds mild reinforcement by explaining the `recent` fallback semantics and dry_run preview behavior, but provides no meaningfully new parameter context beyond the schema.

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 states a specific verb + resource: "saves the currently-playing track (or the last `recent` recently-played tracks) straight to your library." It also differentiates from siblings by naming the exact pipeline it collapses (get_currently_playing → save_to_library), so an agent can distinguish it from the standalone get/save tools without opening 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?

The description makes the use case clear via "One-call 'like this song'" and explicitly names the two-step alternative it collapses (get_currently_playing → save_to_library), which effectively tells the agent when this convenience wrapper is appropriate. It lacks an explicit 'when-not' or 'use X instead when you need finer control' exclusion, so it stops just short of full routing guidance.

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