Merge playlists

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

Annotations already declare non-read-only, non-destructive, non-idempotent, open-world, so the safety profile is covered. The description adds real value beyond that: it discloses the dedup key set (URI, ISRC, title+artist) and clarifies the result is an unpublished draft, not a live playlist. It doesn't state error behavior or whether duplicates across input drafts are counted, keeping this below a 5.

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?

Three compact sentences, front-loaded with the action and its output, then the dedup rule, then routing to siblings. Every clause earns its place and none repeats schema-only facts.

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?

No output schema exists, so the description must convey the return artifact, and it does ("one ready draft") plus the publish path. Dedup semantics are stated. It could go further on order/defaults and on whether the source playlists are modified, but for a 7-param merge tool this is close to sufficient.

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 only 14%, so the description must carry more of the burden than it does. It clarifies the playlists parameter (1-6, links or names, drafts or "library"), but says nothing about name, public, maxTracks, excludeExplicit, description, and only implicitly about order. Most parameters remain undocumented in both places.

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 (combine/merge), the resource (1-6 Spotify playlists, drafts, or library), the count bound, and the output artifact (one ready draft). It also names the sibling it is not (expand_playlist), so an agent can discriminate without opening the schema.

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?

Explicitly routes the agent: "Then create_playlist to publish" describes the follow-up step, and "For 'add more songs by these artists' use expand_playlist instead" names the alternative and the condition that selects it. Nothing is left to inference.

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