list_my_playlists

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

With no annotations at all, the description carries the full behavioral burden, and it does meaningful work: it explains the cache-state semantics of the last field ("current", "changed" since loading, or null), which an agent could not infer from the empty schema. It still doesn't state explicitly that this is a read-only, non-mutating call, nor anything about result size, ordering, or pagination, which matters for a user with many playlists.

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 sentences, front-loaded with what the tool returns and followed by the required workflow step. No filler, no restatement of the tool name, and the trailing conditional ("before calling load_playlists") earns its place by preventing a wrong sibling call.

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?

There is no output schema, so the description compensates by enumerating the returned fields and decoding the tri-state cache value — exactly the information an agent would otherwise lack. Combined with the workflow instruction toward load_playlists, nothing an agent needs to invoke and then act on this tool is missing.

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 tool takes zero parameters, so there is nothing for the description to disambiguate and the baseline of 4 applies. The description instead spends its space on the return shape, which is the more useful information here.

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 uses a specific verb and scoped resource: "The user's Spotify playlists" (i.e., list the current user's own playlists, not arbitrary ones), and immediately enumerates the returned fields (id, name, track count, ownership, link, cache state). That is enough to distinguish it from siblings such as get_playlist_tracks, find_tracks, or collection_stats without opening any 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?

It gives an explicit next-step protocol: "Show the list to the user and ask which playlists they want to load before calling load_playlists." That names the alternative tool and the precondition that selects it, so an agent knows this is the discovery step preceding load_playlists rather than a substitute for it.

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