add_to_playlist

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

With no annotations provided, the description carries the full behavioral burden and falls short: it doesn't disclose that this is a write/mutation requiring user authorization, whether duplicates are allowed, whether tracks are appended or replace existing entries, or what the response contains (e.g. a snapshot id). Only the bare action is stated.

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 short sentences, action front-loaded with the requirement following, and no wasted words. It is efficient, though the terseness borders on under-specification rather than genuine conciseness.

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 two-parameter tool with a fully described schema and no output schema, the description is minimally adequate. However, as a mutation with no annotations, it should have covered authorization requirements and duplicate/append behavior to be complete.

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 schema already documents both parameters ('Track URIs', 'Playlist ID, URI or link'), establishing the baseline of 3. The description adds nothing beyond repeating that the two parameters are required, but no compensation is needed given the complete 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?

States a specific verb and resource ('Add tracks to a playlist'), so the agent knows exactly what it does. It doesn't explicitly distinguish itself from the close siblings add_current_to_playlist and add_to_queue, but the plural 'tracks' plus the required 'uris' param implies arbitrary track selection rather than the currently playing track.

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?

There is no guidance on when to use this versus add_current_to_playlist, add_to_queue, or create_playlist. 'Needs playlist_id and uris' merely restates the required parameters rather than giving situational context or prerequisites such as authentication.

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