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

Annotations already declare read-only, idempotent, non-destructive, and open-world behavior; the description adds value by disclosing the playlist-ordering guarantee, private-playlist error behavior (playlist_private), and the 1-credit cost. It does not discuss pagination or the limit behavior, but the schema documents the limit and the output schema covers the response.

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?

Every sentence earns its place: purpose/order, accepted input formats, privacy constraint and remediation, credit cost, and downstream workflow. It is front-loaded with the core behavior and has no redundant 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 read-only list tool, the description covers input, ordering, privacy edge case, cost, and next-step chaining, and the output schema covers return structure. The only notable gap is that 'every video' is not reconciled with the schema's default/max limit, though the schema itself provides that information.

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 100%, so the baseline is a 3; the description adds value beyond the schema by specifying that a bare playlist id of 13, 18, 26, or 34 characters is accepted and that a URL or the list= value works. The limit parameter is left to the schema, which is acceptable at full coverage.

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?

Opens with a specific verb and resource: 'List every video in a YouTube playlist, in playlist order,' which makes the operation and its ordering behavior immediately clear. This distinguishes it from sibling tools like get_channel_videos or get_latest_videos by focusing on the playlist resource. The phrase 'every' is a little strong given the optional limit, but the core purpose is unambiguous.

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 gives practical use context: it accepts playlist URLs or bare IDs, requires public/unlisted visibility, explains what to do about private playlists, and recommends chaining into get_transcripts for bulk extraction. It does not explicitly list alternative sibling tools, but the playlist-specific scope plus sibling names makes selection clear.

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