itunes_merge_playlists

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

The parenthetical '(skipping duplicate songs)' is a genuinely valuable behavioral disclosure—it tells the user that output is deduplicated, not error-prone. With zero annotations provided, the description carries the full transparency burden and passes, but it stops short of revealing side effects (e.g., whether playlists are validated to exist, whether a missing playlist creates a new one, or if the master playlist is created in iCloud vs local).

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?

The description is exceptionally lean: one sentence of behavior followed by a three-line Args block that adds zero fluff. Every word earns its place, and the core action is front-loaded.

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?

Given the tool's low complexity—only 3 string parameters, no output schema, no enums—the description is nearly sufficient on its own. It captures inputs, the merge behavior, the dedupe rule, and the target output. A small gap remains around error handling (e.g., what if playlists are identical or empty?), but for a simple function the bar is met and slightly exceeded.

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 0% (parameters are only typed strings), so the description's Args block must compensate. It does, by defining each parameter's role: 'First source playlist,' 'Second source playlist,' and 'Target master playlist name.' This disambiguates the two sources from the output exactly when it matters—though it mostly restates what the identifiers already imply.

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 opening sentence states a specific verb, resource, and output: 'Merge tracks from two playlists into a new master playlist (skipping duplicate songs).' It immediately differentiates the tool from siblings—no other sibling natively merges two playlists—while disclosing the dedupe behavior up front.

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 clearly scopes the use case: merge exactly two playlists into a new one, with the word 'new' implying originals are untouched. However, it never explicitly states when NOT to use this tool or names a fallback alternative (e.g., copy-with-add-to-playlist for single-playlist duplication), leaving some ambiguity about edge cases.

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