create_tag

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

With no annotations, the description carries the full burden. It discloses that this is a mutating operation, that it returns the tag with its new id, and that labels are unique library-wide (case-sensitive) — a genuinely useful failure-mode warning. However, it does not say what happens on a duplicate-label attempt or whether category_id must reference an existing category.

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 with zero waste. The primary action is front-loaded, and the second sentence delivers a high-value constraint (uniqueness + case-sensitivity) that an agent needs before calling. Both sentences earn their place.

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 2-parameter create tool with an output schema covering the return shape, the description is adequate but not full. It omits duplicate-handling behavior (especially salient given the uniqueness warning), whether the category must already exist, and any usage guidance relative to sibling tag tools.

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 0%, so the description must compensate. 'Inside a category' clarifies the role of category_id, and 'Tag labels are unique' implies label is the tag's name — meaning beyond the bare property titles. But neither parameter is explicitly defined, and format or validity constraints are left to inference.

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 (create) and resource (custom tag inside a category), and adds the return behavior (new id). This clearly distinguishes it from siblings like create_tag_category (creates a category), set_custom_tags / bulk_apply_tags (apply tags to tracks), and create_smartlist (a different entity).

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 uniqueness warning gives implicit guidance (ensure the label doesn't already exist before calling), and the phrasing implies this is for creating a tag rather than applying or listing tags. But there is no explicit when-to-use statement, no named alternatives, and no stated condition for choosing this over create_tag_category or set_custom_tags.

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