create_folder

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

With no annotations, the description carries the full burden and does well: it discloses that a new folder track is created above the tracks, that they route through it, and that effects on the folder act like a bus. It does not say whether the operation is reversible (undo), what happens to pre-existing folder membership, or what the call returns, which keeps it short of a 5 for a mutation tool.

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, zero waste, front-loaded with what the tool produces, then the disambiguating alternative. Nothing is repeated from the schema or annotations.

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 structural mutation with no annotations and no output schema, the description covers the essential semantics: what gets created, how routing changes, and the bus behavior. The only notable gap is the absence of any statement about the return value or reversibility, which would matter for a routing-altering operation.

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 name, color (#RRGGBB) and tracks are already documented in the schema. The description adds only the concept of grouping 'tracks', which the schema already conveys; baseline 3 is appropriate.

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 states a specific verb+resource ('Groups tracks in a folder') and immediately explains the resulting structure: a new folder track above the grouped tracks that they play through. It also explicitly names the sibling it is not (create_bus), so an agent can distinguish the two without opening either 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 alternative and the condition that selects it: 'Use create_bus instead to keep tracks where they are and send them.' This is a clean when-to-use-this vs when-to-use-the-other statement, which is exactly what an agent needs to route between the two grouping tools.

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