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

Annotations already declare the safety profile (readOnlyHint=false, destructiveHint=false, idempotentHint=false), so the bar is lower. The description still adds two meaningful facts beyond them: the call is free (relevant given credit-related siblings) and it returns the new folder with its id. It does not mention that repeated calls create duplicates, which the non-idempotent hint implies.

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?

Three short sentences, no filler, with the core action front-loaded and the cost/return facts following. Every clause carries information an agent would otherwise have to infer.

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 creation tool with no output schema, the description covers what it does, the optional nesting, the cost, and the return shape. The remaining gap is failure behavior (invalid parent_id, name conflicts), which is minor but not stated.

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 only 50%: parent_id is documented in the schema, while name is not described anywhere. The description compensates partly by making explicit that parent_id is optional and should be sourced from list_folders, but it says nothing about the name parameter's meaning or the 80-character limit.

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?

"Creates a folder" is a specific verb+resource, and "optionally inside another one" states the nesting scope. It also points at list_folders for the parent, which orients the agent among siblings, though it does not contrast itself with any other creation tool (none exist here) beyond that reference.

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 implies usage context by noting parent_id comes from list_folders and that the operation is free, which steers the agent away from estimate_cost/buy_credits style siblings. It does not state when not to use it, nor what happens on duplicate names or invalid parents.

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