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

Annotations already declare this is a non-read-only, non-destructive, non-idempotent mutation. The description goes beyond that by spelling out the tri-state parent semantics and the rejection case ('a string together with clearParent: true is rejected') — real behavioral nuance an agent must know. It does not cover permissions or side effects, keeping it from a 5.

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 front-loaded sentences; the field list and the tri-state rule are ordered so the most consequential detail (parent handling) comes immediately after the summary. No padding, though the bracket-free tri-state clause is slightly dense.

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?

With annotations covering the safety profile, full schema coverage, and no output schema, the description only needs to add behavioral nuance — which it does via the tri-state rule. It is largely complete, missing only auth/precondition context for a mutation.

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 already 100%, so the baseline is 3, but the description adds value by explaining the parentId/clearParent interaction and the invalid combination. Note a minor tension with the schema: the schema says clearParent 'overrides any parentId' while the description says a string plus clearParent:true is 'rejected' — the conflict weakens but does not eliminate the added meaning.

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 ('Update a folder') and enumerates the mutable fields (name, parent, color, description, sort), so the agent knows exactly what operation this performs. It does not explicitly contrast itself with folder-create/folder-delete/folder-get, but the operation is unambiguous from the name and text.

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?

Usage is implied by the mutation semantics and the field list, but there is no explicit when-to-use guidance, no prerequisites (e.g. that the folder must exist or that the caller needs edit rights), and no routing to alternative siblings. Adequate but with clear gaps.

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