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

Annotations only declare destructiveHint=false, so the description carries the behavioral burden and largely fails it: no mention of ownership requirements, duplicate-name behavior, idempotency, or side effects. 'Mirrors POST /api/v1/folders' adds an endpoint mapping but no runtime behavior.

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 short sentences, front-loaded with the core action and no filler. Every clause earns its 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 simple two-parameter creation tool with a fully documented schema and no output schema, the description covers the essential scope and the parent-nesting option. It is only slightly thin on failure modes and permission requirements, which the schema partially covers via 'must be a folder you own'.

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% — both name and parent_id are fully documented in the schema, including the ownership constraint and null/omit semantics. The description adds nothing beyond the schema, so the baseline 3 applies.

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 (media library folder) plus the optional nesting behavior, so it is clearly distinct from delete_folder, update_folder, get_folder and list_folders. It stops short of naming any sibling explicitly, which keeps it from a 5.

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 says what the tool does but gives no when-to-use guidance, no prerequisites (e.g. auth/ownership needed to create), and no routing to alternatives. The only usage signal is the incidental note that nesting is optional.

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