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

With no annotations, the description carries the full burden and does so well: it reveals the mkdir -p behavior (parent dirs included), the idempotent safe call (reply distinguishes `created` vs `existed`), and points to sibling behavior for bundleId. This directly informs an agent about expected side effects and non-error 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?

Three sentences, each essential: the action, the key idempotent behavior with use-case, and the sibling reference. No filler or redundancy. Front-loaded with the main verb.

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 3-param tool with no output schema, the description covers the purpose, the critical behavior on existing paths, and points to a sibling for bundleId semantics. It doesn't document full return format or error conditions, but the `created` vs `existed` mention provides enough for a simple directory-creation tool.

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 100% per context, so baseline is 3. The description adds value by noting 'parent directories included' (clarifies remotePath's recursive behavior) and cross-referencing ios_file_list for bundleId semantics, which the schema itself doesn't explicitly state (though it's detailed). This nudges the score to 4.

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 'Create a directory on an iOS device, parent directories included' — a specific verb-object-action phrase that clearly identifies the tool's function. It distinguishes from sibling file operations (copy, move, delete, list) by the act of creating directories, and the addition of parent-directory behavior adds scope clarity.

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 a concrete use case: 'staging a temp folder needs no existence check first', which tells the agent when this idempotent behavior is advantageous. It also references 'Same bundleId root selection as ios_file_list' to orient the user with existing sibling semantics, though it doesn't explicitly exclude alternative tools.

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