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

With no annotations provided, the description carries the full behavioral burden and does so well. It discloses parent-directory creation, idempotent behavior when the directory already exists, and the distinct `created` vs `existed` reply values. It does not cover error conditions or permission prerequisites, but for a simple directory-creation operation the core behavioral contract is transparent.

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?

The description is three sentences, front-loaded with the primary action and then the idempotency behavior, followed by a concise cross-reference to ios_file_list. Every sentence earns its place, with no filler or redundant restatement.

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?

The definition covers the core action, parent-directory creation, idempotency, reply semantics, and the bundleId root-selection behavior. Since no output schema is present, the explicit mention of `created` vs `existed` is helpful. A full description of the reply payload or common failure modes would make it completely self-sufficient.

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 the input schema already documents udid, bundleId, and remotePath in detail. The description adds only the cross-reference that bundleId root selection matches ios_file_list, which does not materially extend parameter understanding. The baseline of 3 is appropriate because the schema carries the semantic load.

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 opens with a specific verb and resource: 'Create a directory on an iOS device, parent directories included.' This clearly differentiates it from related iOS file tools like ios_file_list, ios_file_push, and ios_file_stat, and the platform scope is explicit. The additional note about existing directories further characterizes the operation rather than merely restating the tool name.

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 provides an explicit use case: staging a temp folder requires no existence check because the tool tolerates an already-existing directory. It also cross-references ios_file_list for the shared bundleId root-selection rule, which helps an agent choose consistent parameters. However, it does not compare against the generic device_file_mkdir sibling or state when this iOS-specific version should be preferred over it.

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