create_directories

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

Beyond the lone destructiveHint=false annotation, the description discloses real behavioral traits: the operation is atomic, existing directories are reused rather than replaced, and idempotency keys are persisted. It does not cover what happens if the path collides with a file or how partial failures surface, which keeps 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 tightly packed sentences with zero filler, and the core atomicity/reuse constraint is front-loaded before the idempotency note.

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 only two parameters, full schema coverage, and an output schema to describe results, the description covers what an agent needs to invoke it correctly. Missing are edge-case behavior (path already exists as a file, error semantics) that a mutation-style tool would ideally state.

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% and both parameters are documented in-schema, including the 128-byte limit on the key, so the baseline is 3. The description only restates the path/reuse behavior and adds no new meaning about the idempotency key beyond what the schema already says.

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 names a specific verb and resource ('create missing parent directories') plus the reuse semantics, so the operation is unambiguous. It does not, however, distinguish itself from the sibling create_folder, which an agent must resolve on its own.

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 only implied: 'missing parent directories' and 'reuse existing directories' suggest this is the right call for nested absolute paths created in one shot. There is no explicit when-to-use versus create_folder, no stated preconditions, and no exclusion guidance.

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