Write or append to a file

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

Annotations already declare destructiveHint=true and idempotentHint=false, and the description reinforces this by flagging overwrite semantics without contradicting them. It adds genuinely non-structured context: atomic writes for overwrite mode, automatic parent directory creation, and that a small JSON summary is returned.

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?

Four short sentences with no filler, and the most important information (create/overwrite/append into an allowed directory) is front-loaded. Slightly episodic but every sentence carries information.

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 mutation tool with no output schema, the description covers the destructive overwrite behavior, atomicity, directory creation, and return shape. The main remaining gap is guidance on choosing it over edit_file.

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 all five parameters are already documented, and the description adds only a loose reference to parent directory creation. It contributes no syntax, defaults, or edge-case behavior beyond what the schema states.

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 concrete verbs (create, overwrite, append) against a specific resource (text file) and adds a scoping constraint (inside an allowed directory). It does not differentiate from the closely related edit_file sibling, so an agent must still infer which write tool to pick.

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 'create, overwrite or append' and the allowed-directory constraint, but there is no explicit when-to-use or when-not guidance. Nothing tells the agent to prefer edit_file for in-place changes or read_file/stat_path for verification.

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