write_file

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 it delivers: it explains overwrite refusal, the destructive risk of full rewrites, filesystem confinement to download root and BIONIC_PROJECT_ROOTS, automatic creation of missing parent directories, no CRLF translation, byte-for-byte newline fidelity, and UTF-8 encoding. This is exemplary disclosure for a mutating file tool.

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 organized and front-loaded: the purpose appears first, followed by the critical overwrite caveat, sibling routing, filesystem constraints, and encoding guarantees. Every sentence adds operational value; nothing is filler or redundant with the schema.

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 mutating tool with no annotations and no schema-level parameter descriptions, this description is remarkably complete. It covers success behavior, failure/refusal behavior, scope restrictions, edge cases like missing directories, and byte-level output guarantees. The presence of an output schema means return value details are not required in the description.

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 0%, so the description must compensate for all parameters. It explains overwrite semantics clearly, path confinement, parent-directory creation, and content encoding/newline behavior. The only minor gap is that the exact path format or how roots are specified is not directly stated, but the confinement rule gives enough practical guidance.

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 text file, or replace one entirely.' It clearly distinguishes itself from sibling edit_file by stating that partial changes should use edit_file and that write_file is reserved for creating new files (or full replacements). An agent can tell exactly what this tool does and what it is not for.

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 gives explicit when-to-use guidance: use write_file for creating new files, use edit_file for changing part of a file. It also explains the deliberate default of refusing overwrite unless overwrite is true, and warns against using full-file rewrites for small changes. This is strong routing and usage instruction.

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