write_file

3 findings on this tool

1. highexcessive agencyf-r3-write_file

   Tool `write_file` name implies a side effect that is not declared

   `write_file` looks like a side-effecting tool (its name contains a mutation verb), but its `side_effects` declaration is []. A policy synthesizer cannot produce safe rules for this tool because it cannot tell what it actually does.

   fix: Declare the tool's true side effects explicitly. If the tool is genuinely read-only, rename it to match (e.g. `email.preview` rather than `email.send`).

   OWASP LLM08NIST MEASURE-2.6ATLAS T0051CAST-01
2. highfilesystem egressf-r9-write_file

   Tool `write_file` writes to or deletes from the host filesystem

   `write_file` appears to write, create, move, or delete files on the host filesystem ( Write or append to file contents. IMPORTANT: DO NOT use this tool to create PDF files. Use 'write_pdf' for all PDF creation tasks. DO NOT use this tool to edit DOCX files. Use 'edit_block' with old_string/new_string instead. To CREATE a new DOCX, use write_file with .docx extension — text content with markdown headings (#, ##, ###) is converted to styled DOCX paragraphs. CHUNKING IS STANDARD PRACTICE: Always write files in chunks of 25-30 lines maximum. This is the normal, recommended way to write files - not an emergency measure. STANDARD PROCESS FOR ANY FILE: 1. FIRST → write_file(filePath, firstChunk, {mode: 'rewrite'}) [≤30 lines] 2. THEN → write_file(filePath, secondChunk, {mode: 'append'}) [≤30 lines] 3. CONTINUE → write_file(filePath, nextChunk, {mode: 'append'}) [≤30 lines] ALWAYS CHUNK PROACTIVELY - don't wait for performance warnings! WHEN TO CHUNK (always be proactive): 1. Any file expected to be longer than 25-30 lines 2. When writing multiple files in sequence 3. When creating documentation, code files, or configuration files HANDLING CONTINUATION ("Continue" prompts): If user asks to "Continue" after an incomplete operation: 1. Read the file to see what was successfully written 2. Continue writing ONLY the remaining content using {mode: 'append'} 3. Keep chunks to 25-30 lines each FORMAT HANDLING (by extension): - Text files: String content - Excel (.xlsx, .xls, .xlsm): JSON 2D array or {"SheetName": [[...]]} Example: '[["Name","Age"],["Alice",30]]' Files over 50 lines will generate performance notes but are still written successfully. Only works within allowed directories. IMPORTANT: Always use absolute paths for reliability. Paths are automatically normalized regardless of slash direction. Relative paths may fail as they depend on the current working directory. Tilde paths (~/...) might not work in all contexts. Unless the user explicitly asks for relative paths, use absolute paths. This command can be referenced as "DC: ..." or "use Desktop Commander to ..." in your instructions.). An agent manipulated by an indirect-injection payload can target sensitive paths (SSH keys, shell configs, application secrets) or establish persistence via cron / systemd.

   fix: Restrict the tool to an explicit allow-list of safe directories. Validate all path parameters server-side, reject traversal sequences (`../`), and gate write / delete operations behind a capframe-bind `path starts_with /safe/dir` caveat.

   OWASP LLM08NIST MANAGE-2.2ATLAS T0051CAST-01
3. mediumunconstrained inputf-r1-write_file

   Tool `write_file` accepts unconstrained string input

   The following string parameter(s) have no `maxLength` constraint: `content`, `path`. Unbounded strings let an attacker stuff arbitrary payloads through the tool, including indirect-injection content.

   fix: Add a `maxLength` to each string property, or constrain with an `enum` or `pattern`. Most legitimate tool inputs fit under a few hundred bytes.

   OWASP LLM01NIST MEASURE-2.3ATLAS T0051CAST-03