file_write_commit
Finalize an upload as an app file (create or overwrite by path) — the chunked equivalent of file_write. The upload is consumed either way; on failure, restart from file_write_begin.
This record as markdown: /tools/2nd1st-open-mcp-apps/file-write-commit.md
What file_write_commit does on Open Mcp Apps
AI agents use file_write_commit to create or update resources in Open Mcp Apps, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Open Mcp Apps environment.
Why file_write_commit is rated Medium
This tool creates or modifies files persistently in the app's file system. While it can overwrite existing files, the operation is reversible (a subsequent write can change it back), distinguishing it from a Destructive delete operation. The 'high' severity reflects that an AI agent could overwrite critical application files, configurations, or user data if provided malicious or incorrect file paths and content.
From the tool's definition Tool description states 'create or overwrite by path' and 'Finalize an upload as an app file.' The use of 'overwrite' and 'commit' indicates data modification capability.
Attacks that exploit this kind of access
The rule that runs file_write_commit safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Open Mcp Apps, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For file_write_commit, this is the rule to start with:
file_write_commit stays usable, but capped: an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Open Mcp Apps, apply this rule, and every file_write_commit call is checked against it from then on.
Questions about file_write_commit
Finalize an upload as an app file (create or overwrite by path) — the chunked equivalent of file_write. The upload is consumed either way; on failure, restart from file_write_begin. It is categorised as a Write tool in the Open Mcp Apps MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Open Mcp Apps MCP server in PolicyLayer and add a rule for file_write_commit: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Open Mcp Apps. Nothing to install.
file_write_commit is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the file_write_commit rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for file_write_commit. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
file_write_commit is provided by the Open Mcp Apps MCP server (@2nd1st/open-mcp-apps). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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