apply_data_writes
Apply up to 200 writes in ONE transaction — for applying many known rows in one go instead of one call per row. Each command is exactly what you would send to data_add_item / data_update_item / data_move_item, as {type, ...args}: type is add_item | update_item | move_item. Deletion is not one of ...
This record as markdown: /tools/2nd1st-open-mcp-apps/apply-data-writes.md
What apply_data_writes does on Open Mcp Apps
AI agents use apply_data_writes 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 apply_data_writes is rated Medium
Batch creates or modifies data reversibly; transactional rollback prevents accidental partial updates.
From the tool's definition Apply up to 200 writes in ONE transaction — add_item / update_item / move_item
Risk signalsBulk/mass operation — affects multiple targets
Attacks that exploit this kind of access
The rule that runs apply_data_writes 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 apply_data_writes, this is the rule to start with:
apply_data_writes 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 apply_data_writes call is checked against it from then on.
Questions about apply_data_writes
Apply up to 200 writes in ONE transaction — for applying many known rows in one go instead of one call per row. Each command is exactly what you would send to data_add_item / data_update_item / data_move_item, as {type, ...args}: type is add_item | update_item | move_item. Deletion is not one of them: a delete needs its own confirmation, which an all-or-nothing batch cannot give per row, so it goes through data_delete_item. All or nothing: the first failure rolls back everything and names which command failed. The reply is one line per command ({id, seq}) — not the rows, which you already have. 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 apply_data_writes: 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.
apply_data_writes 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 apply_data_writes 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 apply_data_writes. 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.
apply_data_writes 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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