# file_write_chunk

Append the next chunk of bytes (base64) to an upload started with file_write_begin. Send chunks strictly in order, one at a time. Pass

Agent View of the PolicyLayer registry record for `file_write_chunk`. HTML page: https://policylayer.com/tools/2nd1st-open-mcp-apps/file-write-chunk

## Facts

- Tool: `file_write_chunk`
- Server: Open Mcp Apps (`@2nd1st/open-mcp-apps`) — https://policylayer.com/tools/2nd1st-open-mcp-apps.md
- Install: `npx -y @2nd1st/open-mcp-apps`
- Homepage: https://github.com/2nd1st/open-mcp-apps
- Risk category: Write (Medium risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 0
- Recommended policy verdict: Rate-limited

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "file_write_chunk",
    "arguments": {}
  }
}
```

## Why file_write_chunk is rated Medium

Tool writes data to files in chunks; reversible but can overwrite existing content with repeated calls.

From the tool's own definition: "Append chunk of bytes to upload; creates/modifies files sequentially"

## Use case

AI agents use file_write_chunk 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.

## Recommended policy (PolicyLayer)

Verdict: **Rate-limited**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Open Mcp Apps:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "file_write_chunk": {
      "limits": [
        {
          "counter": "file_write_chunk_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}
```

## Other tools on Open Mcp Apps (31)

- `data_delete_item` — Destructive — https://policylayer.com/tools/2nd1st-open-mcp-apps/data-delete-item.md
- `delete_app` — Destructive — https://policylayer.com/tools/2nd1st-open-mcp-apps/delete-app.md
- `file_delete` — Destructive — https://policylayer.com/tools/2nd1st-open-mcp-apps/file-delete.md
- `call_function` — Execute — https://policylayer.com/tools/2nd1st-open-mcp-apps/call-function.md
- `app_store_list` — Read — https://policylayer.com/tools/2nd1st-open-mcp-apps/app-store-list.md
- `data_changes` — Read — https://policylayer.com/tools/2nd1st-open-mcp-apps/data-changes.md
- `data_list` — Read — https://policylayer.com/tools/2nd1st-open-mcp-apps/data-list.md
- `file_list` — Read — https://policylayer.com/tools/2nd1st-open-mcp-apps/file-list.md
- `file_read` — Read — https://policylayer.com/tools/2nd1st-open-mcp-apps/file-read.md
- `get_app` — Read — https://policylayer.com/tools/2nd1st-open-mcp-apps/get-app.md
- `get_app_guide` — Read — https://policylayer.com/tools/2nd1st-open-mcp-apps/get-app-guide.md
- `get_app_html` — Read — https://policylayer.com/tools/2nd1st-open-mcp-apps/get-app-html.md
- `get_data_version` — Read — https://policylayer.com/tools/2nd1st-open-mcp-apps/get-data-version.md
- `get_ui_preference_schema` — Read — https://policylayer.com/tools/2nd1st-open-mcp-apps/get-ui-preference-schema.md
- `list_app_checkpoints` — Read — https://policylayer.com/tools/2nd1st-open-mcp-apps/list-app-checkpoints.md
- `list_apps` — Read — https://policylayer.com/tools/2nd1st-open-mcp-apps/list-apps.md
- `list_data_collections` — Read — https://policylayer.com/tools/2nd1st-open-mcp-apps/list-data-collections.md
- `preview_app_store_entry` — Read — https://policylayer.com/tools/2nd1st-open-mcp-apps/preview-app-store-entry.md
- `apply_data_writes` — Write — https://policylayer.com/tools/2nd1st-open-mcp-apps/apply-data-writes.md
- `data_add_item` — Write — https://policylayer.com/tools/2nd1st-open-mcp-apps/data-add-item.md
- `data_move_item` — Write — https://policylayer.com/tools/2nd1st-open-mcp-apps/data-move-item.md
- `data_update_item` — Write — https://policylayer.com/tools/2nd1st-open-mcp-apps/data-update-item.md
- `edit_app` — Write — https://policylayer.com/tools/2nd1st-open-mcp-apps/edit-app.md
- `file_write` — Write — https://policylayer.com/tools/2nd1st-open-mcp-apps/file-write.md
- `file_write_begin` — Write — https://policylayer.com/tools/2nd1st-open-mcp-apps/file-write-begin.md
- `file_write_commit` — Write — https://policylayer.com/tools/2nd1st-open-mcp-apps/file-write-commit.md
- `install_from_app_store` — Write — https://policylayer.com/tools/2nd1st-open-mcp-apps/install-from-app-store.md
- `promote_app` — Write — https://policylayer.com/tools/2nd1st-open-mcp-apps/promote-app.md
- `restore_app` — Write — https://policylayer.com/tools/2nd1st-open-mcp-apps/restore-app.md
- `save_app` — Write — https://policylayer.com/tools/2nd1st-open-mcp-apps/save-app.md
- …and 1 more: https://policylayer.com/tools/2nd1st-open-mcp-apps.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

---

Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=2nd1st-open-mcp-apps · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/2nd1st-open-mcp-apps