browser_file_upload
Attach files to an <input type=file>. Pass either local_paths (absolute host paths) or data (list of {name, mime, base64} blobs written to /tmp). 25MB cap per file.
This record as markdown: /tools/io-github-saloprj-dialogbrain/browser-file-upload.md
What browser_file_upload does on Dialogbrain
AI agents use browser_file_upload to create or update resources in Dialogbrain, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Dialogbrain environment.
| Parameter | Type | Required | Description |
|---|---|---|---|
ref | string | Yes | |
data | object | — | |
page_id | string | Yes | |
local_paths | object | — |
Parameters from the server's own tool schema.
Why browser_file_upload is rated Medium
This is a Write operation: it creates or modifies files on the system (either writing provided data to /tmp or attaching local files). While it doesn't execute code directly, it can stage files that may later be executed or sent through the messaging system.
From the tool's definition Tool attaches/uploads files to file input elements and writes data to /tmp filesystem. Description states 'Attach files' and 'written to /tmp', indicating file creation/modification operations.
Attacks that exploit this kind of access
The rule that runs browser_file_upload safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Dialogbrain, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For browser_file_upload, this is the rule to start with:
browser_file_upload 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 Dialogbrain, apply this rule, and every browser_file_upload call is checked against it from then on.
Questions about browser_file_upload
Attach files to an <input type=file>. Pass either local_paths (absolute host paths) or data (list of {name, mime, base64} blobs written to /tmp). 25MB cap per file. It is categorised as a Write tool in the Dialogbrain MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
browser_file_upload accepts 4 parameters: ref, data, page_id, local_paths. Required: ref, page_id. The full parameter table on this page comes from the server's own tool schema.
Register the Dialogbrain MCP server in PolicyLayer and add a rule for browser_file_upload: 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 Dialogbrain. Nothing to install.
browser_file_upload 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 browser_file_upload 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 browser_file_upload. 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.
browser_file_upload is provided by the Dialogbrain MCP server (https://api.dialogbrain.com/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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