send_reaction · Wa Bridge MCP: Risk & Policy

WHAT IT DOES

What send_reaction does on Wa Bridge

AI agents use send_reaction to create or update resources in Wa Bridge — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Wa Bridge environment.

WHY IT NEEDS A POLICY

Why send_reaction needs a policy

This tool creates or modifies data (emoji reactions on messages) in a reversible manner. While it affects message metadata and conversation state, the action is undoable (reactions can be added and removed). It does not execute arbitrary code, delete data permanently, or involve financial transactions.

From the tool's definition 'React to a message with a single emoji' - modifies message state by adding or removing reactions. The empty string parameter indicates reversible modification: 'Pass an empty string for emoji to remove an existing reaction.'

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

send_reaction Rate-limited

send_reaction 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.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "send_reaction": {
      "limits": [
        {
          "counter": "send_reaction_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Wa Bridge, so you can run agents against it safely.

FAQ

Questions about send_reaction

What does the send_reaction tool do? +

React to a message with a single emoji. Pass an empty string for emoji to remove an existing reaction. It is categorised as a Write tool in the Wa Bridge MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on send_reaction? +

Register the Wa Bridge MCP server in PolicyLayer and add a rule for send_reaction: 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 Wa Bridge. Nothing to install.

What risk level is send_reaction? +

send_reaction is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit send_reaction? +

Yes. Add a rate_limit block to the send_reaction 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.

How do I block send_reaction completely? +

Set action: deny in the PolicyLayer policy for send_reaction. 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.

What MCP server provides send_reaction? +

send_reaction is provided by the Wa Bridge MCP server (obirimensah05/whatsapp-bridge). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.