mark_read · Telegram MCP: Risk & Policy

WHAT IT DOES

What mark_read does on Telegram

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

WHY IT NEEDS A POLICY

Why mark_read needs a policy

This tool modifies message metadata (read/unread status) but does not create, delete, or execute code. The operation is reversible and affects only visibility state, not data integrity or content. While it performs a write operation, the blast radius is minimal since it only changes UI/notification state within a single chat, and the user can manually re-mark messages as unread.

From the tool's definition Tool performs 'Mark all messages in a chat as read' — a state change operation that modifies the read status of messages, reversible by marking them unread.

Risk signalsBulk/mass operation — affects multiple targets

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

mark_read Rate-limited

mark_read 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": {
    "mark_read": {
      "limits": [
        {
          "counter": "mark_read_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 Telegram, so you can run agents against it safely.

FAQ

Questions about mark_read

What does the mark_read tool do? +

Mark all messages in a chat as read. It is categorised as a Write tool in the Telegram MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on mark_read? +

Register the Telegram MCP server in PolicyLayer and add a rule for mark_read: 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 Telegram. Nothing to install.

What risk level is mark_read? +

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

Can I rate-limit mark_read? +

Yes. Add a rate_limit block to the mark_read 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 mark_read completely? +

Set action: deny in the PolicyLayer policy for mark_read. 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 mark_read? +

mark_read is provided by the Telegram MCP server (vovavindar/telegram-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.