Write an entry to the TRAIL content log. Use to explicitly record content actions.
AI agents use mark_trail to create or update resources in Telegram Api — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Telegram Api environment.
This tool creates or modifies log entries in a content audit trail, which is a reversible write operation. While it doesn't directly manipulate user data or Telegram conversations, it writes to an internal logging system.
From the tool's definition Tool name "mark_trail" and description "Write an entry to the TRAIL content log" explicitly indicates writing/recording data to a log system.
Documented attack patterns abuse exactly the kind of access mark_trail gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Telegram Api, and nothing reaches the server without passing your rules. This is the rule we recommend for mark_trail:
{
"version": "1",
"default": "deny",
"tools": {
"mark_trail": {
"limits": [
{
"counter": "mark_trail_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}mark_trail 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.
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Write an entry to the TRAIL content log. Use to explicitly record content actions. It is categorised as a Write tool in the Telegram Api MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Telegram Api MCP server in PolicyLayer and add a rule for mark_trail: 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 Api. Nothing to install.
mark_trail 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 mark_trail 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 mark_trail. 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.
mark_trail is provided by the Telegram Api MCP server (timoncool/telegram-api-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Telegram Api, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
6 Telegram Api tools catalogued and risk-classified — across an index of 43,000+ MCP servers.