Initiates a Slack RTM session providing a single-use WebSocket URL (valid 30s) for event streaming; does not set initial presence status.
Single-target operation
Part of the Slack MCP server. Enforce policies on this tool with Intercept, the open-source MCP proxy.
AI agents invoke SLACK_START_REAL_TIME_MESSAGING_SESSION to trigger processes or run actions in Slack. Execute operations can have side effects beyond the immediate call -- triggering builds, sending notifications, or starting workflows. Rate limits and argument validation are essential to prevent runaway execution.
SLACK_START_REAL_TIME_MESSAGING_SESSION can trigger processes with real-world consequences. An uncontrolled agent might start dozens of builds, send mass notifications, or kick off expensive compute jobs. Intercept enforces rate limits and validates arguments to keep execution within safe bounds.
Execute tools trigger processes. Rate-limit and validate arguments to prevent unintended side effects.
tools:
SLACK_START_REAL_TIME_MESSAGING_SESSION:
rules:
- action: allow
rate_limit:
max: 10
window: 60
validate:
required_args: trueSee the full Slack policy for all 143 tools.
Agents calling execute-class tools like SLACK_START_REAL_TIME_MESSAGING_SESSION have been implicated in these attack patterns. Read the full case and prevention policy for each:
Other tools in the Execute risk category across the catalogue. The same policy patterns (rate-limit, validate) apply to each.
SLACK_START_REAL_TIME_MESSAGING_SESSION is one of the high-risk operations in Slack. For the full severity-focused view — only the high-risk tools with their recommended policies — see the breakdown for this server, or browse all high-risk tools across every MCP server.
Initiates a Slack RTM session providing a single-use WebSocket URL (valid 30s) for event streaming; does not set initial presence status.. It is categorised as a Execute tool in the Slack MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Add a rule in your Intercept YAML policy under the tools section for SLACK_START_REAL_TIME_MESSAGING_SESSION. You can allow, deny, rate-limit, or validate arguments. Then run Intercept as a proxy in front of the Slack MCP server.
SLACK_START_REAL_TIME_MESSAGING_SESSION is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the SLACK_START_REAL_TIME_MESSAGING_SESSION rule in your Intercept 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 Intercept policy for SLACK_START_REAL_TIME_MESSAGING_SESSION. 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.
SLACK_START_REAL_TIME_MESSAGING_SESSION is provided by the Slack MCP server (@modelcontextprotocol/server-slack). Intercept sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Open source. One binary. Zero dependencies.
npx -y @policylayer/intercept