Invoke any OpenTabs tool by name. Pass the tool name and its arguments. Use opentabs_list_tools first to discover available tools and their schemas.
AI agents invoke opentabs_call to trigger actions in OpenTabs. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.
opentabs_call is a generic execution interface for invoking arbitrary tools across 100+ web applications with the user's authenticated session. The blast radius is critical because an AI agent could invoke any tool with any arguments across all integrated services—creating messages in Slack, modifying code in GitHub, changing Jira tickets, posting to social media, etc.
From the tool's definition Tool description states 'Invoke any OpenTabs tool by name' with arbitrary arguments. Server grants access to 100+ authenticated web applications (Slack, Discord, GitHub, Jira, Notion, Reddit, X, etc.) through browser APIs.
Documented attack patterns abuse exactly the kind of access opentabs_call gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and OpenTabs, and nothing reaches the server without passing your rules. This is the rule we recommend for opentabs_call:
{
"version": "1",
"default": "deny",
"tools": {
"opentabs_call": {
"limits": [
{
"counter": "opentabs_call_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}opentabs_call stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.
Free to start. No card required.
Invoke any OpenTabs tool by name. Pass the tool name and its arguments. Use opentabs_list_tools first to discover available tools and their schemas. It is categorised as a Execute tool in the OpenTabs MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the OpenTabs MCP server in PolicyLayer and add a rule for opentabs_call: 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 OpenTabs. Nothing to install.
opentabs_call 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 opentabs_call 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 opentabs_call. 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.
opentabs_call is provided by the OpenTabs MCP server (opentabs-dev/opentabs). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 4 OpenTabs tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
4 OpenTabs tools catalogued and risk-classified — across an index of 42,500+ MCP servers.