concurrency-queued
A mutex tool with queue (maxConcurrent: 1, queueTimeout: 3s)
This record as markdown: /tools/frontmcp/concurrency-queued.md
What concurrency-queued does on Frontmcp
AI agents invoke concurrency-queued to trigger actions in Frontmcp. 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.
Why concurrency-queued is rated High
A mutex/queue tool controls execution flow by serializing operations, enforcing concurrency limits, and timing out queued requests. This implies it triggers or gates execution of other operations, placing it in the Execute category. The blast radius is medium: misuse could cause deadlocks, starvation, or denial-of-service by exhausting the queue, but it doesn't directly destroy data or move money.
From the tool's definition 'A mutex tool with queue (maxConcurrent: 1, queueTimeout: 3s)' — describes a concurrency control mechanism that queues and executes operations serially
Attacks that exploit this kind of access
The rule that runs concurrency-queued safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Frontmcp, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For concurrency-queued, this is the rule to start with:
concurrency-queued 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.
The button opens the PolicyLayer dashboard: create your workspace, connect Frontmcp, apply this rule, and every concurrency-queued call is checked against it from then on.
Questions about concurrency-queued
A mutex tool with queue (maxConcurrent: 1, queueTimeout: 3s). It is categorised as a Execute tool in the Frontmcp MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Front MCP server in PolicyLayer and add a rule for concurrency-queued: 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 Frontmcp. Nothing to install.
concurrency-queued 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 concurrency-queued 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 concurrency-queued. 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.
concurrency-queued is provided by the Front MCP server (agentfront/frontmcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
More on Front, and thousands of servers like it.
Across the catalogue