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Concurrency Guard
x402
Concurrency Guard is a paid API for AI agents from phion.systems, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-27).
Enforces concurrent execution slot limits to prevent agents or workflows from exceeding defined parallelism thresholds
Price / call$0.002
Success—
StatusUnknown
How this service works
Enforce concurrent slot limits
Output
Returns a decision indicating whether a new concurrent execution slot is available or the limit has been reached, along with the current active slot count and whether the requesting agent/task is permitted to proceed.
Example use cases
Agent fleet parallelism cap
“I have 10 agents that could all fire at once — can you enforce that no more than 3 run concurrently? Check before each one starts whether a slot is free.”
Rate-limit-safe API batch processing
“We're about to kick off a batch of 20 API calls but the downstream service only allows 4 concurrent connections — use the concurrency guard to make sure we never exceed 4 at a time.”
Multi-tenant workflow isolation
“Each of our tenants should only be allowed 2 simultaneous workflow executions — enforce that limit and block any new job from starting if both slots are already occupied.”
Technical details
Endpoint
POSThttps://phion.systems/v1/paid/trust/concurrency-guard?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need a lightweight, policy-enforcing gate to cap parallelism across agent tasks, API calls, or workflow jobs — especially in agentic systems where many tasks can fire simultaneously and downstream services have strict concurrency limits. Prefer it over client-side counters when you need a centralized, authoritative source of truth for slot availability shared across distributed agents.
Side effects
- Slot count already at maximum — request denied, agent must wait or retry
- Missing or invalid resource/session identifier in request body
- Concurrent write conflict when multiple agents check simultaneously (race condition)
- Service unavailable or timeout if the guard store is unreachable
- Stale slot state if a previous execution did not properly release its slot
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| outputrequired | object |
Output
Schema · Response
{
"type": "json"
}Tags
x402
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