AxonFlow v8.1.0 Release Notes

Released 2026-05-23. Two additive features ship under the v8.1.0 platform tag: HITL outbound webhook callbacks and HTTP Idempotency-Key deduplication. No breaking changes.

What changed in v8.1.0

HITL outbound webhook callback (notify_url)

POST /api/v1/hitl/queue now accepts an optional notify_url field. When set, the platform fires a signed HTTP POST to that URL after the HITL row reaches a terminal state (approved, rejected, overridden, or expired).

Webhook envelope payload:

Field	Description
approval_id	Unique identifier for the HITL request
status	Terminal status: approved, rejected, overridden, expired
decided_by	Identity of the approver (or system for expiration)
decided_at	ISO 8601 timestamp of the decision
original_query	The original query submitted for approval
request_type	HITL request type (e.g. tool_call, query)
severity	Severity level of the original request
decision_envelope	Full decision metadata including any reviewer notes

Signature verification: The webhook POST includes an X-AxonFlow-Signature: sha256=<hex> header. The signature is HMAC-SHA256 over the raw request body, keyed by the value of AXONFLOW_HITL_WEBHOOK_SIGNING_KEY. Verify the signature before processing the payload.

Delivery behavior: Delivery is asynchronous. Failed deliveries retry at 5s, 30s, and 5m intervals. Each attempt is logged.

HTTP Idempotency-Key header deduplication

Three endpoints now consume the Idempotency-Key request header and deduplicate retries within a 24-hour window:

• POST /api/v1/mcp/check-input
• POST /api/v1/audit/tool-call
• POST /api/v1/hitl/queue

A retry with the same key within 24 hours returns the cached response with an Idempotent-Replayed: true header. Successful (2xx) and client-error (4xx) responses are cached; server errors (5xx) are not cached so the request can be retried.

Key format: validated against ^[A-Za-z0-9_.:\-/]+$, maximum 256 characters. Cross-tenant isolation is enforced — the same key used by different tenants produces independent results.

HITL feature map

GET /api/v1/hitl/status now advertises notify_url: true and idempotency_key: true in its feature map, allowing SDK clients to discover these capabilities at runtime.

What's fixed

• HITL stale-request expiration under FORCE RLS. The background expiration sweep for stale HITL requests now runs correctly under FORCE Row-Level Security. Previously, the sweep silently matched zero rows when the agent connected as axonflow_app_role — a sister bug to the heartbeat path fixed in v8.0.0.

Configuration

Env var	Required	Description
AXONFLOW_HITL_WEBHOOK_SIGNING_KEY	To enable webhooks	HMAC-SHA256 signing key for outbound webhook payloads. When unset, webhook deliveries are logged as DROP.

Schema changes

• Migration 114: adds notify_url TEXT NULL column to hitl_approval_queue.
• Migration 115: creates idempotency_keys table with FORCE Row-Level Security enabled. Composite primary key on (key, tenant_id, endpoint).

What's NOT changed

• SDK floor: Python / TypeScript / Go / Java now ship at v8.2.0; Rust preview at v0.4.0. Previous SDK versions (v8.1.0 / v0.3.1) keep working.
• Plugin floor: claude / cursor / codex at v1.5.0; openclaw at v2.5.0. Unchanged from v8.0.0.
• Compatibility: every v7.x / v8.0.x client keeps working.

Upgrade notes

Self-hosted Community (Docker / docker compose up)

Pull the v8.1.0 image and apply the two new migrations (114 + 115). To enable HITL webhooks, set AXONFLOW_HITL_WEBHOOK_SIGNING_KEY in your environment. When unset, the webhook feature is inactive and deliveries are logged as DROP.

In-VPC Enterprise

No preflight required for v8.0.x to v8.1.0. Existing licenses, credentials, and DSN secrets keep working.

Community-SaaS users

No action required.

SDK users

Upgrade to v8.2.0 (Python / TypeScript / Go / Java) or Rust v0.4.0 when released. The v8.2.0 SDKs add the create_hitl_request() helper for programmatic HITL queue submission. Existing v8.1.0 SDK callers keep working.

Plugin users

No action required. Existing plugins keep working.

Companion SDK release

SDK	Version	What's new
Python	v8.2.0	create_hitl_request() helper for programmatic HITL queue submission
TypeScript	v8.2.0	createHitlRequest() helper
Go	v8.2.0	CreateHITLRequest() helper
Java	v8.2.0	createHitlRequest() helper
Rust	v0.4.0	Full HITL surface including create_hitl_request()

Migration resources

• v8.0.0 Release Notes — the headline v8 release with FORCE RLS and application-role default flip.
• v7 → v8 Migration Guide — deployment-shape decision tree and simple-path community upgrade.