The core agent supports allow_arbitrary_tags (default false, env DD_ALLOW_ARBITRARY_TAGS). When enabled, the forwarder adds an Allow-Arbitrary-Tag-Value: true HTTP header to every outbound request, signaling the Datadog backend to relax server-side tag validation (length limits, character restrictions, etc.). The agent itself performs no tag validation based on this setting — it is purely a pass-through signal.
This was introduced in DataDog/datadog-agent#6630 for Database Monitoring (DBM), which submits metrics tagged with raw SQL query text (e.g. query:select * from mytable). These values violate standard tag format rules and would be rejected or stripped without the header. The feature was originally a beta opt-in requiring both the agent flag and a corresponding backend-side feature flag.
ADP's forwarder does not read this config key and does not send the header. A customer with allow_arbitrary_tags: true running ADP would have non-standard tags silently rejected or stripped by the backend.
Worth checking whether DBM (now GA) still requires customers to set this flag, or whether the backend has moved to accepting arbitrary tags unconditionally for DBM workloads. If the flag is still active, implement support — it is a one-line header addition in the forwarder middleware.
The core agent supports
allow_arbitrary_tags(defaultfalse, envDD_ALLOW_ARBITRARY_TAGS). When enabled, the forwarder adds anAllow-Arbitrary-Tag-Value: trueHTTP header to every outbound request, signaling the Datadog backend to relax server-side tag validation (length limits, character restrictions, etc.). The agent itself performs no tag validation based on this setting — it is purely a pass-through signal.This was introduced in DataDog/datadog-agent#6630 for Database Monitoring (DBM), which submits metrics tagged with raw SQL query text (e.g.
query:select * from mytable). These values violate standard tag format rules and would be rejected or stripped without the header. The feature was originally a beta opt-in requiring both the agent flag and a corresponding backend-side feature flag.ADP's forwarder does not read this config key and does not send the header. A customer with
allow_arbitrary_tags: truerunning ADP would have non-standard tags silently rejected or stripped by the backend.Worth checking whether DBM (now GA) still requires customers to set this flag, or whether the backend has moved to accepting arbitrary tags unconditionally for DBM workloads. If the flag is still active, implement support — it is a one-line header addition in the forwarder middleware.