Errors - LexQ Docs

Error Response Format

All errors follow the same envelope:

{
  "result": "ERROR",
  "code": "P-001",
  "message": "Policy group not found."
}

The code field is the stable identifier — pin your integration logic on this value, not on the human-readable message. Messages are localized via the Accept-Language header (en or ko) and may be reworded over time; codes are not.

Code numbers are stable identifiers — once assigned, a code is never reused for a different meaning, even if the original meaning is removed. Gaps in numbering (e.g., missing ACT-007, ACT-008, ACT-010, ACT-011, ACT-012) reflect codes that were retired during the engine’s domain-agnostic primitive refactor.

Common (C)

Code	HTTP	Description
`C-001`	400	Invalid input value
`C-002`	405	HTTP method not allowed
`C-003`	404	Requested resource not found
`C-004`	500	Internal server error
`C-005`	400	Invalid data type
`C-006`	409	Duplicate resource
`C-007`	429	Too many requests (TPS limit exceeded)
`C-008`	400	Invalid timezone
`C-009`	400	Invalid status transition

Auth (A)

Code	HTTP	Description
`A-001`	401	Authentication failed
`A-002`	403	Access denied
`A-003`	401	Invalid API key
`A-004`	409	Email already registered
`A-005`	409	Maximum API keys exceeded
`A-006`	401	Invalid email or password
`A-007`	409	Phone number already registered
`A-008`	401	Google Sign-In required for this account
`A-009`	401	Google account email not verified
`A-010`	401	Google authentication failed
`A-011`	400	Password reset unavailable for Google account
`A-012`	400	Password change unavailable for Google account
`A-013`	400	New password must differ from current
`A-014`	400	Password reset link expired or invalid
`A-015`	503	Verification email send failed
`A-016`	401	Session expired
`A-017`	401	Invalid session
`A-018`	403	System account required
`A-019`	403	System Manager account is immutable
`A-020`	401	Password incorrect

Policy Engine (P)

Code	HTTP	Description
`P-001`	404	Policy group not found
`P-002`	404	Policy version not found
`P-003`	400	Policy execution failed
`P-004`	400	Policy version not approved
`P-005`	404	Policy rule not found
`P-006`	400	Cannot modify version (only DRAFT allowed)
`P-007`	400	Cannot publish a version with no rules
`P-008`	400	Operation not allowed in current status
`P-009`	403	Policy group is disabled
`P-010`	400	Rule reorder ID mismatch
`P-011`	400	Activation Mode/Strategy mismatch within group
`P-012`	400	Mutex Mode/Strategy mismatch within group
`P-013`	400	No previous version available for rollback
`P-014`	404	Deployment history not found
`P-015`	400	Required input facts missing from execution request
`P-016`	400	Version does not belong to the target policy group
`P-017`	409	Version is currently deployed or used in active A/B test
`P-018`	400	Effective period invalid (start after end)
`P-019`	400	No deployed version exists for this group
`P-020`	409	Cannot delete group with live deployment
`P-021`	409	Cannot delete group with active A/B test
`P-022`	400	Condition field required for SINGLE conditions
`P-023`	400	Condition operator required for SINGLE conditions
`P-024`	400	Condition tree exceeds maximum depth

Idempotency (I)

Code	HTTP	Description
`I-001`	409	Request already processed (duplicate idempotency key)
`I-002`	409	Request currently being processed

System / Crypto (S)

Code	HTTP	Description
`S-001`	500	Encryption failed
`S-002`	500	Decryption failed

Billing (B)

Code	HTTP	Description
`B-001`	404	Plan not found
`B-002`	404	Subscription not found
`B-003`	409	Active subscription already exists
`B-004`	400	Invalid subscription status
`B-005`	404	Invoice not found
`B-006`	500	No payment processor for the requested currency
`B-007`	502	Payment processing failed
`B-008`	403	Service quota exceeded
`B-009`	400	Free plan cannot be canceled
`B-010`	400	Payment method required before paid subscription
`B-011`	400	Billing profile required before paid subscription
`B-012`	400	Invoice already paid
`B-013`	400	Already subscribed to this plan
`B-014`	400	Cross-currency plan change not supported
`B-015`	400	Cannot downgrade directly to Free plan — cancel first
`B-016`	409	Cannot delete plan currently in use
`B-017`	400	Currency immutable while subscribed to paid plan
`B-018`	400	No scheduled downgrade to cancel
`B-019`	409	A public plan with this tier and currency already exists
`B-020`	400	Invalid currency code

Member & Account (M)

Code	HTTP	Description
`M-001`	404	Member not found
`M-002`	403	Email verification required
`M-003`	403	Account suspended
`M-004`	403	Account withdrawn
`M-005`	400	Invalid or expired verification code
`M-006`	400	Member already active
`M-007`	400	Invitation expired
`M-008`	400	Invalid invitation token
`M-009`	400	Cannot perform this action on yourself
`M-010`	400	Cannot remove or demote the last admin
`M-011`	409	Phone number already registered
`M-012`	403	Account suspended (with reason)
`M-013`	400	Admin role cannot be assigned via invitation

Analytics & Simulation (AN)

Code	HTTP	Description
`AN-001`	500	Simulation processing failed
`AN-002`	404	Dataset not found
`AN-003`	400	Dataset too large
`AN-004`	400	Dataset contains no records
`AN-005`	400	Invalid dataset format
`AN-006`	400	Unsupported dataset source
`AN-007`	500	Dataset storage error
`AN-008`	400	Invalid baseline version
`AN-009`	404	Simulation not found
`AN-010`	400	Only PENDING or RUNNING simulations can be canceled
`AN-011`	400	Only completed simulations can be exported
`AN-012`	500	Simulation export failed
`AN-013`	404	Uploaded dataset file not found
`AN-014`	400	Dataset file parse failed
`AN-015`	500	Simulation result data malformed
`AN-016`	400	Required fact missing in dataset
`AN-017`	400	Fact type mismatch in dataset
`AN-018`	400	Date range required for HISTORICAL datasets
`AN-019`	400	File path required for UPLOADED datasets
`AN-020`	400	Selected dataset file is empty
`AN-021`	400	Dataset file exceeds size limit
`AN-022`	400	Unsupported dataset file type

Action & Calculation (ACT)

Code	HTTP	Description
`ACT-001`	400	Action parameters are empty
`ACT-002`	400	Reference variable `refVar` is required
`ACT-003`	400	Invalid calculation method (allowed: PERCENTAGE, AMOUNT)
`ACT-004`	400	Rate parameter required for PERCENTAGE method
`ACT-005`	400	Value parameter required for AMOUNT method
`ACT-006`	400	Invalid action type
`ACT-009`	400	Integration ID required for external service action
`ACT-013`	400	Webhook URL or integration reference required
`ACT-014`	400	Fact key required for SET_FACT action
`ACT-015`	400	Tag value required for ADD_TAG action
`ACT-016`	400	`targetVar` required for INCREMENT_FACT action
`ACT-017`	400	Rounding option must be an object
`ACT-018`	400	Rounding scale must be an integer
`ACT-019`	400	Rounding scale out of range `[0, 16]`
`ACT-020`	400	Invalid rounding mode
`ACT-021`	400	Operator required for MUTATE_FACT action
`ACT-022`	400	Invalid operator
`ACT-023`	400	Invalid operator-method combination (e.g., DIV + PERCENTAGE)
`ACT-024`	400	Division by zero not allowed
`ACT-025`	400	`refVar` not found in input facts
`ACT-026`	400	`targetVar` not found in input facts
`ACT-027`	400	EMIT_EVENT requires non-empty `eventPayload`
`ACT-028`	400	EMIT_NOTIFICATION requires non-empty `notificationPayload`

Codes ACT-007, ACT-008, ACT-010, ACT-011, ACT-012 were retired when the engine moved to domain-agnostic action primitives. Their numbers are not reused.

Fact Definition (FD)

Code	HTTP	Description
`FD-001`	409	Fact key already exists
`FD-002`	404	Fact not found
`FD-003`	403	System fact cannot be modified or deleted
`FD-004`	400	Invalid fact key format

Integration (INT)

Code	HTTP	Description
`INT-001`	404	Integration not found
`INT-002`	409	Integration name already exists
`INT-003`	400	Invalid integration configuration
`INT-004`	400	Integration type cannot be changed
`INT-005`	400	Integration config missing required field
`INT-006`	400	Invalid HTTP method for integration
`INT-007`	400	Required integration config field missing

Failure Log (FL)

Code	HTTP	Description
`FL-001`	404	Failure log not found
`FL-002`	400	Action invalid for failure log in current state
`FL-003`	400	Retry not supported for this task type

Webhook Subscription (WH)

Code	HTTP	Description
`WH-001`	404	Webhook subscription not found
`WH-002`	409	Webhook subscription name already exists
`WH-003`	502	Webhook test delivery failed

​Error Response Format

​Common (C)

​Auth (A)

​Policy Engine (P)

​Idempotency (I)

​System / Crypto (S)

​Billing (B)

​Member & Account (M)

​Analytics & Simulation (AN)

​Action & Calculation (ACT)

​Fact Definition (FD)

​Integration (INT)

​Failure Log (FL)

​Webhook Subscription (WH)

Error Response Format

Common (C)

Auth (A)

Policy Engine (P)

Idempotency (I)

System / Crypto (S)

Billing (B)

Member & Account (M)

Analytics & Simulation (AN)

Action & Calculation (ACT)

Fact Definition (FD)

Integration (INT)

Failure Log (FL)

Webhook Subscription (WH)