From eef1db0f0abc7195e08ecdbc4a3c9bf32cf65594 Mon Sep 17 00:00:00 2001
From: shankar0123 <skreddy040@gmail.com>
Date: Sat, 18 Apr 2026 13:02:04 +0000
Subject: [PATCH] fix(policies): stop 400ing the "+ New Policy" button + add
 per-rule severity (D-005, D-006)
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Coverage Gap Audit findings D-005 (P0) + D-006 (P1) fixed together in a
single commit because they share the same root cause — policy CRUD sending
values the backend silently rejects — and splitting them would leave a
half-working UI between commits.

## D-005 (P0): PoliciesPage dropdown 400s every Create Policy

Root cause
----------
`web/src/pages/PoliciesPage.tsx` populated the Type `<select>` from a
hardcoded `['key_algorithm', 'ownership', 'allowed_issuers', ...]` array.
The backend's `internal/api/handler/validators.go::ValidatePolicyType`
enforces the TitleCase allowlist `AllowedIssuers`, `AllowedDomains`,
`RequiredMetadata`, `AllowedEnvironments`, `RenewalLeadTime` — defined in
`internal/domain/policy.go`. Every Create Policy request was rejected with
`400 invalid policy type`. The error surfaced only as a transient toast;
the modal closed anyway. Silent user-visible failure.

Fix
---
- `web/src/api/types.ts`: added `POLICY_TYPES` and `POLICY_SEVERITIES`
  tuples with `as const` and narrowed `PolicyRule.type`, `.severity`, and
  `PolicyViolation.severity` to the literal-union types. Dropdown is now
  sourced from the tuple; casing drift becomes a compile error.
- `web/src/pages/PoliciesPage.tsx`: rekeyed `severityStyles` /
  `severityDots` to the TitleCase values, added `humanize()` for display
  (AllowedIssuers → "Allowed Issuers"), removed the `badge-neutral`
  fallback that was papering over the mismatch.
- `web/src/api/types.test.ts` (new): pins both tuples exactly. If anyone
  edits one side of the frontend/backend contract without the other, CI
  fails with a clear assertion. Pure-TS vitest, no RTL dependency.

## D-006 (P1): `severity` field silently dropped on create/update

Root cause
----------
`PolicyRule` had no `Severity` field in `internal/domain/policy.go`. The
frontend has always sent `severity` on create/update, but Go's
`json.Decoder` (default settings, no `DisallowUnknownFields`) silently
dropped it. The value never reached PostgreSQL. Every rule rendered with
the same severity because there was no severity — just a display
computation downstream.

Fix: option (b), full-stack schema add (not delete-the-field)
-------------------------------------------------------------
- Migration `000013_policy_rule_severity` (up + down): adds
  `severity VARCHAR(50) NOT NULL DEFAULT 'Warning'` to `policy_rules` with
  CHECK constraint `severity IN ('Warning', 'Error', 'Critical')`. No
  index — three-value column on a low-thousands-rows table, planner will
  seq-scan regardless. PG 11+ metadata-only ADD COLUMN, safe on live data.
- `internal/domain/policy.go`: added `Severity PolicySeverity` field.
- `internal/repository/postgres/policy.go`: plumbed `severity` through
  ListRules SELECT + Scan, GetRule SELECT + Scan, CreateRule INSERT,
  UpdateRule UPDATE (4 queries).
- `internal/service/policy.go::UpdatePolicy`: if the client omits
  severity on a PUT (zero-value empty string), fetch the existing rule
  and preserve its severity. Without this, partial updates would trip the
  NOT NULL CHECK and 500. Preserves pre-existing behavior for Name/Type
  (out of scope).
- `internal/api/handler/policies.go::CreatePolicy`: default empty severity
  to `'Warning'`, then validate via `ValidatePolicySeverity`. 400 with
  clear message instead of 500 on CHECK violation. `UpdatePolicy`:
  validates severity only when provided.
- `internal/mcp/types.go` + `internal/mcp/tools.go`: added optional
  `severity` on the MCP `create_policy` / `update_policy` tool inputs so
  LLM callers stay in sync with the wire contract.
- `api/openapi.yaml`: added `severity` to the `PolicyRule` schema with
  the enum and default.

Acceptance criterion (user-defined)
-----------------------------------
"Create a rule with severity=Critical, reload the page, and still see
Critical — no silent drops." Verified end-to-end: frontend sends
`severity: "Critical"`, handler validates, service persists, DB stores,
GET returns, React renders the correct badge.

Seed data
---------
`migrations/seed.sql`: four demo rules now have differentiated severities
— `pr-require-owner` → Warning, `pr-allowed-environments` → Error,
`pr-max-certificate-lifetime` → Critical, `pr-min-renewal-window` →
Warning. The user called out that seeding all four at the same severity
makes the feature look decorative; differentiation demonstrates the
column carries real signal.

## Integration test fix (side effect of D-006)

`internal/integration/e2e_test.go::TestCrossResourceWorkflow/CreatePolicy`
was sending `"severity": "High"` — a value from the pre-audit severity
vocabulary that the new `ValidatePolicySeverity` correctly rejects with
400. Changed to `"Error"` (closest semantic match in the new TitleCase
allowlist). Only severity reference in the integration/ directory;
verified via grep.

## Out of scope, logged for follow-up (d/D-008)

Three policy-engine drift issues orthogonal to D-005 + D-006, explicitly
deferred per direction:

1. `migrations/seed.sql` policy_rules INSERTs use lowercase TYPE values
   (`'ownership'`, `'environment'`, `'lifetime'`, `'renewal_window'`).
   These are load-bearing on `internal/service/policy.go::evaluateRule`'s
   `switch rule.Type` (which also uses the lowercase strings). Migrating
   requires coordinated changes across seed + evaluation engine.
2. `migrations/seed_demo.sql:482-483` contains lowercase `'critical'`
   severity — will now fail the new CHECK constraint. Separate fix.
3. `evaluateRule` hardcodes `Severity: domain.PolicySeverityWarning` on
   emitted violations and ignores the configured `rule.Config`. The new
   severity column is read correctly on the CRUD path but not yet
   consulted during evaluation.

## Verification

Backend:
- `go build ./...` — clean
- `go vet ./...` — clean
- `go test -short ./...` — all packages green, including
  `internal/service` (policy service), `internal/api/handler` (policy +
  MCP handler tests), `internal/integration` (e2e_test.go after fix),
  `internal/domain`, `internal/repository/postgres`.

Frontend:
- `tsc --noEmit` — clean
- `vitest run` — 223/223 passing (4 new assertions in types.test.ts)
- `vite build` — clean (only the pre-existing chunk-size warning)
---
 api/openapi.yaml                              |  3 +
 internal/api/handler/policies.go              | 17 +++++
 internal/domain/policy.go                     |  1 +
 internal/integration/e2e_test.go              |  2 +-
 internal/mcp/tools.go                         |  4 +-
 internal/mcp/types.go                         | 22 +++---
 internal/repository/postgres/policy.go        | 21 +++---
 internal/service/policy.go                    | 14 ++++
 .../000013_policy_rule_severity.down.sql      |  8 ++
 migrations/000013_policy_rule_severity.up.sql | 24 ++++++
 migrations/seed.sql                           | 26 +++++--
 web/src/api/types.test.ts                     | 59 +++++++++++++++
 web/src/api/types.ts                          | 32 +++++++-
 web/src/pages/PoliciesPage.tsx                | 73 +++++++++++--------
 14 files changed, 243 insertions(+), 63 deletions(-)
 create mode 100644 migrations/000013_policy_rule_severity.down.sql
 create mode 100644 migrations/000013_policy_rule_severity.up.sql
 create mode 100644 web/src/api/types.test.ts

diff --git a/api/openapi.yaml b/api/openapi.yaml
index df890d2..65140e8 100644
--- a/api/openapi.yaml
+++ b/api/openapi.yaml
@@ -3480,6 +3480,9 @@ components:
           description: Policy-specific configuration (varies by type)
         enabled:
           type: boolean
+        severity:
+          $ref: "#/components/schemas/PolicySeverity"
+          description: Severity level applied to violations of this rule. Defaults to Warning on create when omitted.
         created_at:
           type: string
           format: date-time
diff --git a/internal/api/handler/policies.go b/internal/api/handler/policies.go
index 9c74076..8acfd64 100644
--- a/internal/api/handler/policies.go
+++ b/internal/api/handler/policies.go
@@ -127,6 +127,17 @@ func (h PolicyHandler) CreatePolicy(w http.ResponseWriter, r *http.Request) {
 		ErrorWithRequestID(w, http.StatusBadRequest, err.Error(), requestID)
 		return
 	}
+	// Severity is optional on create; default matches the DB default.
+	// Any explicit value must pass the TitleCase allowlist; the DB CHECK
+	// constraint enforces the same set, but catching it here gives a 400
+	// with a clear message instead of a 500 on constraint violation.
+	if policy.Severity == "" {
+		policy.Severity = domain.PolicySeverityWarning
+	}
+	if err := ValidatePolicySeverity(policy.Severity); err != nil {
+		ErrorWithRequestID(w, http.StatusBadRequest, err.Error(), requestID)
+		return
+	}
 
 	created, err := h.svc.CreatePolicy(r.Context(), policy)
 	if err != nil {
@@ -174,6 +185,12 @@ func (h PolicyHandler) UpdatePolicy(w http.ResponseWriter, r *http.Request) {
 			return
 		}
 	}
+	if policy.Severity != "" {
+		if err := ValidatePolicySeverity(policy.Severity); err != nil {
+			ErrorWithRequestID(w, http.StatusBadRequest, err.Error(), requestID)
+			return
+		}
+	}
 
 	updated, err := h.svc.UpdatePolicy(r.Context(), id, policy)
 	if err != nil {
diff --git a/internal/domain/policy.go b/internal/domain/policy.go
index aae73c0..312a24c 100644
--- a/internal/domain/policy.go
+++ b/internal/domain/policy.go
@@ -12,6 +12,7 @@ type PolicyRule struct {
 	Type      PolicyType      `json:"type"`
 	Config    json.RawMessage `json:"config"`
 	Enabled   bool            `json:"enabled"`
+	Severity  PolicySeverity  `json:"severity"`
 	CreatedAt time.Time       `json:"created_at"`
 	UpdatedAt time.Time       `json:"updated_at"`
 }
diff --git a/internal/integration/e2e_test.go b/internal/integration/e2e_test.go
index 91656ff..2b1dc20 100644
--- a/internal/integration/e2e_test.go
+++ b/internal/integration/e2e_test.go
@@ -158,7 +158,7 @@ func TestCrossResourceWorkflow(t *testing.T) {
 		payload := map[string]interface{}{
 			"name":        "Allowed Domains Policy",
 			"type":        "AllowedDomains",
-			"severity":    "High",
+			"severity":    "Error",
 			"config":      json.RawMessage(`{"domains": ["example.com", "*.example.com"]}`),
 			"description": "Restrict issuance to example.com domains",
 		}
diff --git a/internal/mcp/tools.go b/internal/mcp/tools.go
index d960be0..1ab0197 100644
--- a/internal/mcp/tools.go
+++ b/internal/mcp/tools.go
@@ -610,7 +610,7 @@ func registerPolicyTools(s *gomcp.Server, c *Client) {
 
 	gomcp.AddTool(s, &gomcp.Tool{
 		Name:        "certctl_create_policy",
-		Description: "Create a new policy rule. Requires name and type.",
+		Description: "Create a new policy rule. Requires name and type. Optional severity (Warning, Error, Critical) defaults to Warning.",
 	}, func(ctx context.Context, req *gomcp.CallToolRequest, input CreatePolicyInput) (*gomcp.CallToolResult, any, error) {
 		data, err := c.Post("/api/v1/policies", input)
 		if err != nil {
@@ -621,7 +621,7 @@ func registerPolicyTools(s *gomcp.Server, c *Client) {
 
 	gomcp.AddTool(s, &gomcp.Tool{
 		Name:        "certctl_update_policy",
-		Description: "Update a policy rule's name, type, configuration, or enabled status.",
+		Description: "Update a policy rule's name, type, configuration, enabled status, or severity.",
 	}, func(ctx context.Context, req *gomcp.CallToolRequest, input UpdatePolicyInput) (*gomcp.CallToolResult, any, error) {
 		data, err := c.Put("/api/v1/policies/"+input.ID, input)
 		if err != nil {
diff --git a/internal/mcp/types.go b/internal/mcp/types.go
index ac4d228..16e0503 100644
--- a/internal/mcp/types.go
+++ b/internal/mcp/types.go
@@ -168,19 +168,21 @@ type RejectJobInput struct {
 // ── Policies ────────────────────────────────────────────────────────
 
 type CreatePolicyInput struct {
-	ID      string      `json:"id,omitempty" jsonschema:"Policy ID"`
-	Name    string      `json:"name" jsonschema:"Policy display name"`
-	Type    string      `json:"type" jsonschema:"Policy type: AllowedIssuers, AllowedDomains, RequiredMetadata, AllowedEnvironments, RenewalLeadTime"`
-	Config  interface{} `json:"config,omitempty" jsonschema:"Policy-specific configuration"`
-	Enabled bool        `json:"enabled,omitempty" jsonschema:"Whether the policy is enabled"`
+	ID       string      `json:"id,omitempty" jsonschema:"Policy ID"`
+	Name     string      `json:"name" jsonschema:"Policy display name"`
+	Type     string      `json:"type" jsonschema:"Policy type: AllowedIssuers, AllowedDomains, RequiredMetadata, AllowedEnvironments, RenewalLeadTime"`
+	Config   interface{} `json:"config,omitempty" jsonschema:"Policy-specific configuration"`
+	Enabled  bool        `json:"enabled,omitempty" jsonschema:"Whether the policy is enabled"`
+	Severity string      `json:"severity,omitempty" jsonschema:"Violation severity: Warning, Error, or Critical (default: Warning)"`
 }
 
 type UpdatePolicyInput struct {
-	ID      string      `json:"id" jsonschema:"Policy ID to update"`
-	Name    string      `json:"name,omitempty" jsonschema:"Policy display name"`
-	Type    string      `json:"type,omitempty" jsonschema:"Policy type"`
-	Config  interface{} `json:"config,omitempty" jsonschema:"Policy-specific configuration"`
-	Enabled *bool       `json:"enabled,omitempty" jsonschema:"Whether the policy is enabled"`
+	ID       string      `json:"id" jsonschema:"Policy ID to update"`
+	Name     string      `json:"name,omitempty" jsonschema:"Policy display name"`
+	Type     string      `json:"type,omitempty" jsonschema:"Policy type"`
+	Config   interface{} `json:"config,omitempty" jsonschema:"Policy-specific configuration"`
+	Enabled  *bool       `json:"enabled,omitempty" jsonschema:"Whether the policy is enabled"`
+	Severity string      `json:"severity,omitempty" jsonschema:"Violation severity: Warning, Error, or Critical"`
 }
 
 type ListViolationsInput struct {
diff --git a/internal/repository/postgres/policy.go b/internal/repository/postgres/policy.go
index 46a0c61..1d828bf 100644
--- a/internal/repository/postgres/policy.go
+++ b/internal/repository/postgres/policy.go
@@ -24,7 +24,7 @@ func NewPolicyRepository(db *sql.DB) *PolicyRepository {
 // ListRules returns all policy rules
 func (r *PolicyRepository) ListRules(ctx context.Context) ([]*domain.PolicyRule, error) {
 	rows, err := r.db.QueryContext(ctx, `
-		SELECT id, name, type, config, enabled, created_at, updated_at
+		SELECT id, name, type, config, enabled, severity, created_at, updated_at
 		FROM policy_rules
 		ORDER BY created_at DESC
 	`)
@@ -38,7 +38,7 @@ func (r *PolicyRepository) ListRules(ctx context.Context) ([]*domain.PolicyRule,
 	for rows.Next() {
 		var rule domain.PolicyRule
 		if err := rows.Scan(&rule.ID, &rule.Name, &rule.Type, &rule.Config,
-			&rule.Enabled, &rule.CreatedAt, &rule.UpdatedAt); err != nil {
+			&rule.Enabled, &rule.Severity, &rule.CreatedAt, &rule.UpdatedAt); err != nil {
 			return nil, fmt.Errorf("failed to scan policy rule: %w", err)
 		}
 		rules = append(rules, &rule)
@@ -55,11 +55,11 @@ func (r *PolicyRepository) ListRules(ctx context.Context) ([]*domain.PolicyRule,
 func (r *PolicyRepository) GetRule(ctx context.Context, id string) (*domain.PolicyRule, error) {
 	var rule domain.PolicyRule
 	err := r.db.QueryRowContext(ctx, `
-		SELECT id, name, type, config, enabled, created_at, updated_at
+		SELECT id, name, type, config, enabled, severity, created_at, updated_at
 		FROM policy_rules
 		WHERE id = $1
 	`, id).Scan(&rule.ID, &rule.Name, &rule.Type, &rule.Config,
-		&rule.Enabled, &rule.CreatedAt, &rule.UpdatedAt)
+		&rule.Enabled, &rule.Severity, &rule.CreatedAt, &rule.UpdatedAt)
 
 	if err != nil {
 		if err == sql.ErrNoRows {
@@ -78,11 +78,11 @@ func (r *PolicyRepository) CreateRule(ctx context.Context, rule *domain.PolicyRu
 	}
 
 	err := r.db.QueryRowContext(ctx, `
-		INSERT INTO policy_rules (id, name, type, config, enabled, created_at, updated_at)
-		VALUES ($1, $2, $3, $4, $5, $6, $7)
+		INSERT INTO policy_rules (id, name, type, config, enabled, severity, created_at, updated_at)
+		VALUES ($1, $2, $3, $4, $5, $6, $7, $8)
 		RETURNING id
 	`, rule.ID, rule.Name, rule.Type, rule.Config, rule.Enabled,
-		rule.CreatedAt, rule.UpdatedAt).Scan(&rule.ID)
+		rule.Severity, rule.CreatedAt, rule.UpdatedAt).Scan(&rule.ID)
 
 	if err != nil {
 		return fmt.Errorf("failed to create policy rule: %w", err)
@@ -99,9 +99,10 @@ func (r *PolicyRepository) UpdateRule(ctx context.Context, rule *domain.PolicyRu
 			type = $2,
 			config = $3,
 			enabled = $4,
-			updated_at = $5
-		WHERE id = $6
-	`, rule.Name, rule.Type, rule.Config, rule.Enabled, rule.UpdatedAt, rule.ID)
+			severity = $5,
+			updated_at = $6
+		WHERE id = $7
+	`, rule.Name, rule.Type, rule.Config, rule.Enabled, rule.Severity, rule.UpdatedAt, rule.ID)
 
 	if err != nil {
 		return fmt.Errorf("failed to update policy rule: %w", err)
diff --git a/internal/service/policy.go b/internal/service/policy.go
index 45ba127..e411791 100644
--- a/internal/service/policy.go
+++ b/internal/service/policy.go
@@ -288,6 +288,20 @@ func (s *PolicyService) UpdatePolicy(ctx context.Context, id string, policy doma
 	policy.ID = id
 	policy.UpdatedAt = time.Now()
 
+	// Severity is NOT NULL with a CHECK constraint at the DB level
+	// (migration 000013). If the client omits severity on a PUT (zero-value
+	// empty string after json.Decode), preserve the existing severity rather
+	// than letting the CHECK reject the write. Preserves partial-update
+	// semantics for the new column without changing the pre-existing behavior
+	// for Name/Type, which is out of scope for D-005/D-006.
+	if policy.Severity == "" {
+		existing, err := s.policyRepo.GetRule(ctx, id)
+		if err != nil {
+			return nil, fmt.Errorf("failed to fetch existing rule for severity preservation: %w", err)
+		}
+		policy.Severity = existing.Severity
+	}
+
 	if err := s.policyRepo.UpdateRule(ctx, &policy); err != nil {
 		return nil, fmt.Errorf("failed to update policy: %w", err)
 	}
diff --git a/migrations/000013_policy_rule_severity.down.sql b/migrations/000013_policy_rule_severity.down.sql
new file mode 100644
index 0000000..5cd6a56
--- /dev/null
+++ b/migrations/000013_policy_rule_severity.down.sql
@@ -0,0 +1,8 @@
+-- Rollback migration 000013: remove per-rule severity.
+--
+-- DROP COLUMN removes the column, its CHECK constraint, and the default in
+-- one statement. Any downstream code still referencing severity after
+-- rollback will fail at query time — that's intentional, since running this
+-- rollback implies severity as a concept is being abandoned.
+
+ALTER TABLE policy_rules DROP COLUMN IF EXISTS severity;
diff --git a/migrations/000013_policy_rule_severity.up.sql b/migrations/000013_policy_rule_severity.up.sql
new file mode 100644
index 0000000..8799203
--- /dev/null
+++ b/migrations/000013_policy_rule_severity.up.sql
@@ -0,0 +1,24 @@
+-- Migration 000013: Per-Rule Severity on policy_rules
+--
+-- Prior to this migration, PolicyRule had no severity column. The TypeScript
+-- frontend (PoliciesPage.tsx) sent a `severity` field on create/update, but
+-- Go's json.Decoder silently dropped it (no matching struct field) and the
+-- value never reached PostgreSQL. Reloading the page always showed severity
+-- reverting to a default — the classic "silent drop" bug.
+--
+-- This migration adds severity as a first-class column on policy_rules.
+-- Default `'Warning'` covers pre-existing rows; the CHECK constraint gives
+-- defense-in-depth against casing drift (the application-layer validator in
+-- internal/api/handler/validation.go already enforces the TitleCase allowlist,
+-- but the DB should reject a bypassed write too).
+--
+-- No index: three-value column on a table that stays in the low thousands of
+-- rows. The planner will seq-scan regardless; write cost without read benefit.
+-- If measurements later justify it, add the index then.
+--
+-- PG 11+ makes ADD COLUMN with a literal DEFAULT a metadata-only operation
+-- (no table rewrite), so this is safe to run on a live server.
+
+ALTER TABLE policy_rules
+    ADD COLUMN IF NOT EXISTS severity VARCHAR(50) NOT NULL DEFAULT 'Warning'
+        CHECK (severity IN ('Warning', 'Error', 'Critical'));
diff --git a/migrations/seed.sql b/migrations/seed.sql
index 63065ab..06d5a63 100644
--- a/migrations/seed.sql
+++ b/migrations/seed.sql
@@ -13,41 +13,51 @@ VALUES (
 ) ON CONFLICT (id) DO NOTHING;
 
 -- Policy rules: Require owner assignment
-INSERT INTO policy_rules (id, name, type, config, enabled)
+-- Severity differentiated per rule to demonstrate the field means something
+-- (D-006). The backend CHECK constraint (migration 000013) enforces the
+-- TitleCase allowlist Warning/Error/Critical. Type-value drift
+-- (ownership/environment/lifetime/renewal_window vs. the engine's TitleCase
+-- canonicals) is tracked separately in d/D-008 and intentionally left
+-- unchanged in this commit.
+INSERT INTO policy_rules (id, name, type, config, enabled, severity)
 VALUES (
   'pr-require-owner',
   'require-owner',
   'ownership',
   '{"requirement": "owner_id must be set"}'::jsonb,
-  true
+  true,
+  'Warning'
 ) ON CONFLICT (id) DO NOTHING;
 
 -- Policy rules: Allowed environments
-INSERT INTO policy_rules (id, name, type, config, enabled)
+INSERT INTO policy_rules (id, name, type, config, enabled, severity)
 VALUES (
   'pr-allowed-environments',
   'allowed-environments',
   'environment',
   '{"allowed": ["production", "staging", "development"]}'::jsonb,
-  true
+  true,
+  'Error'
 ) ON CONFLICT (id) DO NOTHING;
 
 -- Policy rules: Maximum certificate lifetime
-INSERT INTO policy_rules (id, name, type, config, enabled)
+INSERT INTO policy_rules (id, name, type, config, enabled, severity)
 VALUES (
   'pr-max-certificate-lifetime',
   'max-certificate-lifetime',
   'lifetime',
   '{"max_days": 90}'::jsonb,
-  true
+  true,
+  'Critical'
 ) ON CONFLICT (id) DO NOTHING;
 
 -- Policy rules: Minimum renewal window
-INSERT INTO policy_rules (id, name, type, config, enabled)
+INSERT INTO policy_rules (id, name, type, config, enabled, severity)
 VALUES (
   'pr-min-renewal-window',
   'min-renewal-window',
   'renewal_window',
   '{"min_days": 14}'::jsonb,
-  true
+  true,
+  'Warning'
 ) ON CONFLICT (id) DO NOTHING;
diff --git a/web/src/api/types.test.ts b/web/src/api/types.test.ts
new file mode 100644
index 0000000..957305f
--- /dev/null
+++ b/web/src/api/types.test.ts
@@ -0,0 +1,59 @@
+import { describe, it, expect } from 'vitest';
+import { POLICY_TYPES, POLICY_SEVERITIES } from './types';
+
+/**
+ * Regression tests for the policy enum tuples.
+ *
+ * These tuples are the GUI's source of truth for the policy type and severity
+ * dropdowns. They MUST stay in lockstep with the backend enum values:
+ *   - internal/domain/policy.go defines the PolicyType / PolicySeverity consts
+ *   - internal/api/handler/validators.go rejects anything outside the allowlist
+ *   - migration 000013 enforces the severity allowlist at the DB level via CHECK
+ *
+ * Audit history (D-005, D-006):
+ *   - The GUI previously sent lowercase values (e.g. 'key_algorithm',
+ *     'ownership'), which the backend validator rejected with a 400. Every
+ *     attempt to create a policy from the "+ New Policy" button silently
+ *     failed until the modal was closed.
+ *   - The severity dropdown carried a four-value `low/medium/high/critical`
+ *     tuple that shared zero values with the backend's
+ *     `Warning/Error/Critical` — the `medium` option has no backend analog
+ *     and is removed.
+ *
+ * If these tests fail because a backend enum changed, DO NOT update the
+ * expected arrays without also updating the backend consts and the migration.
+ * Frontend/backend drift on these tuples is precisely what this regression
+ * guards against.
+ */
+
+describe('POLICY_TYPES', () => {
+  it('matches the backend PolicyType TitleCase allowlist exactly', () => {
+    expect(POLICY_TYPES).toEqual([
+      'AllowedIssuers',
+      'AllowedDomains',
+      'RequiredMetadata',
+      'AllowedEnvironments',
+      'RenewalLeadTime',
+    ]);
+  });
+
+  it('has no duplicate entries', () => {
+    expect(new Set(POLICY_TYPES).size).toBe(POLICY_TYPES.length);
+  });
+});
+
+describe('POLICY_SEVERITIES', () => {
+  it('matches the backend PolicySeverity TitleCase allowlist exactly', () => {
+    expect(POLICY_SEVERITIES).toEqual(['Warning', 'Error', 'Critical']);
+  });
+
+  it('has no duplicate entries', () => {
+    expect(new Set(POLICY_SEVERITIES).size).toBe(POLICY_SEVERITIES.length);
+  });
+
+  it('does not include the removed pre-fix `medium` value', () => {
+    // Explicit negative assertion. Pre-fix the GUI offered four severities
+    // (low/medium/high/critical); `medium` never had a backend analog.
+    expect(POLICY_SEVERITIES as readonly string[]).not.toContain('medium');
+  });
+});
diff --git a/web/src/api/types.ts b/web/src/api/types.ts
index 46fcea5..c58cb70 100644
--- a/web/src/api/types.ts
+++ b/web/src/api/types.ts
@@ -112,11 +112,37 @@ export interface AuditEvent {
   timestamp: string;
 }
 
+/**
+ * Policy rule type enum — pinned to the backend's TitleCase constants in
+ * internal/domain/policy.go. Historical note (D-005): the GUI previously sent
+ * lowercase values (`ownership`, `environment`, etc.) that the handler's
+ * ValidatePolicyType rejected with a 400. These tuples are the canonical
+ * source of truth for the dropdown options; the regression test in
+ * types.test.ts pins them so future drift is caught at CI time.
+ */
+export const POLICY_TYPES = [
+  'AllowedIssuers',
+  'AllowedDomains',
+  'RequiredMetadata',
+  'AllowedEnvironments',
+  'RenewalLeadTime',
+] as const;
+export type PolicyType = (typeof POLICY_TYPES)[number];
+
+/**
+ * Policy severity enum — pinned to the backend's PolicySeverity constants.
+ * The backend CHECK constraint on policy_rules.severity enforces the same
+ * allowlist (migration 000013). The 4-value `medium` option that used to
+ * appear in the GUI was never a valid backend value and has been removed.
+ */
+export const POLICY_SEVERITIES = ['Warning', 'Error', 'Critical'] as const;
+export type PolicySeverity = (typeof POLICY_SEVERITIES)[number];
+
 export interface PolicyRule {
   id: string;
   name: string;
-  type: string;
-  severity: string;
+  type: PolicyType;
+  severity: PolicySeverity;
   config: Record<string, unknown>;
   enabled: boolean;
   created_at: string;
@@ -127,7 +153,7 @@ export interface PolicyViolation {
   id: string;
   rule_id: string;
   certificate_id: string;
-  severity: string;
+  severity: PolicySeverity;
   message: string;
   created_at: string;
 }
diff --git a/web/src/pages/PoliciesPage.tsx b/web/src/pages/PoliciesPage.tsx
index 483c305..073d521 100644
--- a/web/src/pages/PoliciesPage.tsx
+++ b/web/src/pages/PoliciesPage.tsx
@@ -6,22 +6,40 @@ import DataTable from '../components/DataTable';
 import type { Column } from '../components/DataTable';
 import ErrorState from '../components/ErrorState';
 import { formatDateTime } from '../api/utils';
-import type { PolicyRule } from '../api/types';
+import {
+  POLICY_TYPES,
+  POLICY_SEVERITIES,
+  type PolicyRule,
+  type PolicyType,
+  type PolicySeverity,
+} from '../api/types';
 
-const severityStyles: Record<string, string> = {
-  low: 'badge-info',
-  medium: 'badge-warning',
-  high: 'badge-danger',
-  critical: 'badge-danger',
+/**
+ * Severity → badge style. Keyed on the backend's TitleCase PolicySeverity
+ * enum values (D-006). The pre-fix map keyed on `low`/`medium`/`high`/`critical`
+ * which never matched the backend's `Warning`/`Error`/`Critical`, so every
+ * existing rule fell through to the `badge-neutral` default.
+ */
+const severityStyles: Record<PolicySeverity, string> = {
+  Warning: 'badge-warning',
+  Error: 'badge-danger',
+  Critical: 'badge-danger',
 };
 
-const severityDots: Record<string, string> = {
-  low: 'bg-emerald-500',
-  medium: 'bg-amber-500',
-  high: 'bg-orange-500',
-  critical: 'bg-red-500',
+const severityDots: Record<PolicySeverity, string> = {
+  Warning: 'bg-amber-500',
+  Error: 'bg-orange-500',
+  Critical: 'bg-red-500',
 };
 
+/**
+ * Convert TitleCase enum value to a human-readable label for display.
+ * "AllowedIssuers" → "Allowed Issuers"
+ */
+function humanize(s: string): string {
+  return s.replace(/([A-Z])/g, ' $1').trim();
+}
+
 interface CreatePolicyModalProps {
   isOpen: boolean;
   onClose: () => void;
@@ -32,8 +50,8 @@ interface CreatePolicyModalProps {
 
 function CreatePolicyModal({ isOpen, onClose, onSuccess, isLoading, error }: CreatePolicyModalProps) {
   const [name, setName] = useState('');
-  const [type, setType] = useState('key_algorithm');
-  const [severity, setSeverity] = useState('medium');
+  const [type, setType] = useState<PolicyType>(POLICY_TYPES[0]);
+  const [severity, setSeverity] = useState<PolicySeverity>('Warning');
   const [configStr, setConfigStr] = useState('{}');
   const [enabled, setEnabled] = useState(true);
 
@@ -43,8 +61,8 @@ function CreatePolicyModal({ isOpen, onClose, onSuccess, isLoading, error }: Cre
     const config = JSON.parse(configStr);
     await createPolicy({ name: name.trim(), type, severity, config, enabled });
     setName('');
-    setType('key_algorithm');
-    setSeverity('medium');
+    setType(POLICY_TYPES[0]);
+    setSeverity('Warning');
     setConfigStr('{}');
     setEnabled(true);
     onSuccess();
@@ -72,27 +90,24 @@ function CreatePolicyModal({ isOpen, onClose, onSuccess, isLoading, error }: Cre
             <label className="block text-sm font-medium text-ink mb-1">Type *</label>
             <select
               value={type}
-              onChange={e => setType(e.target.value)}
+              onChange={e => setType(e.target.value as PolicyType)}
               className="w-full bg-white border border-surface-border rounded px-3 py-2 text-sm text-ink focus:outline-none focus:border-brand-400"
             >
-              <option value="key_algorithm">Key Algorithm</option>
-              <option value="cert_lifetime">Certificate Lifetime</option>
-              <option value="san_pattern">SAN Pattern</option>
-              <option value="key_usage">Key Usage</option>
-              <option value="revocation_check">Revocation Check</option>
+              {POLICY_TYPES.map(t => (
+                <option key={t} value={t}>{humanize(t)}</option>
+              ))}
             </select>
           </div>
           <div>
             <label className="block text-sm font-medium text-ink mb-1">Severity *</label>
             <select
               value={severity}
-              onChange={e => setSeverity(e.target.value)}
+              onChange={e => setSeverity(e.target.value as PolicySeverity)}
               className="w-full bg-white border border-surface-border rounded px-3 py-2 text-sm text-ink focus:outline-none focus:border-brand-400"
             >
-              <option value="low">Low</option>
-              <option value="medium">Medium</option>
-              <option value="high">High</option>
-              <option value="critical">Critical</option>
+              {POLICY_SEVERITIES.map(s => (
+                <option key={s} value={s}>{s}</option>
+              ))}
             </select>
           </div>
           <div>
@@ -182,7 +197,7 @@ export default function PoliciesPage() {
         </div>
       ),
     },
-    { key: 'type', label: 'Type', render: (p) => <span className="text-sm text-ink">{p.type.replace(/_/g, ' ')}</span> },
+    { key: 'type', label: 'Type', render: (p) => <span className="text-sm text-ink">{humanize(p.type)}</span> },
     {
       key: 'severity',
       label: 'Severity',
@@ -248,8 +263,8 @@ export default function PoliciesPage() {
           </div>
           {Object.entries(bySeverity).map(([sev, count]) => (
             <div key={sev} className="flex items-center gap-1.5">
-              <div className={`w-2 h-2 rounded-full ${severityDots[sev] || 'bg-slate-400'}`} />
-              <span className="text-xs text-ink capitalize">{sev}</span>
+              <div className={`w-2 h-2 rounded-full ${severityDots[sev as PolicySeverity] || 'bg-slate-400'}`} />
+              <span className="text-xs text-ink">{sev}</span>
               <span className="text-xs text-ink-faint">{count}</span>
             </div>
           ))}