diff --git a/src/infra/db/connection-policy.ts b/src/infra/db/connection-policy.ts
index fa7ec70..b9267e7 100644
--- a/src/infra/db/connection-policy.ts
+++ b/src/infra/db/connection-policy.ts
@@ -170,10 +170,16 @@ export type PostgresClientOptions = {
   idle_timeout: number;
   max_lifetime: number;
   ssl?: { rejectUnauthorized: true };
-  connection?: { family: 4 };
 };
 
-/** Opções do driver. Em ambiente implantado o certificado é verificado sempre. */
+/**
+ * Opções do driver. Em ambiente implantado o certificado é verificado sempre.
+ *
+ * `connection` no postgres.js é um parâmetro de startup, não uma opção do
+ * socket. Enviar `family=4` faz o PostgreSQL recusar a sessão com 42704
+ * (`unrecognized configuration parameter "family"`) antes da primeira
+ * consulta. O IPv4 continua garantido pelo host do Session Pooler.
+ */
 export function buildPostgresOptions(connectionString: string, purpose: DbPurpose, env: EnvMap = process.env): PostgresClientOptions {
   const deployed = isDeployedEnv(env);
   if (deployed) assertDeployedUrl(connectionString, purpose, env);
@@ -185,10 +191,7 @@ export function buildPostgresOptions(connectionString: string, purpose: DbPurpos
     idle_timeout: 20,
     max_lifetime: 60 * 30,
   };
-  if (deployed) {
-    options.ssl = { rejectUnauthorized: true };
-    options.connection = { family: 4 };
-  }
+  if (deployed) options.ssl = { rejectUnauthorized: true };
   return options;
 }
 
diff --git a/src/infra/db/target-guard.ts b/src/infra/db/target-guard.ts
index 71a42aa..b1ce2e9 100644
--- a/src/infra/db/target-guard.ts
+++ b/src/infra/db/target-guard.ts
@@ -113,6 +113,13 @@ function postgresErrorCode(error: unknown): string | null {
   return null;
 }
 
+/** Código do driver, sem a mensagem. A mensagem pode conter usuário, host ou senha. */
+function unavailableIdentityCode(error: unknown): string {
+  const code = postgresErrorCode(error);
+  if (code && /^[A-Z0-9_]{2,48}$/.test(code)) return `identidade_indisponivel:${code}`;
+  return "identidade_indisponivel";
+}
+
 async function readRole(db: Db): Promise<FactRow> {
   try {
     const rows = await db.withService((query) =>
@@ -132,7 +139,7 @@ async function readRole(db: Db): Promise<FactRow> {
     return facts;
   } catch (error) {
     if (error instanceof DatabaseGuardError) throw error;
-    throw new DatabaseGuardError("identidade_indisponivel");
+    throw new DatabaseGuardError(unavailableIdentityCode(error));
   }
 }
 
diff --git a/tests/unit/database-guard.test.ts b/tests/unit/database-guard.test.ts
index 7185fce..710fe8d 100644
--- a/tests/unit/database-guard.test.ts
+++ b/tests/unit/database-guard.test.ts
@@ -5,6 +5,7 @@ import {
   DatabaseGuardError,
   assertDeployedUrl,
   assertLocalDatabaseUrl,
+  buildPostgresOptions,
   expectedPoolerHost,
   resolvePoolMax,
   scrubDbError,
@@ -12,7 +13,8 @@ import {
 import { readFileSync, readdirSync } from "node:fs";
 import path from "node:path";
 import { assertInitAuthorized, projectIdentityDefinitionSql, projectIdentityRevertSql } from "@/infra/db/project-identity";
-import { evaluateAdminIdentity, evaluateProjectIdentity, evaluateRuntimeRole, type AdminAttestation } from "@/infra/db/target-guard";
+import { assertAdminTarget, evaluateAdminIdentity, evaluateProjectIdentity, evaluateRuntimeRole, type AdminAttestation } from "@/infra/db/target-guard";
+import type { Db } from "@/infra/db/types";
 
 const REF = "abcdefghijabcdefghij";
 const REF_COM_DIGITO = "abcd1234abcd1234wxyz";
@@ -165,6 +167,16 @@ describe("barreira do banco de homologação", () => {
     expect(resolvePoolMax("web", env)).toBe(2);
     expect(resolvePoolMax("worker", env)).toBe(2);
     expect(resolvePoolMax("admin", env)).toBe(1);
+    const deployed = buildPostgresOptions(adminUrl(), "admin", env);
+    const production = buildPostgresOptions(adminUrl(), "admin", { ...env, ADAPTER_ENV: "production" });
+    for (const options of [deployed, production]) {
+      expect(options.ssl).toEqual({ rejectUnauthorized: true });
+      expect(options).not.toHaveProperty("connection");
+      expect(JSON.stringify(options)).not.toContain("family");
+    }
+    expect(buildPostgresOptions("postgres://adaptador:local@127.0.0.1:5432/adaptador", "local", { ADAPTER_ENV: "development" })).not.toHaveProperty(
+      "connection",
+    );
   });
 
   it("recusa a credencial administrativa na web e BYPASSRLS no worker", () => {
@@ -207,6 +219,41 @@ describe("barreira do banco de homologação", () => {
     );
   });
 
+  it("classifica a falha de conexão pelo código do driver e omite a mensagem", async () => {
+    const db = {
+      exec: async () => undefined,
+      close: async () => undefined,
+      withUser: async () => {
+        throw new Error("nao");
+      },
+      withService: async () => {
+        throw Object.assign(new Error("postgres://postgres.ref:segredo@host/db family"), { code: "42704" });
+      },
+    } as Db;
+    await expect(assertAdminTarget(db, env)).rejects.toMatchObject({
+      code: "identidade_indisponivel:42704",
+    });
+    await expect(assertAdminTarget(db, env)).rejects.not.toThrow(/segredo/);
+
+    const semCodigo = {
+      ...db,
+      withService: async () => {
+        throw new Error("postgres://postgres.ref:segredo@host/db");
+      },
+    } as Db;
+    await expect(assertAdminTarget(semCodigo, env)).rejects.toMatchObject({ code: "identidade_indisponivel" });
+    await expect(assertAdminTarget(semCodigo, env)).rejects.not.toThrow(/segredo/);
+
+    const codigoInseguro = {
+      ...db,
+      withService: async () => {
+        throw Object.assign(new Error("falha"), { code: "postgres://segredo" });
+      },
+    } as Db;
+    await expect(assertAdminTarget(codigoInseguro, env)).rejects.toMatchObject({ code: "identidade_indisponivel" });
+    await expect(assertAdminTarget(codigoInseguro, env)).rejects.not.toThrow(/segredo/);
+  });
+
   it("não deixa senha nem URL no erro visível", () => {
     const scrubbed = scrubDbError(new Error("falha em postgres://postgres.abc:segredo@aws-0-us-west-2.pooler.supabase.com:5432/postgres"));
     expect(scrubbed).not.toContain("segredo");