diff --git a/crates/nuncio-cli/src/runner.rs b/crates/nuncio-cli/src/runner.rs
index 10fd6a3..7afe09a 100644
--- a/crates/nuncio-cli/src/runner.rs
+++ b/crates/nuncio-cli/src/runner.rs
@@ -53,6 +53,20 @@ fn parse_account_protocol(protocol: &str) -> Result<nuncio_proto::v1::AccountPro
     }
 }
 
+/// Parses a `filter export --format` CLI string into its wire-format
+/// `nuncio.v1.RuleExportFormat` value. Rejects anything else rather than
+/// silently falling back to one rendering, since a typo'd format should
+/// surface as an error, not a surprising output shape.
+fn parse_rule_export_format(format: &str) -> Result<nuncio_proto::v1::RuleExportFormat, String> {
+    match format.to_ascii_lowercase().as_str() {
+        "sql" => Ok(nuncio_proto::v1::RuleExportFormat::Sql),
+        "json" => Ok(nuncio_proto::v1::RuleExportFormat::Json),
+        other => Err(format!(
+            "invalid export format '{other}' (expected sql or json)"
+        )),
+    }
+}
+
 /// Renders a wire-format `google.protobuf.Timestamp` as an RFC 3339 UTC
 /// string for human-readable and `--json` output. `nanos` outside
 /// `0..1_000_000_000` (never produced by the daemon's own mappers) and an
@@ -1561,6 +1575,11 @@ impl HeadlessRunner {
     /// the daemon's real, persistent store -- not this runner's own
     /// ephemeral local `db`.
     async fn handle_filter_export(&self, format: &str, json_mode: bool) -> String {
+        let format = match parse_rule_export_format(format) {
+            Ok(f) => f,
+            Err(e) => return Self::render_error(&e, json_mode),
+        };
+
         let mut client = match self.connect_filters_client().await {
             Ok(client) => client,
             Err(e) => return Self::render_error(&e, json_mode),
@@ -1568,7 +1587,7 @@ impl HeadlessRunner {
 
         match client
             .export_rules(nuncio_proto::v1::ExportRulesRequest {
-                format: format.to_string(),
+                format: format.into(),
             })
             .await
         {
@@ -1863,7 +1882,6 @@ impl HeadlessRunner {
                 imap_host.to_string()
             },
             server_port: if is_caldav { 0 } else { u32::from(imap_port) },
-            use_tls: true,
             imap_tls_mode: map_tls_mode_to_proto(imap_tls_mode).into(),
             smtp_tls_mode: map_tls_mode_to_proto(smtp_tls_mode).into(),
             keyring_secret_key: keyring_key.clone(),
@@ -1974,7 +1992,6 @@ impl HeadlessRunner {
                                 "server_port": a.server_port,
                                 "smtp_host": a.smtp_host,
                                 "smtp_port": a.smtp_port,
-                                "use_tls": a.use_tls,
                                 "imap_tls_mode": a.imap_tls_mode().as_str_name(),
                                 "smtp_tls_mode": a.smtp_tls_mode().as_str_name(),
                                 "keyring_secret_key": a.keyring_secret_key,
@@ -1997,15 +2014,16 @@ impl HeadlessRunner {
                             ));
                         } else {
                             out.push_str(&format!(
-                                "\n  [{}] {} <{}>  IMAP {}:{}  SMTP {}:{}  TLS={}",
+                                "\n  [{}] {} <{}>  IMAP {}:{} ({})  SMTP {}:{} ({})",
                                 a.id,
                                 a.name,
                                 a.email_address,
                                 a.server_host,
                                 a.server_port,
+                                a.imap_tls_mode().as_str_name(),
                                 a.smtp_host,
                                 a.smtp_port,
-                                a.use_tls,
+                                a.smtp_tls_mode().as_str_name(),
                             ));
                         }
                     }
@@ -2069,7 +2087,6 @@ impl HeadlessRunner {
                 "server_port": account.server_port,
                 "smtp_host": account.smtp_host,
                 "smtp_port": account.smtp_port,
-                "use_tls": account.use_tls,
                 "imap_tls_mode": account.imap_tls_mode().as_str_name(),
                 "smtp_tls_mode": account.smtp_tls_mode().as_str_name(),
                 "keyring_secret_key": account.keyring_secret_key,
@@ -3103,7 +3120,6 @@ mod tests {
                         protocol: AccountProtocolProto::ImapSmtp.into(),
                         server_host: "imap.nuncio.mx".to_string(),
                         server_port: 993,
-                        use_tls: true,
                         imap_tls_mode: TlsModeProto::ImplicitTls.into(),
                         smtp_tls_mode: TlsModeProto::ImplicitTls.into(),
                         keyring_secret_key: "nuncio/acct-stub-1".to_string(),
@@ -4320,7 +4336,7 @@ mod tests {
                 request: tonic::Request<ExportRulesRequest>,
             ) -> Result<tonic::Response<ExportRulesResponse>, tonic::Status> {
                 let req = request.into_inner();
-                let content = if req.format == "json" {
+                let content = if req.format() == nuncio_proto::v1::RuleExportFormat::Json {
                     r#"[{"id":"rule-stub-1"}]"#.to_string()
                 } else {
                     "SELECT * FROM emails WHERE subject CONTAINS 'Urgent' ACTION MARK READ"
diff --git a/crates/nuncio-core/src/config.rs b/crates/nuncio-core/src/config.rs
index df39c9c..348bbec 100644
--- a/crates/nuncio-core/src/config.rs
+++ b/crates/nuncio-core/src/config.rs
@@ -95,8 +95,6 @@ pub struct AccountConfig {
     pub smtp_host: String,
     /// SMTP server port number, used for outbound mail.
     pub smtp_port: u16,
-    /// Whether TLS connection encryption is enabled.
-    pub use_tls: bool,
     /// IMAP connection security transport mode.
     pub imap_tls_mode: TlsMode,
     /// SMTP connection security transport mode.
@@ -247,7 +245,6 @@ mod tests {
             server_port: 443,
             smtp_host: "smtp.nuncio.mx".to_string(),
             smtp_port: 465,
-            use_tls: true,
             imap_tls_mode: TlsMode::ImplicitTls,
             smtp_tls_mode: TlsMode::ImplicitTls,
             keyring_secret_key: "nuncio/acct-123".to_string(),
@@ -266,7 +263,6 @@ mod tests {
             server_port: 0,
             smtp_host: String::new(),
             smtp_port: 0,
-            use_tls: true,
             imap_tls_mode: TlsMode::ImplicitTls,
             smtp_tls_mode: TlsMode::ImplicitTls,
             keyring_secret_key: "nuncio/acct-cal-1".to_string(),
diff --git a/crates/nuncio-proto/proto/nuncio/v1/descriptor.bin b/crates/nuncio-proto/proto/nuncio/v1/descriptor.bin
index b13188a..21045b8 100644
Binary files a/crates/nuncio-proto/proto/nuncio/v1/descriptor.bin and b/crates/nuncio-proto/proto/nuncio/v1/descriptor.bin differ
diff --git a/crates/nuncio-proto/proto/nuncio/v1/nuncio.proto b/crates/nuncio-proto/proto/nuncio/v1/nuncio.proto
index 742c34b..6275953 100644
--- a/crates/nuncio-proto/proto/nuncio/v1/nuncio.proto
+++ b/crates/nuncio-proto/proto/nuncio/v1/nuncio.proto
@@ -270,8 +270,8 @@ message AccountConfig {
   string server_host = 5;
   // Server port number (1..=65535) (IMAP/JMAP).
   uint32 server_port = 6;
-  // Whether TLS connection encryption is enabled.
-  bool use_tls = 7;
+  reserved 7;
+  reserved "use_tls";
   // IMAP connection security transport mode.
   TlsMode imap_tls_mode = 8;
   // SMTP connection security transport mode.
@@ -844,10 +844,21 @@ message UpdateRuleResponse {
   FilterRule rule = 1;
 }
 
+// Rendering format for `ExportRules`. Kept distinct from `ExportFormat`
+// (the mailbox `Export` service's format enum) because the two have no
+// overlapping members and no shared meaning -- rule export renders lossless
+// NSQL source or a JSON array of rule definitions, never MBOX/EML/JSONL.
+enum RuleExportFormat {
+  RULE_EXPORT_FORMAT_UNSPECIFIED = 0;
+  // Lossless NSQL source text, one rule per line.
+  RULE_EXPORT_FORMAT_SQL = 1;
+  // JSON array of rule definitions.
+  RULE_EXPORT_FORMAT_JSON = 2;
+}
+
 // ExportRulesRequest names the rendering format for `ExportRules`.
 message ExportRulesRequest {
-  // "sql" or "json".
-  string format = 1;
+  RuleExportFormat format = 1;
 }
 
 // ExportRulesResponse carries every persisted rule pre-rendered as a single
diff --git a/crates/nuncio-store/src/db.rs b/crates/nuncio-store/src/db.rs
index c58912c..2ff1c62 100644
--- a/crates/nuncio-store/src/db.rs
+++ b/crates/nuncio-store/src/db.rs
@@ -499,7 +499,11 @@ impl DatabaseEngine {
                 protocol TEXT NOT NULL,
                 server_host TEXT NOT NULL,
                 server_port INTEGER NOT NULL,
-                use_tls INTEGER NOT NULL,
+                -- Retained (with a default) for on-disk compatibility with
+                -- rows written before `imap_tls_mode`/`smtp_tls_mode` became
+                -- the authoritative transport-security setting; no code
+                -- reads or writes this column anymore.
+                use_tls INTEGER NOT NULL DEFAULT 1,
                 keyring_secret_key TEXT NOT NULL,
                 sync_interval_secs INTEGER NOT NULL,
                 smtp_host TEXT,
@@ -964,7 +968,13 @@ impl DatabaseEngine {
         .bind(protocol_str)
         .bind(&config.server_host)
         .bind(config.server_port as i64)
-        .bind(if config.use_tls { 1i64 } else { 0i64 })
+        // `use_tls` is a retained-but-unread on-disk column (see the
+        // `CREATE TABLE`'s comment) -- written as a fixed placeholder since
+        // no `AccountConfig` field backs it anymore, satisfying its
+        // pre-existing `NOT NULL` constraint on every accounts table
+        // regardless of whether it was created before or after this column
+        // stopped being read.
+        .bind(1i64)
         .bind(&config.keyring_secret_key)
         .bind(config.sync_interval_secs as i64)
         .bind(&config.smtp_host)
@@ -1010,7 +1020,6 @@ impl DatabaseEngine {
             String,
             String,
             i64,
-            i64,
             String,
             i64,
             Option<String>,
@@ -1020,7 +1029,7 @@ impl DatabaseEngine {
             Option<String>,
         )> = sqlx::query_as(
             r#"
-            SELECT id, name, email_address, protocol, server_host, server_port, use_tls, keyring_secret_key, sync_interval_secs, smtp_host, smtp_port, imap_tls_mode, smtp_tls_mode, collection_url
+            SELECT id, name, email_address, protocol, server_host, server_port, keyring_secret_key, sync_interval_secs, smtp_host, smtp_port, imap_tls_mode, smtp_tls_mode, collection_url
             FROM accounts
             "#,
         )
@@ -1038,7 +1047,6 @@ impl DatabaseEngine {
                     protocol_str,
                     server_host,
                     server_port,
-                    use_tls,
                     keyring_secret_key,
                     sync_interval_secs,
                     smtp_host,
@@ -1069,7 +1077,6 @@ impl DatabaseEngine {
                         server_port: server_port as u16,
                         smtp_host: resolved_smtp_host,
                         smtp_port: resolved_smtp_port,
-                        use_tls: use_tls != 0,
                         imap_tls_mode: tls_mode_from_db(&imap_tls_mode),
                         smtp_tls_mode: tls_mode_from_db(&smtp_tls_mode),
                         keyring_secret_key,
@@ -2765,7 +2772,6 @@ mod tests {
                 server_port: 993,
                 smtp_host: "smtp.nuncio.mx".to_string(),
                 smtp_port: 465,
-                use_tls: true,
                 imap_tls_mode: nuncio_core::TlsMode::ImplicitTls,
                 smtp_tls_mode: nuncio_core::TlsMode::ImplicitTls,
                 keyring_secret_key: "nuncio/acct-contended-1".to_string(),
@@ -3345,7 +3351,6 @@ mod tests {
             server_port: 993,
             smtp_host: "smtp.nuncio.mx".to_string(),
             smtp_port: 465,
-            use_tls: true,
             imap_tls_mode: nuncio_core::TlsMode::ImplicitTls,
             smtp_tls_mode: nuncio_core::TlsMode::ImplicitTls,
             keyring_secret_key: "nuncio/acct-test-1".to_string(),
@@ -3389,7 +3394,6 @@ mod tests {
             server_port: 143,
             smtp_host: "smtp.nuncio.mx".to_string(),
             smtp_port: 25,
-            use_tls: false,
             imap_tls_mode: nuncio_core::TlsMode::StartTls,
             smtp_tls_mode: nuncio_core::TlsMode::Plain,
             keyring_secret_key: "nuncio/acct-tls-1".to_string(),
@@ -3430,7 +3434,6 @@ mod tests {
             server_port: 0,
             smtp_host: String::new(),
             smtp_port: 0,
-            use_tls: true,
             imap_tls_mode: nuncio_core::TlsMode::ImplicitTls,
             smtp_tls_mode: nuncio_core::TlsMode::ImplicitTls,
             keyring_secret_key: "nuncio/acct-caldav-store-1".to_string(),
@@ -3468,7 +3471,6 @@ mod tests {
             server_port: 993,
             smtp_host: "smtp.nuncio.mx".to_string(),
             smtp_port: 465,
-            use_tls: true,
             imap_tls_mode: nuncio_core::TlsMode::ImplicitTls,
             smtp_tls_mode: nuncio_core::TlsMode::ImplicitTls,
             keyring_secret_key: "nuncio/acct-del-1".to_string(),
@@ -3660,7 +3662,6 @@ mod tests {
             server_port: 993,
             smtp_host: "smtp.nuncio.mx".to_string(),
             smtp_port: 587,
-            use_tls: true,
             imap_tls_mode: nuncio_core::TlsMode::ImplicitTls,
             smtp_tls_mode: nuncio_core::TlsMode::StartTls,
             keyring_secret_key: "nuncio/acct-post-migration".to_string(),
diff --git a/crates/nuncio-store/src/recovery.rs b/crates/nuncio-store/src/recovery.rs
index 6bc97ef..30a1fa0 100644
--- a/crates/nuncio-store/src/recovery.rs
+++ b/crates/nuncio-store/src/recovery.rs
@@ -18,7 +18,6 @@ type SalvagedAccountRow = (
     String,
     String,
     i64,
-    i64,
     String,
     i64,
     Option<String>,
@@ -384,7 +383,7 @@ impl SqliteRecoveryEngine {
 
     async fn salvage_accounts(pool: &sqlx::SqlitePool) -> Vec<nuncio_core::AccountConfig> {
         let rows: Result<Vec<SalvagedAccountRow>, _> = sqlx::query_as(
-            "SELECT id, name, email_address, protocol, server_host, server_port, use_tls, keyring_secret_key, sync_interval_secs, smtp_host, smtp_port, imap_tls_mode, smtp_tls_mode, collection_url FROM accounts"
+            "SELECT id, name, email_address, protocol, server_host, server_port, keyring_secret_key, sync_interval_secs, smtp_host, smtp_port, imap_tls_mode, smtp_tls_mode, collection_url FROM accounts"
         )
         .fetch_all(pool)
         .await;
@@ -400,7 +399,6 @@ impl SqliteRecoveryEngine {
                         protocol_str,
                         server_host,
                         server_port,
-                        use_tls,
                         keyring_secret_key,
                         sync_interval_secs,
                         smtp_host,
@@ -433,7 +431,6 @@ impl SqliteRecoveryEngine {
                             server_port: server_port as u16,
                             smtp_host: resolved_smtp_host,
                             smtp_port: resolved_smtp_port,
-                            use_tls: use_tls != 0,
                             imap_tls_mode,
                             smtp_tls_mode,
                             keyring_secret_key,
@@ -606,7 +603,6 @@ mod tests {
                 server_port: 993,
                 smtp_host: "smtp.nuncio.mx".to_string(),
                 smtp_port: 465,
-                use_tls: true,
                 imap_tls_mode: nuncio_core::TlsMode::ImplicitTls,
                 smtp_tls_mode: nuncio_core::TlsMode::ImplicitTls,
                 keyring_secret_key: "nuncio/acct-test-1".to_string(),
@@ -668,7 +664,6 @@ mod tests {
                 server_port: 993,
                 smtp_host: "smtp.nuncio.mx".to_string(),
                 smtp_port: 465,
-                use_tls: true,
                 imap_tls_mode: nuncio_core::TlsMode::ImplicitTls,
                 smtp_tls_mode: nuncio_core::TlsMode::ImplicitTls,
                 keyring_secret_key: "nuncio/acct-salvage-1".to_string(),
@@ -806,7 +801,6 @@ mod tests {
                 server_port: 143,
                 smtp_host: "smtp.nuncio.mx".to_string(),
                 smtp_port: 587,
-                use_tls: true,
                 imap_tls_mode: nuncio_core::TlsMode::StartTls,
                 smtp_tls_mode: nuncio_core::TlsMode::Plain,
                 keyring_secret_key: "nuncio/acct-starttls-1".to_string(),
diff --git a/crates/nunciod/src/grpc.rs b/crates/nunciod/src/grpc.rs
index 0b95c1c..d436516 100644
--- a/crates/nunciod/src/grpc.rs
+++ b/crates/nunciod/src/grpc.rs
@@ -41,13 +41,14 @@ use nuncio_proto::v1::{
     ListFoldersResponse, ListMessagesRequest, ListMessagesResponse, ListRecordsRequest,
     ListRecordsResponse, ListRulesRequest, ListRulesResponse, MarkReadRequest, MarkReadResponse,
     Message as MessageProto, MessageFlagsChanged, MessageSearchHit, PreviewRuleRequest,
-    PreviewRuleResponse, RemoveAccountRequest, RemoveAccountResponse, SearchMessagesRequest,
-    SearchMessagesResponse, SendMessageRequest, SendMessageResponse, ShuttingDown,
-    SubscribeRequest, SyncCompleted, SyncRequest, SyncResponse, SyncStarted,
-    TestAccountConnectionRequest, TestAccountConnectionResponse, TlsMode as TlsModeProto,
-    TriageProgress, TriageRequest, UpdateAccountRequest, UpdateAccountResponse, UpdateAvailable,
-    UpdateRuleRequest, UpdateRuleResponse, ValidateRuleRequest, ValidateRuleResponse,
-    VerifyChainRequest, VerifyChainResponse,
+    PreviewRuleResponse, RemoveAccountRequest, RemoveAccountResponse,
+    RuleExportFormat as RuleExportFormatProto, SearchMessagesRequest, SearchMessagesResponse,
+    SendMessageRequest, SendMessageResponse, ShuttingDown, SubscribeRequest, SyncCompleted,
+    SyncRequest, SyncResponse, SyncStarted, TestAccountConnectionRequest,
+    TestAccountConnectionResponse, TlsMode as TlsModeProto, TriageProgress, TriageRequest,
+    UpdateAccountRequest, UpdateAccountResponse, UpdateAvailable, UpdateRuleRequest,
+    UpdateRuleResponse, ValidateRuleRequest, ValidateRuleResponse, VerifyChainRequest,
+    VerifyChainResponse,
 };
 use nuncio_store::db::DatabaseEngine;
 use nuncio_store::search::SearchEngine;
@@ -282,7 +283,6 @@ fn map_account_config_to_proto(config: nuncio_core::AccountConfig) -> AccountCon
         protocol: map_account_protocol_to_proto(config.protocol).into(),
         server_host: config.server_host,
         server_port: u32::from(config.server_port),
-        use_tls: config.use_tls,
         imap_tls_mode: map_tls_mode_to_proto(config.imap_tls_mode).into(),
         smtp_tls_mode: map_tls_mode_to_proto(config.smtp_tls_mode).into(),
         keyring_secret_key: config.keyring_secret_key,
@@ -321,7 +321,6 @@ fn map_account_config_from_proto(
         server_port,
         smtp_host: config.smtp_host,
         smtp_port,
-        use_tls: config.use_tls,
         imap_tls_mode,
         smtp_tls_mode,
         keyring_secret_key: config.keyring_secret_key,
@@ -2024,6 +2023,7 @@ impl Filters for FiltersGrpcService {
         request: Request<ExportRulesRequest>,
     ) -> Result<Response<ExportRulesResponse>, Status> {
         let req = request.into_inner();
+        let format = req.format();
 
         let rules = self
             .db
@@ -2031,15 +2031,17 @@ impl Filters for FiltersGrpcService {
             .await
             .map_err(|e| Status::internal(format!("failed to list filter rules: {e}")))?;
 
-        let content = if req.format == "json" {
-            serde_json::to_string_pretty(&rules)
-                .map_err(|e| Status::internal(format!("failed to render rules as JSON: {e}")))?
-        } else {
-            rules
+        let content = match format {
+            RuleExportFormatProto::Sql => rules
                 .iter()
                 .map(|r| r.to_nsql())
                 .collect::<Vec<_>>()
-                .join("\n")
+                .join("\n"),
+            RuleExportFormatProto::Json => serde_json::to_string_pretty(&rules)
+                .map_err(|e| Status::internal(format!("failed to render rules as JSON: {e}")))?,
+            RuleExportFormatProto::Unspecified => {
+                return Err(Status::invalid_argument("rule export format is required"))
+            }
         };
 
         Ok(Response::new(ExportRulesResponse { content }))
@@ -3342,7 +3344,6 @@ mod tests {
             protocol: AccountProtocolProto::ImapSmtp.into(),
             server_host: "imap.nuncio.mx".to_string(),
             server_port: 993,
-            use_tls: true,
             imap_tls_mode: TlsModeProto::ImplicitTls.into(),
             smtp_tls_mode: TlsModeProto::ImplicitTls.into(),
             keyring_secret_key: keyring_secret_key.to_string(),
@@ -3737,7 +3738,6 @@ mod tests {
             server_port: 993,
             smtp_host: "smtp.nuncio.mx".to_string(),
             smtp_port: 465,
-            use_tls: true,
             imap_tls_mode: nuncio_core::TlsMode::ImplicitTls,
             smtp_tls_mode: nuncio_core::TlsMode::ImplicitTls,
             keyring_secret_key: key.to_string(),
@@ -3781,7 +3781,6 @@ mod tests {
             server_port: 993,
             smtp_host: "smtp.nuncio.mx".to_string(),
             smtp_port: 465,
-            use_tls: true,
             imap_tls_mode: nuncio_core::TlsMode::ImplicitTls,
             smtp_tls_mode: nuncio_core::TlsMode::ImplicitTls,
             keyring_secret_key: key.to_string(),
@@ -4349,7 +4348,6 @@ mod tests {
             server_port: 993,
             smtp_host: "127.0.0.1".to_string(),
             smtp_port: 1,
-            use_tls: true,
             imap_tls_mode: nuncio_core::TlsMode::ImplicitTls,
             smtp_tls_mode: nuncio_core::TlsMode::ImplicitTls,
             keyring_secret_key: "nuncio/acct-send-1".to_string(),
@@ -4518,7 +4516,6 @@ mod tests {
             server_port: 993,
             smtp_host: "smtp.nuncio.mx".to_string(),
             smtp_port: 465,
-            use_tls: true,
             imap_tls_mode: nuncio_core::TlsMode::ImplicitTls,
             smtp_tls_mode: nuncio_core::TlsMode::ImplicitTls,
             keyring_secret_key: "nuncio/acct-injected-send-1".to_string(),
@@ -4635,7 +4632,6 @@ mod tests {
             server_port: 993,
             smtp_host: "smtp.nuncio.mx".to_string(),
             smtp_port: 465,
-            use_tls: true,
             imap_tls_mode: nuncio_core::TlsMode::ImplicitTls,
             smtp_tls_mode: nuncio_core::TlsMode::ImplicitTls,
             keyring_secret_key: "nuncio/acct-injected-send-fail-1".to_string(),
@@ -4789,7 +4785,7 @@ mod tests {
 
         let err = client
             .export_rules(ExportRulesRequest {
-                format: "sql".to_string(),
+                format: RuleExportFormatProto::Sql.into(),
             })
             .await
             .expect_err("missing bearer token must be rejected");
@@ -5366,7 +5362,7 @@ mod tests {
 
         let sql_export = client
             .export_rules(authed_bearer_request(ExportRulesRequest {
-                format: "sql".to_string(),
+                format: RuleExportFormatProto::Sql.into(),
             }))
             .await
             .expect("export_rules succeeds")
@@ -5376,7 +5372,7 @@ mod tests {
 
         let json_export = client
             .export_rules(authed_bearer_request(ExportRulesRequest {
-                format: "json".to_string(),
+                format: RuleExportFormatProto::Json.into(),
             }))
             .await
             .expect("export_rules succeeds")
@@ -5385,6 +5381,25 @@ mod tests {
         assert!(json_export.content.contains("Export Me"));
     }
 
+    /// `ExportRules` rejects an unspecified format rather than silently
+    /// defaulting to one rendering.
+    #[tokio::test]
+    async fn export_rules_rejects_unspecified_format() {
+        let (addr, _handle, _db, _engine, _dir) = spawn_filters_test_server("correct-token").await;
+
+        let mut client = FiltersClient::connect(format!("http://{addr}"))
+            .await
+            .expect("client connects");
+
+        let err = client
+            .export_rules(authed_bearer_request(ExportRulesRequest {
+                format: RuleExportFormatProto::Unspecified.into(),
+            }))
+            .await
+            .expect_err("unspecified format must be rejected");
+        assert_eq!(err.code(), Code::InvalidArgument);
+    }
+
     /// `ImportRules` persists every line that parses AND reports the parse
     /// error for every line that does not -- proving failures are surfaced
     /// rather than silently dropped.
diff --git a/crates/nunciod/src/orchestrator.rs b/crates/nunciod/src/orchestrator.rs
index 2fa48f3..5147754 100644
--- a/crates/nunciod/src/orchestrator.rs
+++ b/crates/nunciod/src/orchestrator.rs
@@ -157,7 +157,6 @@ mod tests {
                 server_port: 993,
                 smtp_host: "smtp.nuncio.mx".to_string(),
                 smtp_port: 465,
-                use_tls: true,
                 imap_tls_mode: nuncio_core::TlsMode::ImplicitTls,
                 smtp_tls_mode: nuncio_core::TlsMode::ImplicitTls,
                 keyring_secret_key: "nuncio/acct-orch-1".to_string(),
diff --git a/crates/nunciod/src/send.rs b/crates/nunciod/src/send.rs
index 3593ab5..ee800db 100644
--- a/crates/nunciod/src/send.rs
+++ b/crates/nunciod/src/send.rs
@@ -238,7 +238,6 @@ mod tests {
             server_port: 993,
             smtp_host: "127.0.0.1".to_string(),
             smtp_port: 1,
-            use_tls: true,
             imap_tls_mode: TlsMode::ImplicitTls,
             smtp_tls_mode: TlsMode::ImplicitTls,
             keyring_secret_key: format!("nuncio/{id}"),
diff --git a/crates/nunciod/src/sync.rs b/crates/nunciod/src/sync.rs
index 98dc78a..e2983ba 100644
--- a/crates/nunciod/src/sync.rs
+++ b/crates/nunciod/src/sync.rs
@@ -520,7 +520,6 @@ mod tests {
             server_port: 443,
             smtp_host: "smtp.nuncio.mx".to_string(),
             smtp_port: 465,
-            use_tls: true,
             imap_tls_mode: TlsMode::ImplicitTls,
             smtp_tls_mode: TlsMode::ImplicitTls,
             keyring_secret_key: format!("nuncio/{id}"),
@@ -612,7 +611,6 @@ mod tests {
             server_port: 993,
             smtp_host: "smtp.nuncio.mx".to_string(),
             smtp_port: 465,
-            use_tls: true,
             imap_tls_mode: TlsMode::ImplicitTls,
             smtp_tls_mode: TlsMode::ImplicitTls,
             keyring_secret_key: format!("nuncio/{id}"),
diff --git a/crates/nunciod/tests/accounts_lifecycle_e2e_test.rs b/crates/nunciod/tests/accounts_lifecycle_e2e_test.rs
index 37a5b33..68c53d8 100644
--- a/crates/nunciod/tests/accounts_lifecycle_e2e_test.rs
+++ b/crates/nunciod/tests/accounts_lifecycle_e2e_test.rs
@@ -82,7 +82,6 @@ fn sample_account_config() -> AccountConfig {
         protocol: AccountProtocol::ImapSmtp.into(),
         server_host: "imap.nuncio.mx".to_string(),
         server_port: 143,
-        use_tls: false,
         imap_tls_mode: TlsMode::StartTls.into(),
         smtp_tls_mode: TlsMode::Plain.into(),
         keyring_secret_key: KEYRING_KEY.to_string(),
diff --git a/crates/nunciod/tests/caldav_production_e2e_test.rs b/crates/nunciod/tests/caldav_production_e2e_test.rs
index 6a210f3..566c911 100644
--- a/crates/nunciod/tests/caldav_production_e2e_test.rs
+++ b/crates/nunciod/tests/caldav_production_e2e_test.rs
@@ -161,7 +161,6 @@ async fn caldav_production_sync_builds_real_client_and_persists_events() {
                 protocol: AccountProtocolProto::Caldav.into(),
                 server_host: String::new(),
                 server_port: 0,
-                use_tls: true,
                 imap_tls_mode: TlsModeProto::ImplicitTls.into(),
                 smtp_tls_mode: TlsModeProto::ImplicitTls.into(),
                 keyring_secret_key: KEYRING_KEY.to_string(),
diff --git a/crates/nunciod/tests/outbox_executor_e2e_test.rs b/crates/nunciod/tests/outbox_executor_e2e_test.rs
index d6fd97f..d4a4e4d 100644
--- a/crates/nunciod/tests/outbox_executor_e2e_test.rs
+++ b/crates/nunciod/tests/outbox_executor_e2e_test.rs
@@ -104,7 +104,6 @@ fn sample_account() -> nuncio_core::AccountConfig {
         server_port: 993,
         smtp_host: "smtp.nuncio.mx".to_string(),
         smtp_port: 465,
-        use_tls: true,
         imap_tls_mode: nuncio_core::TlsMode::ImplicitTls,
         smtp_tls_mode: nuncio_core::TlsMode::ImplicitTls,
         keyring_secret_key: format!("nuncio/{ACCOUNT_ID}"),
diff --git a/crates/nunciod/tests/spine_e2e_test.rs b/crates/nunciod/tests/spine_e2e_test.rs
index e99d5b3..be1b8d2 100644
--- a/crates/nunciod/tests/spine_e2e_test.rs
+++ b/crates/nunciod/tests/spine_e2e_test.rs
@@ -61,7 +61,6 @@ fn sample_account_config() -> AccountConfig {
         protocol: AccountProtocol::ImapSmtp.into(),
         server_host: "imap.nuncio.mx".to_string(),
         server_port: 993,
-        use_tls: true,
         imap_tls_mode: TlsMode::ImplicitTls.into(),
         smtp_tls_mode: TlsMode::ImplicitTls.into(),
         keyring_secret_key: KEYRING_KEY.to_string(),