diff --git a/desktop/src-tauri/src/commands/personas/inbound.rs b/desktop/src-tauri/src/commands/personas/inbound.rs
index c322e6cb6e8..e804584c473 100644
--- a/desktop/src-tauri/src/commands/personas/inbound.rs
+++ b/desktop/src-tauri/src/commands/personas/inbound.rs
@@ -194,6 +194,12 @@ fn reconcile_inbound_persona_event_blocking(
     if let Some(managed_agent) = &inbound_managed_agent {
         validate_inbound_managed_agent_definition(managed_agent)?;
     }
+    let inbound_team = (kind == KIND_TEAM)
+        .then(|| team_content_from_event(&event))
+        .transpose()?;
+    if let Some(team) = &inbound_team {
+        validate_inbound_team_definition(team)?;
+    }
     let d_tag = match &inbound_persona {
         Some(persona) => persona_d_tag(persona),
         None => event_d_tag(&event)?,
@@ -255,10 +261,12 @@ fn reconcile_inbound_persona_event_blocking(
         }
         KIND_TEAM => {
             let mut teams = load_teams(&app)?;
+            let team = inbound_team
+                .ok_or_else(|| "team content was not parsed before retention".to_string())?;
             commit_inbound_team(
                 &mut teams,
                 d_tag,
-                team_content_from_event(&event)?,
+                team,
                 |teams| save_teams(&app, teams),
                 || load_managed_agents(&app),
                 |records| save_managed_agents(&app, records),
@@ -359,6 +367,15 @@ fn validate_inbound_managed_agent_definition(
     .map_err(|error| format!("Inbound managed-agent definition is unsafe: {error}"))
 }
 
+fn validate_inbound_team_definition(team: &TeamEventContent) -> Result<(), String> {
+    let instructions = match &team.instructions {
+        Some(inner) => inner.as_deref(),
+        None => None,
+    };
+    crate::managed_agents::validate_team_definition_text(&team.name, instructions)
+        .map_err(|error| format!("Inbound team definition is unsafe: {error}"))
+}
+
 /// Parse an inbound wire event and enforce the signature gate. Everything
 /// downstream trusts `event.pubkey` (ownership routing, tombstone scoping,
 /// behavioral-quad application), so a forged pubkey must die here — the
diff --git a/desktop/src-tauri/src/commands/personas/inbound/inbound_tests.rs b/desktop/src-tauri/src/commands/personas/inbound/inbound_tests.rs
index c0526222151..b1332481721 100644
--- a/desktop/src-tauri/src/commands/personas/inbound/inbound_tests.rs
+++ b/desktop/src-tauri/src/commands/personas/inbound/inbound_tests.rs
@@ -909,3 +909,32 @@ fn inbound_definition_less_agent_accepts_visible_multiline_prompt() {
 
     assert!(validate_inbound_managed_agent_definition(&inbound).is_ok());
 }
+
+#[test]
+fn inbound_team_rejects_invisible_instructions() {
+    let mut inbound = team_content("Review Team");
+    inbound.instructions = Some(Some("Be\u{200B} thorough.".to_string()));
+
+    let error = validate_inbound_team_definition(&inbound)
+        .expect_err("relay sync must reject invisible team instructions");
+
+    assert!(error.contains("U+200B"));
+}
+
+#[test]
+fn inbound_team_rejects_bidirectional_name() {
+    let inbound = team_content("Review\u{202E} Team");
+
+    let error = validate_inbound_team_definition(&inbound)
+        .expect_err("relay sync must reject bidirectional team names");
+
+    assert!(error.contains("U+202E"));
+}
+
+#[test]
+fn inbound_team_accepts_visible_multiline_instructions() {
+    let mut inbound = team_content("Review Team");
+    inbound.instructions = Some(Some("Review changes.\n\tCall out risks.".to_string()));
+
+    assert!(validate_inbound_team_definition(&inbound).is_ok());
+}
diff --git a/desktop/src-tauri/src/commands/team_snapshot.rs b/desktop/src-tauri/src/commands/team_snapshot.rs
index 8315f39a362..f1658bce14d 100644
--- a/desktop/src-tauri/src/commands/team_snapshot.rs
+++ b/desktop/src-tauri/src/commands/team_snapshot.rs
@@ -18,7 +18,8 @@ use crate::{
     managed_agents::{
         agent_snapshot::{build_snapshot, AgentSnapshot, AgentSnapshotMemoryEntry, MemoryLevel},
         load_managed_agents, load_personas, load_teams, load_teams_readonly, save_managed_agents,
-        save_personas, save_teams, AgentDefinition, ManagedAgentRecord, TeamRecord,
+        save_personas, save_teams, validate_team_definition_text, AgentDefinition,
+        ManagedAgentRecord, TeamRecord,
     },
     relay::{effective_agent_relay_url, relay_ws_url_with_override, sync_managed_agent_profile},
     util::now_iso,
@@ -164,6 +165,7 @@ pub(crate) fn build_import_team(
     if name.is_empty() {
         return Err("Team snapshot name is empty.".to_string());
     }
+    validate_team_definition_text(name, snapshot.team.instructions.as_deref())?;
 
     Ok(TeamRecord {
         id: Uuid::new_v4().to_string(),
@@ -270,6 +272,8 @@ fn build_team_export_snapshot(
     memory_level: MemoryLevel,
     memory_entries_by_persona: &std::collections::HashMap<String, Vec<AgentSnapshotMemoryEntry>>,
 ) -> Result<TeamSnapshot, String> {
+    validate_team_definition_text(&team.name, team.instructions.as_deref())
+        .map_err(|error| format!("Team snapshot is unsafe to export: {error}"))?;
     let members = team
         .persona_ids
         .iter()
@@ -461,6 +465,10 @@ pub async fn preview_team_snapshot_import(
 ) -> Result<TeamSnapshotImportPreview, String> {
     tokio::task::spawn_blocking(move || {
         let snapshot = decode_team_snapshot_from_bytes(&file_bytes)?;
+        validate_team_definition_text(
+            snapshot.team.name.trim(),
+            snapshot.team.instructions.as_deref(),
+        )?;
         let members: Vec<_> = snapshot.members.iter().map(member_preview).collect();
         Ok(TeamSnapshotImportPreview {
             name: snapshot.team.name,
diff --git a/desktop/src-tauri/src/commands/team_snapshot/tests.rs b/desktop/src-tauri/src/commands/team_snapshot/tests.rs
index a466228160a..ed587be899a 100644
--- a/desktop/src-tauri/src/commands/team_snapshot/tests.rs
+++ b/desktop/src-tauri/src/commands/team_snapshot/tests.rs
@@ -330,6 +330,91 @@ fn team_import_definitions_are_built_for_all_members() {
     assert_eq!(definitions[0].system_prompt, "Alice prompt");
 }
 
+#[test]
+fn team_import_rejects_invisible_team_instructions() {
+    let mut source = snapshot(vec![member("Alice")]);
+    source.team.instructions = Some("Be\u{200B} thorough.".to_string());
+
+    let error = build_import_team(&source, vec!["alice".to_string()], "now")
+        .expect_err("snapshot import must reject invisible team instructions");
+
+    assert!(error.contains("U+200B"));
+}
+
+#[test]
+fn team_import_rejects_bidirectional_team_name() {
+    let mut source = snapshot(vec![member("Alice")]);
+    source.team.name = "Review\u{202E} Team".to_string();
+
+    let error = build_import_team(&source, vec!["alice".to_string()], "now")
+        .expect_err("snapshot import must reject bidirectional team names");
+
+    assert!(error.contains("U+202E"));
+}
+
+#[test]
+fn team_export_rejects_unsafe_name_and_instructions() {
+    let definitions = vec![AgentDefinition {
+        id: "alice".to_string(),
+        display_name: "Alice".to_string(),
+        avatar_url: None,
+        system_prompt: "Alice prompt".to_string(),
+        runtime: Some("goose".to_string()),
+        model: None,
+        provider: None,
+        name_pool: vec![],
+        is_builtin: false,
+        is_active: true,
+        shared: false,
+        source_team: None,
+        source_team_persona_slug: None,
+        catalog_source: None,
+        env_vars: Default::default(),
+        respond_to: None,
+        respond_to_allowlist: vec![],
+        parallelism: None,
+        created_at: "now".to_string(),
+        updated_at: "now".to_string(),
+    }];
+    let mut team = TeamRecord {
+        id: "review".to_string(),
+        name: "Review Team".to_string(),
+        description: None,
+        instructions: Some("Be thorough.".to_string()),
+        persona_ids: vec!["alice".to_string()],
+        is_builtin: false,
+        source_dir: None,
+        is_symlink: false,
+        symlink_target: None,
+        version: None,
+        created_at: "now".to_string(),
+        updated_at: "now".to_string(),
+    };
+
+    team.name = "Review\u{200B} Team".to_string();
+    let error = build_team_export_snapshot(
+        &team,
+        &definitions,
+        &[],
+        MemoryLevel::None,
+        &std::collections::HashMap::new(),
+    )
+    .expect_err("export must reject an invisible team name");
+    assert!(error.contains("U+200B"), "unexpected error: {error}");
+
+    team.name = "Review Team".to_string();
+    team.instructions = Some("Be\u{202E} thorough.".to_string());
+    let error = build_team_export_snapshot(
+        &team,
+        &definitions,
+        &[],
+        MemoryLevel::None,
+        &std::collections::HashMap::new(),
+    )
+    .expect_err("export must reject bidi formatting in team instructions");
+    assert!(error.contains("U+202E"), "unexpected error: {error}");
+}
+
 #[test]
 fn team_import_keeps_or_clears_every_member_allowlist_with_one_toggle() {
     let source = snapshot(vec![member("Alice"), member("Bob")]);
diff --git a/desktop/src-tauri/src/commands/teams.rs b/desktop/src-tauri/src/commands/teams.rs
index e17c5bdb247..a6366bdf1e2 100644
--- a/desktop/src-tauri/src/commands/teams.rs
+++ b/desktop/src-tauri/src/commands/teams.rs
@@ -6,7 +6,7 @@ use crate::{
     managed_agents::{
         delete_team_with_cascade, ensure_persona_ids_are_active, load_managed_agents,
         load_personas, load_teams, save_managed_agents, save_teams, try_regenerate_nest,
-        CreateTeamRequest, TeamRecord, UpdateTeamRequest,
+        validate_team_definition_text, CreateTeamRequest, TeamRecord, UpdateTeamRequest,
     },
     util::now_iso,
 };
@@ -317,6 +317,7 @@ pub async fn create_team(input: CreateTeamRequest, app: AppHandle) -> Result<Tea
         let name = trim_required(&input.name, "Team name")?;
         let description = trim_optional(input.description);
         let instructions = trim_optional(input.instructions);
+        validate_team_definition_text(&name, instructions.as_deref())?;
         let now = now_iso();
 
         let _store_guard = state
@@ -363,6 +364,9 @@ pub async fn update_team(input: UpdateTeamRequest, app: AppHandle) -> Result<Tea
         let name = trim_required(&input.name, "Team name")?;
         let description = trim_optional(input.description);
         let instructions = trim_optional(input.instructions);
+        // Validate before the store lock so a rejected update cannot leave a
+        // partial in-memory write, let alone a teams.json write.
+        validate_team_definition_text(&name, instructions.as_deref())?;
 
         let _store_guard = state
             .managed_agents_store_lock
diff --git a/desktop/src-tauri/src/managed_agents/definition_validation.rs b/desktop/src-tauri/src/managed_agents/definition_validation.rs
index 92445604d2e..182116dcab2 100644
--- a/desktop/src-tauri/src/managed_agents/definition_validation.rs
+++ b/desktop/src-tauri/src/managed_agents/definition_validation.rs
@@ -1,9 +1,9 @@
-//! Validation for human-reviewed agent definition text.
+//! Validation for human-reviewed agent and team definition text.
 //!
-//! Shared definitions are executable configuration: `system_prompt` is shown
-//! to a person, then delivered verbatim to an ACP harness. Characters that
-//! consume input bytes without a visible glyph break that review invariant and
-//! are rejected rather than silently stripped.
+//! Shared definitions are executable configuration: agent `system_prompt` and
+//! team instructions are shown to a person, then delivered verbatim to an ACP
+//! harness. Characters that consume input bytes without a visible glyph break
+//! that review invariant and are rejected rather than silently stripped.
 
 use regex::Regex;
 use std::sync::LazyLock;
@@ -60,6 +60,38 @@ pub(crate) fn validate_managed_agent_definition_text(
     validate_agent_definition_text(name, executable_prompt)
 }
 
+/// Validate the human-visible fields of a team definition.
+///
+/// Team names and instructions are shared and executed at launch, so they use
+/// the same reviewable-text contract as agent definitions. Absent instructions
+/// are allowed; present instructions must be reviewable.
+pub(crate) fn validate_team_definition_text(
+    name: &str,
+    instructions: Option<&str>,
+) -> Result<(), String> {
+    if name.trim().is_empty() {
+        return Err("Team name is required".to_string());
+    }
+    let name_chars = name.chars().count();
+    if name_chars > MAX_DISPLAY_NAME_CHARS {
+        return Err(format!(
+            "Team name is too long ({name_chars} characters, max {MAX_DISPLAY_NAME_CHARS})"
+        ));
+    }
+    validate_visible_text(name, "Team name", false)?;
+
+    let Some(instructions) = instructions else {
+        return Ok(());
+    };
+    if instructions.len() > MAX_SYSTEM_PROMPT_BYTES {
+        return Err(format!(
+            "Team instructions are too long ({} bytes, max {MAX_SYSTEM_PROMPT_BYTES})",
+            instructions.len()
+        ));
+    }
+    validate_visible_text(instructions, "Team instructions", true)
+}
+
 fn validate_visible_text(
     value: &str,
     label: &str,
@@ -267,4 +299,32 @@ mod tests {
         )
         .is_ok());
     }
+
+    #[test]
+    fn accepts_plain_team_name_and_multiline_instructions() {
+        assert!(validate_team_definition_text(
+            "Review Team 🐝",
+            Some("Review changes.\n\tCall out security risks."),
+        )
+        .is_ok());
+        assert!(validate_team_definition_text("Review Team", None).is_ok());
+    }
+
+    #[test]
+    fn rejects_invisible_characters_in_team_name_or_instructions() {
+        assert!(
+            validate_team_definition_text("Review\u{200B} Team", Some("Be thorough.")).is_err()
+        );
+        assert!(
+            validate_team_definition_text("Review Team", Some("Be\u{200B} thorough.")).is_err()
+        );
+    }
+
+    #[test]
+    fn enforces_team_name_and_instruction_bounds() {
+        assert!(validate_team_definition_text(&"a".repeat(129), None).is_err());
+        assert!(
+            validate_team_definition_text("Review Team", Some(&"a".repeat(64 * 1024 + 1))).is_err()
+        );
+    }
 }
diff --git a/desktop/src-tauri/src/managed_agents/mod.rs b/desktop/src-tauri/src/managed_agents/mod.rs
index 16234aa3d69..df410becda0 100644
--- a/desktop/src-tauri/src/managed_agents/mod.rs
+++ b/desktop/src-tauri/src/managed_agents/mod.rs
@@ -55,6 +55,7 @@ pub(crate) fn lock_path_mutex() -> std::sync::MutexGuard<'static, ()> {
 pub use backend::*;
 pub(crate) use definition_validation::{
     validate_agent_definition_text, validate_managed_agent_definition_text,
+    validate_team_definition_text,
 };
 pub use discovery::*;
 pub use env_vars::*;
diff --git a/desktop/src-tauri/src/managed_agents/team_events.rs b/desktop/src-tauri/src/managed_agents/team_events.rs
index 64861c0dec6..51801eb03eb 100644
--- a/desktop/src-tauri/src/managed_agents/team_events.rs
+++ b/desktop/src-tauri/src/managed_agents/team_events.rs
@@ -64,8 +64,12 @@ pub fn team_event_content(record: &TeamRecord) -> TeamEventContent {
 
 /// Build a kind:30176 event from a `TeamRecord`.
 ///
-/// Returns an unsigned `EventBuilder` — the caller signs and submits.
+/// Returns an unsigned `EventBuilder` — the caller signs and submits. Unsafe
+/// names or instructions fail here so a dirty `teams.json` cannot be signed
+/// during startup migration, matching [`super::agent_events::build_agent_event`].
 pub fn build_team_event(record: &TeamRecord) -> Result<EventBuilder, String> {
+    super::validate_team_definition_text(&record.name, record.instructions.as_deref())
+        .map_err(|error| format!("Team definition is unsafe to publish: {error}"))?;
     let content = serde_json::to_string(&team_event_content(record))
         .map_err(|e| format!("failed to serialize team content: {e}"))?;
     let tags =
@@ -129,6 +133,21 @@ mod tests {
         assert_eq!(event.kind.as_u16() as u32, KIND_TEAM);
     }
 
+    #[test]
+    fn publication_rejects_unsafe_team_name_and_instructions() {
+        let mut unsafe_name = sample_team();
+        unsafe_name.name = "Review\u{200B} Team".to_string();
+        let error = build_team_event(&unsafe_name)
+            .expect_err("publication must reject an invisible team name");
+        assert!(error.contains("U+200B"), "unexpected error: {error}");
+
+        let mut unsafe_instructions = sample_team();
+        unsafe_instructions.instructions = Some("Be\u{202E} thorough.".to_string());
+        let error = build_team_event(&unsafe_instructions)
+            .expect_err("publication must reject bidi formatting in team instructions");
+        assert!(error.contains("U+202E"), "unexpected error: {error}");
+    }
+
     #[test]
     fn d_tag_is_team_id() {
         let builder = build_team_event(&sample_team()).unwrap();