diff --git a/hive-ag3nt/src/bin/hive-ag3nt.rs b/hive-ag3nt/src/bin/hive-ag3nt.rs
index 7c661a0f..ee77d296 100644
--- a/hive-ag3nt/src/bin/hive-ag3nt.rs
+++ b/hive-ag3nt/src/bin/hive-ag3nt.rs
@@ -56,24 +56,16 @@ async fn main() -> Result<()> {
             let initial = LoginState::from_dir(&claude_dir);
             tracing::info!(state = ?initial, claude_dir = %claude_dir.display(), "harness boot");
             let login_state = Arc::new(Mutex::new(initial));
-            let ui_state = login_state.clone();
             let bus = Bus::new();
-            let ui_bus = bus.clone();
-            let ui_socket = cli.socket.clone();
-            tokio::spawn(async move {
-                if let Err(e) = web_ui::serve(
-                    label,
-                    port,
-                    ui_state,
-                    ui_bus,
-                    ui_socket,
-                    web_ui::Flavor::Agent,
-                )
-                .await
-                {
-                    tracing::error!(error = ?e, "web ui failed");
-                }
-            });
+            let files = turn::TurnFiles::prepare(&cli.socket, &label, mcp::Flavor::Agent).await?;
+            tokio::spawn(web_ui::serve(
+                label,
+                port,
+                login_state.clone(),
+                bus.clone(),
+                cli.socket.clone(),
+                files.clone(),
+            ));
             match initial {
                 LoginState::Online => {
                     serve(
@@ -81,6 +73,7 @@ async fn main() -> Result<()> {
                         Duration::from_millis(poll_ms),
                         login_state,
                         bus,
+                        &files,
                     )
                     .await
                 }
@@ -94,6 +87,7 @@ async fn main() -> Result<()> {
                         Duration::from_millis(poll_ms),
                         login_state,
                         bus,
+                        &files,
                     )
                     .await
                 }
@@ -108,13 +102,10 @@ async fn serve(
     interval: Duration,
     state: Arc<Mutex<LoginState>>,
     bus: Bus,
+    files: &turn::TurnFiles,
 ) -> Result<()> {
     tracing::info!(socket = %socket.display(), "hive-ag3nt serve");
     let _ = state; // reserved for future state transitions (turn-loop -> needs-login)
-    let mcp_config = turn::write_mcp_config(socket).await?;
-    let settings = turn::write_settings(socket).await?;
-    let label = std::env::var("HIVE_LABEL").unwrap_or_else(|_| "hive-ag3nt".into());
-    let system_prompt = turn::write_system_prompt(socket, &label, mcp::Flavor::Agent).await?;
     loop {
         let recv: Result<AgentResponse> =
             client::request(socket, &AgentRequest::Recv { wait_seconds: None }).await;
@@ -129,15 +120,7 @@ async fn serve(
                 });
                 bus.set_state(TurnState::Thinking);
                 let prompt = format_wake_prompt(&from, &body, unread);
-                let outcome = turn::drive_turn(
-                    &prompt,
-                    &mcp_config,
-                    &system_prompt,
-                    &settings,
-                    &bus,
-                    mcp::Flavor::Agent,
-                )
-                .await;
+                let outcome = turn::drive_turn(&prompt, files, &bus).await;
                 turn::emit_turn_end(&bus, &outcome);
                 bus.set_state(TurnState::Idle);
             }
diff --git a/hive-ag3nt/src/bin/hive-m1nd.rs b/hive-ag3nt/src/bin/hive-m1nd.rs
index bf997162..9e508062 100644
--- a/hive-ag3nt/src/bin/hive-m1nd.rs
+++ b/hive-ag3nt/src/bin/hive-m1nd.rs
@@ -59,29 +59,23 @@ async fn main() -> Result<()> {
             let initial = LoginState::from_dir(&claude_dir);
             tracing::info!(state = ?initial, claude_dir = %claude_dir.display(), "hm1nd boot");
             let login_state = Arc::new(Mutex::new(initial));
-            let ui_state = login_state.clone();
             let bus = Bus::new();
-            let ui_bus = bus.clone();
-            let ui_socket = cli.socket.clone();
-            tokio::spawn(async move {
-                if let Err(e) = web_ui::serve(
-                    label,
-                    port,
-                    ui_state,
-                    ui_bus,
-                    ui_socket,
-                    web_ui::Flavor::Manager,
-                )
-                .await
-                {
-                    tracing::error!(error = ?e, "web ui failed");
-                }
-            });
+            let files = turn::TurnFiles::prepare(&cli.socket, &label, mcp::Flavor::Manager).await?;
+            tokio::spawn(web_ui::serve(
+                label,
+                port,
+                login_state.clone(),
+                bus.clone(),
+                cli.socket.clone(),
+                files.clone(),
+            ));
             match initial {
-                LoginState::Online => serve(&cli.socket, Duration::from_millis(poll_ms), bus).await,
+                LoginState::Online => {
+                    serve(&cli.socket, Duration::from_millis(poll_ms), bus, &files).await
+                }
                 LoginState::NeedsLogin => {
                     turn::wait_for_login(&claude_dir, login_state, poll_ms).await;
-                    serve(&cli.socket, Duration::from_millis(poll_ms), bus).await
+                    serve(&cli.socket, Duration::from_millis(poll_ms), bus, &files).await
                 }
             }
         }
@@ -89,12 +83,13 @@ async fn main() -> Result<()> {
     }
 }
 
-async fn serve(socket: &Path, interval: Duration, bus: Bus) -> Result<()> {
+async fn serve(
+    socket: &Path,
+    interval: Duration,
+    bus: Bus,
+    files: &turn::TurnFiles,
+) -> Result<()> {
     tracing::info!(socket = %socket.display(), "hive-m1nd serve");
-    let mcp_config = turn::write_mcp_config(socket).await?;
-    let settings = turn::write_settings(socket).await?;
-    let label = std::env::var("HIVE_LABEL").unwrap_or_else(|_| "hm1nd".into());
-    let system_prompt = turn::write_system_prompt(socket, &label, mcp::Flavor::Manager).await?;
     loop {
         let recv: Result<ManagerResponse> =
             client::request(socket, &ManagerRequest::Recv { wait_seconds: None }).await;
@@ -126,15 +121,7 @@ async fn serve(socket: &Path, interval: Duration, bus: Bus) -> Result<()> {
                 });
                 let prompt = format_wake_prompt(&from, &body, unread);
                 bus.set_state(TurnState::Thinking);
-                let outcome = turn::drive_turn(
-                    &prompt,
-                    &mcp_config,
-                    &system_prompt,
-                    &settings,
-                    &bus,
-                    mcp::Flavor::Manager,
-                )
-                .await;
+                let outcome = turn::drive_turn(&prompt, files, &bus).await;
                 turn::emit_turn_end(&bus, &outcome);
                 bus.set_state(TurnState::Idle);
             }
diff --git a/hive-ag3nt/src/turn.rs b/hive-ag3nt/src/turn.rs
index 1c49981c..d85ef8cf 100644
--- a/hive-ag3nt/src/turn.rs
+++ b/hive-ag3nt/src/turn.rs
@@ -33,6 +33,34 @@ const CLAUDE_SETTINGS: &str = include_str!("../prompts/claude-settings.json");
 /// claude exit with a useful error in the live view.
 const PROMPT_TOO_LONG_MARKER: &str = "Prompt is too long";
 
+/// The set of files claude reads on every invocation: the MCP server
+/// config (`--mcp-config`), static settings (`--settings`), and the
+/// pre-rendered role/tools system prompt (`--system-prompt-file`).
+/// Materialised once at harness startup; shared between the turn loop
+/// and the operator-driven `/compact` path so both invocations look
+/// identical to claude (same MCP surface, same allowed tools, same
+/// role prompt — only the stdin payload differs).
+#[derive(Clone)]
+pub struct TurnFiles {
+    pub mcp_config: PathBuf,
+    pub settings: PathBuf,
+    pub system_prompt: PathBuf,
+    pub flavor: mcp::Flavor,
+}
+
+impl TurnFiles {
+    /// Write all three files into the per-agent runtime dir alongside
+    /// `socket`. Idempotent — overwrites whatever was there.
+    pub async fn prepare(socket: &Path, label: &str, flavor: mcp::Flavor) -> Result<Self> {
+        Ok(Self {
+            mcp_config: write_mcp_config(socket).await?,
+            settings: write_settings(socket).await?,
+            system_prompt: write_system_prompt(socket, label, flavor).await?,
+            flavor,
+        })
+    }
+}
+
 /// Drop the MCP config blob claude reads from `--mcp-config <path>`.
 /// `socket` is the hyperhive per-container socket (forwarded to the child
 /// as `--socket <path>`); `binary_subcommand` is e.g. `"mcp"` for sub-agents
@@ -99,21 +127,14 @@ pub enum TurnOutcome {
 
 /// Drive one turn end-to-end, transparently compacting + retrying once on
 /// `Prompt is too long`. Both the sub-agent and manager loops call this.
-pub async fn drive_turn(
-    prompt: &str,
-    mcp_config: &Path,
-    system_prompt: &Path,
-    settings: &Path,
-    bus: &Bus,
-    flavor: mcp::Flavor,
-) -> TurnOutcome {
-    match run_turn(prompt, mcp_config, system_prompt, settings, bus, flavor).await {
+pub async fn drive_turn(prompt: &str, files: &TurnFiles, bus: &Bus) -> TurnOutcome {
+    match run_turn(prompt, files, bus).await {
         TurnOutcome::PromptTooLong => {
-            if let Err(e) = compact_session(settings, bus).await {
+            if let Err(e) = compact_session(files, bus).await {
                 tracing::warn!(error = %format!("{e:#}"), "compact failed");
                 return TurnOutcome::Failed(e);
             }
-            run_turn(prompt, mcp_config, system_prompt, settings, bus, flavor).await
+            run_turn(prompt, files, bus).await
         }
         other => other,
     }
@@ -166,25 +187,8 @@ pub async fn wait_for_login(claude_dir: &Path, state: Arc<Mutex<LoginState>>, po
 /// prompt). The session is persistent across turns via `--continue` and
 /// claude's in-session auto-compact is disabled via `--settings` so it
 /// doesn't stall mid-turn — hyperhive owns compaction.
-pub async fn run_turn(
-    prompt: &str,
-    mcp_config: &Path,
-    system_prompt: &Path,
-    settings: &Path,
-    bus: &Bus,
-    flavor: mcp::Flavor,
-) -> TurnOutcome {
-    match run_claude(
-        prompt,
-        mcp_config,
-        Some(system_prompt),
-        settings,
-        bus,
-        flavor,
-        ClaudeMode::Turn,
-    )
-    .await
-    {
+pub async fn run_turn(prompt: &str, files: &TurnFiles, bus: &Bus) -> TurnOutcome {
+    match run_claude(prompt, files, bus).await {
         Ok(too_long) if too_long => TurnOutcome::PromptTooLong,
         Ok(_) => TurnOutcome::Ok,
         Err(e) => TurnOutcome::Failed(e),
@@ -192,49 +196,23 @@ pub async fn run_turn(
 }
 
 /// Run claude's built-in `/compact` slash command on the persistent
-/// session so the next turn can fit. No MCP tools needed; we just feed
-/// `/compact` over stdin and let claude rewrite its own history.
-pub async fn compact_session(settings: &Path, bus: &Bus) -> Result<()> {
+/// session. Takes the *same* params as `run_turn` because compact
+/// re-initialises claude with the full session shape — same MCP
+/// surface, same system prompt, same allowed-tools — so the post-
+/// compact state matches a normal turn's. Only the prompt over stdin
+/// differs (`/compact` vs the wake-up payload).
+pub async fn compact_session(files: &TurnFiles, bus: &Bus) -> Result<()> {
     bus.emit(LiveEvent::Note(
         "context overflow — running /compact on the persistent session".into(),
     ));
-    let _ = run_claude(
-        "/compact",
-        Path::new("/dev/null"),
-        None,
-        settings,
-        bus,
-        mcp::Flavor::Agent, // tool surface unused for /compact
-        ClaudeMode::Compact,
-    )
-    .await?;
+    let _ = run_claude("/compact", files, bus).await?;
     bus.emit(LiveEvent::Note("/compact done".into()));
     Ok(())
 }
 
-#[derive(Clone, Copy)]
-enum ClaudeMode {
-    Turn,
-    Compact,
-}
-
-async fn run_claude(
-    prompt: &str,
-    mcp_config: &Path,
-    system_prompt: Option<&Path>,
-    settings: &Path,
-    bus: &Bus,
-    flavor: mcp::Flavor,
-    mode: ClaudeMode,
-) -> Result<bool> {
+async fn run_claude(prompt: &str, files: &TurnFiles, bus: &Bus) -> Result<bool> {
     let model = bus.model();
-    // /compact must always run against the existing session — otherwise
-    // there's nothing to compact. Only normal turns honor the
-    // operator's "new session" one-shot flag.
-    let resume = match mode {
-        ClaudeMode::Turn => !bus.take_skip_continue(),
-        ClaudeMode::Compact => true,
-    };
+    let resume = !bus.take_skip_continue();
     if !resume {
         bus.emit(LiveEvent::Note(
             "fresh session (--continue suppressed for this turn)".into(),
@@ -258,22 +236,18 @@ async fn run_claude(
         .arg("--model")
         .arg(&model)
         .arg("--settings")
-        .arg(settings);
+        .arg(&files.settings);
     if resume {
         cmd.arg("--continue");
     }
-    if let Some(p) = system_prompt {
-        cmd.arg("--system-prompt-file").arg(p);
-    }
-    if let ClaudeMode::Turn = mode {
-        cmd.arg("--mcp-config")
-            .arg(mcp_config)
-            .arg("--strict-mcp-config")
-            .arg("--tools")
-            .arg(mcp::builtin_tools_arg())
-            .arg("--allowedTools")
-            .arg(mcp::allowed_tools_arg(flavor));
-    }
+    cmd.arg("--system-prompt-file").arg(&files.system_prompt);
+    cmd.arg("--mcp-config")
+        .arg(&files.mcp_config)
+        .arg("--strict-mcp-config")
+        .arg("--tools")
+        .arg(mcp::builtin_tools_arg())
+        .arg("--allowedTools")
+        .arg(mcp::allowed_tools_arg(files.flavor));
     let mut child = cmd
         .stdin(Stdio::piped())
         .stdout(Stdio::piped())
diff --git a/hive-ag3nt/src/web_ui.rs b/hive-ag3nt/src/web_ui.rs
index c9d759e5..931ec2d6 100644
--- a/hive-ag3nt/src/web_ui.rs
+++ b/hive-ag3nt/src/web_ui.rs
@@ -28,6 +28,8 @@ use crate::client;
 use crate::events::Bus;
 use crate::login::LoginState;
 use crate::login_session::{LoginSession, drop_if_finished};
+use crate::mcp;
+use crate::turn::TurnFiles;
 
 /// Live login state for the web UI. The harness updates this in place as it
 /// transitions between `NeedsLogin` and `Online`; the UI reads on each
@@ -41,16 +43,25 @@ struct AppState {
     session: Arc<Mutex<Option<Arc<LoginSession>>>>,
     bus: Bus,
     socket: PathBuf,
-    flavor: Flavor,
+    /// Same `TurnFiles` the harness's turn loop uses. Shared so
+    /// `/api/compact` re-uses the exact MCP config / system prompt /
+    /// settings claude saw on the last regular turn — keeps the
+    /// session shape identical across compact + normal turns.
+    files: TurnFiles,
+}
+
+impl AppState {
+    fn flavor(&self) -> Flavor {
+        self.files.flavor
+    }
 }
 
 /// Which wire protocol the per-agent UI's `/send` handler should speak.
-/// Sub-agent → `AgentRequest::OperatorMsg`; manager → `ManagerRequest::OperatorMsg`.
-#[derive(Debug, Clone, Copy)]
-pub enum Flavor {
-    Agent,
-    Manager,
-}
+/// Sub-agent → `AgentRequest::OperatorMsg`; manager →
+/// `ManagerRequest::OperatorMsg`. Reuses the MCP-side enum so a
+/// single value drives both the send protocol and (in
+/// `post_compact`) the allowed-tools surface claude sees.
+pub type Flavor = mcp::Flavor;
 
 pub async fn serve(
     label: String,
@@ -58,7 +69,7 @@ pub async fn serve(
     login: LoginStateCell,
     bus: Bus,
     socket: PathBuf,
-    flavor: Flavor,
+    files: TurnFiles,
 ) -> Result<()> {
     let state = AppState {
         label,
@@ -66,7 +77,7 @@ pub async fn serve(
         session: Arc::new(Mutex::new(None)),
         bus,
         socket,
-        flavor,
+        files,
     };
     let app = Router::new()
         .route("/", get(serve_index))
@@ -208,7 +219,7 @@ async fn api_state(State(state): State<AppState>) -> axum::Json<StateSnapshot> {
         .ok()
         .and_then(|s| s.parse::<u16>().ok())
         .unwrap_or(7000);
-    let inbox = recent_inbox(&state.socket, state.flavor).await;
+    let inbox = recent_inbox(&state.socket, state.flavor()).await;
     let (turn_state, turn_state_since) = state.bus.state_snapshot();
     let model = state.bus.model();
     axum::Json(StateSnapshot {
@@ -268,7 +279,7 @@ async fn post_send(State(state): State<AppState>, Form(form): Form<SendForm>) ->
     if body.is_empty() {
         return error_response("send: `body` required");
     }
-    let result = match state.flavor {
+    let result = match state.flavor() {
         Flavor::Agent => match client::request::<_, hive_sh4re::AgentResponse>(
             &state.socket,
             &hive_sh4re::AgentRequest::OperatorMsg { body },
@@ -396,22 +407,13 @@ async fn post_set_model(State(state): State<AppState>, Form(form): Form<ModelFor
 
 async fn post_compact(State(state): State<AppState>) -> Response {
     let bus = state.bus.clone();
-    let socket = state.socket.clone();
+    let files = state.files.clone();
     tokio::spawn(async move {
         bus.emit(crate::events::LiveEvent::Note(
             "operator: /compact — running on persistent session".into(),
         ));
-        let settings = match crate::turn::write_settings(&socket).await {
-            Ok(p) => p,
-            Err(e) => {
-                bus.emit(crate::events::LiveEvent::Note(format!(
-                    "/compact failed: settings write — {e:#}"
-                )));
-                return;
-            }
-        };
         bus.set_state(crate::events::TurnState::Compacting);
-        let r = crate::turn::compact_session(&settings, &bus).await;
+        let r = crate::turn::compact_session(&files, &bus).await;
         bus.set_state(crate::events::TurnState::Idle);
         if let Err(e) = r {
             bus.emit(crate::events::LiveEvent::Note(format!(
diff --git a/hive-c0re/src/meta.rs b/hive-c0re/src/meta.rs
index 023ded47..afb30b9a 100644
--- a/hive-c0re/src/meta.rs
+++ b/hive-c0re/src/meta.rs
@@ -73,8 +73,18 @@ pub async fn sync_agents(
     if initial {
         git(&dir, &["init", "--initial-branch=main"]).await?;
     }
+    // Stage flake.nix *before* running nix flake lock. When meta is
+    // a git repo, nix treats it as a `git+file://` self-reference;
+    // its dirty-tree fetcher includes index entries (tracked +
+    // staged) but skips untracked files, so without the stage step
+    // an untracked flake.nix surfaces as "source tree does not
+    // contain '/flake.nix'". Lock then commit once with both
+    // flake.nix and flake.lock — single commit per change.
+    git(&dir, &["add", "flake.nix"]).await?;
     nix(&dir, &["flake", "lock"]).await?;
-    git(&dir, &["add", "-A"]).await?;
+    if std::path::Path::new(&dir).join("flake.lock").exists() {
+        git(&dir, &["add", "flake.lock"]).await?;
+    }
     let msg = if initial {
         format!("seed meta from {} agent(s)", agents.len())
     } else {
@@ -86,39 +96,60 @@ pub async fn sync_agents(
 
 /// Phase 1 of an apply-commit deploy. Updates the locked rev of
 /// `agent-<name>` to whatever `applied/<name>/main` currently points
-/// at. **Doesn't commit** — caller must follow with
-/// `finalize_deploy` on build success or `abort_deploy` on failure.
+/// at and **stages** the lock so `nixos-container update --flake
+/// meta#<n>` (which reads via `git+file://`) sees the new rev via
+/// the index. Doesn't commit — `finalize_deploy` commits on build
+/// success, `abort_deploy` drops the staged change on failure so
+/// meta history only carries successful deploys.
 #[allow(dead_code)] // wired up by actions::run_apply_commit in a later commit
 pub async fn prepare_deploy(name: &str) -> Result<()> {
     let dir = meta_dir();
     let input = format!("agent-{name}");
-    nix(&dir, &["flake", "update", &input]).await
+    nix(&dir, &["flake", "update", &input]).await?;
+    // Stage the new lock — git+file://'s dirty-tree fetcher reads
+    // index entries, so the upcoming nixos-container update sees the
+    // bumped rev without a commit yet.
+    git(&dir, &["add", "flake.lock"]).await
 }
 
-/// Phase 2-success. Commits the staged `flake.lock` change with a
-/// deploy-shaped message. No-op (clean working tree) is tolerated —
-/// some lock-updates resolve to the same rev that's already locked.
+/// Phase 2-success. Commit the staged lock with the deployed tag +
+/// sha as the message. No-op when the rev was already at the right
+/// place (nothing staged → nothing to commit).
 #[allow(dead_code)]
 pub async fn finalize_deploy(name: &str, sha: &str, tag: &str) -> Result<()> {
     let dir = meta_dir();
-    if git_is_clean(&dir).await? {
+    if !has_staged_changes(&dir).await? {
         return Ok(());
     }
-    git(&dir, &["add", "flake.lock"]).await?;
     let short = &sha[..sha.len().min(12)];
     git_commit(&dir, &format!("deploy {name} {tag} {short}")).await
 }
 
-/// Phase 2-failure. Drops the uncommitted `flake.lock` change so meta
-/// stays pinned at the previously-deployed shas. The failed proposal
-/// is still captured in `applied/<n>`'s annotated `failed/<id>` tag —
-/// meta's history only carries successful deploys.
+/// Phase 2-failure. Unstage + restore the lock so meta returns to
+/// the previously-committed shas. The failed proposal is still
+/// captured in `applied/<n>`'s annotated `failed/<id>` tag.
 #[allow(dead_code)]
 pub async fn abort_deploy() -> Result<()> {
     let dir = meta_dir();
+    git(&dir, &["restore", "--staged", "flake.lock"]).await?;
     git(&dir, &["restore", "flake.lock"]).await
 }
 
+async fn has_staged_changes(dir: &Path) -> Result<bool> {
+    let st = lifecycle::git_command()
+        .current_dir(dir)
+        .args(["diff", "--cached", "--quiet"])
+        .status()
+        .await
+        .with_context(|| format!("git diff --cached in {}", dir.display()))?;
+    // exit 1 = differences present, 0 = no diff, other = error
+    match st.code() {
+        Some(0) => Ok(false),
+        Some(1) => Ok(true),
+        _ => bail!("git diff --cached exited unexpectedly"),
+    }
+}
+
 /// One-shot used by the manual-rebuild path: relock just one
 /// agent's input and commit the lock change if any. Single-phase
 /// (no separate finalize) because rebuild has no failure-revert
@@ -128,11 +159,11 @@ pub async fn lock_update_for_rebuild(name: &str) -> Result<()> {
     let dir = meta_dir();
     let input = format!("agent-{name}");
     nix(&dir, &["flake", "update", &input]).await?;
-    if !git_is_clean(&dir).await? {
-        git(&dir, &["add", "flake.lock"]).await?;
-        git_commit(&dir, &format!("rebuild {name}: lock update")).await?;
+    if git_is_clean(&dir).await? {
+        return Ok(());
     }
-    Ok(())
+    git(&dir, &["add", "flake.lock"]).await?;
+    git_commit(&dir, &format!("rebuild {name}: lock update")).await
 }
 
 /// One-shot used by the auto-update path: pin the latest hyperhive
@@ -142,11 +173,11 @@ pub async fn lock_update_for_rebuild(name: &str) -> Result<()> {
 pub async fn lock_update_hyperhive() -> Result<()> {
     let dir = meta_dir();
     nix(&dir, &["flake", "update", "hyperhive"]).await?;
-    if !git_is_clean(&dir).await? {
-        git(&dir, &["add", "flake.lock"]).await?;
-        git_commit(&dir, "bump hyperhive").await?;
+    if git_is_clean(&dir).await? {
+        return Ok(());
     }
-    Ok(())
+    git(&dir, &["add", "flake.lock"]).await?;
+    git_commit(&dir, "bump hyperhive").await
 }
 
 fn render_flake(hyperhive_flake: &str, dashboard_port: u16, agents: &[AgentSpec]) -> String {