diff --git a/README.md b/README.md
index faa2ef4..3234932 100644
--- a/README.md
+++ b/README.md
@@ -2,7 +2,7 @@
 
 Sound is terrain. A sampling instrument where material is cut in a quarry, laid as stones in a nave, and played by a hand or an agent through the same verbs.
 
-This repository is **P1c**: the engine, the wire, the descent, the material room, a project that survives a restart, and a microphone. A found or recorded sound is cut into sixteen faces, laid on a vein and heard in the loop; tempo, gains and pattern edits are autosaved and reversible. The visual demo in [`reference/demo`](reference/demo) remains a design reference, not the codebase. The roadmap is in [`docs/PLAN.md`](docs/PLAN.md).
+This repository is **P1d**: the engine, the wire, the descent, the material room, a project that survives a restart, a microphone, and a waveform you can cut. A found or recorded sound is cut into sixteen faces by hand or by analysis, laid on a vein and heard in the loop; tempo, gains, pattern and face edits are autosaved and reversible. The visual demo in [`reference/demo`](reference/demo) remains a design reference, not the codebase. The roadmap is in [`docs/PLAN.md`](docs/PLAN.md).
 
 ![The quarry](preview-p1-quarry.png)
 
@@ -12,6 +12,8 @@ This repository is **P1c**: the engine, the wire, the descent, the material room
 
 ![P1c · a recorded take](preview-p1c-record.png)
 
+![P1d · a cut and trimmed core](preview-p1d-faces.png)
+
 ## What is real
 
 - **Rust engine.** `cpal` output at 48 kHz, five veins, a sixteen-step phrase, a fixed voice pool, per-vein levels and gains, a bar clock. Procedural voices for empty pattern rows; real sample voices for rows with a face. No Web Audio.
@@ -19,6 +21,7 @@ This repository is **P1c**: the engine, the wire, the descent, the material room
 - **Project.** A portable folder: `project.db` (SQLite) plus `assets/`. On daemon start it loads the cores, pattern, tempo, gains and journal; every project edit autosaves. The default is `~/.local/share/zhila/descent-04`; use `--project PATH` for another. The project name is shown in the top rail.
 - **Undo/redo.** Tempo, gains and pattern steps/faces push a small history; `Ctrl/⌘+Z` and `Shift+Ctrl/⌘+Z`, or the rail buttons. The journal records every edit. History is per session: after a reload the project is restored, the undo stack starts empty.
 - **Recording.** `record` in the quarry opens the microphone, captures mono PCM through an AudioWorklet, encodes a 16-bit WAV in the surface and sends it through the same import path. The take becomes a core with sixteen faces, seal `recorded`, and is autosaved in the project. Stops at 30 s; no monitoring.
+- **Quarry editing.** Drag any of the seventeen seams on the waveform: the inner seams recut the sixteen faces, the outer seams trim the playable range. The core recomputes RMS and rank from the samples; the engine hears the new ranges on the next trigger; the project stores the cuts; the edit is undoable.
 - **Quarry.** Import, core strip, zoomed waveform with face boundaries, sixteen-face wall, face audition, seal and stats; assign a face to a pattern row; edit the sixteen steps; strike a face; all against the live session.
 - **Protocol v1.** JSON control frames, a 31-byte binary meter frame, and a binary import path (an import header followed by the audio bytes). Snapshot, results, events, token and origin guard.
 - **Session + journal.** Validation, revisions, a journal for project edits (tempo, gains, pattern faces and steps); play, stop and strikes are performance, not history.
@@ -61,7 +64,7 @@ cd app
 ./src-tauri/target/release/zhila-app
 ```
 
-The built window embeds the surface and connects to the daemon at `ws://127.0.0.1:4317`; start the daemon first. `tauri dev` uses the Vite server at `127.0.0.1:5173`. The engine is still the separate daemon in this phase. Rebuild the native app after any UI change; the binary embeds `ui/dist` at compile time. The recording UI is in the shared surface; WebKitGTK microphone permission still needs a manual check on this machine.
+The built window embeds the surface and connects to the daemon at `ws://127.0.0.1:4317`; start the daemon first. `tauri dev` uses the Vite server at `127.0.0.1:5173`. The engine is still the separate daemon in this phase. Rebuild the native app after any UI change; the binary embeds `ui/dist` at compile time. The recording and cutting UI are in the shared surface; WebKitGTK microphone permission still needs a manual check on this machine.
 
 Controls: `space` play/stop · `s` strike the selected face in the quarry or the selected vein in the nave · `1`–`5` select a vein (nave) or a pattern row (quarry) · click a face to select, double-click to strike · tempo `−` / `+`.
 
@@ -94,20 +97,22 @@ npm --prefix ui run smoke             # daemon + Vite: P0 regression, screenshot
 npm --prefix ui run quarry-smoke      # daemon + Vite: import, assign, play, screenshots
 npm --prefix ui run project-smoke     # daemon + Vite: project, undo, import, screenshots
 npm --prefix ui run record-smoke      # daemon + Vite: fake microphone take, faces, seal
+npm --prefix ui run faces-smoke       # daemon + Vite: drag a seam, trim, save, screenshot
 npm --prefix ui run restored-smoke    # after restarting the daemon on the saved project
 ```
 
 `npm --prefix ui run smoke` writes `preview-p0*.png`; `quarry-smoke` writes `preview-p1-*.png`.
 
-## P1c limits (next, not hidden)
+## P1d limits (next, not hidden)
 
 - The project persists, but undo history does not: after a reload the undo stack starts empty. The journal is stored for audit, not reconstructed into undo.
 - Recording is mono, 16-bit, requested 48 kHz, up to 30 s, no monitoring and no input device choice. WebKitGTK/Tauri microphone permission is untested; the browser path is verified with Chromium's fake capture.
-- No waveform trimming, no manual cut/loop points; the sixteen faces are automatic seams.
+- Face editing is seventeen contiguous cuts: no zoom, fades or per-face loop points. The trim is the outer pair of cuts; the source bytes are untouched.
+- The Tauri binary still embeds an older surface and starts no engine; it is a viewer in this phase.
 - One fixed two-bar phrase and five veins; pattern rows are veins, one face per row, no per-step face or pitch.
 - The Tauri binary currently embeds an older surface build; rebuild it after UI changes (`npm --prefix ui run build`, then `tauri build`). The engine remains the separate daemon.
 - Formats depend on symphonia; WAV is the tested path. AIFF, multi-channel files and very long files are not specifically handled.
 - No agent/MCP in this phase.
 - The Tauri shell now builds and runs; the engine is still the separate daemon (embedding is next).
 
-The next slice is P1d: waveform trimming and manual faces, reconstructed undo across reloads, and embedding the engine inside the Tauri backend. Then the arrangement and the agent. The plan is in [`docs/PLAN.md`](docs/PLAN.md); the phase notes are in [`docs/P1.md`](docs/P1.md).
+The next slice is P1e: undo history across reloads and the engine host inside the Tauri backend. Then the arrangement and the agent. The plan is in [`docs/PLAN.md`](docs/PLAN.md); the phase notes are in [`docs/P1.md`](docs/P1.md).
diff --git a/crates/zhila-core/src/lib.rs b/crates/zhila-core/src/lib.rs
index 7728cf1..74bc7e1 100644
--- a/crates/zhila-core/src/lib.rs
+++ b/crates/zhila-core/src/lib.rs
@@ -10,9 +10,9 @@ use std::time::{SystemTime, UNIX_EPOCH};
 use serde::{Deserialize, Serialize};
 use thiserror::Error;
 use zhila_protocol::{
-    Actor, AudioInfo, Command, CommandResult, CoreSummary, Event, FaceRef, LOOP_BARS, LOOP_STEPS,
-    MAX_BPM, MAX_GAIN, MIN_BPM, MIN_GAIN, MeterFrame, Pattern, PatternRow, STEPS_PER_BAR, State,
-    TransportState, VEIN_COUNT, VeinId, VeinState,
+    Actor, AudioInfo, Command, CommandResult, CoreSummary, Event, FACE_COUNT, FaceRef, FaceSummary,
+    LOOP_BARS, LOOP_STEPS, MAX_BPM, MAX_GAIN, MIN_BPM, MIN_GAIN, MeterFrame, Pattern, PatternRow,
+    STEPS_PER_BAR, State, TransportState, VEIN_COUNT, VeinId, VeinState,
 };
 
 pub const INITIAL_GAINS: [f32; VEIN_COUNT] = [0.82, 0.72, 0.76, 0.62, 0.66];
@@ -36,6 +36,85 @@ pub struct Core {
     pub faces: Vec<AudioFace>,
 }
 
+impl Core {
+    pub fn face_boundaries(&self) -> Vec<f32> {
+        summary_boundaries(&self.summary)
+    }
+
+    /// Replace the sixteen automatic faces with manual, contiguous cuts. The
+    /// source samples and the waveform peaks are untouched; the RMS and rank
+    /// are recomputed from the new ranges.
+    pub fn set_face_boundaries(&mut self, boundaries: &[f32]) -> Result<(), FaceError> {
+        if boundaries.len() != FACE_COUNT + 1 {
+            return Err(FaceError::Count);
+        }
+        let sample_rate = self.summary.sample_rate as f32;
+        let total = self.samples.len();
+        if total < FACE_COUNT + 1 || !sample_rate.is_finite() || sample_rate <= 0.0 {
+            return Err(FaceError::Short);
+        }
+        let mut indices = [0usize; FACE_COUNT + 1];
+        for (index, seconds) in boundaries.iter().enumerate() {
+            if !seconds.is_finite() || *seconds < 0.0 {
+                return Err(FaceError::Range);
+            }
+            let sample = (*seconds * sample_rate).round();
+            if sample > total as f32 {
+                return Err(FaceError::Range);
+            }
+            let sample = sample as usize;
+            if index > 0 && sample <= indices[index - 1] {
+                return Err(FaceError::Order);
+            }
+            indices[index] = sample;
+        }
+        let mut faces = Vec::with_capacity(FACE_COUNT);
+        let mut summaries = Vec::with_capacity(FACE_COUNT);
+        for index in 0..FACE_COUNT {
+            let start = indices[index];
+            let end = indices[index + 1];
+            if end <= start {
+                return Err(FaceError::Short);
+            }
+            let segment = &self.samples[start..end];
+            let rms = (segment.iter().map(|sample| sample * sample).sum::<f32>()
+                / segment.len() as f32)
+                .sqrt();
+            faces.push(AudioFace {
+                index: index as u8,
+                start: start as u32,
+                end: end as u32,
+                rms,
+            });
+            summaries.push(FaceSummary {
+                index: index as u8,
+                rank: 0,
+                start_sec: start as f32 / sample_rate,
+                end_sec: end as f32 / sample_rate,
+                rms,
+            });
+        }
+        let mut ranked: Vec<usize> = (0..summaries.len()).collect();
+        ranked.sort_by(|a, b| summaries[*b].rms.total_cmp(&summaries[*a].rms));
+        for (rank, index) in ranked.into_iter().enumerate() {
+            summaries[index].rank = rank as u8;
+        }
+        self.faces = faces;
+        self.summary.faces = summaries;
+        Ok(())
+    }
+}
+
+pub fn summary_boundaries(summary: &CoreSummary) -> Vec<f32> {
+    let mut faces: Vec<&zhila_protocol::FaceSummary> = summary.faces.iter().collect();
+    faces.sort_by_key(|face| face.index);
+    let mut boundaries: Vec<f32> = faces.iter().map(|face| face.start_sec).collect();
+    if let Some(last) = faces.last() {
+        boundaries.push(last.end_sec);
+    }
+    boundaries
+}
+
 #[derive(Clone)]
 pub struct AudioCore {
     pub id: String,
@@ -64,11 +143,18 @@ pub struct ProjectData {
     pub seq: u64,
 }
 
-#[derive(Clone)]
-struct ProjectEdit {
-    bpm: f32,
-    gains: [f32; VEIN_COUNT],
-    pattern: Pattern,
+#[derive(Clone, Serialize, Deserialize)]
+pub struct CoreEdit {
+    pub core: String,
+    pub boundaries: Vec<f32>,
+}
+
+#[derive(Clone, Serialize, Deserialize)]
+pub struct ProjectEdit {
+    pub bpm: f32,
+    pub gains: [f32; VEIN_COUNT],
+    pub pattern: Pattern,
+    pub cores: Vec<CoreEdit>,
 }
 
 const MAX_HISTORY: usize = 64;
@@ -101,10 +187,31 @@ pub enum CoreError {
     InvalidStep,
     #[error("no such core or face")]
     UnknownFace,
+    #[error("face boundaries must be sixteen ordered cuts inside the core")]
+    InvalidFaces,
     #[error("this command only exists on the binary import path")]
     UnsupportedCommand,
 }
 
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum FaceError {
+    Count,
+    Order,
+    Range,
+    Short,
+}
+
+impl std::fmt::Display for FaceError {
+    fn fmt(&self, formatter: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Self::Count => write!(formatter, "expected {} boundaries", FACE_COUNT + 1),
+            Self::Order => write!(formatter, "boundaries must be strictly ascending"),
+            Self::Range => write!(formatter, "boundaries must lie inside the core"),
+            Self::Short => write!(formatter, "every face needs at least one sample"),
+        }
+    }
+}
+
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
 pub struct JournalEntry {
     pub seq: u64,
@@ -218,6 +325,14 @@ impl Session {
             bpm: self.bpm,
             gains: self.gains,
             pattern: self.pattern.clone(),
+            cores: self
+                .cores
+                .iter()
+                .map(|core| CoreEdit {
+                    core: core.summary.id.clone(),
+                    boundaries: core.face_boundaries(),
+                })
+                .collect(),
         }
     }
 
@@ -233,6 +348,15 @@ impl Session {
         self.bpm = edit.bpm;
         self.gains = edit.gains;
         self.pattern = edit.pattern;
+        for core_edit in &edit.cores {
+            if let Some(core) = self
+                .cores
+                .iter_mut()
+                .find(|core| core.summary.id == core_edit.core)
+            {
+                let _ = core.set_face_boundaries(&core_edit.boundaries);
+            }
+        }
         self.engine.set_tempo(self.bpm);
         for (index, gain) in self.gains.iter().enumerate() {
             if let Some(vein) = VeinId::from_index(index) {
@@ -423,6 +547,9 @@ impl Session {
             Command::SetPatternFace { row, core, face } => {
                 self.set_pattern_face(row, &core, face, actor)
             }
+            Command::SetCoreFaces { core, boundaries } => {
+                self.set_core_faces(&core, &boundaries, actor)
+            }
             Command::Undo => {
                 let Some(edit) = self.history.pop() else {
                     return Ok((
@@ -494,6 +621,61 @@ impl Session {
     }
 
     /// Called by the daemon after the binary import and the analysis.
+    pub fn set_core_faces(
+        &mut self,
+        core_id: &str,
+        boundaries: &[f32],
+        actor: Actor,
+    ) -> Result<(CommandResult, Vec<Event>), CoreError> {
+        let Some(existing) = self.cores.iter().find(|core| core.summary.id == core_id) else {
+            return Err(CoreError::UnknownFace);
+        };
+        let current = existing.face_boundaries();
+        if current.len() == boundaries.len()
+            && current
+                .iter()
+                .zip(boundaries)
+                .all(|(left, right)| (left - right).abs() < 0.0001)
+        {
+            return Ok((
+                CommandResult::State {
+                    state: self.snapshot(),
+                },
+                Vec::new(),
+            ));
+        }
+        let mut preview = existing.clone();
+        preview
+            .set_face_boundaries(boundaries)
+            .map_err(|_| CoreError::InvalidFaces)?;
+        self.push_history();
+        let summary = {
+            let core = self
+                .cores
+                .iter_mut()
+                .find(|core| core.summary.id == core_id)
+                .expect("core was checked");
+            core.set_face_boundaries(boundaries)
+                .map_err(|_| CoreError::InvalidFaces)?;
+            core.summary.clone()
+        };
+        self.revision += 1;
+        self.record(
+            actor,
+            Command::SetCoreFaces {
+                core: core_id.to_string(),
+                boundaries: boundaries.to_vec(),
+            },
+        );
+        self.sync_material();
+        Ok((
+            CommandResult::State {
+                state: self.snapshot(),
+            },
+            vec![Event::CoreFaces { core: summary }],
+        ))
+    }
+
     pub fn import_core(&mut self, core: Core, actor: Actor) -> State {
         let name = core.summary.name.clone();
         let seal = core.summary.seal;
@@ -1057,6 +1239,55 @@ mod tests {
         assert!(!state.can_undo);
     }
 
+    #[test]
+    fn manual_faces_are_validated_and_undoable() {
+        let (mut session, _) = session();
+        session.import_core(test_core(), Actor::Hand);
+        let before = session.snapshot();
+        let original = before.cores[0].faces.clone();
+        let original_boundaries: Vec<f32> = original
+            .iter()
+            .map(|face| face.start_sec)
+            .chain(std::iter::once(original.last().unwrap().end_sec))
+            .collect();
+        let mut boundaries = original_boundaries.clone();
+        boundaries[8] += 0.01;
+
+        let (result, events) = session
+            .set_core_faces("core-test", &boundaries, Actor::Hand)
+            .unwrap();
+        let CommandResult::State { state } = result else {
+            panic!("expected state");
+        };
+        assert!((state.cores[0].faces[7].end_sec - boundaries[8]).abs() < 0.001);
+        assert!(matches!(events.as_slice(), [Event::CoreFaces { .. }]));
+        assert!(state.can_undo);
+
+        let (result, _) = session.apply(Command::Undo, Actor::Hand).unwrap();
+        let CommandResult::State { state } = result else {
+            panic!("expected state");
+        };
+        let restored: Vec<f32> = state.cores[0]
+            .faces
+            .iter()
+            .map(|face| face.start_sec)
+            .chain(std::iter::once(
+                state.cores[0].faces.last().unwrap().end_sec,
+            ))
+            .collect();
+        assert_eq!(restored.len(), original_boundaries.len());
+        for (left, right) in restored.iter().zip(&original_boundaries) {
+            assert!((left - right).abs() < 1e-6);
+        }
+
+        let mut bad = boundaries.clone();
+        bad[3] = bad[2] - 0.01;
+        let error = session
+            .set_core_faces("core-test", &bad, Actor::Hand)
+            .unwrap_err();
+        assert!(matches!(error, CoreError::InvalidFaces));
+    }
+
     #[test]
     fn faces_are_validated_and_can_be_struck() {
         let (mut session, engine) = session();
diff --git a/crates/zhila-daemon/src/main.rs b/crates/zhila-daemon/src/main.rs
index 4c23439..4c16412 100644
--- a/crates/zhila-daemon/src/main.rs
+++ b/crates/zhila-daemon/src/main.rs
@@ -580,6 +580,7 @@ fn error_code(error: &CoreError) -> ErrorCode {
         | CoreError::InvalidRow
         | CoreError::InvalidStep
         | CoreError::UnknownFace
+        | CoreError::InvalidFaces
         | CoreError::UnsupportedCommand => ErrorCode::BadRequest,
     }
 }
diff --git a/crates/zhila-project/src/lib.rs b/crates/zhila-project/src/lib.rs
index 5018126..c060cac 100644
--- a/crates/zhila-project/src/lib.rs
+++ b/crates/zhila-project/src/lib.rs
@@ -76,6 +76,7 @@ impl ProjectStore {
                seal TEXT NOT NULL,
                asset TEXT NOT NULL DEFAULT '',
                source_name TEXT NOT NULL DEFAULT '',
+               faces TEXT,
                imported_at INTEGER NOT NULL
              );
              CREATE TABLE IF NOT EXISTS journal (
@@ -86,6 +87,7 @@ impl ProjectStore {
                command TEXT NOT NULL
              );",
         )?;
+        let _ = conn.execute("ALTER TABLE cores ADD COLUMN faces TEXT", []);
         conn.execute(
             "INSERT INTO meta (key, value) VALUES ('schema', ?1)
              ON CONFLICT(key) DO UPDATE SET value = excluded.value",
@@ -134,7 +136,7 @@ impl ProjectStore {
         let mut cores = Vec::new();
         {
             let mut statement = self.conn.prepare(
-                "SELECT id, name, seal, asset, source_name FROM cores ORDER BY imported_at",
+                "SELECT id, name, seal, asset, source_name, faces FROM cores ORDER BY imported_at",
             )?;
             let rows = statement.query_map([], |row| {
                 Ok((
@@ -143,10 +145,11 @@ impl ProjectStore {
                     row.get::<_, String>(2)?,
                     row.get::<_, String>(3)?,
                     row.get::<_, String>(4)?,
+                    row.get::<_, Option<String>>(5)?,
                 ))
             })?;
             for row in rows {
-                let (id, name, seal_text, asset, source_name) = row?;
+                let (id, name, seal_text, asset, source_name, faces_json) = row?;
                 if asset.is_empty() {
                     warnings.push(format!("{id}: no asset recorded"));
                     continue;
@@ -166,6 +169,16 @@ impl ProjectStore {
                         if core.summary.id != id {
                             warnings.push(format!("{id}: content hash is {}", core.summary.id));
                         }
+                        if let Some(json) = faces_json {
+                            match serde_json::from_str::<Vec<f32>>(&json) {
+                                Ok(boundaries) => {
+                                    if let Err(error) = core.set_face_boundaries(&boundaries) {
+                                        warnings.push(format!("{id}: manual faces: {error}"));
+                                    }
+                                }
+                                Err(error) => warnings.push(format!("{id}: faces JSON: {error}")),
+                            }
+                        }
                         cores.push(core);
                     }
                     Err(error) => warnings.push(format!("{id}: {error}")),
@@ -271,16 +284,20 @@ impl ProjectStore {
             ],
         )?;
         for core in snapshot.cores {
+            let boundaries = zhila_core::summary_boundaries(core);
+            let faces = serde_json::to_string(&boundaries)?;
             tx.execute(
-                "INSERT INTO cores (id, name, seal, imported_at)
-                 VALUES (?1, ?2, ?3, ?4)
+                "INSERT INTO cores (id, name, seal, faces, imported_at)
+                 VALUES (?1, ?2, ?3, ?4, ?5)
                  ON CONFLICT(id) DO UPDATE SET
                    name = excluded.name,
-                   seal = excluded.seal",
+                   seal = excluded.seal,
+                   faces = excluded.faces",
                 params![
                     core.id,
                     core.name,
                     serde_json::to_string(&core.seal)?,
+                    faces,
                     now_ms() as i64
                 ],
             )?;
@@ -452,8 +469,12 @@ mod tests {
         assert!(store.load().unwrap().is_none());
 
         let bytes = fixture();
-        let core =
+        let mut core =
             zhila_material::import_bytes("clicks-01.wav", Seal::Found, bytes.clone()).unwrap();
+        let mut boundaries = core.face_boundaries();
+        boundaries[8] += 0.01;
+        core.set_face_boundaries(&boundaries).unwrap();
+        let expected_edge = core.summary.faces[7].end_sec;
         let pattern = pattern_with_face(&core);
         let gains = [0.8, 0.7, 0.6, 0.5, 0.4];
         let journal = vec![JournalEntry {
@@ -488,6 +509,7 @@ mod tests {
         assert_eq!(loaded.data.cores.len(), 1);
         assert_eq!(loaded.data.cores[0].summary.id, core.summary.id);
         assert_eq!(loaded.data.cores[0].faces.len(), 16);
+        assert!((loaded.data.cores[0].summary.faces[7].end_sec - expected_edge).abs() < 1e-4);
         assert_eq!(loaded.data.pattern.rows.len(), 5);
         assert_eq!(loaded.data.pattern.rows[0].velocities[0], 96);
         assert_eq!(
diff --git a/crates/zhila-protocol/src/lib.rs b/crates/zhila-protocol/src/lib.rs
index a25e0fe..3e2e2c0 100644
--- a/crates/zhila-protocol/src/lib.rs
+++ b/crates/zhila-protocol/src/lib.rs
@@ -10,6 +10,7 @@ pub const VEIN_COUNT: usize = 5;
 pub const LOOP_STEPS: usize = 16;
 pub const STEPS_PER_BAR: usize = 8;
 pub const LOOP_BARS: f32 = 2.0;
+pub const FACE_COUNT: usize = 16;
 pub const MIN_BPM: f32 = 40.0;
 pub const MAX_BPM: f32 = 220.0;
 pub const MIN_GAIN: f32 = 0.0;
@@ -203,6 +204,10 @@ pub enum Command {
         core: String,
         face: u8,
     },
+    SetCoreFaces {
+        core: String,
+        boundaries: Vec<f32>,
+    },
     Undo,
     Redo,
     /// Journal-only: a core was imported through the binary path.
@@ -255,6 +260,9 @@ pub enum Event {
         can_undo: bool,
         can_redo: bool,
     },
+    CoreFaces {
+        core: CoreSummary,
+    },
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
diff --git a/docs/P1.md b/docs/P1.md
index 2fef78e..760bb86 100644
--- a/docs/P1.md
+++ b/docs/P1.md
@@ -143,3 +143,36 @@ Screenshot: `preview-p1c-record.png`.
 - WebKitGTK/Tauri microphone support is untested; the Tauri binary also embeds an older surface build and must be rebuilt to see the record button.
 - No trim, fade or manual loop points yet; the take is cut by the automatic seams.
 - The take is stored as the encoded WAV, not the float PCM; trimming will later add derived assets.
+
+---
+
+# P1d · manual faces and trim
+
+The waveform is now an editor. A core's sixteen faces are seventeen contiguous boundaries; dragging any seam updates the core.
+
+## Backend
+
+- `Core::set_face_boundaries(&[f32])` validates seventeen strictly ascending cuts inside the core, recomputes each face's RMS from the source samples and reranks the faces. The source bytes and the waveform peaks are untouched.
+- `Core::face_boundaries()` / `summary_boundaries()` expose the cuts.
+- `Command::SetCoreFaces { core, boundaries }`, event `CoreFaces { core: CoreSummary }`. The core rejects unordered/out-of-range cuts with `InvalidFaces`; a no-op does not journal.
+- Face edits are project edits: they journal, autosave and push the undo snapshot. `ProjectEdit` now snapshots every core's boundaries as well as bpm/gains/pattern, so undo restores cuts and trim. The edit remains valid when the pattern references the same face indices.
+- The store gained a `faces` JSON column on `cores` (migrated with `ALTER TABLE`); it saves the boundaries and applies them after re-importing the asset on load. Invalid stored cuts warn and fall back to the analysis.
+
+## Surface
+
+- The waveform draws the seventeen seams; the outer seams are the trim, the inner are cuts. Drag with the pointer; the neighboring seams constrain the move (20 ms minimum); on release the command is sent.
+- The side facts show the current `trim`; the selected face keeps its shade and label.
+- The hint says "drag a seam to cut · outer seams trim".
+
+## Verification
+
+- `cargo test --workspace`: 13 core tests (manual faces, undo, invalid cuts), 1 store test with a manual face across save/load.
+- `node scripts/persistence-smoke.mjs`: imports, cuts face 8 by 20 ms, restarts the daemon and verifies the loaded face edge and trim.
+- `npm --prefix ui run faces-smoke`: drags the left outer seam in Chromium; checks the trim text, the `cut` wire command and the enabled undo; writes `preview-p1d-faces.png`.
+- The default project now carries the cut `clicks-01` core.
+
+## Limits
+
+- Seventeen contiguous cuts only: no zoom, fade, loop points or per-face gain.
+- The trim is the outer boundaries of the sixteen faces; the original asset is not rewritten.
+- Cut history survives the session but not yet a reload (the next slice).
diff --git a/docs/PLAN.md b/docs/PLAN.md
index 0fd53ce..c5365fe 100644
--- a/docs/PLAN.md
+++ b/docs/PLAN.md
@@ -1,7 +1,7 @@
 # ZHILA — план проекта
 
 Черновик v1.1 · 1 ноября 2026
-Статус: **P0, P1a, P1b и P1c выполнены** (см. `P0.md`, `P1.md`). Демо `reference/demo/` — референс, не кодовая база.
+Статус: **P0, P1a, P1b, P1c и P1d выполнены** (см. `P0.md`, `P1.md`). Демо `reference/demo/` — референс, не кодовая база.
 
 **Зафиксировано 1 ноября:** descent — основной вид; камень = паттерн; климат — на жилу (концепт погоды остаётся); платформа v1 — Linux; UI — Svelte 5. Журнал — §9.
 
diff --git a/docs/PROTOCOL.md b/docs/PROTOCOL.md
index 4c25654..6af3bf5 100644
--- a/docs/PROTOCOL.md
+++ b/docs/PROTOCOL.md
@@ -156,3 +156,7 @@ The project is loaded by the daemon from its `--project` folder and saved after
 ## P1c addition
 
 `Seal` gains `recorded`. Recording introduces no new wire messages: the surface encodes a WAV and uses the existing `import_core` header + binary payload. The recorded seal is persisted with the core row and is visible in the snapshot.
+
+## P1d additions
+
+`Command::set_core_faces` takes `{ core, boundaries: [f32; 17] }` (seconds, strictly ascending). The daemon answers with the state and broadcasts `core_faces { core: CoreSummary }`. The core rejects unordered or out-of-range boundaries. Boundaries are persisted in the project's `cores.faces` column and applied after the asset is decoded again on load; the source bytes and peaks stay unchanged.
diff --git a/preview-p1d-faces.png b/preview-p1d-faces.png
new file mode 100644
index 0000000..94f9fde
Binary files /dev/null and b/preview-p1d-faces.png differ
diff --git a/scripts/persistence-smoke.mjs b/scripts/persistence-smoke.mjs
index 3624d3a..b2b7b85 100644
--- a/scripts/persistence-smoke.mjs
+++ b/scripts/persistence-smoke.mjs
@@ -84,6 +84,14 @@ try {
   if (!assigned) throw new Error('redo did not restore the face');
   await client.command(23, { type: 'set_pattern_step', row: 0, step: 0, velocity: 96 });
   await client.command(24, { type: 'set_tempo', bpm: 132 });
+  const sortedFaces = [...core.faces].sort((a, b) => a.index - b.index);
+  const boundaries = sortedFaces.map((face) => face.start_sec);
+  boundaries.push(sortedFaces[sortedFaces.length - 1].end_sec);
+  const beforeCut = boundaries[8];
+  boundaries[8] += 0.02;
+  await client.command(25, { type: 'set_core_faces', core: core.id, boundaries });
+  const cutEdge = client.snapshot.cores[0].faces[7].end_sec;
+  if (Math.abs(cutEdge - boundaries[8]) > 0.002) throw new Error('manual face did not apply');
   client.ws.close();
   await new Promise((resolve) => { child.once('exit', resolve); child.kill('SIGTERM'); });
 
@@ -96,6 +104,8 @@ try {
   if (!restored.face || restored.face.face !== assigned.face) throw new Error('pattern face did not survive');
   if (restored.velocities[0] !== 96) throw new Error('step did not survive');
   if (second.transport.bpm !== 132) throw new Error('tempo did not survive');
+  const loadedEdge = second.cores[0].faces[7].end_sec;
+  if (Math.abs(loadedEdge - cutEdge) > 0.002) throw new Error('manual face did not survive');
   if (second.project_name !== first.project_name) throw new Error('project name changed');
   console.log(JSON.stringify({
     project: second.project_name,
@@ -105,6 +115,7 @@ try {
     face: restored.face,
     step: restored.velocities[0],
     bpm: second.transport.bpm,
+    cut: { before: beforeCut, after: loadedEdge },
     journal: second.journal_len,
     db: existsSync(join(project, 'project.db'))
   }, null, 2));
diff --git a/ui/package.json b/ui/package.json
index a59caba..8ac2eee 100644
--- a/ui/package.json
+++ b/ui/package.json
@@ -12,6 +12,7 @@
     "quarry-smoke": "node scripts/quarry-smoke.mjs",
     "project-smoke": "node scripts/project-smoke.mjs",
     "record-smoke": "node scripts/record-smoke.mjs",
+    "faces-smoke": "node scripts/faces-smoke.mjs",
     "restored-smoke": "node scripts/restored-smoke.mjs"
   },
   "devDependencies": {
diff --git a/ui/scripts/faces-smoke.mjs b/ui/scripts/faces-smoke.mjs
new file mode 100644
index 0000000..6a72eef
--- /dev/null
+++ b/ui/scripts/faces-smoke.mjs
@@ -0,0 +1,47 @@
+import { chromium } from 'playwright-core';
+
+const chrome = process.env.CHROME_PATH ?? '/home/emil/.cache/ms-playwright/chromium-1248/chrome-linux64/chrome';
+const browser = await chromium.launch({ executablePath: chrome, args: ['--no-sandbox'] });
+const page = await browser.newPage({ viewport: { width: 1600, height: 1000 }, deviceScaleFactor: 1 });
+const errors = [];
+page.on('pageerror', (error) => errors.push(`pageerror: ${error.message}`));
+page.on('console', (message) => { if (message.type() === 'error') errors.push(`console: ${message.text()}`); });
+
+await page.goto('http://127.0.0.1:5173/', { waitUntil: 'load' });
+await page.waitForTimeout(2200);
+await page.locator('.room', { hasText: 'quarry' }).click();
+await page.waitForTimeout(600);
+await page.locator('.core-tab').first().click();
+await page.waitForTimeout(400);
+
+const stats = page.locator('.face-stats');
+const before = (await stats.textContent())?.replace(/\s+/g, ' ').trim();
+const canvas = page.locator('canvas.wave');
+const box = await canvas.boundingBox();
+if (!box) throw new Error('no waveform');
+await page.mouse.move(box.x + 3, box.y + 60);
+await page.mouse.down();
+await page.mouse.move(box.x + 70, box.y + 60, { steps: 10 });
+await page.mouse.up();
+await page.waitForTimeout(900);
+const after = (await stats.textContent())?.replace(/\s+/g, ' ').trim();
+await page.screenshot({ path: '../preview-p1d-faces.png' });
+const report = await page.evaluate(() => ({
+  trim: document.querySelector('.face-stats')?.textContent?.replace(/\s+/g, ' ').trim(),
+  wire: [...document.querySelectorAll('.wire-label')].map((el) => el.textContent).slice(-5),
+  undoDisabled: document.querySelector('.history-button[aria-label="undo"]')?.hasAttribute('disabled'),
+  face: document.querySelector('.face.is-on .face-index')?.textContent,
+  selected: document.querySelector('.core-tab.is-on .core-name')?.textContent
+}));
+console.log(JSON.stringify({ before, after, report, errors }, null, 2));
+const failures = [];
+if (!before || !after || before === after) failures.push('trim did not change');
+if (!report.wire.some((label) => label?.startsWith('cut'))) failures.push('no cut command on the wire');
+if (report.undoDisabled) failures.push('undo did not enable after the cut');
+if (errors.length) failures.push('console errors');
+await browser.close();
+if (failures.length) {
+  console.error('FACES SMOKE FAILED: ' + failures.join('; '));
+  process.exit(1);
+}
+console.log('faces smoke passed');
diff --git a/ui/src/App.svelte b/ui/src/App.svelte
index 2fd9a59..0008db6 100644
--- a/ui/src/App.svelte
+++ b/ui/src/App.svelte
@@ -102,6 +102,9 @@
     } else if (event.kind === 'history') {
       project.can_undo = event.can_undo;
       project.can_redo = event.can_redo;
+    } else if (event.kind === 'core_faces') {
+      const index = project.cores.findIndex((core) => core.id === event.core.id);
+      if (index >= 0) project.cores[index] = event.core;
     }
   }
 
@@ -193,6 +196,10 @@
     void run({ type: 'set_pattern_step', row, step, velocity: on ? 0 : 96 });
   }
 
+  function setCoreFaces(core: string, boundaries: number[]) {
+    void run({ type: 'set_core_faces', core, boundaries });
+  }
+
   function undo() {
     if (project?.can_undo) void run({ type: 'undo' });
   }
@@ -326,6 +333,7 @@
         onassign={assignFace}
         onstrikeface={strikeFace}
         onstep={toggleStep}
+        onfaces={setCoreFaces}
       />
     {/if}
     <Wire {entries} {status} onreconnect={reconnect} />
diff --git a/ui/src/app.css b/ui/src/app.css
index 372743c..fac0c5f 100644
--- a/ui/src/app.css
+++ b/ui/src/app.css
@@ -1367,17 +1367,26 @@ button.room {
   margin-top: 7px;
   border-top: 1px solid rgba(155, 133, 121, 0.12);
   border-bottom: 1px solid rgba(155, 133, 121, 0.12);
+  cursor: ew-resize;
+  touch-action: none;
 }
 
 .wave-axis {
   display: flex;
   justify-content: space-between;
-  padding: 4px 0 9px;
+  padding: 4px 0 2px;
   font-size: 8px;
   color: var(--ash-2);
   font-variant-numeric: tabular-nums;
 }
 
+.wave-hint {
+  padding: 2px 0 8px;
+  font-size: 8px;
+  letter-spacing: 0.05em;
+  color: var(--ash-2);
+}
+
 .face-wall {
   display: grid;
   grid-template-columns: repeat(8, minmax(0, 1fr));
diff --git a/ui/src/components/Quarry.svelte b/ui/src/components/Quarry.svelte
index 9e2aba3..473baf9 100644
--- a/ui/src/components/Quarry.svelte
+++ b/ui/src/components/Quarry.svelte
@@ -18,7 +18,8 @@
     onimport,
     onassign,
     onstrikeface,
-    onstep
+    onstep,
+    onfaces
   }: {
     cores: CoreSummary[];
     pattern: Pattern | null;
@@ -33,6 +34,7 @@
     onassign: () => void;
     onstrikeface: (core: string, face: number) => void;
     onstep: (row: number, step: number, on: boolean) => void;
+    onfaces: (core: string, boundaries: number[]) => void;
   } = $props();
 
   let fileInput: HTMLInputElement | null = null;
@@ -42,6 +44,8 @@
   let recordError = $state<string | null>(null);
   let finishing = $state(false);
   let takeIndex = $state(1);
+  let draft = $state<number[] | null>(null);
+  let dragging: { index: number; pointer: number } | null = null;
   let observer: ResizeObserver | null = null;
 
   const core = $derived(cores.find((item) => item.id === selectedCore) ?? cores[0] ?? null);
@@ -50,6 +54,8 @@
       core?.faces.find((item) => item.rank === 0) ??
       null
   );
+  const boundaries = $derived(core ? faceBoundaries(core) : []);
+  const trim = $derived(draft ?? boundaries);
 
   onMount(() => {
     if (!wave) return;
@@ -62,6 +68,7 @@
   $effect(() => {
     core;
     face;
+    draft;
     draw();
   });
 
@@ -82,20 +89,24 @@
     const center = height / 2;
     const duration = Math.max(0.001, core.duration_sec);
 
-    for (const item of core.faces) {
-      const start = (item.start_sec / duration) * width;
-      const end = (item.end_sec / duration) * width;
-      if (face && item.index === face.index) {
-        context.fillStyle = 'rgba(232,64,42,0.08)';
-        context.fillRect(start, 0, end - start, height);
-      }
-      context.strokeStyle =
-        item.index % 4 === 0 ? 'rgba(232,64,42,0.34)' : 'rgba(155,133,121,0.14)';
-      context.lineWidth = 1;
-      context.beginPath();
-      context.moveTo(start + 0.5, 0);
-      context.lineTo(start + 0.5, height);
-      context.stroke();
+    const limits = draft ?? boundaries;
+    const selected = face ? face.index : -1;
+
+    if (limits.length) {
+      context.fillStyle = 'rgba(12,9,8,0.55)';
+      const left = (limits[0] / duration) * width;
+      const right = (limits[limits.length - 1] / duration) * width;
+      if (left > 0) context.fillRect(0, 0, left, height);
+      if (right < width) context.fillRect(right, 0, width - right, height);
+    }
+    if (selected >= 0 && limits[selected] !== undefined && limits[selected + 1] !== undefined) {
+      context.fillStyle = 'rgba(232,64,42,0.08)';
+      context.fillRect(
+        (limits[selected] / duration) * width,
+        0,
+        ((limits[selected + 1] - limits[selected]) / duration) * width,
+        height
+      );
     }
 
     const step = width / Math.max(1, core.peaks.length - 1);
@@ -110,9 +121,24 @@
     context.lineTo(width, center + 0.5);
     context.stroke();
 
-    if (face) {
-      const start = (face.start_sec / duration) * width;
-      const end = (face.end_sec / duration) * width;
+    for (let index = 0; index < limits.length; index += 1) {
+      const x = (limits[index] / duration) * width;
+      const outer = index === 0 || index === limits.length - 1;
+      context.strokeStyle = outer
+        ? 'rgba(232,64,42,0.5)'
+        : index % 4 === 0
+          ? 'rgba(232,64,42,0.28)'
+          : 'rgba(155,133,121,0.16)';
+      context.lineWidth = 1;
+      context.beginPath();
+      context.moveTo(x + 0.5, 0);
+      context.lineTo(x + 0.5, height);
+      context.stroke();
+    }
+
+    if (face && limits[face.index] !== undefined) {
+      const start = (limits[face.index] / duration) * width;
+      const end = (limits[face.index + 1] / duration) * width;
       context.strokeStyle = 'rgba(239,228,212,0.72)';
       context.lineWidth = 1;
       context.strokeRect(start + 0.5, 0.5, Math.max(1, end - start - 1), height - 1);
@@ -131,6 +157,77 @@
     return `${Math.floor(whole / 60)}:${String(whole % 60).padStart(2, '0')}`;
   }
 
+  function faceBoundaries(item: CoreSummary): number[] {
+    const faces = [...item.faces].sort((left, right) => left.index - right.index);
+    if (!faces.length) return [];
+    return [...faces.map((entry) => entry.start_sec), faces[faces.length - 1].end_sec];
+  }
+
+  function canvasPoint(event: PointerEvent): number {
+    const canvas = wave;
+    if (!canvas) return 0;
+    return event.clientX - canvas.getBoundingClientRect().left;
+  }
+
+  function nearestBoundary(x: number): number | null {
+    const canvas = wave;
+    if (!canvas || !core) return null;
+    const width = Math.max(1, canvas.clientWidth);
+    const duration = Math.max(0.001, core.duration_sec);
+    let best: number | null = null;
+    let distance = 9;
+    for (let index = 0; index < boundaries.length; index += 1) {
+      const candidate = Math.abs((boundaries[index] / duration) * width - x);
+      if (candidate < distance) {
+        best = index;
+        distance = candidate;
+      }
+    }
+    return best;
+  }
+
+  function onBoundaryDown(event: PointerEvent) {
+    if (!core || !wave) return;
+    const index = nearestBoundary(canvasPoint(event));
+    if (index === null) return;
+    event.preventDefault();
+    wave.setPointerCapture(event.pointerId);
+    dragging = { index, pointer: event.pointerId };
+    draft = [...boundaries];
+  }
+
+  function onBoundaryMove(event: PointerEvent) {
+    const current = dragging;
+    if (!current || !core || !wave || event.pointerId !== current.pointer) return;
+    const width = Math.max(1, wave.clientWidth);
+    const duration = Math.max(0.001, core.duration_sec);
+    const x = Math.max(0, Math.min(width, canvasPoint(event)));
+    const seconds = (x / width) * duration;
+    const limits = draft ?? boundaries;
+    const min = Math.min(0.02, duration / 64);
+    const lower = current.index === 0 ? 0 : limits[current.index - 1] + min;
+    const upper =
+      current.index === limits.length - 1 ? duration : limits[current.index + 1] - min;
+    const value = Math.max(lower, Math.min(upper, seconds));
+    draft = limits.map((entry, index) => (index === current.index ? value : entry));
+  }
+
+  function onBoundaryUp(event: PointerEvent) {
+    if (!dragging) return;
+    const limits = draft;
+    if (wave?.hasPointerCapture(event.pointerId)) wave.releasePointerCapture(event.pointerId);
+    dragging = null;
+    draft = null;
+    if (
+      limits &&
+      core &&
+      limits.length === boundaries.length &&
+      limits.some((entry, index) => Math.abs(entry - boundaries[index]) > 0.0005)
+    ) {
+      onfaces(core.id, limits);
+    }
+  }
+
   async function toggleRecording() {
     if (finishing) return;
     if (!recording) {
@@ -271,11 +368,20 @@
           </div>
         </div>
 
-        <canvas class="wave" bind:this={wave} aria-hidden="true"></canvas>
+        <canvas
+          class="wave"
+          bind:this={wave}
+          aria-hidden="true"
+          onpointerdown={onBoundaryDown}
+          onpointermove={onBoundaryMove}
+          onpointerup={onBoundaryUp}
+          onpointercancel={onBoundaryUp}
+        ></canvas>
         <div class="wave-axis">
           <span>0.0 s</span>
           <span>{core.duration_sec.toFixed(1)} s</span>
         </div>
+        <div class="wave-hint">drag a seam to cut · outer seams trim</div>
 
         <div class="face-wall" role="group" aria-label="sixteen faces">
           {#each core.faces as item}
@@ -349,6 +455,10 @@
           rank 01.
         </p>
         <div class="face-stats">
+          <div>
+            <span>trim</span>
+            <b>{trim.length ? `${trim[0].toFixed(2)}–${trim[trim.length - 1].toFixed(2)} s` : '—'}</b>
+          </div>
           <div><span>rank</span><b>{face ? String(face.rank + 1).padStart(2, '0') : '—'}</b></div>
           <div><span>rms</span><b>{face ? face.rms.toFixed(3) : '—'}</b></div>
           <div><span>length</span><b>{face ? `${(face.end_sec - face.start_sec).toFixed(2)} s` : '—'}</b></div>
diff --git a/ui/src/lib/format.ts b/ui/src/lib/format.ts
index 08628a7..e32ff00 100644
--- a/ui/src/lib/format.ts
+++ b/ui/src/lib/format.ts
@@ -33,6 +33,7 @@ export function commandLabel(command: Command): string {
     case 'strike_face': return `strike ${command.core} f${command.face + 1}`;
     case 'set_pattern_step': return `step ${command.row + 1}:${command.step + 1} at ${command.velocity}`;
     case 'set_pattern_face': return `${command.core} f${command.face + 1} on row ${command.row + 1}`;
+    case 'set_core_faces': return `cut ${command.core}`;
     case 'undo': return 'undo';
     case 'redo': return 'redo';
     case 'get_snapshot': return 'snapshot';
diff --git a/ui/src/lib/types.ts b/ui/src/lib/types.ts
index b939baa..f6809fd 100644
--- a/ui/src/lib/types.ts
+++ b/ui/src/lib/types.ts
@@ -80,7 +80,8 @@ export type Event =
   | { kind: 'pattern_step'; row: number; step: number; velocity: number }
   | { kind: 'pattern_face'; row: number; core: string; face: number }
   | { kind: 'face_struck'; core: string; face: number; velocity: number }
-  | { kind: 'history'; can_undo: boolean; can_redo: boolean };
+  | { kind: 'history'; can_undo: boolean; can_redo: boolean }
+  | { kind: 'core_faces'; core: CoreSummary };
 
 export type Command =
   | { type: 'get_snapshot' }
@@ -92,6 +93,7 @@ export type Command =
   | { type: 'strike_face'; core: string; face: number; velocity: number }
   | { type: 'set_pattern_step'; row: number; step: number; velocity: number }
   | { type: 'set_pattern_face'; row: number; core: string; face: number }
+  | { type: 'set_core_faces'; core: string; boundaries: number[] }
   | { type: 'undo' }
   | { type: 'redo' };