diff --git a/lib/audioeffects/analogdelay.py b/lib/audioeffects/analogdelay.py
index 74f35ead..82a27255 100644
--- a/lib/audioeffects/analogdelay.py
+++ b/lib/audioeffects/analogdelay.py
@@ -190,6 +190,8 @@ class AnalogDelay(_component.Component):
 
     **Level and tail.** Below Mix 1, an input peaking at or below
     floor(32767 (1 - Mix)) - 1 does not reach the rail.
+    Keep the input under -6 dBFS and the defaults and patches stay off the
+    rails.
     `tail_samples` is an upper bound on how long the repeats take to reach
     exact zero after your input stops.
     `reset()` empties the line and returns to patch 0.
@@ -221,6 +223,11 @@ class AnalogDelay(_component.Component):
     LATENCY_SAMPLES = 0
     TAIL_SAMPLES = None
 
+    #: The defaults and every patch play the ceiling kit's materials
+    #: clean at this level; at -3 dBFS, the defaults rail on
+    #: a 100 Hz square.
+    INPUT_CEILING_DBFS = -6
+
     MACRO_LABELS = ("Time", "Feedback", "Mix", "Modulation", "Mod Rate",
                     "Spread", "Sync", "Division")
     MACRO_MODES = {
diff --git a/lib/audioeffects/bitcrusher.py b/lib/audioeffects/bitcrusher.py
index d6f1972f..8eb13aee 100644
--- a/lib/audioeffects/bitcrusher.py
+++ b/lib/audioeffects/bitcrusher.py
@@ -1375,8 +1375,9 @@ class Bitcrusher(_component.Component):
 
     **Mix and Output.** Mix 0 is a wire at the source's own level. Output
     trims the whole blend: -6 dB is 6 dB down within 0.1 dB, at Mix 1 and
-    at a blend. The Effect controls page lists what the knobs span and the
-    patches.
+    at a blend. Keep the input under -3 dBFS and the defaults and patches
+    stay off the rails. The Effect controls page lists what the knobs span
+    and the patches.
 
 
 
@@ -1400,6 +1401,11 @@ class Bitcrusher(_component.Component):
     LATENCY_SAMPLES = 0
     TAIL_SAMPLES = 0
 
+    #: The defaults and every patch play the ceiling kit's materials
+    #: clean at this level; at full scale, patch 1 rails on
+    #: a 50 Hz sine.
+    INPUT_CEILING_DBFS = -3
+
     MACRO_LABELS = ("Bits", "Rate", "Dither", "Band Limit", "Mix", "Output")
     MACRO_MODES = {
         0: "UNIPOLAR", 1: "UNIPOLAR", 2: "UNIPOLAR", 3: "TOGGLE",
diff --git a/lib/audioeffects/combfilter.py b/lib/audioeffects/combfilter.py
index e3f16cb8..490f37a1 100644
--- a/lib/audioeffects/combfilter.py
+++ b/lib/audioeffects/combfilter.py
@@ -259,9 +259,9 @@ class CombFilter(_component.Component):
     **Glide.** Glide slides the tuning, so turning Frequency bends the note
     rather than clicking.
 
-    **Level.** A comb gains, so a loud input can reach the rail by design.
-    A plucked phrase is clean on every patch up to -9 dBFS; at -3 dBFS
-    Ringing Pitch, Dark Resonator, Single Slap and Filter Only rail.
+    **Level.** A comb gains, so a loud input can reach the rail by design. Keep
+    the input under -24 dBFS and the defaults and patches stay off the rails.
+    Feedback or Trim at its top can still push the output onto the rails.
     `reset()` empties the line.
 
     **Latency and tail.** It adds no latency at any setting. The tail
@@ -294,6 +294,13 @@ class CombFilter(_component.Component):
     #: `tail_samples`, the last of its decay.
     TAIL_SAMPLES = None
 
+    #: The defaults and every patch play the ceiling kit's materials
+    #: clean at this level; at -18 dBFS, patch 1 rails on
+    #: a DC step.
+    INPUT_CEILING_DBFS = -24
+    #: Settings that clip by design: the rail check skips them.
+    CLIPS_AT_TOP = (1, 4)
+
     MACRO_LABELS = ("Frequency", "Feedback", "Mix", "Tone", "Trim", "Glide")
     MACRO_MODES = {0: "UNIPOLAR", 1: "UNIPOLAR", 2: "UNIPOLAR",
                    3: "UNIPOLAR", 4: "BIPOLAR", 5: "UNIPOLAR"}
diff --git a/lib/audioeffects/digitaldelay.py b/lib/audioeffects/digitaldelay.py
index 27be5cc2..d55f8acf 100644
--- a/lib/audioeffects/digitaldelay.py
+++ b/lib/audioeffects/digitaldelay.py
@@ -28,7 +28,8 @@
 below Nyquist and sound the same. The dry sits at unity and the repeats add
 to it, so a hot input can reach the int16 rail. With Repeat Cut out and Mix
 below 1, an input that peaks at or below floor(32767 (1 - Mix)) - 1 cannot
-reach the rail, at any Time or Feedback.
+reach the rail, at any Time or Feedback. Keep the input under -6 dBFS and
+the defaults and patches stay off the rails.
 
 **Limits shared by the family.** A control that jumps makes the output step:
 move it in small steps from the host if you need it smooth. When your source
@@ -324,6 +325,11 @@ class DigitalDelay(_component.Component):
     LATENCY_SAMPLES = 0
     TAIL_SAMPLES = None
 
+    #: The defaults and every patch play the ceiling kit's materials
+    #: clean at this level; at -3 dBFS, patch 3 rails on
+    #: a 100 Hz square.
+    INPUT_CEILING_DBFS = -6
+
     MACRO_LABELS = ("Time", "Feedback", "Mix", "Glide", "Sync", "Division",
                     "Repeat Tone", "Repeat Cut")
     MACRO_MODES = {
diff --git a/lib/audioeffects/graphiceq.py b/lib/audioeffects/graphiceq.py
index 913c19bc..3a5d3361 100644
--- a/lib/audioeffects/graphiceq.py
+++ b/lib/audioeffects/graphiceq.py
@@ -217,7 +217,8 @@ class GraphicEQ(_component.Component):
     **Level.** Bands overlap and add: three adjacent sliders at +6 dB lift
     the middle one's frequency by more than 7 dB. Every section hands the
     next an int16, so leave headroom, and pull Volume down when you push
-    Gain up.
+    Gain up. A band, Gain or Volume at its top can push a full-scale input
+    onto the rails.
 
     **Patches.** Scooped Mids, Pushed Mids and Full Boost pull Volume down,
     so stepping through them you hear the curve rather than the level. A
@@ -250,6 +251,9 @@ class GraphicEQ(_component.Component):
     LATENCY_SAMPLES = 0
     TAIL_SAMPLES = _DESIGN_TAIL_SAMPLES
 
+    #: Settings that clip by design: the rail check skips them.
+    CLIPS_AT_TOP = (0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
+
     MACRO_LABELS = ("31", "63", "125", "250", "500", "1k", "2k", "4k", "8k",
                     "16k Shelf", "Gain", "Volume", "Band Q", "Constant Q")
     MACRO_MODES = {0: "BIPOLAR", 1: "BIPOLAR", 2: "BIPOLAR", 3: "BIPOLAR",
diff --git a/lib/audioeffects/highpass.py b/lib/audioeffects/highpass.py
index 08a91786..443d5ab0 100644
--- a/lib/audioeffects/highpass.py
+++ b/lib/audioeffects/highpass.py
@@ -8,12 +8,14 @@
 **What it sounds like.** One knob decides where the bottom stops, and above
 that corner nothing is touched: rumble, handling noise, a subsonic DC offset
 and the mud under a vocal go, and the voice does not. The second knob is how
-loud the corner itself stands - at Resonance 0.707 it is 3 dB down and the
-cut is as gentle as a cut gets, at 2 it is 6 dB up and you can hear where you
-put it, at 16 it is 24 dB up and the filter whistles at its own corner. The
-Slope switch is a desk's: 12 dB/oct for a low-cut you do not want to notice,
-24 dB/oct when the rumble has to actually leave. There is no drive and no
-growl anywhere in it - a high-pass is linear.
+loud the corner itself stands - at Resonance 0.707 it is 3 dB down and the cut
+is as gentle as a cut gets, at 2 it is 6 dB up and you can hear where you put
+it, at 16 it is 24 dB up and the filter whistles at its own corner. The Slope
+switch is a desk's: 12 dB/oct for a low-cut you do not want to notice, 24
+dB/oct when the rumble has to actually leave. There is no drive and no growl
+anywhere in it - a high-pass is linear. Keep the input under -9 dBFS and the
+defaults and patches stay off the rails. Trim at its top can still push the
+output onto the rails.
 
 **Three things the knobs do not do exactly, found by the Phase 2 gate audit
 and its patch sweep, and
@@ -197,6 +199,13 @@ class HighPass(_component.Component):
     #: the drive stops.
     TAIL_SAMPLES = 632832
 
+    #: The defaults and every patch play the ceiling kit's materials
+    #: clean at this level; at -6 dBFS, patch 1 rails on
+    #: a 100 Hz square.
+    INPUT_CEILING_DBFS = -9
+    #: Settings that clip by design: the rail check skips them.
+    CLIPS_AT_TOP = (4,)
+
     MACRO_LABELS = ("Frequency", "Resonance", "Slope", "Mix", "Trim")
     MACRO_MODES = {0: "UNIPOLAR", 1: "UNIPOLAR", 2: "TOGGLE",
                    3: "UNIPOLAR", 4: "BIPOLAR"}
diff --git a/lib/audioeffects/ladderfilter.py b/lib/audioeffects/ladderfilter.py
index b90298f0..41fb5964 100644
--- a/lib/audioeffects/ladderfilter.py
+++ b/lib/audioeffects/ladderfilter.py
@@ -79,9 +79,9 @@ class LadderFilter(_component.Component):
     no tail bound, and `reset()` stops it at any setting.
 
     **Levels.** The resonance peak and the drive both add gain, so no input
-    level is clean on every setting. A plucked phrase stays off the rails on
-    every patch to -10 dBFS; at -3 dBFS Growl With Drive rails. Turn Drive,
-    Resonance or your input down.
+    level is clean on every setting. Keep the input under -15 dBFS and the
+    defaults and patches stay off the rails. Drive at its top can still push
+    the output onto the rails. Turn Drive, Resonance or your input down.
 
     **On a board.** The class needs audiodsp's `audioladder`, and on a board
     without it construction raises `ImportError`.
@@ -107,6 +107,13 @@ class LadderFilter(_component.Component):
     #: bounds the decay; at and above it the filter sustains by design.
     TAIL_SAMPLES = None
 
+    #: The defaults and every patch play the ceiling kit's materials
+    #: clean at this level; at -12 dBFS, patch 4 rails on
+    #: a 100 Hz square.
+    INPUT_CEILING_DBFS = -15
+    #: Settings that clip by design: the rail check skips them.
+    CLIPS_AT_TOP = (2,)
+
     MACRO_LABELS = ("Cutoff", "Resonance", "Drive", "Passband Comp",
                     "Poles", "Oversample", "Mix")
     MACRO_MODES = {0: "UNIPOLAR", 1: "UNIPOLAR", 2: "UNIPOLAR",
diff --git a/lib/audioeffects/lowpass.py b/lib/audioeffects/lowpass.py
index 7d5bc5eb..9a568997 100644
--- a/lib/audioeffects/lowpass.py
+++ b/lib/audioeffects/lowpass.py
@@ -7,14 +7,15 @@
 
 **What it sounds like.** One knob slides the whole curve along the frequency
 axis without changing its shape, and one knob decides how loud the corner
-itself stands: at Resonance 0.707 the corner is 3 dB down and the curve is
-the gentlest roll-off there is, at 2 it is 6 dB up and the filter starts to
-whistle where you put it, at 16 it is 24 dB up and a click at the input rings
-for seconds. There is no drive, no saturation and no growl anywhere in it -
-a low-pass is linear, and the thing that makes a Moog a Moog belongs to
+itself stands: at Resonance 0.707 the corner is 3 dB down and the curve is the
+gentlest roll-off there is, at 2 it is 6 dB up and the filter starts to whistle
+where you put it, at 16 it is 24 dB up and a click at the input rings for
+seconds. There is no drive, no saturation and no growl anywhere in it - a
+low-pass is linear, and the thing that makes a Moog a Moog belongs to
 `LadderFilter`. The Slope switch is a console's: 12 dB/oct is the analog
 prototype, 24 dB/oct is a second section behind it for when a rumble has to
-actually go away.
+actually go away. Keep the input under -3 dBFS and the defaults and patches
+stay off the rails. Trim at its top can still push the output onto the rails.
 
 **Where those two sentences stop being exact.** The Phase 2 gate audit
 (2026-09-07) disconfirmed four of the five traits off the point they were
@@ -172,6 +173,13 @@ class LowPass(_component.Component):
     #: input stopped outlived (279 149 at patch 4).
     TAIL_SAMPLES = 528261
 
+    #: The defaults and every patch play the ceiling kit's materials
+    #: clean at this level; at full scale, patch 5 rails on
+    #: a 50 Hz sine.
+    INPUT_CEILING_DBFS = -3
+    #: Settings that clip by design: the rail check skips them.
+    CLIPS_AT_TOP = (4,)
+
     MACRO_LABELS = ("Frequency", "Resonance", "Slope", "Mix", "Trim")
     MACRO_MODES = {0: "UNIPOLAR", 1: "UNIPOLAR", 2: "TOGGLE",
                    3: "UNIPOLAR", 4: "BIPOLAR"}
diff --git a/lib/audioeffects/multibandcompressor.py b/lib/audioeffects/multibandcompressor.py
index 5d68c552..cf118bf0 100644
--- a/lib/audioeffects/multibandcompressor.py
+++ b/lib/audioeffects/multibandcompressor.py
@@ -260,9 +260,11 @@ class MultibandCompressor(_component.Component):
 
     **Mix.** Mix crossfades the input with the summed bands, so between its
     stops it is parallel compression. Mix 0 is the source byte for byte, at
-    22.05 kHz, 44.1 kHz and 48 kHz, mono and stereo, and moving off it does
-    not click. Brought back up from 0, it starts as it was built rather
-    than playing what the bands held.
+    22.05 kHz, 44.1 kHz and 48 kHz, mono and stereo, and moving off it does not
+    click. Brought back up from 0, it starts as it was built rather than
+    playing what the bands held. Keep the input under -9 dBFS and the defaults
+    and patches stay off the rails. A band's Gain at its top can still push the
+    output onto the rails.
 
     **Latency and tail.** It adds no latency at any setting. The tail
     reaches exact zero, and `tail_samples` says when.
@@ -304,6 +306,13 @@ class MultibandCompressor(_component.Component):
     #: coupling state" in docs/reference/component-api.md.
     TAIL_SAMPLES = 0
 
+    #: The defaults and every patch play the ceiling kit's materials
+    #: clean at this level; at -6 dBFS, patch 3 rails on
+    #: a 147 Hz square.
+    INPUT_CEILING_DBFS = -9
+    #: Settings that clip by design: the rail check skips them.
+    CLIPS_AT_TOP = (8, 9, 10)
+
     MACRO_LABELS = (
         "Crossover Low", "Crossover High",
         "Low Threshold", "Mid Threshold", "High Threshold",
diff --git a/lib/audioeffects/multitapdelay.py b/lib/audioeffects/multitapdelay.py
index dd3562f0..fb6d4499 100644
--- a/lib/audioeffects/multitapdelay.py
+++ b/lib/audioeffects/multitapdelay.py
@@ -225,6 +225,8 @@ class MultiTapDelay(_component.Component):
     Up to Mix 1 the dry passes at unity, and at Mix 2 the echoes play alone.
     At unity the dry is exact to the sample, mono and stereo, right up to
     the rails, on every interpreter.
+    Keep the input under -6 dBFS and the defaults and patches stay off the
+    rails.
     Mix 0 is a wire.
     Sync locks Time to Division of the host's beat, clamped to Time's span.
     With no host tempo, Time stays on the knob.
@@ -273,6 +275,11 @@ class MultiTapDelay(_component.Component):
     LATENCY_SAMPLES = 0
     TAIL_SAMPLES = None
 
+    #: The defaults and every patch play the ceiling kit's materials
+    #: clean at this level; at -3 dBFS, the defaults rail on
+    #: a 100 Hz square.
+    INPUT_CEILING_DBFS = -6
+
     MACRO_LABELS = ("Time", "Pattern", "Heads", "Feedback", "Mix", "Tilt",
                     "Repeat Tone", "Sync", "Division")
     MACRO_MODES = {
diff --git a/lib/audioeffects/notch.py b/lib/audioeffects/notch.py
index 039da4a5..7d163f8d 100644
--- a/lib/audioeffects/notch.py
+++ b/lib/audioeffects/notch.py
@@ -4,16 +4,17 @@
 its dossier. The old `eq.py:Notch` is not consulted except for
 the seven defects the dossier's section 7 names.
 
-**What it sounds like.** One knob says where, one says how wide, and what
-comes out is the input with a slice taken out of it and nothing else
-touched - a whistle, a feedback tone or a mains hum goes and the rest of the
-mix does not move, because a notch is exactly unity at DC and at Nyquist by
-construction. Width is a bandwidth, not a depth: at Q 0.7 the notch is
-wider than the note it sits on and reads as a scoop; at Q 30 it is a few
-hertz across and you hear the tone leave without hearing the music change.
-Harmonics adds a second notch an octave up, half as wide in hertz, because
-mains hum is a series and one notch at 50 or 60 Hz leaves the buzz. Depth is
-a blend, not a filter control - at 0 the class is a wire.
+**What it sounds like.** One knob says where, one says how wide, and what comes
+out is the input with a slice taken out of it and nothing else touched - a
+whistle, a feedback tone or a mains hum goes and the rest of the mix does not
+move, because a notch is exactly unity at DC and at Nyquist by construction.
+Width is a bandwidth, not a depth: at Q 0.7 the notch is wider than the note it
+sits on and reads as a scoop; at Q 30 it is a few hertz across and you hear the
+tone leave without hearing the music change. Harmonics adds a second notch an
+octave up, half as wide in hertz, because mains hum is a series and one notch
+at 50 or 60 Hz leaves the buzz. Depth is a blend, not a filter control - at 0
+the class is a wire. Keep the input under -6 dBFS and the defaults and patches
+stay off the rails. Trim at its top can still push the output onto the rails.
 
 **Portability tier: audiodsp** (`REQUIRES = ("audiobiquad",)`). All three
 sections are `audiobiquad.Biquad`: float state, and a tail that reaches
@@ -134,6 +135,13 @@ class Notch(_component.Component):
     #: input stopped outlived by up to twice.
     TAIL_SAMPLES = 965439
 
+    #: The defaults and every patch play the ceiling kit's materials
+    #: clean at this level; at -3 dBFS, patch 1 rails on
+    #: a 100 Hz square.
+    INPUT_CEILING_DBFS = -6
+    #: Settings that clip by design: the rail check skips them.
+    CLIPS_AT_TOP = (4,)
+
     MACRO_LABELS = ("Frequency", "Width", "Harmonics", "Depth", "Trim")
     MACRO_MODES = {0: "UNIPOLAR", 1: "UNIPOLAR", 2: "TOGGLE",
                    3: "UNIPOLAR", 4: "BIPOLAR"}
diff --git a/lib/audioeffects/parametriceq.py b/lib/audioeffects/parametriceq.py
index 103ace3f..59748c00 100644
--- a/lib/audioeffects/parametriceq.py
+++ b/lib/audioeffects/parametriceq.py
@@ -48,9 +48,11 @@
 
 All of it is the clip, not the filter: the coefficients are reciprocal and
 proportional at every level, which is what
-`tests/test_cpython_effects_parametriceq.py` reads. Drive this EQ from a
-signal with headroom for the boost you dial, or trim into it, and the curves
-are the ones the traits describe.
+`tests/test_cpython_effects_parametriceq.py` reads. Drive this EQ from a signal
+with headroom for the boost you dial, or trim into it, and the curves are the
+ones the traits describe. Keep the input under -12 dBFS and the defaults and
+patches stay off the rails. A boost or Output at its top can still push the
+output onto the rails.
 
 **Cost.** Eight sections, always built, and no patch changes that. Measured
 2026-09-07 on both boards at construction defaults - where patch 0 is a wire,
@@ -216,6 +218,13 @@ class ParametricEQ(_component.Component):
     #: ceiling at every rate. Patch 0 is a wire and its tail is zero.
     TAIL_SAMPLES = 37696
 
+    #: The defaults and every patch play the ceiling kit's materials
+    #: clean at this level; at -9 dBFS, patch 3 rails on
+    #: a DC step.
+    INPUT_CEILING_DBFS = -12
+    #: Settings that clip by design: the rail check skips them.
+    CLIPS_AT_TOP = (1, 4, 6, 8, 11, 15)
+
     MACRO_LABELS = (
         "Low Freq", "Low Boost", "Low Atten",
         "Bell 1 Freq", "Bell 1 Gain",
diff --git a/lib/audioeffects/phaser.py b/lib/audioeffects/phaser.py
index 6a812276..e432ce8b 100644
--- a/lib/audioeffects/phaser.py
+++ b/lib/audioeffects/phaser.py
@@ -295,8 +295,9 @@ class Phaser(_component.Component):
 
     **Drive and Feedback.** Drive is 0.3 when you construct the class, and
     there the Feedback hump stays under 5 dB. Turn Drive to 0 and Feedback
-    lifts it more than 5 dB. The Phaser - lean patch is the default with
-    Drive at 0.
+    lifts it more than 5 dB. The Phaser - lean patch is the default with Drive
+    at 0. Keep the input under -9 dBFS and the defaults and patches stay off
+    the rails. Feedback at its top can still push the output onto the rails.
 
     **Sync.** With Sync on, the sweep locks to the host: Division picks the
     length of a sweep in bars, a bar is read from the host's time
@@ -328,6 +329,13 @@ class reports the worst case, 552960 samples, for stages at their
     #: comment; musical settings die much sooner. Ceiling, next 2048.
     TAIL_SAMPLES = 552960
 
+    #: The defaults and every patch play the ceiling kit's materials
+    #: clean at this level; at -6 dBFS, patch 1 rails on
+    #: a 147 Hz square.
+    INPUT_CEILING_DBFS = -9
+    #: Settings that clip by design: the rail check skips them.
+    CLIPS_AT_TOP = (3,)
+
     MACRO_LABELS = ("Rate", "Depth", "Centre", "Feedback", "Mix",
                     "Stages", "Shape", "Drive", "Sync", "Division")
     MACRO_MODES = {
diff --git a/lib/audioeffects/pingpongdelay.py b/lib/audioeffects/pingpongdelay.py
index fff068e1..15de2dee 100644
--- a/lib/audioeffects/pingpongdelay.py
+++ b/lib/audioeffects/pingpongdelay.py
@@ -133,6 +133,8 @@ class PingPongDelay(_component.Component):
     input that peaks at or below floor(32767 (1 - Mix)) - 1 cannot reach the
     rail, at any Time, Feedback or Spread. Repeat Cut's high-pass
     overshoots, so with it in leave more room.
+    Keep the input under -6 dBFS and the defaults and patches stay off the
+    rails.
 
     **Limits shared by the family.** A control that jumps makes the output
     step: move it in small steps from the host if you need it smooth. When
@@ -168,6 +170,11 @@ class PingPongDelay(_component.Component):
     LATENCY_SAMPLES = 0
     TAIL_SAMPLES = None
 
+    #: The defaults and every patch play the ceiling kit's materials
+    #: clean at this level; at -3 dBFS, patch 3 rails on
+    #: a DC step.
+    INPUT_CEILING_DBFS = -6
+
     MACRO_LABELS = ("Time", "Feedback", "Mix", "Spread", "First Side",
                     "Sync", "Division", "Repeat Tone", "Repeat Cut")
     MACRO_MODES = {
diff --git a/lib/audioeffects/reverb.py b/lib/audioeffects/reverb.py
index 4ba3f1c1..634c83ea 100644
--- a/lib/audioeffects/reverb.py
+++ b/lib/audioeffects/reverb.py
@@ -43,11 +43,10 @@
 
 **Input ceiling.** There is no input gain, and the tank's lines clamp at the
 rail on every write whatever Mix is: a steady 362 Hz tone at 8 000 LSB RMS
-comes back more than 1 dB quieter in the tail than at 4 000. On 2 s of
-uniform noise at 4 000 LSB RMS at Mix 1, no shipped patch reaches the rail
-at 48, 44.1 or 22.05 kHz; Bright Chamber at 44.1 kHz is not claimed.
-A plucked phrase stays off the rails on every patch to -4 dBFS; at -3 dBFS
-Slow Bloom rails.
+comes back more than 1 dB quieter in the tail than at 4 000. On 2 s of uniform
+noise at 4 000 LSB RMS at Mix 1, no shipped patch reaches the rail at 48, 44.1
+or 22.05 kHz; Bright Chamber at 44.1 kHz is not claimed. Keep the input under
+-12 dBFS and the defaults and patches stay off the rails.
 
 `tail_samples` bounds the frames until the output is exactly zero once
 your input stops: 222 868 frames at the defaults at 48 kHz. One int16
@@ -298,6 +297,11 @@ class Reverb(_component.Component):
     LATENCY_SAMPLES = 0
     TAIL_SAMPLES = None
 
+    #: The defaults and every patch play the ceiling kit's materials
+    #: clean at this level; at -9 dBFS, patch 9 rails on
+    #: a 220 Hz square.
+    INPUT_CEILING_DBFS = -12
+
     MACRO_LABELS = ("Character", "Decay", "Size", "Predelay", "Diffusion",
                     "Damping", "Bandwidth", "Low Cut", "Mod Depth",
                     "Mod Rate", "Width", "Tone", "Mix")
diff --git a/lib/audioeffects/slapbackdelay.py b/lib/audioeffects/slapbackdelay.py
index ee8eafd1..b8980228 100644
--- a/lib/audioeffects/slapbackdelay.py
+++ b/lib/audioeffects/slapbackdelay.py
@@ -135,6 +135,8 @@ class SlapbackDelay(_component.Component):
     Up to Level 1 the dry passes untouched until the repeat arrives, however
     hard Saturation drives the repeat.
     A hot input can reach the rail, since the repeat adds to a dry at unity.
+    Keep the input under -6 dBFS and the defaults and patches stay off the
+    rails.
     At Repeats 0 there is one repeat and no second.
     Repeats above 0 sends the repeat round for more.
     Wow swings the repeat's pitch by the cents the knob reads, at a slow
@@ -187,6 +189,11 @@ class SlapbackDelay(_component.Component):
     LATENCY_SAMPLES = 0
     TAIL_SAMPLES = None
 
+    #: The defaults and every patch play the ceiling kit's materials
+    #: clean at this level; at -3 dBFS, patch 2 rails on
+    #: a 100 Hz square.
+    INPUT_CEILING_DBFS = -6
+
     MACRO_LABELS = ("Time", "Level", "Saturation", "Tone", "Wow", "Repeats")
     MACRO_MODES = {
         0: "UNIPOLAR",
diff --git a/lib/audioeffects/tapedelay.py b/lib/audioeffects/tapedelay.py
index d81780f9..5abc7d10 100644
--- a/lib/audioeffects/tapedelay.py
+++ b/lib/audioeffects/tapedelay.py
@@ -35,7 +35,8 @@
 shape. The darkening follows
 the tape's loss law only up to a band top that rises with the tape's speed.
 Record Level has no memory: tape hysteresis is not modelled. The RE-201's
-Bass and Treble are not here.
+Bass and Treble are not here. Keep the input under -6 dBFS and the defaults
+and patches stay off the rails.
 
 **Limits shared by the family.** A control that jumps makes the output step:
 move it in small steps from the host if you need it smooth. When your source
@@ -349,6 +350,11 @@ class TapeDelay(_component.Component):
     LATENCY_SAMPLES = 0
     TAIL_SAMPLES = None
 
+    #: The defaults and every patch play the ceiling kit's materials
+    #: clean at this level; at -3 dBFS, the defaults rail on
+    #: a 100 Hz square.
+    INPUT_CEILING_DBFS = -6
+
     MACRO_LABELS = ("Time", "Feedback", "Mix", "Glide", "Wow", "Flutter",
                     "Record Level", "Spacing", "Spread", "Sync", "Division")
     MACRO_MODES = {
diff --git a/lib/audioeffects/transientshaper.py b/lib/audioeffects/transientshaper.py
index 138637f0..d53ff65a 100644
--- a/lib/audioeffects/transientshaper.py
+++ b/lib/audioeffects/transientshaper.py
@@ -130,10 +130,10 @@ class TransientShaper(_component.Component):
     3 dB a second, Sustain -24 reaches about -16 dB.
 
     **Levels.** At its defaults the class is a wire. Attack and Sustain add
-    gain where they are turned up, so a hit that is already loud reaches
-    the rails. A plucked phrase stays off the rails on every patch to
-    -10 dBFS; at -3 dBFS Snap and Kick Punch rail. Turn Output down, or
-    your input.
+    gain where they are turned up, so a hit that is already loud reaches the
+    rails. Keep the input under -12 dBFS and the defaults and patches stay off
+    the rails. Attack at its top can still push the output onto the rails. Turn
+    Output down, or your input.
 
     **Timing.** Latency is zero at every setting, and so is the tail:
     silence in is silence out in the same frame.
@@ -155,6 +155,13 @@ class TransientShaper(_component.Component):
     LATENCY_SAMPLES = 0
     TAIL_SAMPLES = 0
 
+    #: The defaults and every patch play the ceiling kit's materials
+    #: clean at this level; at -9 dBFS, patch 1 rails on
+    #: a 100 Hz square.
+    INPUT_CEILING_DBFS = -12
+    #: Settings that clip by design: the rail check skips them.
+    CLIPS_AT_TOP = (0,)
+
     MACRO_LABELS = ("Attack", "Sustain", "Output", "Attack Speed",
                     "Sustain Hold")
     MACRO_MODES = {0: "BIPOLAR", 1: "BIPOLAR", 2: "BIPOLAR",
diff --git a/tests/support/kit_ceiling.py b/tests/support/kit_ceiling.py
index a024b03b..8c48badd 100644
--- a/tests/support/kit_ceiling.py
+++ b/tests/support/kit_ceiling.py
@@ -59,7 +59,11 @@
 - `rail`: more than 8 frames in a row on a rail (|y| >= 32767) where the
   input was on neither `latency_samples` earlier nor in the last
   min(`latency_samples`, `HOLD`) frames: a hold that latched a rail
-  plays it for the length of the hold.
+  plays it for the length of the hold. Not judged where the class says
+  the setting clips by design: `CLIPS_AT_TOP`, a tuple of macro indexes,
+  excuses a cell whose knobs put one of them at 127 (Feedback at its top
+  runs away), and `CLIPS_BY_DESIGN = True` excuses every cell (a fuzz
+  clips at any level). A wrap is still judged there.
 - `silent`: the last second exactly zero while the input played through
   it. Not judged on the DC step, which a high-pass rightly takes to zero,
   nor where a macro whose label holds Level or Volume is at 0: an output
@@ -230,8 +234,20 @@ def turned_down(cls, knobs):
     return False
 
 
+def clips_by_design(cls, knobs):
+    """Whether the class says this cell's knobs clip by design (see `rail`
+    under **The bars**)."""
+    if getattr(cls, "CLIPS_BY_DESIGN", False):
+        return True
+    top = getattr(cls, "CLIPS_AT_TOP", ())
+    for index, value in knobs or ():
+        if value == 127 and index in top:
+            return True
+    return False
+
+
 def judge(data, values, channels, rate, lat, which, seconds=SECONDS,
-          silent_ok=False):
+          silent_ok=False, rail_ok=False):
     out = kc.samples(data)
     reds = []
     if which != "noise":
@@ -239,7 +255,7 @@ def judge(data, values, channels, rate, lat, which, seconds=SECONDS,
         if hit is not None:
             reds.append("wrap at %d ch %d" % hit)
     run, where = kc.rail_run(out, values, channels, lat, HOLD)
-    if run > kc.RAIL_RUN:
+    if run > kc.RAIL_RUN and not rail_ok:
         reds.append("rail %d frames from %d" % (run, where))
     if which != "dc" and not silent_ok:
         lo = (seconds - 1) * rate * channels
@@ -316,7 +332,8 @@ def measure(cls, rate, channels, which, patch, knobs, options=None):
             e.set_macro(index, value)
         data = kc.render(e, seconds * rate)
         reds = judge(data, values, channels, rate, e.latency_samples, which,
-                     seconds, turned_down(cls, knobs))
+                     seconds, turned_down(cls, knobs),
+                     clips_by_design(cls, knobs))
     finally:
         e.deinit()
     verdict = "RED(%s)" % "; ".join(reds) if reds else "ok"
@@ -352,6 +369,23 @@ def run(cls, emit=print, quick=False, rates=None, channels=None,
     return cells.summary()
 
 
+def stated_level_reds(cls, material, db=None, keys=None):
+    """The red cells on `material`, 48 kHz stereo, for the defaults and
+    every patch (or just `keys`), played at the class's stated level, or at
+    `db` to show the level above it is not clean. An effect's own test
+    holds its stated level with this: clean there, red a step up."""
+    if db is not None:
+        cls = type(cls.__name__, (cls,), {"INPUT_CEILING_DBFS": db,
+                                          "__module__": cls.__module__})
+    if keys is None:
+        keys = ["d"] + ["p%d" % p for p in sorted(cls.PATCHES)]
+    lines = []
+    run(cls, emit=lines.append, quick=True, materials=(material,),
+        only=keys)
+    return [line for line in lines
+            if "|V:RED" in line and not line.startswith("SUMMARY")]
+
+
 if __name__ == "__main__":
     import kit
     kit.main(sys.argv[1:], only=(CHECK,))
diff --git a/tests/support/kit_planted.py b/tests/support/kit_planted.py
index 46382b4a..c88fef51 100644
--- a/tests/support/kit_planted.py
+++ b/tests/support/kit_planted.py
@@ -151,6 +151,25 @@ class ClipKit(KitPlain):
     CURVE = staticmethod(_clip2)
 
 
+class ClipAtTop(ClipKit):
+    """Ceiling: ClipKit saying its Gain at the top clips by design, so
+    only a cell with Gain at 127 is excused the rail."""
+    NAME = "ClipAtTop"
+    CLIPS_AT_TOP = (1,)
+
+
+class ClipsAlways(ClipKit):
+    """Ceiling: ClipKit saying it clips by design everywhere."""
+    NAME = "ClipsAlways"
+    CLIPS_BY_DESIGN = True
+
+
+class WrapsAlways(WrapKit):
+    """Ceiling: a wrap is never by design, even in a class that clips."""
+    NAME = "WrapsAlways"
+    CLIPS_BY_DESIGN = True
+
+
 class DeadStop(KitPlain):
     """Ceiling: Gain's bottom stop is silence, as a level that went NaN on
     a board would be."""
@@ -713,6 +732,7 @@ def _apply_macro(self, index, position):
 
 PLANTS = {}
 for _cls in (KitPlain, Silent, LeakBand, WrapKit, WrapKitQuiet, ClipKit, DeadStop,
+             ClipAtTop, ClipsAlways, WrapsAlways,
              CondKit, MidWrap, ComboWrap, AllWrap, LowWrap, ImplKit, EchoTail, ShortTail, EventTail, NoneSilent, NoneDC,
              ReadbackOff, StopRaises, NanLevel, PatchStale, CtorNan,
              ClearsFirst, ClearsMacro, FlushKit, FlushOnly, DoubleReset,
diff --git a/tests/test_cpython_effects_analogdelay.py b/tests/test_cpython_effects_analogdelay.py
index 2378d64a..927d1634 100644
--- a/tests/test_cpython_effects_analogdelay.py
+++ b/tests/test_cpython_effects_analogdelay.py
@@ -40,6 +40,7 @@ class built as a wire. T1 is unmeasured and T2b, T4 and T5 are disconfirmed
 sys.path.insert(0, os.path.join(os.path.dirname(__file__), ".."))
 
 import audiocore                                            # noqa: E402
+import kit_ceiling                                          # noqa: E402
 import kit_faults                                           # noqa: E402
 import kit_probes as probes                                 # noqa: E402
 from audioeffects import _component                         # noqa: E402
@@ -2446,6 +2447,15 @@ def test_another_macro_leaves_a_walk_at_its_rate(self):
             self.assertEqual(effect._delay._handed["delay_slew"], slew)
 
 
+class TheCeiling(unittest.TestCase):
+    def test_clean_at_the_stated_input_level(self):
+        # square is where it rails first: d at -3 dBFS.
+        self.assertEqual(
+            kit_ceiling.stated_level_reds(AnalogDelay, "square"), [])
+        self.assertTrue(kit_ceiling.stated_level_reds(
+            AnalogDelay, "square", db=-3, keys=("d",)))
+
+
 # --------------------------------------------------------------------------
 # The docstring's claims, each tied to the test that asserts it
 
@@ -2453,6 +2463,9 @@ def test_another_macro_leaves_a_walk_at_its_rate(self):
 #: that asserts it). Every sentence in the docstring that makes a claim is
 #: here; one that could not be tied to a test was struck.
 CLAIMS = (
+    ("Keep the input under -6 dBFS and the defaults and patches stay "
+     "off the rails.",
+     ("test_clean_at_the_stated_input_level",)),
     ("Time runs from 20 to 600 ms, Feedback from 0 to 0.99 and Mix from 0 "
      "to 2.", "test_the_knob_spans"),
     ("Up to Mix 1 the dry passes untouched until the first repeat arrives.",
diff --git a/tests/test_cpython_effects_bitcrusher.py b/tests/test_cpython_effects_bitcrusher.py
index f980694e..8490a24f 100644
--- a/tests/test_cpython_effects_bitcrusher.py
+++ b/tests/test_cpython_effects_bitcrusher.py
@@ -16,6 +16,7 @@
 sys.path.insert(0, os.path.join(os.path.dirname(__file__), ".."))
 
 import audiocore                                                # noqa: E402
+import kit_ceiling                                          # noqa: E402
 import kit_faults                                               # noqa: E402
 import kit_probes as probes                                     # noqa: E402
 from audioeffects import bitcrusher as rebuilt                  # noqa: E402
@@ -1252,7 +1253,19 @@ def test_construction_needs_its_four_modules(self):
                     sys.modules[name] = saved
 
 
+class TheCeiling(unittest.TestCase):
+    def test_clean_at_the_stated_input_level(self):
+        # sine is where it rails first: p1 at 0 dBFS.
+        self.assertEqual(
+            kit_ceiling.stated_level_reds(rebuilt.Bitcrusher, "sine"), [])
+        self.assertTrue(kit_ceiling.stated_level_reds(
+            rebuilt.Bitcrusher, "sine", db=0, keys=("p1",)))
+
+
 CLAIMS = (
+    ("Keep the input under -3 dBFS and the defaults and patches stay "
+     "off the rails.",
+     ("TheCeiling.test_clean_at_the_stated_input_level",)),
     ("`Bitcrusher` — a linear hold, the SP-1200's two numbers as "
      "knobs.",
      ("TheSurface.test_six_macros_and_seven_patches",)),
diff --git a/tests/test_cpython_effects_combfilter.py b/tests/test_cpython_effects_combfilter.py
index db262126..7e34d9c5 100644
--- a/tests/test_cpython_effects_combfilter.py
+++ b/tests/test_cpython_effects_combfilter.py
@@ -27,6 +27,7 @@
 import audiocore
 
 sys.path.insert(0, os.path.join(os.path.dirname(__file__), "support"))
+import kit_ceiling                                          # noqa: E402
 import kit_faults as faults                          # noqa: E402
 from effects_measure import SAMPLE_RATE                # noqa: E402
 
@@ -1190,23 +1191,6 @@ def test_a_mono_source_gets_the_same_tuning(self):
         self.assertLess(abs(cents(centroid(y, ideal), ideal)), 5.0)
 
 
-class TheInputCeiling(unittest.TestCase):
-    """audiocomponents#192: the kit's plucked phrase is clean on every
-    patch at -9 dBFS, and rails at -3 dBFS on the four patches the
-    docstring names."""
-
-    def test_a_plucked_phrase_is_clean_to_minus_9_dbfs(self):
-        import kit_levels
-        self.assertEqual(kit_levels.red_patches(combfilter.CombFilter, -9),
-                         [])
-
-    def test_at_minus_3_dbfs_four_patches_rail(self):
-        import kit_levels
-        self.assertEqual(kit_levels.red_patches(combfilter.CombFilter, -3),
-                         [1, 3, 4, 5])
-        names = [combfilter.CombFilter.PATCHES[k][0] for k in (1, 3, 4, 5)]
-        self.assertEqual(names, ["Ringing Pitch", "Dark Resonator",
-                                 "Single Slap", "Filter Only"])
 
 
 class TheClaims(unittest.TestCase):
@@ -1235,7 +1219,19 @@ def test_construction_needs_its_two_modules(self):
                     sys.modules[name] = saved
 
 
+class TheCeiling(unittest.TestCase):
+    def test_clean_at_the_stated_input_level(self):
+        # dc is where it rails first: p1 at -18 dBFS.
+        self.assertEqual(
+            kit_ceiling.stated_level_reds(combfilter.CombFilter, "dc"), [])
+        self.assertTrue(kit_ceiling.stated_level_reds(
+            combfilter.CombFilter, "dc", db=-18, keys=("p1",)))
+
+
 CLAIMS = (
+    ("Keep the input under -24 dBFS and the defaults and patches stay "
+     "off the rails.",
+     ("TheCeiling.test_clean_at_the_stated_input_level",)),
     ("A tuned comb: a delay line short enough to be a pitch, fed back on "
      "itself, so noise turns into a note and a chord turns metallic.",
      ("TheCombTunesFractionally.test_every_request_lands_within_five_cents",
@@ -1286,11 +1282,7 @@ def test_construction_needs_its_two_modules(self):
      ("TheTuningKnobIsClickFree.test_the_boundary_is_not_findable",
       "TheTuningKnobIsClickFree.test_a_jumped_read_head_is_red")),
     ("A comb gains, so a loud input can reach the rail by design.",
-     ("TheInputCeiling.test_at_minus_3_dbfs_four_patches_rail",)),
-    ("A plucked phrase is clean on every patch up to -9 dBFS; at -3 dBFS "
-     "Ringing Pitch, Dark Resonator, Single Slap and Filter Only rail.",
-     ("TheInputCeiling.test_a_plucked_phrase_is_clean_to_minus_9_dbfs",
-      "TheInputCeiling.test_at_minus_3_dbfs_four_patches_rail")),
+     ("TheCeiling.test_clean_at_the_stated_input_level",)),
     ("`reset()` empties the line.",
      ("ResetEmptiesTheLine.test_reset_leaves_the_line_silent_and_the_"
       "source_rendering",)),
@@ -1344,7 +1336,7 @@ def test_every_claim_is_in_the_docstring_and_tested(self):
         # docstring does not carry, a test that does not exist.
         self.assertTrue(claim_problems(doc + " It reads 12 ms."))
         self.assertTrue(claim_problems(_flat(doc).replace(
-            "up to -9 dBFS", "up to -6 dBFS")))
+            "under -24 dBFS", "under -18 dBFS")))
         self.assertTrue(claim_problems(
             doc, CLAIMS + (("Latency", ("TheClaims.test_nothing_here",)),)))
 
diff --git a/tests/test_cpython_effects_digitaldelay.py b/tests/test_cpython_effects_digitaldelay.py
index fcf332df..218748f8 100644
--- a/tests/test_cpython_effects_digitaldelay.py
+++ b/tests/test_cpython_effects_digitaldelay.py
@@ -87,6 +87,7 @@ class of the node's walk, and the edge test goes red at the old edge. A
 sys.path.insert(0, os.path.join(os.path.dirname(__file__), ".."))
 
 import audiocore                                            # noqa: E402
+import kit_ceiling                                          # noqa: E402
 import kit_faults                                           # noqa: E402
 import kit_probes as probes                                 # noqa: E402
 import lifecycle                                            # noqa: E402
@@ -2902,12 +2903,24 @@ def touch(effect, _index=index):
             effect.deinit()
 
 
+class TheCeiling(unittest.TestCase):
+    def test_clean_at_the_stated_input_level(self):
+        # square is where it rails first: p3 at -3 dBFS.
+        self.assertEqual(
+            kit_ceiling.stated_level_reds(dd.DigitalDelay, "square"), [])
+        self.assertTrue(kit_ceiling.stated_level_reds(
+            dd.DigitalDelay, "square", db=-3, keys=("p3",)))
+
+
 # --------------------------------------------------------------------------
 # The docstring's claims
 
 #: Every claim the module docstring makes, word for word, and the tests that
 #: assert it ("Class.test_name", in this file).
 CLAIMS = (
+    ("Keep the input under -6 dBFS and the defaults and patches stay "
+     "off the rails.",
+     ("TheCeiling.test_clean_at_the_stated_input_level",)),
     ("Time is the delay, from 12.5 to 800 ms, and Feedback is how much of "
      "each repeat goes round again, up to 0.99.",
      ("T4TimeLaw.test_the_map_at_the_stops_and_between",
diff --git a/tests/test_cpython_effects_highpass.py b/tests/test_cpython_effects_highpass.py
index 85369d7a..e1a75b14 100644
--- a/tests/test_cpython_effects_highpass.py
+++ b/tests/test_cpython_effects_highpass.py
@@ -31,6 +31,7 @@
 import synthio
 
 sys.path.insert(0, os.path.join(os.path.dirname(__file__), "support"))
+import kit_ceiling                                          # noqa: E402
 from effects_measure import SAMPLE_RATE, source        # noqa: E402
 
 from audioeffects import _component                    # noqa: E402
@@ -602,5 +603,14 @@ def test_deinit_releases_every_node_and_is_idempotent(self):
             built.output
 
 
+class TheCeiling(unittest.TestCase):
+    def test_clean_at_the_stated_input_level(self):
+        # square is where it rails first: p1 at -6 dBFS.
+        self.assertEqual(
+            kit_ceiling.stated_level_reds(highpass.HighPass, "square"), [])
+        self.assertTrue(kit_ceiling.stated_level_reds(
+            highpass.HighPass, "square", db=-6, keys=("p1",)))
+
+
 if __name__ == "__main__":
     unittest.main()
diff --git a/tests/test_cpython_effects_ladderfilter.py b/tests/test_cpython_effects_ladderfilter.py
index 2c2b6784..875bf094 100644
--- a/tests/test_cpython_effects_ladderfilter.py
+++ b/tests/test_cpython_effects_ladderfilter.py
@@ -1,7 +1,5 @@
-"""`LadderFilter`'s input ceiling: the kit's plucked phrase is clean on
-every patch at -10 dBFS and rails at -3 dBFS on Growl With Drive alone
-(audiocomponents#192), and the class docstring's claims, each tied to its
-test by the `CLAIMS` table.
+"""`LadderFilter`'s input ceiling and the class docstring's claims, each
+tied to its test by the `CLAIMS` table.
 
     python -m unittest tests.test_cpython_effects_ladderfilter
 """
@@ -16,7 +14,7 @@
 sys.path.insert(0, os.path.join(ROOT, "lib"))
 sys.path.insert(0, os.path.join(ROOT, "tests", "support"))
 
-import kit_levels                                         # noqa: E402
+import kit_ceiling                                          # noqa: E402
 import kit_probes as probes                               # noqa: E402
 import numpy as np                                        # noqa: E402
 from audioeffects import ladderfilter                     # noqa: E402
@@ -52,14 +50,6 @@ def burst_then_silence(seconds=2.0):
                  + [0] * int(2 * seconds * RATE))
 
 
-class TheInputCeiling(unittest.TestCase):
-
-    def test_a_plucked_phrase_is_clean_to_minus_10_dbfs(self):
-        self.assertEqual(kit_levels.red_patches(LadderFilter, -10), [])
-
-    def test_at_minus_3_dbfs_growl_with_drive_rails(self):
-        self.assertEqual(kit_levels.red_patches(LadderFilter, -3), [4])
-        self.assertEqual(LadderFilter.PATCHES[4][0], "Growl With Drive")
 
 
 class TheClaims(unittest.TestCase):
@@ -182,7 +172,19 @@ def test_construction_needs_audioladder(self):
         self.assertEqual(LadderFilter.REQUIRES, ("audioladder",))
 
 
+class TheCeiling(unittest.TestCase):
+    def test_clean_at_the_stated_input_level(self):
+        # square is where it rails first: p4 at -12 dBFS.
+        self.assertEqual(
+            kit_ceiling.stated_level_reds(LadderFilter, "square"), [])
+        self.assertTrue(kit_ceiling.stated_level_reds(
+            LadderFilter, "square", db=-12, keys=("p4",)))
+
+
 CLAIMS = (
+    ("Keep the input under -15 dBFS and the defaults and patches stay "
+     "off the rails.",
+     ("TheCeiling.test_clean_at_the_stated_input_level",)),
     ("`LadderFilter` - the Moog transistor ladder, rebuilt on "
      "`audioladder`.",
      ("TheClaims.test_construction_needs_audioladder",)),
@@ -236,11 +238,7 @@ def test_construction_needs_audioladder(self):
       "TheClaims.test_reset_stops_the_tone")),
     ("The resonance peak and the drive both add gain, so no input level is "
      "clean on every setting.",
-     ("TheInputCeiling.test_at_minus_3_dbfs_growl_with_drive_rails",)),
-    ("A plucked phrase stays off the rails on every patch to -10 dBFS; at "
-     "-3 dBFS Growl With Drive rails.",
-     ("TheInputCeiling.test_a_plucked_phrase_is_clean_to_minus_10_dbfs",
-      "TheInputCeiling.test_at_minus_3_dbfs_growl_with_drive_rails")),
+     ("TheCeiling.test_clean_at_the_stated_input_level",)),
     ("The class needs audiodsp's `audioladder`, and on a board without it "
      "construction raises `ImportError`.",
      ("TheClaims.test_construction_needs_audioladder",)),
diff --git a/tests/test_cpython_effects_lowpass.py b/tests/test_cpython_effects_lowpass.py
index ab7c96d7..e3959622 100644
--- a/tests/test_cpython_effects_lowpass.py
+++ b/tests/test_cpython_effects_lowpass.py
@@ -28,6 +28,7 @@ class clamps now, and the dossier's section 7 names the raise as the defect)
 import audioeffects
 
 sys.path.insert(0, os.path.join(os.path.dirname(__file__), "support"))
+import kit_ceiling                                          # noqa: E402
 from effects_measure import SAMPLE_RATE, source        # noqa: E402
 import kit_faults as faults                            # noqa: E402
 
@@ -671,6 +672,15 @@ def build_twelve(cls):
                 lambda effect: float(effect._pole_two.mix), build_twelve)
 
 
+class TheCeiling(unittest.TestCase):
+    def test_clean_at_the_stated_input_level(self):
+        # sine is where it rails first: p5 at 0 dBFS.
+        self.assertEqual(
+            kit_ceiling.stated_level_reds(lowpass.LowPass, "sine"), [])
+        self.assertTrue(kit_ceiling.stated_level_reds(
+            lowpass.LowPass, "sine", db=0, keys=("p5",)))
+
+
 if __name__ == "__main__":
     unittest.main()
 
diff --git a/tests/test_cpython_effects_multiband.py b/tests/test_cpython_effects_multiband.py
index 811182fb..7ededd7a 100644
--- a/tests/test_cpython_effects_multiband.py
+++ b/tests/test_cpython_effects_multiband.py
@@ -32,6 +32,7 @@
 #: `audioeffects/multibandcompressor.py`; `rebuilt.ADOPTED` no longer lists
 #: it. These tests still import the home module so a planted-fault subclass
 #: is measured against this file, not only `create()`.
+import kit_ceiling                                          # noqa: E402
 import kit_probes as probes                                     # noqa: E402
 from audioeffects import _component                             # noqa: E402
 from tools import effect_measurements as kit                    # noqa: E402
@@ -990,7 +991,19 @@ def test_construction_needs_its_three_modules(self):
                     sys.modules[name] = saved
 
 
+class TheCeiling(unittest.TestCase):
+    def test_clean_at_the_stated_input_level(self):
+        # sq147 is where it rails first: p3 at -6 dBFS.
+        cls = multibandcompressor.MultibandCompressor
+        self.assertEqual(kit_ceiling.stated_level_reds(cls, "sq147"), [])
+        self.assertTrue(kit_ceiling.stated_level_reds(
+            cls, "sq147", db=-6, keys=("p3",)))
+
+
 CLAIMS = (
+    ("Keep the input under -9 dBFS and the defaults and patches stay "
+     "off the rails.",
+     ("TheCeiling.test_clean_at_the_stated_input_level",)),
     ("Split-band compression: the mix split into two or three bands, each "
      "with its own compressor, then summed back flat.",
      ("Traits.test_m1_the_bands_sum_flat_at_three_bands",
diff --git a/tests/test_cpython_effects_multitapdelay.py b/tests/test_cpython_effects_multitapdelay.py
index 4fb9c67f..74260393 100644
--- a/tests/test_cpython_effects_multitapdelay.py
+++ b/tests/test_cpython_effects_multitapdelay.py
@@ -60,6 +60,7 @@ class built as a wire. The full spans, the three interpreters and the rates
 import audiomixer                                           # noqa: E402
 import audioroute                                           # noqa: E402
 import synthio                                              # noqa: E402
+import kit_ceiling                                          # noqa: E402
 import kit_faults                                           # noqa: E402
 import kit_probes as probes                                 # noqa: E402
 import audioeffects                                         # noqa: E402
@@ -2953,6 +2954,15 @@ def test_the_tail_reading_is_red_on_a_bound_one_lap_short(self):
             self.assertGreater(planted, short, (rate, channels))
 
 
+class TheCeiling(unittest.TestCase):
+    def test_clean_at_the_stated_input_level(self):
+        # square is where it rails first: d at -3 dBFS.
+        self.assertEqual(
+            kit_ceiling.stated_level_reds(mtd.MultiTapDelay, "square"), [])
+        self.assertTrue(kit_ceiling.stated_level_reds(
+            mtd.MultiTapDelay, "square", db=-3, keys=("d",)))
+
+
 # --------------------------------------------------------------------------
 # The docstring's claims, each tied to the test that asserts it
 
@@ -2961,6 +2971,9 @@ def test_the_tail_reading_is_red_on_a_bound_one_lap_short(self):
 #: claim is here; one that could not be tied to a test was struck (the
 #: trial fixer's dated note in the dossier lists them).
 CLAIMS = (
+    ("Keep the input under -6 dBFS and the defaults and patches stay "
+     "off the rails.",
+     ("test_clean_at_the_stated_input_level",)),
     ("Measured at v0.6.3, patch 4 costs 5.567 ms a block on the "
      "ESP32-S3, where a block lasts 5.333 ms, so it needs a P4-class "
      "board: the ESP32-P4 runs it in 3.865 ms.",
diff --git a/tests/test_cpython_effects_notch.py b/tests/test_cpython_effects_notch.py
index 0cca27bc..7c7510ec 100644
--- a/tests/test_cpython_effects_notch.py
+++ b/tests/test_cpython_effects_notch.py
@@ -31,6 +31,7 @@ class actually built and not a re-derivation of RBJ standing beside it. The
 import synthio
 
 sys.path.insert(0, os.path.join(os.path.dirname(__file__), "support"))
+import kit_ceiling                                          # noqa: E402
 import kit_faults as faults                            # noqa: E402
 from effects_measure import SAMPLE_RATE                # noqa: E402
 
@@ -573,6 +574,15 @@ def test_deinit_releases_every_node_the_class_built(self):
             self.assertTrue(getattr(node, "_deinited", True))
 
 
+class TheCeiling(unittest.TestCase):
+    def test_clean_at_the_stated_input_level(self):
+        # square is where it rails first: p1 at -3 dBFS.
+        self.assertEqual(
+            kit_ceiling.stated_level_reds(notch_module.Notch, "square"), [])
+        self.assertTrue(kit_ceiling.stated_level_reds(
+            notch_module.Notch, "square", db=-3, keys=("p1",)))
+
+
 if __name__ == "__main__":
     unittest.main()
 
diff --git a/tests/test_cpython_effects_parametriceq.py b/tests/test_cpython_effects_parametriceq.py
index d6150fa7..b1c88c1d 100644
--- a/tests/test_cpython_effects_parametriceq.py
+++ b/tests/test_cpython_effects_parametriceq.py
@@ -27,6 +27,7 @@
 
 sys.path.insert(0, os.path.join(os.path.dirname(__file__), "support"))
 import effects_measure                                # noqa: E402
+import kit_ceiling                                          # noqa: E402
 from effects_measure import SAMPLE_RATE, source        # noqa: E402
 
 from audioeffects import _component                    # noqa: E402
@@ -456,5 +457,14 @@ def __init__(self, sample):
         self.output = sample
 
 
+class TheCeiling(unittest.TestCase):
+    def test_clean_at_the_stated_input_level(self):
+        # dc is where it rails first: p3 at -9 dBFS.
+        self.assertEqual(
+            kit_ceiling.stated_level_reds(parametriceq.ParametricEQ, "dc"), [])
+        self.assertTrue(kit_ceiling.stated_level_reds(
+            parametriceq.ParametricEQ, "dc", db=-9, keys=("p3",)))
+
+
 if __name__ == "__main__":
     unittest.main()
diff --git a/tests/test_cpython_effects_phaser.py b/tests/test_cpython_effects_phaser.py
index fa902f56..f02910aa 100644
--- a/tests/test_cpython_effects_phaser.py
+++ b/tests/test_cpython_effects_phaser.py
@@ -25,6 +25,7 @@
 from audioeffects import _component                            # noqa: E402
 from audioeffects import phaser as phaser_module               # noqa: E402
 from tools import effect_measurements as kit                   # noqa: E402
+import kit_ceiling                                          # noqa: E402
 import kit_faults as faults                                    # noqa: E402
 
 VENDOR = "PyDevices"
@@ -911,7 +912,19 @@ def test_construction_needs_audiobiquad_and_audioshaper(self):
                     sys.modules[name] = saved
 
 
+class TheCeiling(unittest.TestCase):
+    def test_clean_at_the_stated_input_level(self):
+        # sq147 is where it rails first: p1 at -6 dBFS.
+        self.assertEqual(
+            kit_ceiling.stated_level_reds(Phaser, "sq147"), [])
+        self.assertTrue(kit_ceiling.stated_level_reds(
+            Phaser, "sq147", db=-6, keys=("p1",)))
+
+
 CLAIMS = (
+    ("Keep the input under -9 dBFS and the defaults and patches stay "
+     "off the rails.",
+     ("TheCeiling.test_clean_at_the_stated_input_level",)),
     ("`Phaser` - four first-order all-pass stages swept the way a Phase 90 "
      "is.",
      ("TestPhaserTraits.test_p1_two_notches_at_defaults_six_stages_is_"
diff --git a/tests/test_cpython_effects_pingpongdelay.py b/tests/test_cpython_effects_pingpongdelay.py
index aae72360..fc864a58 100644
--- a/tests/test_cpython_effects_pingpongdelay.py
+++ b/tests/test_cpython_effects_pingpongdelay.py
@@ -30,6 +30,7 @@
 sys.path.insert(0, os.path.join(os.path.dirname(__file__), ".."))
 
 import audiocore                                            # noqa: E402
+import kit_ceiling                                          # noqa: E402
 import kit_faults                                          # noqa: E402
 import kit_probes as probes                                 # noqa: E402
 from audioeffects import _component                         # noqa: E402
@@ -2427,12 +2428,24 @@ def test_construction_needs_audioecho(self):
                 sys.modules["audioecho"] = saved
 
 
+class TheCeiling(unittest.TestCase):
+    def test_clean_at_the_stated_input_level(self):
+        # dc is where it rails first: p3 at -3 dBFS.
+        self.assertEqual(
+            kit_ceiling.stated_level_reds(PingPongDelay, "dc"), [])
+        self.assertTrue(kit_ceiling.stated_level_reds(
+            PingPongDelay, "dc", db=-3, keys=("p3",)))
+
+
 # --------------------------------------------------------------------------
 # The docstring's claims
 
 #: Every claim the class docstring makes, word for word, and the tests that
 #: assert it ("Class.test_name", in this file).
 CLAIMS = (
+    ("Keep the input under -6 dBFS and the defaults and patches stay "
+     "off the rails.",
+     ("TheCeiling.test_clean_at_the_stated_input_level",)),
     ("Two delay lines crossed into each other: the repeats bounce between "
      "the speakers.",
      ("T1RepeatsAlternate.test_the_three_feedbacks_at_three_rates",)),
diff --git a/tests/test_cpython_effects_reverb.py b/tests/test_cpython_effects_reverb.py
index 64bf8c51..ce610788 100644
--- a/tests/test_cpython_effects_reverb.py
+++ b/tests/test_cpython_effects_reverb.py
@@ -24,6 +24,7 @@
 sys.path.insert(0, os.path.join(os.path.dirname(__file__), ".."))
 
 import audiocore                                            # noqa: E402
+import kit_ceiling                                          # noqa: E402
 import kit_faults                                           # noqa: E402
 import kit_probes as probes                                 # noqa: E402
 from audioeffects import _component                         # noqa: E402
@@ -1804,14 +1805,6 @@ def sine_wet_gain(hz, rms, rate=RATE):
 
 
 class InputCeiling(unittest.TestCase):
-    def test_a_plucked_phrase_is_clean_to_minus_4_dbfs(self):
-        """audiocomponents#192: the kit's phrase is clean on every patch
-        at -4 dBFS, and rails at -3 dBFS on Slow Bloom alone."""
-        import kit_levels
-        self.assertEqual(kit_levels.red_patches(Reverb, -4), [])
-        self.assertEqual(kit_levels.red_patches(Reverb, -3), [9])
-        self.assertEqual(Reverb.PATCHES[9][0], "Slow Bloom")
-
     def test_no_patch_reaches_the_rail_at_4000_lsb_rms(self):
         # on eight noise seeds, at three rates, each patch's peak stays
         # under the rail by more than the spread of its peaks
@@ -1838,12 +1831,24 @@ def test_the_tanks_lines_compress_from_8000_lsb_rms(self):
         self.assertLess(g8 - g4, -1.0, (g4, g8))
 
 
+class TheInputCeiling(unittest.TestCase):
+    def test_clean_at_the_stated_input_level(self):
+        # sq220 is where it rails first: p9 at -9 dBFS.
+        self.assertEqual(
+            kit_ceiling.stated_level_reds(Reverb, "sq220"), [])
+        self.assertTrue(kit_ceiling.stated_level_reds(
+            Reverb, "sq220", db=-9, keys=("p9",)))
+
+
 # -- the claims ---------------------------------------------------------------
 
 #: Every sentence of the docstrings that makes a claim, word for word, and
 #: the tests that assert it (the trial brief). A sentence that is not here
 #: may hold no number.
 CLAIMS = (
+    ("Keep the input under -12 dBFS and the defaults and patches stay "
+     "off the rails.",
+     ("TheInputCeiling.test_clean_at_the_stated_input_level",)),
     ("Your dry signal passes untouched and a reverb tail rises behind it.",
      ("T7LowCut.test_the_dry_is_flat",)),
     ("Character picks the machine: `plate` is dense from the first "
@@ -1909,9 +1914,6 @@ def test_the_tanks_lines_compress_from_8000_lsb_rms(self):
      "reaches the rail at 48, 44.1 or 22.05 kHz; Bright Chamber at 44.1 kHz "
      "is not claimed.",
      ("InputCeiling.test_no_patch_reaches_the_rail_at_4000_lsb_rms",)),
-    ("A plucked phrase stays off the rails on every patch to -4 dBFS; at "
-     "-3 dBFS Slow Bloom rails.",
-     ("InputCeiling.test_a_plucked_phrase_is_clean_to_minus_4_dbfs",)),
     ("`tail_samples` bounds the frames until the output is exactly zero "
      "once your input stops: 222 868 frames at the defaults at 48 kHz.",
      ("Tier1.test_the_tail_reaches_exact_zero_inside_tail_samples",
diff --git a/tests/test_cpython_effects_slapbackdelay.py b/tests/test_cpython_effects_slapbackdelay.py
index bbd791d5..4a9c88aa 100644
--- a/tests/test_cpython_effects_slapbackdelay.py
+++ b/tests/test_cpython_effects_slapbackdelay.py
@@ -39,6 +39,7 @@
 import audiocore                                            # noqa: E402
 import audiomixer                                           # noqa: E402
 import audioroute                                           # noqa: E402
+import kit_ceiling                                          # noqa: E402
 import kit_faults                                          # noqa: E402
 import kit_probes as probes                                 # noqa: E402
 from audioeffects import _component                         # noqa: E402
@@ -1900,6 +1901,15 @@ def test_the_stated_ceiling_is_clean_and_just_over_is_not(self):
                                               **options), 0, options)
 
 
+class TheCeiling(unittest.TestCase):
+    def test_clean_at_the_stated_input_level(self):
+        # square is where it rails first: p2 at -3 dBFS.
+        self.assertEqual(
+            kit_ceiling.stated_level_reds(SlapbackDelay, "square"), [])
+        self.assertTrue(kit_ceiling.stated_level_reds(
+            SlapbackDelay, "square", db=-3, keys=("p2",)))
+
+
 # --------------------------------------------------------------------------
 # The docstring's claims, each tied to the test that asserts it (the trial
 # of the second process, 2026-09-29)
@@ -1908,6 +1918,9 @@ def test_the_stated_ceiling_is_clean_and_just_over_is_not(self):
 #: that asserts it). Every sentence in the docstring that makes a claim is
 #: here; one that could not be tied to a test was struck.
 CLAIMS = (
+    ("Keep the input under -6 dBFS and the defaults and patches stay "
+     "off the rails.",
+     ("test_clean_at_the_stated_input_level",)),
     ("By default the repeat comes 134.4 ms after the dry, once.",
      "test_defaults_three_rates_stereo_and_mono"),
     ("Time runs from 40 to 250 ms, Level from 0 to 2, Saturation from 0 to "
diff --git a/tests/test_cpython_effects_tapedelay.py b/tests/test_cpython_effects_tapedelay.py
index 13553998..6fe4c48b 100644
--- a/tests/test_cpython_effects_tapedelay.py
+++ b/tests/test_cpython_effects_tapedelay.py
@@ -34,6 +34,7 @@
 
 import audiocore                                            # noqa: E402
 import lifecycle                                            # noqa: E402
+import kit_ceiling                                          # noqa: E402
 import kit_faults                                           # noqa: E402
 import kit_probes as probes                                 # noqa: E402
 from audioeffects import _component                         # noqa: E402
@@ -2954,11 +2955,23 @@ def test_every_demonstrated_row_is_red_on_a_wire(self):
                                  or null["drift_ok"], null)
 
 
+class TheCeiling(unittest.TestCase):
+    def test_clean_at_the_stated_input_level(self):
+        # square is where it rails first: d at -3 dBFS.
+        self.assertEqual(
+            kit_ceiling.stated_level_reds(tape.TapeDelay, "square"), [])
+        self.assertTrue(kit_ceiling.stated_level_reds(
+            tape.TapeDelay, "square", db=-3, keys=("d",)))
+
+
 # -- the docstring's claims -----------------------------------------------
 
 #: Every claim the module docstring makes, word for word, and the tests that
 #: assert it ("Class.test_name", in this file).
 CLAIMS = (
+    ("Keep the input under -6 dBFS and the defaults and patches stay "
+     "off the rails.",
+     ("TheCeiling.test_clean_at_the_stated_input_level",)),
     ("`TapeDelay` - a tape echo with two transports: the Roland RE-201's "
      "motor and the Maestro EP-3's sliding head.",
      ("TheSurface.test_macros_characters_tier_latency",
diff --git a/tests/test_cpython_effects_transientshaper.py b/tests/test_cpython_effects_transientshaper.py
index 29eda36a..478e11cc 100644
--- a/tests/test_cpython_effects_transientshaper.py
+++ b/tests/test_cpython_effects_transientshaper.py
@@ -31,6 +31,7 @@
 #: These tests still import the home module so a planted-fault subclass is
 #: measured against this file, not only `create()`.
 import effect_measurements as kit                         # noqa: E402
+from support import kit_ceiling                             # noqa: E402
 from support import kit_probes as probes                  # noqa: E402
 
 VENDOR = "PyDevices"
@@ -219,21 +220,6 @@ def test_t5_the_rms_detector_settles_where_the_peak_detector_does_not(
         self.assertGreater(steady["peak"], 1.5)
 
 
-class TheInputCeiling(unittest.TestCase):
-    """audiocomponents#192: the kit's plucked phrase is clean on every
-    patch at -10 dBFS, and rails at -3 dBFS on Snap and Kick Punch."""
-
-    def test_a_plucked_phrase_is_clean_to_minus_10_dbfs(self):
-        import kit_levels
-        self.assertEqual(kit_levels.red_patches(
-            transientshaper.TransientShaper, -10), [])
-
-    def test_at_minus_3_dbfs_snap_and_kick_punch_rail(self):
-        import kit_levels
-        cls = transientshaper.TransientShaper
-        self.assertEqual(kit_levels.red_patches(cls, -3), [1, 5])
-        self.assertEqual([cls.PATCHES[k][0] for k in (1, 5)],
-                         ["Snap", "Kick Punch"])
 
 
 def attack(db):
@@ -321,7 +307,19 @@ def test_construction_needs_audiodynamics(self):
             sys.modules["audiodynamics"] = saved
 
 
+class TheCeiling(unittest.TestCase):
+    def test_clean_at_the_stated_input_level(self):
+        # square is where it rails first: p1 at -9 dBFS.
+        cls = transientshaper.TransientShaper
+        self.assertEqual(kit_ceiling.stated_level_reds(cls, "square"), [])
+        self.assertTrue(kit_ceiling.stated_level_reds(
+            cls, "square", db=-9, keys=("p1",)))
+
+
 CLAIMS = (
+    ("Keep the input under -12 dBFS and the defaults and patches stay "
+     "off the rails.",
+     ("TheCeiling.test_clean_at_the_stated_input_level",)),
     ("There is no threshold and no ratio: the gain follows the difference "
      "between two envelopes of your own signal, so between -20 and -40 dBFS "
      "a quiet hit is shaped as hard as a loud one, to within 0.5 dB.",
@@ -344,10 +342,6 @@ def test_construction_needs_audiodynamics(self):
     ("On a slow decay Sustain runs out before its end: on a note fading at "
      "3 dB a second, Sustain -24 reaches about -16 dB.",
      ("TheClaims.test_sustain_runs_out_on_a_slow_decay",)),
-    ("A plucked phrase stays off the rails on every patch to -10 dBFS; at "
-     "-3 dBFS Snap and Kick Punch rail.",
-     ("TheInputCeiling.test_a_plucked_phrase_is_clean_to_minus_10_dbfs",
-      "TheInputCeiling.test_at_minus_3_dbfs_snap_and_kick_punch_rail")),
     ("Latency is zero at every setting, and so is the tail: silence in is "
      "silence out in the same frame.",
      ("TheClaims.test_latency_is_zero",
diff --git a/tests/test_kit.py b/tests/test_kit.py
index 745321ed..ef9dc57c 100644
--- a/tests/test_kit.py
+++ b/tests/test_kit.py
@@ -541,6 +541,26 @@ def test_a_rail_is_red(self):
         # A square at full scale sits on the rail because the input does.
         self.assertEqual(self.v(kp.KitPlain, "square"), "ok")
 
+    def test_a_rail_by_design_is_excused_where_declared(self):
+        self.assertTrue(self.v(kp.ClipAtTop).startswith("RED(rail"))
+        self.assertTrue(self.v(kp.ClipAtTop, knob=(0, 127)).startswith(
+            "RED(rail"))
+        self.assertEqual(self.v(kp.ClipAtTop, knob=(1, 127)), "ok")
+        self.assertEqual(self.v(kp.ClipAtTop, knob=[(0, 127), (1, 127)]),
+                         "ok")
+        self.assertEqual(self.v(kp.ClipsAlways), "ok")
+        # A wrap is still judged.
+        self.assertTrue(self.v(kp.WrapsAlways).startswith("RED(wrap"))
+
+    def test_a_stated_level_holds_and_the_level_above_does_not(self):
+        self.assertEqual(
+            kit_ceiling.stated_level_reds(kp.WrapKitQuiet, "sine"), [])
+        reds = kit_ceiling.stated_level_reds(kp.WrapKitQuiet, "sine", db=0)
+        self.assertEqual(len(reds), 3)          # the defaults, two patches
+        self.assertIn("RED(wrap", reds[0])
+        self.assertEqual(len(kit_ceiling.stated_level_reds(
+            kp.WrapKitQuiet, "sine", db=0, keys=("p1",))), 1)
+
     def test_silence_at_a_stop_is_red(self):
         self.assertTrue(self.v(kp.DeadStop, knob=(1, 0)).startswith(
             "RED(silent"))