diff --git a/docs/conf.py b/docs/conf.py
index d049743..0f7665f 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """Sphinx configuration for the audioeffects documentation.
 
 Everything shared by the PyDevices documentation projects (theme, top bar,
diff --git a/lib/audioeffects/__init__.py b/lib/audioeffects/__init__.py
index 5df65a8..dccd714 100644
--- a/lib/audioeffects/__init__.py
+++ b/lib/audioeffects/__init__.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """Forty-five effect classes built out of audiodsp's audio nodes.
 
 Every class wires itself from an audio source - a synthesizer, an
diff --git a/lib/audioeffects/_component.py b/lib/audioeffects/_component.py
index e2befd1..5e2fc11 100644
--- a/lib/audioeffects/_component.py
+++ b/lib/audioeffects/_component.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """The construction shape every rebuilt effect class is built on.
 
 It replaced `_core.py`, the pre-contract shape, in which a module-level
diff --git a/lib/audioeffects/_iso.py b/lib/audioeffects/_iso.py
index e2f4142..c476caf 100644
--- a/lib/audioeffects/_iso.py
+++ b/lib/audioeffects/_iso.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """ISO centre frequencies, kept as a shared private constant.
 
 The old family GraphicEQ walked these ten centres. The rebuilt GraphicEQ
diff --git a/lib/audioeffects/airspace.py b/lib/audioeffects/airspace.py
index 07b3390..00e0ed5 100644
--- a/lib/audioeffects/airspace.py
+++ b/lib/audioeffects/airspace.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`AirSpace` - a tape echo sent into a chamber, with the dry beside it.
 
 You send your signal to a tape echo whose repeats feed an echo chamber, and
diff --git a/lib/audioeffects/analogdelay.py b/lib/audioeffects/analogdelay.py
index 82a2725..904859c 100644
--- a/lib/audioeffects/analogdelay.py
+++ b/lib/audioeffects/analogdelay.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`AnalogDelay` - a bucket-brigade delay whose Time knob is its clock.
 
 The player's text is the class docstring, and every sentence in it that
diff --git a/lib/audioeffects/autopan.py b/lib/audioeffects/autopan.py
index a62d1e1..8a15515 100644
--- a/lib/audioeffects/autopan.py
+++ b/lib/audioeffects/autopan.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`AutoPan` - an auto-panner: a pan law under an LFO.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's
diff --git a/lib/audioeffects/bandpass.py b/lib/audioeffects/bandpass.py
index 9b90759..e9142c7 100644
--- a/lib/audioeffects/bandpass.py
+++ b/lib/audioeffects/bandpass.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`BandPass` - the two-pole resonant band-pass, rebuilt on `audiobiquad`.
 
 The player's text is the class docstring; the `CLAIMS` table in the
diff --git a/lib/audioeffects/bitcrusher.py b/lib/audioeffects/bitcrusher.py
index 8eb13ae..25bf140 100644
--- a/lib/audioeffects/bitcrusher.py
+++ b/lib/audioeffects/bitcrusher.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Bitcrusher` — a linear hold, the SP-1200's two numbers as knobs.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's
diff --git a/lib/audioeffects/cabinetsim.py b/lib/audioeffects/cabinetsim.py
index 88cfe2b..61c0c5e 100644
--- a/lib/audioeffects/cabinetsim.py
+++ b/lib/audioeffects/cabinetsim.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`CabinetSim` - a designed guitar-cabinet response, two characters.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's
diff --git a/lib/audioeffects/chorus.py b/lib/audioeffects/chorus.py
index 7678725..2c4c755 100644
--- a/lib/audioeffects/chorus.py
+++ b/lib/audioeffects/chorus.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Chorus` - one delayed voice on a clock-modulated bucket-brigade line.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's
diff --git a/lib/audioeffects/combfilter.py b/lib/audioeffects/combfilter.py
index 490f37a..38a5b67 100644
--- a/lib/audioeffects/combfilter.py
+++ b/lib/audioeffects/combfilter.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`CombFilter` - a delay line short enough to be a pitch, fed back on
 itself.
 
diff --git a/lib/audioeffects/compressor.py b/lib/audioeffects/compressor.py
index 0b57baa..1ee2187 100644
--- a/lib/audioeffects/compressor.py
+++ b/lib/audioeffects/compressor.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Compressor` - compressor characters on a shared palette.
 
 The player's text is the class docstring; the `CLAIMS` table in the
diff --git a/lib/audioeffects/convolutionreverb.py b/lib/audioeffects/convolutionreverb.py
index 1cdc6e8..1866885 100644
--- a/lib/audioeffects/convolutionreverb.py
+++ b/lib/audioeffects/convolutionreverb.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`ConvolutionReverb` - a room made by convolution, synthesized or loaded.
 
 The player's text is the class docstring, and every sentence in it that
diff --git a/lib/audioeffects/deesser.py b/lib/audioeffects/deesser.py
index ed338e2..cd02e6a 100644
--- a/lib/audioeffects/deesser.py
+++ b/lib/audioeffects/deesser.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """The dbx 902 de-esser: sibilance measured against the programme, not
 against a threshold knob.
 
diff --git a/lib/audioeffects/digitaldelay.py b/lib/audioeffects/digitaldelay.py
index 373456a..875e74f 100644
--- a/lib/audioeffects/digitaldelay.py
+++ b/lib/audioeffects/digitaldelay.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`DigitalDelay` - a clean digital delay with the Boss DD-2's control law.
 
 Your dry signal passes untouched, and one clean repeat follows it, fed back
diff --git a/lib/audioeffects/distortion.py b/lib/audioeffects/distortion.py
index b9b2e93..52fb190 100644
--- a/lib/audioeffects/distortion.py
+++ b/lib/audioeffects/distortion.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Distortion` - the ProCo Rat, with a Boss pedal as a second character.
 
 The player's text is the class docstring; the `CLAIMS` table in the
diff --git a/lib/audioeffects/dynamiceq.py b/lib/audioeffects/dynamiceq.py
index 365e66a..7ec51b7 100644
--- a/lib/audioeffects/dynamiceq.py
+++ b/lib/audioeffects/dynamiceq.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`DynamicEQ` - one equaliser band that only moves when there is
 something in it.
 
diff --git a/lib/audioeffects/exciter.py b/lib/audioeffects/exciter.py
index beebd62..1ca17d9 100644
--- a/lib/audioeffects/exciter.py
+++ b/lib/audioeffects/exciter.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Exciter` - dry plus a high-passed harmonic branch.
 
 The player's text is the class docstring; the `CLAIMS` table in the
diff --git a/lib/audioeffects/expander.py b/lib/audioeffects/expander.py
index 5843680..63a123c 100644
--- a/lib/audioeffects/expander.py
+++ b/lib/audioeffects/expander.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Expander` - a downward expander in the Drawmer DS201's shape.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's
diff --git a/lib/audioeffects/flanger.py b/lib/audioeffects/flanger.py
index 49e4c6d..3ddcadb 100644
--- a/lib/audioeffects/flanger.py
+++ b/lib/audioeffects/flanger.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Flanger` - a swept comb on CircuitPython's own `audiodelays.Flanger`.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's
diff --git a/lib/audioeffects/fuzz.py b/lib/audioeffects/fuzz.py
index 1311bcd..371a36e 100644
--- a/lib/audioeffects/fuzz.py
+++ b/lib/audioeffects/fuzz.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Fuzz` - a biased germanium pair, with a Big Muff cascade as a second character.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's
diff --git a/lib/audioeffects/graphiceq.py b/lib/audioeffects/graphiceq.py
index 3a5d336..3f7de6c 100644
--- a/lib/audioeffects/graphiceq.py
+++ b/lib/audioeffects/graphiceq.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`GraphicEQ` - ten octave bands and two level sliders, after the MXR
 M-108 Ten Band.
 
diff --git a/lib/audioeffects/harmonizer.py b/lib/audioeffects/harmonizer.py
index 90cbfcd..dc4cadf 100644
--- a/lib/audioeffects/harmonizer.py
+++ b/lib/audioeffects/harmonizer.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Harmonizer` - a harmony of pitch-shifted voices.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's
diff --git a/lib/audioeffects/highpass.py b/lib/audioeffects/highpass.py
index 91a8438..2b54f3f 100644
--- a/lib/audioeffects/highpass.py
+++ b/lib/audioeffects/highpass.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`HighPass` - the low-cut: a two-pole analog high-pass whose transmission
 zero at DC is exact, not nearly.
 
diff --git a/lib/audioeffects/ladderfilter.py b/lib/audioeffects/ladderfilter.py
index 43fd9df..acac7a7 100644
--- a/lib/audioeffects/ladderfilter.py
+++ b/lib/audioeffects/ladderfilter.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`LadderFilter` - the Moog transistor ladder, rebuilt on `audioladder`.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's
diff --git a/lib/audioeffects/limiter.py b/lib/audioeffects/limiter.py
index ea98057..f463bd8 100644
--- a/lib/audioeffects/limiter.py
+++ b/lib/audioeffects/limiter.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """A lookahead brickwall limiter: a ceiling the signal does not get past.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's
diff --git a/lib/audioeffects/lowpass.py b/lib/audioeffects/lowpass.py
index d284bf6..5f4e02f 100644
--- a/lib/audioeffects/lowpass.py
+++ b/lib/audioeffects/lowpass.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`LowPass` - the two-pole analog prototype every synth and console
 low-pass is a version of, digitised without losing its tail.
 
diff --git a/lib/audioeffects/multibandcompressor.py b/lib/audioeffects/multibandcompressor.py
index cf118bf..dc36f03 100644
--- a/lib/audioeffects/multibandcompressor.py
+++ b/lib/audioeffects/multibandcompressor.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`MultibandCompressor` - split-band compression, two or three bands.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's
diff --git a/lib/audioeffects/multitapdelay.py b/lib/audioeffects/multitapdelay.py
index 985484a..83dddbc 100644
--- a/lib/audioeffects/multitapdelay.py
+++ b/lib/audioeffects/multitapdelay.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`MultiTapDelay` - one recording read by several heads on a fixed grid.
 
 The player's text is the class docstring, and every sentence in it that
diff --git a/lib/audioeffects/noisegate.py b/lib/audioeffects/noisegate.py
index 238e555..d8ef842 100644
--- a/lib/audioeffects/noisegate.py
+++ b/lib/audioeffects/noisegate.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`NoiseGate` - a noise gate after the Drawmer DS201.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's
diff --git a/lib/audioeffects/notch.py b/lib/audioeffects/notch.py
index f7a5368..99693ff 100644
--- a/lib/audioeffects/notch.py
+++ b/lib/audioeffects/notch.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Notch` - the two-pole band-stop: everything except one band, tuned.
 
 The player's text is the class docstring; the `CLAIMS` table in the
diff --git a/lib/audioeffects/octaver.py b/lib/audioeffects/octaver.py
index bc5e2b1..f31cecb 100644
--- a/lib/audioeffects/octaver.py
+++ b/lib/audioeffects/octaver.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Octaver` - the analog octave-down.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's
diff --git a/lib/audioeffects/overdrive.py b/lib/audioeffects/overdrive.py
index a167cba..a541037 100644
--- a/lib/audioeffects/overdrive.py
+++ b/lib/audioeffects/overdrive.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Overdrive` - a Tube Screamer-shaped boost: dry plus a clipped shelf.
 
 The player's text is the class docstring; the `CLAIMS` table in the
diff --git a/lib/audioeffects/parametriceq.py b/lib/audioeffects/parametriceq.py
index 0c48587..4cc10f5 100644
--- a/lib/audioeffects/parametriceq.py
+++ b/lib/audioeffects/parametriceq.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`ParametricEQ` - the Pultec EQP-1A's two low networks and its resonant
 top, with three API 550A proportional-Q bells in the middle.
 
diff --git a/lib/audioeffects/phaser.py b/lib/audioeffects/phaser.py
index e432ce8..4d6f812 100644
--- a/lib/audioeffects/phaser.py
+++ b/lib/audioeffects/phaser.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Phaser` - four first-order all-pass stages swept the way a Phase 90 is.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's
diff --git a/lib/audioeffects/pingpongdelay.py b/lib/audioeffects/pingpongdelay.py
index cd18356..cb60add 100644
--- a/lib/audioeffects/pingpongdelay.py
+++ b/lib/audioeffects/pingpongdelay.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`PingPongDelay` - repeats that alternate between the speakers.
 
 The player's text is the class docstring, and every sentence in it that
diff --git a/lib/audioeffects/pitchshifter.py b/lib/audioeffects/pitchshifter.py
index 8f0f758..e15653e 100644
--- a/lib/audioeffects/pitchshifter.py
+++ b/lib/audioeffects/pitchshifter.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`PitchShifter` - a fixed-interval splice pitch shifter.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's
diff --git a/lib/audioeffects/rack.py b/lib/audioeffects/rack.py
index ac674a6..f24d0ab 100644
--- a/lib/audioeffects/rack.py
+++ b/lib/audioeffects/rack.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Rack` - a serial chain of effects, as a single effect.
 
 The player's text is the class docstring, and the sentences in it that make
diff --git a/lib/audioeffects/reverb.py b/lib/audioeffects/reverb.py
index 634c83e..de7ff85 100644
--- a/lib/audioeffects/reverb.py
+++ b/lib/audioeffects/reverb.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Reverb` - Dattorro's plate network, cut four ways: a plate, a room, a
 chamber and a hall.
 
diff --git a/lib/audioeffects/ringmod.py b/lib/audioeffects/ringmod.py
index 73b1d3c..8d19802 100644
--- a/lib/audioeffects/ringmod.py
+++ b/lib/audioeffects/ringmod.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`RingMod` - Bode multiplier-type ring, with a switching character.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's
diff --git a/lib/audioeffects/saturation.py b/lib/audioeffects/saturation.py
index 029c750..f500fcc 100644
--- a/lib/audioeffects/saturation.py
+++ b/lib/audioeffects/saturation.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Saturation` - a tube stage, a tape chain, or transformer iron.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's
diff --git a/lib/audioeffects/shimmerhall.py b/lib/audioeffects/shimmerhall.py
index 4870bd1..2b9f160 100644
--- a/lib/audioeffects/shimmerhall.py
+++ b/lib/audioeffects/shimmerhall.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`ShimmerHall` - a hall that rings an octave above what you play.
 
 You play into a hall, and a pitch shifter beside it makes the tail ring at
diff --git a/lib/audioeffects/slapbackdelay.py b/lib/audioeffects/slapbackdelay.py
index b898022..5a45efc 100644
--- a/lib/audioeffects/slapbackdelay.py
+++ b/lib/audioeffects/slapbackdelay.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`SlapbackDelay` - one tape repeat after the dry, in mono: the Sun Studio slap.
 
 The player's text is the class docstring, and every sentence in it that
diff --git a/lib/audioeffects/stereowidener.py b/lib/audioeffects/stereowidener.py
index 59f0fbd..ab2c876 100644
--- a/lib/audioeffects/stereowidener.py
+++ b/lib/audioeffects/stereowidener.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`StereoWidener` - a stereo widener with Haas and Mid/Side characters.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's
diff --git a/lib/audioeffects/tapedelay.py b/lib/audioeffects/tapedelay.py
index 8bc8f02..f570597 100644
--- a/lib/audioeffects/tapedelay.py
+++ b/lib/audioeffects/tapedelay.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`TapeDelay` - a tape echo with two transports: the Roland RE-201's motor
 and the Maestro EP-3's sliding head.
 
diff --git a/lib/audioeffects/transientshaper.py b/lib/audioeffects/transientshaper.py
index d53ff65..15f00a3 100644
--- a/lib/audioeffects/transientshaper.py
+++ b/lib/audioeffects/transientshaper.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`TransientShaper` - transient shaping in the SPL Transient Designer's shape.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's
diff --git a/lib/audioeffects/tremolo.py b/lib/audioeffects/tremolo.py
index 7b23e47..ddc5607 100644
--- a/lib/audioeffects/tremolo.py
+++ b/lib/audioeffects/tremolo.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Tremolo` — Fender bias-vary and optical characters on one Multiply.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's
diff --git a/lib/audioeffects/vibrato.py b/lib/audioeffects/vibrato.py
index 46831a5..8a7a1c3 100644
--- a/lib/audioeffects/vibrato.py
+++ b/lib/audioeffects/vibrato.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Vibrato` - a clock-modulated bucket-brigade line, wet alone.
 
 The player's text is the class docstring; the `CLAIMS` table in the class's
diff --git a/manifest.py b/manifest.py
index e0d92f6..9c44f8e 100644
--- a/manifest.py
+++ b/manifest.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """Freeze audioeffects into a MicroPython firmware.
 
 A firmware build that names audioeffects takes this file.
diff --git a/tests/airspace_plants.py b/tests/airspace_plants.py
index b9cf629..dab1342 100644
--- a/tests/airspace_plants.py
+++ b/tests/airspace_plants.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`AirSpace`'s planted faults, one or two per trait of its card.
 
 Kept apart from the test module, and free of numpy and unittest, so the
diff --git a/tests/conftest.py b/tests/conftest.py
index af6afc7..901578a 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """pytest's view of the suite, for CI's parallel run (pytest-xdist).
 
 The tests are plain unittest and `python -m unittest discover -s tests`
diff --git a/tests/parity/effects_library_smoke.py b/tests/parity/effects_library_smoke.py
index cc241bf..330b4f1 100644
--- a/tests/parity/effects_library_smoke.py
+++ b/tests/parity/effects_library_smoke.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """Every audioeffects class builds through the factory and renders, on
 whichever interpreter runs this.
 
diff --git a/tests/support/controls_table.py b/tests/support/controls_table.py
index a3a066c..33d76ca 100644
--- a/tests/support/controls_table.py
+++ b/tests/support/controls_table.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """Every effect's knobs, their spans and its patches, built from the classes.
 
 `docs/reference/effect-controls.md` publishes these tables so someone can
diff --git a/tests/support/effects_measure.py b/tests/support/effects_measure.py
index b44a05a..79c3464 100644
--- a/tests/support/effects_measure.py
+++ b/tests/support/effects_measure.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """What the audioeffects test modules build and measure with.
 
 The effects suite is split by what retires each part. The contract-level
diff --git a/tests/support/kit.py b/tests/support/kit.py
index e7ef4d4..3809253 100644
--- a/tests/support/kit.py
+++ b/tests/support/kit.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """The effects kit: nine mechanical checks on one class, no model in the loop.
 
     python tests/support/kit.py DigitalDelay [--only tail,plants,...]
diff --git a/tests/support/kit_args.py b/tests/support/kit_args.py
index 846698c..1169250 100644
--- a/tests/support/kit_args.py
+++ b/tests/support/kit_args.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """Readback and arguments: what the control surface does with the values a
 host can hand it.
 
diff --git a/tests/support/kit_ceiling.py b/tests/support/kit_ceiling.py
index 8c48bad..9e8f8b4 100644
--- a/tests/support/kit_ceiling.py
+++ b/tests/support/kit_ceiling.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """The input ceiling: rendered at the level the class says it is clean at,
 on the worst material, the output never wraps, never sits on a rail the
 input was not on, and never goes silent while the input plays.
diff --git a/tests/support/kit_claims.py b/tests/support/kit_claims.py
index bfa6cdb..6bb87f8 100644
--- a/tests/support/kit_claims.py
+++ b/tests/support/kit_claims.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """The claims check: every sentence in a class's docstring that makes a
 claim is tied to a test, and that test exists and passes.
 
diff --git a/tests/support/kit_common.py b/tests/support/kit_common.py
index 257f751..619ed28 100644
--- a/tests/support/kit_common.py
+++ b/tests/support/kit_common.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """What the effects kit's checks share: material, rendering, the printed
 cell and the table of declared exceptions.
 
diff --git a/tests/support/kit_faults.py b/tests/support/kit_faults.py
index 6067967..1aa6cfa 100644
--- a/tests/support/kit_faults.py
+++ b/tests/support/kit_faults.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """The planted faults for the measurement kit's first ten measurements.
 
 The discipline these are held to: a fault that does not turn its own
diff --git a/tests/support/kit_fresh.py b/tests/support/kit_fresh.py
index 2cc2f5b..7bbb42d 100644
--- a/tests/support/kit_fresh.py
+++ b/tests/support/kit_fresh.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """Reset equals fresh: after `reset()`, from every patch, a class renders
 byte for byte what a fresh instance at patch 0 renders.
 
diff --git a/tests/support/kit_levels.py b/tests/support/kit_levels.py
index ad9ab20..738ae62 100644
--- a/tests/support/kit_levels.py
+++ b/tests/support/kit_levels.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """The level pass: real material at three levels, so a trait measured on
 sines at one level is read again where the input level moves it.
 
diff --git a/tests/support/kit_nogb.py b/tests/support/kit_nogb.py
index 6b6dd0c..9c96d26 100644
--- a/tests/support/kit_nogb.py
+++ b/tests/support/kit_nogb.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """A board build with no `audiocore.get_buffer`.
 
 CircuitPython's default board builds compile `audiocore.get_buffer` out
diff --git a/tests/support/kit_options.py b/tests/support/kit_options.py
index 38f8a87..cabd0b7 100644
--- a/tests/support/kit_options.py
+++ b/tests/support/kit_options.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """The constructor options the kit builds a class with.
 
 Most classes are run at their defaults ({}). A class whose defaults are
diff --git a/tests/support/kit_paperwork.py b/tests/support/kit_paperwork.py
index beb9094..dfc4b98 100644
--- a/tests/support/kit_paperwork.py
+++ b/tests/support/kit_paperwork.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """The paperwork check: the class has a CHANGELOG line, and every source
 citation in its module resolves against the audiodsp pin.
 
diff --git a/tests/support/kit_planted.py b/tests/support/kit_planted.py
index a2329ed..70842d0 100644
--- a/tests/support/kit_planted.py
+++ b/tests/support/kit_planted.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """The kit's planted faults: tiny components that each break one thing a
 kit check measures, beside the controls that break nothing.
 
diff --git a/tests/support/kit_plants.py b/tests/support/kit_plants.py
index 326c26a..e30524d 100644
--- a/tests/support/kit_plants.py
+++ b/tests/support/kit_plants.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """Plant validity: each planted fault a class's tests use differs from the
 clean class at the defaults, and no knob position and no patch of the
 clean class renders what the plant renders.
diff --git a/tests/support/kit_player.py b/tests/support/kit_player.py
index bf13140..7e32635 100644
--- a/tests/support/kit_player.py
+++ b/tests/support/kit_player.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """The player's text against its `CLAIMS` table, and the two readings every
 class's table leans on: latency and the modules it needs.
 
diff --git a/tests/support/kit_probes.py b/tests/support/kit_probes.py
index 29fc270..7b9aea1 100644
--- a/tests/support/kit_probes.py
+++ b/tests/support/kit_probes.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """Probe material and a render loop for the measurement kit's fault battery.
 
 Two things live here, both deliberately small:
diff --git a/tests/support/kit_tail.py b/tests/support/kit_tail.py
index 5b86c5e..77a8b15 100644
--- a/tests/support/kit_tail.py
+++ b/tests/support/kit_tail.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """The tail harness: the output reaches exact zero inside the tail the class
 reports, read after every control event, on a DC step and on low bursts.
 
diff --git a/tests/support/lifecycle.py b/tests/support/lifecycle.py
index 01122ff..7d21cd2 100644
--- a/tests/support/lifecycle.py
+++ b/tests/support/lifecycle.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """The shared lifecycle matrix for audioeffects classes.
 
 One fixed set of lifecycle EVENTS (reset, a host reset of the output,
diff --git a/tests/support/lifecycle_known.py b/tests/support/lifecycle_known.py
index 763645a..0e64620 100644
--- a/tests/support/lifecycle_known.py
+++ b/tests/support/lifecycle_known.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """What is red in the lifecycle matrix today, class by class: the rows
 `tests/test_lifecycle_matrix.py` holds as KNOWN_RED.
 
diff --git a/tests/support/node_matrix.py b/tests/support/node_matrix.py
index 698d654..74b1a91 100644
--- a/tests/support/node_matrix.py
+++ b/tests/support/node_matrix.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """The lifecycle matrix on audiodsp nodes, before any class is built on them.
 
 `lifecycle.py` judges effect classes. This module wraps each node a phase
diff --git a/tests/support/stale_blocks.py b/tests/support/stale_blocks.py
index f000061..ecfa95d 100644
--- a/tests/support/stale_blocks.py
+++ b/tests/support/stale_blocks.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """The stale-block measurement, shared by the ten classes' tests
 (audiocomponents#113).
 
diff --git a/tests/support/tail_ring.py b/tests/support/tail_ring.py
index a51e91f..291125b 100644
--- a/tests/support/tail_ring.py
+++ b/tests/support/tail_ring.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """How long a class rings after its input stops, against what it declares
 (audiocomponents#114).
 
diff --git a/tests/test_audio_component_api.py b/tests/test_audio_component_api.py
index cbd87dc..390736c 100644
--- a/tests/test_audio_component_api.py
+++ b/tests/test_audio_component_api.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 import array
 import math
 import sys
diff --git a/tests/test_bypass_return.py b/tests/test_bypass_return.py
index 84e9d58..7d44827 100644
--- a/tests/test_bypass_return.py
+++ b/tests/test_bypass_return.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """Mix back up from 0 plays nothing from before (Phase 7, step 7f, F3).
 
 At Mix 0 the host reads the source itself, so whatever the node at the head
diff --git a/tests/test_catalogue.py b/tests/test_catalogue.py
index d89a301..a651955 100644
--- a/tests/test_catalogue.py
+++ b/tests/test_catalogue.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """The effects catalogue: what `audioeffects` serves and how `create()`
 finds it.
 
diff --git a/tests/test_component_foundation.py b/tests/test_component_foundation.py
index 5a0716f..c1e7435 100644
--- a/tests/test_component_foundation.py
+++ b/tests/test_component_foundation.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """The Phase 2 construction module, held to what roadmap section 3 asks of it.
 
 Every check that can go wrong quietly is paired with a **planted fault**: a
diff --git a/tests/test_cpython_effects_airspace.py b/tests/test_cpython_effects_airspace.py
index 6f92d9a..c9cd3ac 100644
--- a/tests/test_cpython_effects_airspace.py
+++ b/tests/test_cpython_effects_airspace.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`AirSpace`'s own trait and planted-fault tests.
 
 The card (frozen 2026-10-12) has five traits, T1-T5. Each is measured here
diff --git a/tests/test_cpython_effects_analogdelay.py b/tests/test_cpython_effects_analogdelay.py
index a3e6710..6fd17ac 100644
--- a/tests/test_cpython_effects_analogdelay.py
+++ b/tests/test_cpython_effects_analogdelay.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`AnalogDelay`'s own invariant and planted-fault tests.
 
 The dossier was frozen at the Station A critique revision, with the
diff --git a/tests/test_cpython_effects_autopan.py b/tests/test_cpython_effects_autopan.py
index 0b35857..81b0f31 100644
--- a/tests/test_cpython_effects_autopan.py
+++ b/tests/test_cpython_effects_autopan.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`AutoPan`'s invariant and planted-fault tests (effects Phase 3).
 
 Traits
diff --git a/tests/test_cpython_effects_bandpass.py b/tests/test_cpython_effects_bandpass.py
index 6dae9ea..10bc392 100644
--- a/tests/test_cpython_effects_bandpass.py
+++ b/tests/test_cpython_effects_bandpass.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`BandPass`'s own invariant and planted-fault tests (effects Phase 2).
 
 The dossier's traits were frozen 2026-09-07, and this file's numbers are
diff --git a/tests/test_cpython_effects_bitcrusher.py b/tests/test_cpython_effects_bitcrusher.py
index 78d95a0..d90a38e 100644
--- a/tests/test_cpython_effects_bitcrusher.py
+++ b/tests/test_cpython_effects_bitcrusher.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Bitcrusher`'s own invariant and planted-fault tests.
 
 Exhaustive rate coverage lives in the evidence pack, not here.
diff --git a/tests/test_cpython_effects_cabinetsim.py b/tests/test_cpython_effects_cabinetsim.py
index 0b8e1d4..6fba89b 100644
--- a/tests/test_cpython_effects_cabinetsim.py
+++ b/tests/test_cpython_effects_cabinetsim.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`CabinetSim`'s own invariant and planted-fault tests.
 
 The dossier was frozen
diff --git a/tests/test_cpython_effects_chorus.py b/tests/test_cpython_effects_chorus.py
index 5baf12c..9fce556 100644
--- a/tests/test_cpython_effects_chorus.py
+++ b/tests/test_cpython_effects_chorus.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Chorus`'s own invariant and planted-fault tests.
 
 The dossier's Tier 2
diff --git a/tests/test_cpython_effects_combfilter.py b/tests/test_cpython_effects_combfilter.py
index 1eaef1e..effe4d7 100644
--- a/tests/test_cpython_effects_combfilter.py
+++ b/tests/test_cpython_effects_combfilter.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`CombFilter`'s own invariant and planted-fault tests.
 
 The Tier 2 traits are measured in the evidence pack with the kit; what is
diff --git a/tests/test_cpython_effects_compressor.py b/tests/test_cpython_effects_compressor.py
index bd1541d..cbde297 100644
--- a/tests/test_cpython_effects_compressor.py
+++ b/tests/test_cpython_effects_compressor.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Compressor`'s own planted-fault checks, in the suite.
 
 The class gate asks each rebuilt class for its invariant and planted-fault
diff --git a/tests/test_cpython_effects_convolutionreverb.py b/tests/test_cpython_effects_convolutionreverb.py
index 746e4ea..10b73d9 100644
--- a/tests/test_cpython_effects_convolutionreverb.py
+++ b/tests/test_cpython_effects_convolutionreverb.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`ConvolutionReverb`'s own invariant and planted-fault tests.
 
 The dossier's Tier 2 rows are D1-D6. Each row here is the
diff --git a/tests/test_cpython_effects_deesser.py b/tests/test_cpython_effects_deesser.py
index 636e773..e9236ca 100644
--- a/tests/test_cpython_effects_deesser.py
+++ b/tests/test_cpython_effects_deesser.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`DeEsser`'s own invariant, trait and planted-fault battery.
 
 The class gate asks for two
diff --git a/tests/test_cpython_effects_digitaldelay.py b/tests/test_cpython_effects_digitaldelay.py
index bb3329c..379f3c5 100644
--- a/tests/test_cpython_effects_digitaldelay.py
+++ b/tests/test_cpython_effects_digitaldelay.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`DigitalDelay`'s own invariant and planted-fault tests.
 
 The dossier's Tier 2 rows are T1-T5. Each row here is the
diff --git a/tests/test_cpython_effects_distortion.py b/tests/test_cpython_effects_distortion.py
index 776e682..2e695eb 100644
--- a/tests/test_cpython_effects_distortion.py
+++ b/tests/test_cpython_effects_distortion.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Distortion`'s own invariant and planted-fault tests.
 
 Exhaustive rate coverage lives in the evidence pack. This file stays at
diff --git a/tests/test_cpython_effects_dynamiceq.py b/tests/test_cpython_effects_dynamiceq.py
index b3b83c9..a2560d7 100644
--- a/tests/test_cpython_effects_dynamiceq.py
+++ b/tests/test_cpython_effects_dynamiceq.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`DynamicEQ`'s own invariant, trait and planted-fault battery.
 
 The class gate asks for two
diff --git a/tests/test_cpython_effects_dynamics_eq.py b/tests/test_cpython_effects_dynamics_eq.py
index 1db327d..67e2375 100644
--- a/tests/test_cpython_effects_dynamics_eq.py
+++ b/tests/test_cpython_effects_dynamics_eq.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """What the dynamics and EQ classes do to a signal today.
 
 Where a bell lands, what a corner costs, whether lookahead catches the
diff --git a/tests/test_cpython_effects_exciter.py b/tests/test_cpython_effects_exciter.py
index 4f199a2..db2536b 100644
--- a/tests/test_cpython_effects_exciter.py
+++ b/tests/test_cpython_effects_exciter.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Exciter`'s own invariant and planted-fault tests.
 
 The dossier was frozen
diff --git a/tests/test_cpython_effects_expander.py b/tests/test_cpython_effects_expander.py
index 46e468d..f56ddd8 100644
--- a/tests/test_cpython_effects_expander.py
+++ b/tests/test_cpython_effects_expander.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Expander`'s own planted-fault tests, and the two checks that say a fault
 and a reading are worth citing at all.
 
diff --git a/tests/test_cpython_effects_flanger.py b/tests/test_cpython_effects_flanger.py
index 33badf6..e08111e 100644
--- a/tests/test_cpython_effects_flanger.py
+++ b/tests/test_cpython_effects_flanger.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Flanger`'s trait and planted-fault tests.
 
 Six traits, T1 to T6 (the card's), each with its measurement run over the
diff --git a/tests/test_cpython_effects_fuzz.py b/tests/test_cpython_effects_fuzz.py
index 37535f9..54d3267 100644
--- a/tests/test_cpython_effects_fuzz.py
+++ b/tests/test_cpython_effects_fuzz.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Fuzz`'s own invariant and planted-fault tests.
 
 The dossier was frozen
diff --git a/tests/test_cpython_effects_graphiceq.py b/tests/test_cpython_effects_graphiceq.py
index 1020690..ba58a45 100644
--- a/tests/test_cpython_effects_graphiceq.py
+++ b/tests/test_cpython_effects_graphiceq.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`GraphicEQ`, rebuilt: its Tier 1 invariants and its own planted faults.
 
 This file is the part of the evidence pack that
diff --git a/tests/test_cpython_effects_harmonizer.py b/tests/test_cpython_effects_harmonizer.py
index 3697d6c..f454d08 100644
--- a/tests/test_cpython_effects_harmonizer.py
+++ b/tests/test_cpython_effects_harmonizer.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Harmonizer`'s trait and planted-fault tests.
 
 Six traits, T1 to T6, each with its measurement run over the span listed
diff --git a/tests/test_cpython_effects_highpass.py b/tests/test_cpython_effects_highpass.py
index 0dc7201..7a944f9 100644
--- a/tests/test_cpython_effects_highpass.py
+++ b/tests/test_cpython_effects_highpass.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`HighPass`'s own invariant and planted-fault tests.
 
 The class's Tier 2 traits are measured in the evidence pack with the kit;
diff --git a/tests/test_cpython_effects_ladderfilter.py b/tests/test_cpython_effects_ladderfilter.py
index 7fdd2fe..b873be5 100644
--- a/tests/test_cpython_effects_ladderfilter.py
+++ b/tests/test_cpython_effects_ladderfilter.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`LadderFilter`'s input ceiling and the class docstring's claims, each
 tied to its test by the `CLAIMS` table.
 
diff --git a/tests/test_cpython_effects_library.py b/tests/test_cpython_effects_library.py
index ca7e7ab..7b7cc92 100644
--- a/tests/test_cpython_effects_library.py
+++ b/tests/test_cpython_effects_library.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """The contract every class in `audioeffects.ALL` is held to.
 
 Exports and metadata, the factory and the rate it owns, building and
diff --git a/tests/test_cpython_effects_limiter.py b/tests/test_cpython_effects_limiter.py
index b5aeed3..fe2c6fa 100644
--- a/tests/test_cpython_effects_limiter.py
+++ b/tests/test_cpython_effects_limiter.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Limiter`'s own invariant and planted-fault tests.
 
 The dossier's Tier 2 rows are L1..L7 and each
diff --git a/tests/test_cpython_effects_lowpass.py b/tests/test_cpython_effects_lowpass.py
index e2f64c3..8c4cfb6 100644
--- a/tests/test_cpython_effects_lowpass.py
+++ b/tests/test_cpython_effects_lowpass.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`LowPass`'s own invariant and planted-fault tests.
 
 The class's Tier 2 traits are measured in the evidence pack with the kit;
diff --git a/tests/test_cpython_effects_modulation.py b/tests/test_cpython_effects_modulation.py
index 59f2a9a..a5d4196 100644
--- a/tests/test_cpython_effects_modulation.py
+++ b/tests/test_cpython_effects_modulation.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """What the modulation classes do to a signal today.
 
 Ring modulation is the one modulation trait the old surface pinned: the
diff --git a/tests/test_cpython_effects_multiband.py b/tests/test_cpython_effects_multiband.py
index 529bb15..9cfd822 100644
--- a/tests/test_cpython_effects_multiband.py
+++ b/tests/test_cpython_effects_multiband.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`MultibandCompressor`'s own invariant and planted-fault tests.
 
 The dossier's Tier 2 rows are
diff --git a/tests/test_cpython_effects_multitapdelay.py b/tests/test_cpython_effects_multitapdelay.py
index d53f584..c99a242 100644
--- a/tests/test_cpython_effects_multitapdelay.py
+++ b/tests/test_cpython_effects_multitapdelay.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`MultiTapDelay`'s own invariant and planted-fault tests.
 
 The dossier, frozen at the Station A revision, has Tier 2 rows
diff --git a/tests/test_cpython_effects_notch.py b/tests/test_cpython_effects_notch.py
index 3590b05..7297a91 100644
--- a/tests/test_cpython_effects_notch.py
+++ b/tests/test_cpython_effects_notch.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Notch`'s own invariant and planted-fault tests.
 
 The class's Tier 2 traits are measured in the evidence pack with the kit;
diff --git a/tests/test_cpython_effects_octaver.py b/tests/test_cpython_effects_octaver.py
index b6448d3..880e21b 100644
--- a/tests/test_cpython_effects_octaver.py
+++ b/tests/test_cpython_effects_octaver.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Octaver`'s trait and planted-fault tests.
 
 Six traits, T1 to T6, each with its measurement run over the span listed
diff --git a/tests/test_cpython_effects_overdrive.py b/tests/test_cpython_effects_overdrive.py
index f45aabc..9be1879 100644
--- a/tests/test_cpython_effects_overdrive.py
+++ b/tests/test_cpython_effects_overdrive.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Overdrive`'s own invariant and planted-fault tests.
 
 The dossier was frozen
diff --git a/tests/test_cpython_effects_parametriceq.py b/tests/test_cpython_effects_parametriceq.py
index 1758bbb..35e3439 100644
--- a/tests/test_cpython_effects_parametriceq.py
+++ b/tests/test_cpython_effects_parametriceq.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`ParametricEQ`'s own invariant and planted-fault tests.
 
 The class's Tier 2 traits are measured in the evidence pack with the kit;
diff --git a/tests/test_cpython_effects_phaser.py b/tests/test_cpython_effects_phaser.py
index 45042ae..733333b 100644
--- a/tests/test_cpython_effects_phaser.py
+++ b/tests/test_cpython_effects_phaser.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Phaser`'s own invariant and planted-fault tests.
 
 The dossier's
diff --git a/tests/test_cpython_effects_pingpongdelay.py b/tests/test_cpython_effects_pingpongdelay.py
index ef26a11..d2e651a 100644
--- a/tests/test_cpython_effects_pingpongdelay.py
+++ b/tests/test_cpython_effects_pingpongdelay.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`PingPongDelay`'s own invariant and planted-fault tests.
 
 The dossier, frozen at the Station A critique's re-freeze, has Tier 2
diff --git a/tests/test_cpython_effects_pitchshifter.py b/tests/test_cpython_effects_pitchshifter.py
index 01f2414..28aa863 100644
--- a/tests/test_cpython_effects_pitchshifter.py
+++ b/tests/test_cpython_effects_pitchshifter.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`PitchShifter`'s trait and planted-fault tests.
 
 Four traits: T1 the interval, T2 the splice's arrivals, T3 the repeats
diff --git a/tests/test_cpython_effects_rack.py b/tests/test_cpython_effects_rack.py
index 3718c49..3e619fd 100644
--- a/tests/test_cpython_effects_rack.py
+++ b/tests/test_cpython_effects_rack.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """The rebuilt `Rack`: a serial chain of effects as one effect.
 
 One test per trait of the class card (T1-T6), each shown red on the card's
diff --git a/tests/test_cpython_effects_reverb.py b/tests/test_cpython_effects_reverb.py
index a1731ca..fcf3223 100644
--- a/tests/test_cpython_effects_reverb.py
+++ b/tests/test_cpython_effects_reverb.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Reverb`'s own invariant and planted-fault tests.
 
 The dossier's
diff --git a/tests/test_cpython_effects_ringmod.py b/tests/test_cpython_effects_ringmod.py
index 3689639..ba17b58 100644
--- a/tests/test_cpython_effects_ringmod.py
+++ b/tests/test_cpython_effects_ringmod.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`RingMod`'s own invariant and planted-fault tests.
 
 Exhaustive rates live in the evidence pack, not in this file.
diff --git a/tests/test_cpython_effects_saturation.py b/tests/test_cpython_effects_saturation.py
index 47c39fe..6674200 100644
--- a/tests/test_cpython_effects_saturation.py
+++ b/tests/test_cpython_effects_saturation.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Saturation`'s own invariant and planted-fault tests.
 
 The dossier was frozen
diff --git a/tests/test_cpython_effects_shimmerhall.py b/tests/test_cpython_effects_shimmerhall.py
index d33fe8f..d016b83 100644
--- a/tests/test_cpython_effects_shimmerhall.py
+++ b/tests/test_cpython_effects_shimmerhall.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`ShimmerHall`'s trait and planted-fault tests.
 
 Six traits: T1 the Bloom stagger, T2 the interval, T3 the octaves climbing
diff --git a/tests/test_cpython_effects_slapbackdelay.py b/tests/test_cpython_effects_slapbackdelay.py
index 69f19a4..9b7128b 100644
--- a/tests/test_cpython_effects_slapbackdelay.py
+++ b/tests/test_cpython_effects_slapbackdelay.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`SlapbackDelay`'s own invariant and planted-fault tests.
 
 The dossier, frozen at the Station A critique's re-freeze, has Tier 2
diff --git a/tests/test_cpython_effects_stereowidener.py b/tests/test_cpython_effects_stereowidener.py
index eff3242..8cef080 100644
--- a/tests/test_cpython_effects_stereowidener.py
+++ b/tests/test_cpython_effects_stereowidener.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`StereoWidener`'s trait and planted-fault tests.
 
 Six traits: H1-H3 for Haas, M1-M2 for Mid/Side, W for the wire. Each has
diff --git a/tests/test_cpython_effects_tapedelay.py b/tests/test_cpython_effects_tapedelay.py
index d997f46..ca62ed5 100644
--- a/tests/test_cpython_effects_tapedelay.py
+++ b/tests/test_cpython_effects_tapedelay.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`TapeDelay`'s own invariant and planted-fault tests.
 
 The dossier's Tier 2
diff --git a/tests/test_cpython_effects_transientshaper.py b/tests/test_cpython_effects_transientshaper.py
index 478e11c..41beea9 100644
--- a/tests/test_cpython_effects_transientshaper.py
+++ b/tests/test_cpython_effects_transientshaper.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`TransientShaper`'s own invariant and planted-fault tests (Phase 2).
 
 The class gate asks for these beside the contract-level suite: a fault that
diff --git a/tests/test_cpython_effects_tremolo.py b/tests/test_cpython_effects_tremolo.py
index 1805c37..e769cef 100644
--- a/tests/test_cpython_effects_tremolo.py
+++ b/tests/test_cpython_effects_tremolo.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Tremolo`'s own invariant and planted-fault tests.
 
 Exhaustive rates live in the evidence pack, not in this file.
diff --git a/tests/test_cpython_effects_vibrato.py b/tests/test_cpython_effects_vibrato.py
index 3f2e857..8f840c0 100644
--- a/tests/test_cpython_effects_vibrato.py
+++ b/tests/test_cpython_effects_vibrato.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`Vibrato`'s own invariant and planted-fault tests.
 
 The dossier's Tier 2
diff --git a/tests/test_curve_tables.py b/tests/test_curve_tables.py
index f9f3f29..40a695b 100644
--- a/tests/test_curve_tables.py
+++ b/tests/test_curve_tables.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """Every int16 curve table in the library, held to three bars.
 
 A `Waveshaper` curve is a lookup table, and a lookup table can be wrong in
diff --git a/tests/test_effect_kit.py b/tests/test_effect_kit.py
index 0c603dc..110fb44 100644
--- a/tests/test_effect_kit.py
+++ b/tests/test_effect_kit.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """The measurement kit's planted-fault battery, measurements 1-10.
 
 Every planted fault lands as a test here, in `test_rig_comparator.py`'s shape -
diff --git a/tests/test_effect_kit_11_20.py b/tests/test_effect_kit_11_20.py
index 35a689d..74b56b8 100644
--- a/tests/test_effect_kit_11_20.py
+++ b/tests/test_effect_kit_11_20.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """The planted-fault battery for measurements 11-20 of the kit spec.
 
 A measurement whose planted-fault run
diff --git a/tests/test_effect_kit_graph.py b/tests/test_effect_kit_graph.py
index a7aec4b..b2d9175 100644
--- a/tests/test_effect_kit_graph.py
+++ b/tests/test_effect_kit_graph.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """The kit's two graph guards, each with its planted fault and its control.
 
 audiocomponents#78 read 70 dB of measurement floor off a wet-branch
diff --git a/tests/test_effect_kit_sweep.py b/tests/test_effect_kit_sweep.py
index 9958177..92cf3de 100644
--- a/tests/test_effect_kit_sweep.py
+++ b/tests/test_effect_kit_sweep.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """The sweep driver's battery: a measurement run over the span its trait
 quantifies over, not at a point inside it.
 
diff --git a/tests/test_first_pull.py b/tests/test_first_pull.py
index e28f08d..16cbdcd 100644
--- a/tests/test_first_pull.py
+++ b/tests/test_first_pull.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """Settings changed between construction and the first pull land as a fresh
 instance at those settings would (Phase 7, step 7f).
 
diff --git a/tests/test_kit.py b/tests/test_kit.py
index 22057c8..4ea5864 100644
--- a/tests/test_kit.py
+++ b/tests/test_kit.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """The effects kit's own proof: every check goes red on a planted fault and
 its control is green on the same cell, and a class that does nothing at
 all is never read as a pass.
diff --git a/tests/test_lifecycle_matrix.py b/tests/test_lifecycle_matrix.py
index bd32d44..203a7bb 100644
--- a/tests/test_lifecycle_matrix.py
+++ b/tests/test_lifecycle_matrix.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """The lifecycle matrix (`tests/support/lifecycle.py`) on every effect
 class the package serves (`audioeffects.ALL`, all 45), on CPython and on the
 two native interpreters.
diff --git a/tests/test_measure_effect_cost.py b/tests/test_measure_effect_cost.py
index 61471fc..bac988d 100644
--- a/tests/test_measure_effect_cost.py
+++ b/tests/test_measure_effect_cost.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """The cost tool's Phase 5 additions (housekeeping, 2026-09-28).
 
 `tools/measure_effect_cost.py` is a board tool and its timings are not
diff --git a/tests/test_metadata_contract.py b/tests/test_metadata_contract.py
index f28ad52..8e56893 100644
--- a/tests/test_metadata_contract.py
+++ b/tests/test_metadata_contract.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 import pathlib
 import unittest
 from types import SimpleNamespace
diff --git a/tests/test_nan_options.py b/tests/test_nan_options.py
index 5ae3965..fa2e100 100644
--- a/tests/test_nan_options.py
+++ b/tests/test_nan_options.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """A NaN constructor option is the option left out, on every effect.
 
 The API reference promises it for macros (NaN is the bottom stop) and each
diff --git a/tests/test_node_matrix.py b/tests/test_node_matrix.py
index eadfb93..81df811 100644
--- a/tests/test_node_matrix.py
+++ b/tests/test_node_matrix.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """The lifecycle matrix on the audiodsp nodes the effects stand on
 (`tests/support/node_matrix.py`), on CPython and on the two native
 interpreters.
diff --git a/tests/test_noisegate.py b/tests/test_noisegate.py
index 9cabecd..c3e342c 100644
--- a/tests/test_noisegate.py
+++ b/tests/test_noisegate.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """`NoiseGate`'s own invariants and its planted faults (Phase 2, Drawmer
 DS201).
 
diff --git a/tests/test_panel_view.py b/tests/test_panel_view.py
index 45581e3..bb72705 100644
--- a/tests/test_panel_view.py
+++ b/tests/test_panel_view.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """The effect panel's adapter, on CPython with no LVGL and no audiodsp.
 
 A fake effect stands in for a rebuilt class: the same declarations
diff --git a/tests/test_portability_tier.py b/tests/test_portability_tier.py
index 4b59096..3319a66 100644
--- a/tests/test_portability_tier.py
+++ b/tests/test_portability_tier.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """The portability tier, tested where it can be tested.
 
 Roadmap section 3 gives every class one of two tiers:
diff --git a/tests/test_reset_is_fresh.py b/tests/test_reset_is_fresh.py
index e0f43f9..f3e3b0c 100644
--- a/tests/test_reset_is_fresh.py
+++ b/tests/test_reset_is_fresh.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """A reset comes back as a fresh instance at patch 0, for the classes the
 kit's fresh check found red when it was built (Phase 7, step 7d).
 
diff --git a/tests/test_reset_keeps_source_frames.py b/tests/test_reset_keeps_source_frames.py
index 3f42c1b..5e1e9ab 100644
--- a/tests/test_reset_keeps_source_frames.py
+++ b/tests/test_reset_keeps_source_frames.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """A reset part-way through a source buffer keeps the frames the graph took.
 
 A host that hands an effect 100-frame buffers and resets it after twelve
diff --git a/tests/test_tempo_follow.py b/tests/test_tempo_follow.py
index c7ea12a..28d14a9 100644
--- a/tests/test_tempo_follow.py
+++ b/tests/test_tempo_follow.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """A synced class follows a host tempo change without a control moving
 (audiocomponents#118).
 
diff --git a/tools/compressor_evidence.py b/tools/compressor_evidence.py
index 1c8fd52..376ee72 100644
--- a/tools/compressor_evidence.py
+++ b/tools/compressor_evidence.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """Station C's measurements for `Compressor`, as one runnable file.
 
 Every table in the class's evidence pack is one case here, so a
diff --git a/tools/curves/bitcrusher_curve.py b/tools/curves/bitcrusher_curve.py
index d15d69e..67fb299 100644
--- a/tools/curves/bitcrusher_curve.py
+++ b/tools/curves/bitcrusher_curve.py
@@ -1,4 +1,8 @@
 #!/usr/bin/env python3
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """SP-1200 12-bit linear DAC staircase for `audioeffects.bitcrusher`.
 
 S1: "The DAC is a standard 12 bit linear device" in complement-offset
diff --git a/tools/curves/distortion_curve.py b/tools/curves/distortion_curve.py
index 348e331..6af15ca 100755
--- a/tools/curves/distortion_curve.py
+++ b/tools/curves/distortion_curve.py
@@ -1,4 +1,8 @@
 #!/usr/bin/env python3
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """Derive Distortion's waveshaper tables from the Rat and DS-1 clipper circuits.
 
 The tables are the static solution of a silicon pair to ground:
diff --git a/tools/curves/exciter_curve.py b/tools/curves/exciter_curve.py
index cf93ea8..80c2e22 100644
--- a/tools/curves/exciter_curve.py
+++ b/tools/curves/exciter_curve.py
@@ -1,4 +1,8 @@
 #!/usr/bin/env python3
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """1N914 one-sided clipper curve for `audioeffects.exciter`.
 
 Derives one normalised Q15 table from the component values of the
diff --git a/tools/curves/fuzz_curve.py b/tools/curves/fuzz_curve.py
index b1ac880..2a63097 100644
--- a/tools/curves/fuzz_curve.py
+++ b/tools/curves/fuzz_curve.py
@@ -1,4 +1,8 @@
 #!/usr/bin/env python3
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """Derive the Fuzz waveshaper tables from the dossier's named values.
 
 Run from the audiocomponents worktree:
diff --git a/tools/curves/overdrive_curve.py b/tools/curves/overdrive_curve.py
index abd8fb4..abb1f4f 100644
--- a/tools/curves/overdrive_curve.py
+++ b/tools/curves/overdrive_curve.py
@@ -1,4 +1,8 @@
 #!/usr/bin/env python3
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """TS808 feedback-diode curve for `audioeffects.overdrive`.
 
 Derives one normalised Q15 table from the circuit values of the
diff --git a/tools/curves/phaser_curve.py b/tools/curves/phaser_curve.py
index 940797a..7941fd6 100644
--- a/tools/curves/phaser_curve.py
+++ b/tools/curves/phaser_curve.py
@@ -1,4 +1,8 @@
 #!/usr/bin/env python3
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """Drive curve for `audioeffects.phaser`.
 
 `Phaser`'s Drive is a cubic soft clip, `y = x - x**3 / 3` over x in ±1 - the
diff --git a/tools/curves/saturation_curve.py b/tools/curves/saturation_curve.py
index fc0d603..f4f537c 100644
--- a/tools/curves/saturation_curve.py
+++ b/tools/curves/saturation_curve.py
@@ -1,4 +1,8 @@
 #!/usr/bin/env python3
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """Derive Saturation waveshaper tables from the dossier's named values.
 
 Run from the audiocomponents worktree:
diff --git a/tools/effect_measurements.py b/tools/effect_measurements.py
index 51401b0..05ac1e1 100644
--- a/tools/effect_measurements.py
+++ b/tools/effect_measurements.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """The measurement kit's first ten measurements, over rendered audio.
 
 The kit specifies twenty measurements. This module implements the first ten -
diff --git a/tools/effect_probes/make_probes.py b/tools/effect_probes/make_probes.py
index b221798..70620a0 100644
--- a/tools/effect_probes/make_probes.py
+++ b/tools/effect_probes/make_probes.py
@@ -1,4 +1,8 @@
 #!/usr/bin/env python3
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """Generate the measurement kit's probe material, once, on CPython.
 
     tools/effect_probes/make_probes.py [--dry-run] [--verify] [--ensure]
diff --git a/tools/measure_effect_cost.py b/tools/measure_effect_cost.py
index 58daa6a..8855d83 100644
--- a/tools/measure_effect_cost.py
+++ b/tools/measure_effect_cost.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """What does ONE effect, or ONE audiodsp node, cost this board per block?
 
     mpftp put -d <port> tools/measure_effect_cost.py /measure_effect_cost.py
diff --git a/tools/phase2_probes/parametriceq_traits.py b/tools/phase2_probes/parametriceq_traits.py
index 2fc8c81..508714f 100644
--- a/tools/phase2_probes/parametriceq_traits.py
+++ b/tools/phase2_probes/parametriceq_traits.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """ParametricEQ's Tier 2 traits, measured with the kit, each beside the
 planted fault of the same kind that has to turn it red.
 
diff --git a/tools/provenance_gate.py b/tools/provenance_gate.py
index 72ab44a..ea38362 100644
--- a/tools/provenance_gate.py
+++ b/tools/provenance_gate.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """Refuse a `bin/` interpreter that does not contain the audiodsp this
 repository's gates are read at.
 
diff --git a/tools/render_effect.py b/tools/render_effect.py
index a24a46f..e6885ad 100644
--- a/tools/render_effect.py
+++ b/tools/render_effect.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """Render one audioeffects class over one probe, on any of the three
 interpreters, and export the WAV plus the FNV digest the measurement kit
 compares.
diff --git a/tools/scoped_tests.py b/tools/scoped_tests.py
index 3d89587..5e5de4d 100755
--- a/tools/scoped_tests.py
+++ b/tools/scoped_tests.py
@@ -1,4 +1,8 @@
 #!/usr/bin/env python3
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """Run the tests that this change can break, and no more.
 
 The full suite renders audio and grows with every rebuilt class. Most changes
diff --git a/tools/spice/ds1/analyze.py b/tools/spice/ds1/analyze.py
index c44f327..44dcd1d 100644
--- a/tools/spice/ds1/analyze.py
+++ b/tools/spice/ds1/analyze.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """Print DS-1 clipper peaks/THD from out/."""
 import csv
 import math
diff --git a/tools/spice/fuzzface/analyze.py b/tools/spice/fuzzface/analyze.py
index 15e5fce..628ef1f 100644
--- a/tools/spice/fuzzface/analyze.py
+++ b/tools/spice/fuzzface/analyze.py
@@ -1,4 +1,8 @@
 #!/usr/bin/env python3
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """THD of the last 10 ms of each Fuzz Face transient."""
 import glob
 import math
diff --git a/tools/spice/rat/analyze.py b/tools/spice/rat/analyze.py
index f459bbe..b236f89 100644
--- a/tools/spice/rat/analyze.py
+++ b/tools/spice/rat/analyze.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """Print clipper peaks/THD and the gain-stage AC peak from out/."""
 import csv
 import math
diff --git a/tools/spice/ts808/analyze.py b/tools/spice/ts808/analyze.py
index 8a9c03d..981c895 100755
--- a/tools/spice/ts808/analyze.py
+++ b/tools/spice/ts808/analyze.py
@@ -1,4 +1,8 @@
 #!/usr/bin/env python3
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """analyze.py -- read the CSVs run.sh left in out/ and print the numbers.
 
 numpy only.  Run with a python that has numpy, e.g.
diff --git a/tools/validate_api.py b/tools/validate_api.py
index cad3f77..2044fb5 100644
--- a/tools/validate_api.py
+++ b/tools/validate_api.py
@@ -1,4 +1,8 @@
 #!/usr/bin/env python3
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """Validate the live audio-component API across the provider catalogue.
 
 This is intentionally a small runtime check rather than an inheritance check:
diff --git a/tools/validate_metadata.py b/tools/validate_metadata.py
index dad77da..a7d4d2c 100644
--- a/tools/validate_metadata.py
+++ b/tools/validate_metadata.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """Validate audio component metadata declared by the audiodsp providers.
 
 This module deliberately uses only the Python standard library.  It is a
diff --git a/tools/wheel_gate.py b/tools/wheel_gate.py
index 8581298..af9df3a 100644
--- a/tools/wheel_gate.py
+++ b/tools/wheel_gate.py
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+
 """Build the package's wheel the way a release does, install it into a clean
 venv, and play it.