diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 5832140..edffb60 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -284,12 +284,18 @@ It goes *below* the older copyright. All copyright lines must stay in chronologi
  **************************************************************************/
 ```
 
-If the edit was AI-assisted, add this line just under the header:
+If the edit was AI-assisted and the file does not already carry the line, add this one just under the header, using the comment character the file already uses:
 
 ```c
-// Some portions generated by Claude Code (Opus 5).
+// Portions of this file were generated with AI assistance.
 ```
 
+The text is fixed. It names no product, model or version, and a file carries at most one of it. If the line is already there, leave it alone: do not add a second, and do not amend it because a different tool or a newer model made this edit.
+
+Attribution for the change itself belongs in the commit's `Assisted-by` trailer, which is dated and attached to the diff it describes. `git log --format='%h %(trailers:key=Assisted-by,valueonly)' -- <path>` is the record of which tools have touched a file; a header line cannot keep that record honest, because the code it names gets rewritten and the line stays.
+
+The AI Disclosure paragraph for new files above is different, and keeps its product and model version: a file is created once, so that record cannot grow.
+
 If you copy an existing file to get started on a new one, treat the result as a new file: use the new-file header, do not carry the old one over.
 
 ### Commit attribution
diff --git a/common/inc/zx_api.h b/common/inc/zx_api.h
index 67906a4..184a7d4 100644
--- a/common/inc/zx_api.h
+++ b/common/inc/zx_api.h
@@ -12,7 +12,7 @@
  *
  * SPDX-License-Identifier: MIT and CC0-1.0
  **************************************************************************/
-// Some portions generated by Claude Code (Opus 5).
+// Portions of this file were generated with AI assistance.
 
 /**************************************************************************/
 /*                                                                        */
diff --git a/core/inc/zx_fault.h b/core/inc/zx_fault.h
index 5f944dc..b89e8dc 100644
--- a/core/inc/zx_fault.h
+++ b/core/inc/zx_fault.h
@@ -12,7 +12,7 @@
  *
  * SPDX-License-Identifier: MIT and CC0-1.0
  **************************************************************************/
-// Some portions generated by Claude Code (Opus 5).
+// Portions of this file were generated with AI assistance.
 
 /**************************************************************************/
 /*                                                                        */
diff --git a/core/src/zx_fault.c b/core/src/zx_fault.c
index 5eb9639..a373d81 100644
--- a/core/src/zx_fault.c
+++ b/core/src/zx_fault.c
@@ -12,7 +12,7 @@
  *
  * SPDX-License-Identifier: MIT and CC0-1.0
  **************************************************************************/
-// Some portions generated by Claude Code (Opus 5).
+// Portions of this file were generated with AI assistance.
 
 /**************************************************************************/
 /*                                                                        */
diff --git a/examples/s32z280_evb/tools/run_zx_probe.gdb b/examples/s32z280_evb/tools/run_zx_probe.gdb
index 2c09834..8b00746 100644
--- a/examples/s32z280_evb/tools/run_zx_probe.gdb
+++ b/examples/s32z280_evb/tools/run_zx_probe.gdb
@@ -1,6 +1,6 @@
 # Copyright (c) 2026 Eclipse ThreadX contributors
 # SPDX-License-Identifier: MIT
-# Some portions generated by Claude Code (Opus 5).
+# Portions of this file were generated with AI assistance.
 #
 # Load the ZoneX stage-2 probe onto the S32Z280-594EVB, run it, and report what
 # memory says about the run.
diff --git a/examples/s32z280_evb/tools/run_zx_probe.sh b/examples/s32z280_evb/tools/run_zx_probe.sh
index ad6a527..018d47b 100755
--- a/examples/s32z280_evb/tools/run_zx_probe.sh
+++ b/examples/s32z280_evb/tools/run_zx_probe.sh
@@ -1,7 +1,7 @@
 #!/bin/bash
 # Copyright (c) 2026 Eclipse ThreadX contributors
 # SPDX-License-Identifier: MIT
-# Some portions generated by Claude Code (Opus 5).
+# Portions of this file were generated with AI assistance.
 #
 # Run the ZoneX stage-2 probe on the S32Z280-594EVB and capture the evidence:
 # the console log and the fault registers.
diff --git a/platform/cortex_r52/inc/zx_port.h b/platform/cortex_r52/inc/zx_port.h
index cfaad70..161d66e 100644
--- a/platform/cortex_r52/inc/zx_port.h
+++ b/platform/cortex_r52/inc/zx_port.h
@@ -12,7 +12,7 @@
  *
  * SPDX-License-Identifier: MIT and CC0-1.0
  **************************************************************************/
-// Some portions generated by Claude Code (Opus 5).
+// Portions of this file were generated with AI assistance.
 
 /**************************************************************************/
 /*                                                                        */
diff --git a/platform/cortex_r52/src/zx_console.c b/platform/cortex_r52/src/zx_console.c
index 4e8959e..9bd3ba3 100644
--- a/platform/cortex_r52/src/zx_console.c
+++ b/platform/cortex_r52/src/zx_console.c
@@ -12,7 +12,7 @@
  *
  * SPDX-License-Identifier: MIT and CC0-1.0
  **************************************************************************/
-// Some portions generated by Claude Code (Opus 5).
+// Portions of this file were generated with AI assistance.
 
 /**************************************************************************/
 /*                                                                        */
diff --git a/platform/cortex_r52/src/zx_context.S b/platform/cortex_r52/src/zx_context.S
index e9bf99d..c0bde88 100644
--- a/platform/cortex_r52/src/zx_context.S
+++ b/platform/cortex_r52/src/zx_context.S
@@ -12,7 +12,7 @@
  *
  * SPDX-License-Identifier: MIT and CC0-1.0
  **************************************************************************/
-@ Some portions generated by Claude Code (Opus 5).
+@ Portions of this file were generated with AI assistance.
 
 @ zx_context.S -- Cortex-R52 -- the partition switch, at the exception
 @                 boundary where it has to be assembly and nowhere else.
diff --git a/platform/cortex_r52/src/zx_el2_entry.S b/platform/cortex_r52/src/zx_el2_entry.S
index 70620fa..f0f8f57 100644
--- a/platform/cortex_r52/src/zx_el2_entry.S
+++ b/platform/cortex_r52/src/zx_el2_entry.S
@@ -12,7 +12,7 @@
  *
  * SPDX-License-Identifier: MIT and CC0-1.0
  **************************************************************************/
-@ Some portions generated by Claude Code (Opus 5).
+@ Portions of this file were generated with AI assistance.
 
 @ zx_el2_entry.S -- Cortex-R52 -- the ZoneX EL2 reset and entry path.
 @
diff --git a/platform/cortex_r52/src/zx_stage2_mpu.c b/platform/cortex_r52/src/zx_stage2_mpu.c
index 3e1a280..c0da699 100644
--- a/platform/cortex_r52/src/zx_stage2_mpu.c
+++ b/platform/cortex_r52/src/zx_stage2_mpu.c
@@ -12,7 +12,7 @@
  *
  * SPDX-License-Identifier: MIT and CC0-1.0
  **************************************************************************/
-// Some portions generated by Claude Code (Opus 5).
+// Portions of this file were generated with AI assistance.
 
 /**************************************************************************/
 /*                                                                        */
diff --git a/platform/cortex_r52/src/zx_trap_handler.S b/platform/cortex_r52/src/zx_trap_handler.S
index dfbda0b..d1dedfe 100644
--- a/platform/cortex_r52/src/zx_trap_handler.S
+++ b/platform/cortex_r52/src/zx_trap_handler.S
@@ -12,7 +12,7 @@
  *
  * SPDX-License-Identifier: MIT and CC0-1.0
  **************************************************************************/
-@ Some portions generated by Claude Code (Opus 5).
+@ Portions of this file were generated with AI assistance.
 
 @ zx_trap_handler.S -- Cortex-R52 -- the ZoneX EL2 exception vectors, and the
 @                      launch and recapture of an EL1 payload.
diff --git a/test/fvp/run_fvp_test.py b/test/fvp/run_fvp_test.py
index 276ba37..d203bde 100755
--- a/test/fvp/run_fvp_test.py
+++ b/test/fvp/run_fvp_test.py
@@ -2,7 +2,7 @@
 #
 # Copyright (c) 2026 Eclipse ThreadX contributors
 # SPDX-License-Identifier: MIT
-# Some portions generated by Claude Code (Opus 5).
+# Portions of this file were generated with AI assistance.
 #
 """Run a ZoneX image on the Armv8-R AEM FVP and assert its self-reported result.
 
diff --git a/test/host/zx_test.h b/test/host/zx_test.h
index c8f2c25..cbdd32b 100644
--- a/test/host/zx_test.h
+++ b/test/host/zx_test.h
@@ -12,7 +12,7 @@
  *
  * SPDX-License-Identifier: MIT and CC0-1.0
  **************************************************************************/
-// Some portions generated by Claude Code (Opus 5).
+// Portions of this file were generated with AI assistance.
 
 /**************************************************************************/
 /*                                                                        */