diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index a5d5f3a..825eddf 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -22,6 +22,11 @@ repos:
         args: [--allow-multiple-documents]
       - id: trailing-whitespace
         name: Trim whitespace
+        # llms.txt is generated by scripts/fetch-model.py from upstream
+        # OpenRouter descriptions, which carry trailing whitespace and smart
+        # quotes. Every pipeline run reintroduces them, so a formatting hook
+        # here fails permanently rather than catching anything.
+        exclude: ^model-benchmarks/llms\.txt$
 
   - repo: https://github.com/Lucas-C/pre-commit-hooks
     rev: v1.5.5
@@ -34,6 +39,9 @@ repos:
     hooks:
       - id: fix-smartquotes
         name: Fix smart quotes
+        # Same reason as trailing-whitespace above: llms.txt is regenerated
+        # from upstream model descriptions that contain smart quotes.
+        exclude: ^model-benchmarks/llms\.txt$
       - id: forbid-bidi-controls
         name: Forbid bidirectional text (security)
 
diff --git a/.prettierignore b/.prettierignore
new file mode 100644
index 0000000..df74a01
--- /dev/null
+++ b/.prettierignore
@@ -0,0 +1,19 @@
+# Prettier ignore
+#
+# Script-generated JSON data files. These are written by
+# `model-benchmarks/scripts/*.py` via `json.dump(..., indent=2)`, which expands
+# every array to one element per line. Prettier collapses short arrays onto a
+# single line, so the two formatters disagree permanently: every pipeline run
+# rewrites the file, Prettier reformats it, and the pre-commit hook fails.
+#
+# That conflict left `main` red on six consecutive pre-commit runs (2026-07-25
+# through 2026-07-28) and the failures were misattributed to whichever PR
+# happened to be open, which is how PR #23 sat blocked for five review passes on
+# a check that had nothing to do with it.
+#
+# These files are machine-written and machine-read; their formatting is decided
+# by the generator, not by a human editing them. Prettier has no useful opinion
+# here.
+model-benchmarks/data/model-data.json
+model-benchmarks/data/eqbench-upstream-keys.json
+model-benchmarks/data/eqbench-raw.json