diff --git a/.env.example b/.env.example
index c1a1f06e67..0e3c3c08fb 100644
--- a/.env.example
+++ b/.env.example
@@ -1788,6 +1788,13 @@ APP_LOG_TO_FILE=true
 # SEMANTIC_CACHE_MAX_BYTES=4194304       # Max total cache size in bytes (default: 4 MB)
 # SEMANTIC_CACHE_TTL_MS=1800000          # Cache entry TTL (default: 30 minutes)
 
+# ── Local corpus index cache ──
+# How many local-corpus roots keep a live in-memory index at once. The cache is
+# LRU: reaching the limit evicts the least-recently-used root's index, which is
+# then rebuilt on its next query. Clamped to a minimum of 1; a non-numeric value
+# falls back to the default. Used by: src/lib/localCorpus/configured.ts
+# OMNIROUTE_CORPUS_CACHE_SIZE=5
+
 # ── In-memory log buffers ──
 # Maximum recent stream events kept in memory for the Dashboard live view.
 # STREAM_HISTORY_MAX=50
diff --git a/changelog.d/maintenance/11576-corpus-cache-size-env-doc.md b/changelog.d/maintenance/11576-corpus-cache-size-env-doc.md
new file mode 100644
index 0000000000..97f96e6ca1
--- /dev/null
+++ b/changelog.d/maintenance/11576-corpus-cache-size-env-doc.md
@@ -0,0 +1 @@
+- **docs(env):** document `OMNIROUTE_CORPUS_CACHE_SIZE` in `.env.example` and `ENVIRONMENT.md`, so the env/docs contract check stops failing Docs Gates on every branch ([#11576](https://github.com/diegosouzapw/OmniRoute/pull/11576))
diff --git a/docs/reference/ENVIRONMENT.md b/docs/reference/ENVIRONMENT.md
index b383b5696f..0e6f310e06 100644
--- a/docs/reference/ENVIRONMENT.md
+++ b/docs/reference/ENVIRONMENT.md
@@ -873,6 +873,7 @@ The logging system writes to both stdout and rotated log files. All configuratio
 | `SEMANTIC_CACHE_MAX_SIZE`  | `100`              | Max cached temperature=0 responses.                                                                                                                                                                                                                                               |
 | `SEMANTIC_CACHE_MAX_BYTES` | `4194304` (4 MB)   | Max total semantic cache size.                                                                                                                                                                                                                                                    |
 | `SEMANTIC_CACHE_TTL_MS`    | `1800000` (30 min) | Semantic cache entry TTL.                                                                                                                                                                                                                                                         |
+| `OMNIROUTE_CORPUS_CACHE_SIZE` | `5`             | Local-corpus roots that keep a live in-memory index at once (`src/lib/localCorpus/configured.ts`). LRU: at the limit the least-recently-used root's index is evicted and rebuilt on its next query. Clamped to a minimum of `1`; a non-numeric value falls back to the default.     |
 | `STREAM_HISTORY_MAX`       | `50`               | Max recent stream events in the Dashboard live view buffer.                                                                                                                                                                                                                       |
 | `CONTEXT_LENGTH_DEFAULT`   | `128000`           | Global fallback max context length for models without explicit config.                                                                                                                                                                                                            |
 | `USAGE_TOKEN_BUFFER`       | `100`              | Extra token headroom reserved when tracking usage quotas.                                                                                                                                                                                                                         |