diff --git a/src/ml/imf/registry.ts b/src/ml/imf/registry.ts
index e98b960..4284704 100644
--- a/src/ml/imf/registry.ts
+++ b/src/ml/imf/registry.ts
@@ -9,14 +9,14 @@
  *
  * Node persists to ~/.cache/interscript/models/<id>/ (fs, atomic
  * rename); browsers keep the verified bytes in memory (the Cache API
- * integration is future work). Overrides: SECRYST_INDEX,
- * SECRYST_CACHE.
+ * integration is future work). Overrides: INTERSCRIPT_ML_INDEX / INTERSCRIPT_ML_CACHE
+ * (SECRYST_INDEX / SECRYST_CACHE are deprecated legacy aliases).
  */
 
 import { load as loadYaml } from "js-yaml"
 
 export const DEFAULT_INDEX_URL =
-  "https://github.com/interscript/interscript-ml/releases/download/index-v6/models-index.yaml"
+  "https://github.com/interscript/interscript-ml/releases/download/index-v7/models-index.yaml"
 
 export interface Part {
   url: string
@@ -52,7 +52,7 @@ function cacheDir(): string {
   const env = (globalThis as { process?: { env?: Record<string, string | undefined> } }).process
     ?.env
   const home = env?.["HOME"] ?? env?.["USERPROFILE"] ?? "."
-  return env?.["SECRYST_CACHE"] ?? `${home}/.cache/interscript`
+  return env?.["INTERSCRIPT_ML_CACHE"] ?? env?.["SECRYST_CACHE"] ?? `${home}/.cache/interscript`
 }
 
 async function fetchHttpBytes(url: string): Promise<Uint8Array> {
@@ -297,7 +297,7 @@ export async function resolve(
 ): Promise<ResolvedZip> {
   const env = (globalThis as { process?: { env?: Record<string, string | undefined> } }).process
     ?.env
-  const source = indexUrl ?? env?.["SECRYST_INDEX"] ?? DEFAULT_INDEX_URL
+  const source = indexUrl ?? env?.["INTERSCRIPT_ML_INDEX"] ?? env?.["SECRYST_INDEX"] ?? DEFAULT_INDEX_URL
   let entries: Record<string, IndexEntry>
   try {
     entries = await fetchIndex(source)
diff --git a/test/imf.test.ts b/test/imf.test.ts
index bb69f01..6f5642c 100644
--- a/test/imf.test.ts
+++ b/test/imf.test.ts
@@ -259,11 +259,33 @@ describe("registry", () => {
   it("DEFAULT_INDEX_URL pins a GitHub Release asset, never raw", async () => {
     const { DEFAULT_INDEX_URL } = await import("../src/ml/imf/registry.js")
     expect(DEFAULT_INDEX_URL).toMatch(
-      /^https:\/\/github\.com\/interscript\/interscript-ml\/releases\/download\/index-v6\/models-index\.yaml$/,
+      /^https:\/\/github\.com\/interscript\/interscript-ml\/releases\/download\/index-v7\/models-index\.yaml$/,
     )
     expect(DEFAULT_INDEX_URL).not.toMatch(/raw\.githubusercontent/)
   })
 
+  it("INTERSCRIPT_ML_INDEX is the primary override, SECRYST_INDEX a legacy alias", async () => {
+    const { mkdtempSync, writeFileSync, rmSync } = await import("node:fs")
+    const { tmpdir } = await import("node:os")
+    const { join } = await import("node:path")
+    const { resolve } = await import("../src/ml/imf/registry.js")
+    const dir = mkdtempSync(join(tmpdir(), "imf-envvar-"))
+    writeFileSync(join(dir, "models.yaml"), "version: 1\nmodels:\n  tiny-1.0:\n    filename: t.zip\n    sha256: x\n")
+    const prev = process.env["SECRYST_INDEX"]
+    try {
+      process.env["INTERSCRIPT_ML_INDEX"] = join(dir, "models.yaml")
+      await expect(resolve("nope-9.9")).rejects.toThrow(/unknown model id/)
+      delete process.env["INTERSCRIPT_ML_INDEX"]
+      process.env["SECRYST_INDEX"] = join(dir, "models.yaml")
+      await expect(resolve("nope-9.9")).rejects.toThrow(/unknown model id/)
+    } finally {
+      delete process.env["INTERSCRIPT_ML_INDEX"]
+      if (prev === undefined) delete process.env["SECRYST_INDEX"]
+      else process.env["SECRYST_INDEX"] = prev
+      rmSync(dir, { recursive: true, force: true })
+    }
+  })
+
   it("HTTP index fetch verifies the .sha256 sidecar before parsing", async () => {
     const { createHash } = await import("node:crypto")
     const { createServer } = await import("node:http")
@@ -367,7 +389,7 @@ describe("registry", () => {
     expect(typeof imf!["resolve"]).toBe("function")
     expect(typeof imf!["IMFModel"]).toBe("function")
     expect(imf!["DEFAULT_INDEX_URL"]).toMatch(
-      /github\.com\/interscript\/interscript-ml\/releases\/download\/index-v6\/models-index\.yaml/,
+      /github\.com\/interscript\/interscript-ml\/releases\/download\/index-v7\/models-index\.yaml/,
     )
   })
 })