diff --git a/AGENTS.md b/AGENTS.md
index 7c2477e..494e5c2 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -1,14 +1,14 @@
 # Cataclysm: Bright Nights Mod Registry Agent Instruction
 
-## Tasks
-
-- [x] Update workflows and docs for registry-index syncing
-- [ ] TASK: improve and refactor code according to coding standards
-
 ## Skills
 
 - Add registry manifest skill: `.agents/skills/add-registry/SKILL.md`
 
+## Notes
+
+- Keep public manifest docs and schema output aligned with runtime autoupdate substitution keys.
+- Treat `homepage` as part of manifest URL health checks.
+
 - **Tick the checkbox** in AGENTS.md when you finish a task, and commit (follow conventional commit).
   - **if all subtasks are ticked, erase task checkbox section and update this file accordingly from knowledge gained from session, then amend it**
 - Don't `sed`, just edit the file normally.
diff --git a/site/docs/submit.md b/site/docs/submit.md
index 4a28184..29056b0 100644
--- a/site/docs/submit.md
+++ b/site/docs/submit.md
@@ -87,14 +87,15 @@ id: your_mod_id
 display_name: "Your Mod Name"
 short_description: "A brief description of your mod (max 200 chars)"
 
-author: "Your Name"
-license: "MIT" # Use SPDX identifier
+author:
+  - "Your Name"
+license: "MIT"
 homepage: "https://github.com/yourname/your-mod"
 
 version: "1.0.0"
 
 dependencies:
-  - bn: ">=0.9.1"
+  bn: ">=0.9.1"
 
 categories:
   - content
@@ -129,7 +130,7 @@ deno task check-urls registry-index/manifests/your_mod_id.yaml
 | `id`                | Unique identifier (lowercase, underscores)                |
 | `display_name`      | Human-readable name                                       |
 | `short_description` | Brief description (max 200 chars)                         |
-| `author`            | Mod author(s)                                             |
+| `author`            | Array of mod author names                                 |
 | `license`           | SPDX license ID or `"ALL-RIGHTS-RESERVED"`                |
 | `version`           | Current version                                           |
 | `source.type`       | `"github_archive"`, `"gitlab_archive"`, or `"direct_url"` |
@@ -141,8 +142,8 @@ deno task check-urls registry-index/manifests/your_mod_id.yaml
 | --------------------- | ----------------------------------------------------------------- |
 | `description`         | Full mod description                                              |
 | `homepage`            | Link to repo or documentation                                     |
-| `dependencies`        | List of required mod IDs                                          |
-| `conflicts`           | List of incompatible mod IDs                                      |
+| `dependencies`        | Object mapping required mod IDs to version constraints            |
+| `conflicts`           | Object mapping incompatible mod IDs to version constraints        |
 | `categories`          | Organization categories                                           |
 | `tags`                | Search tags                                                       |
 | `icon_url`            | Icon URL (`.png`, `.svg`, `.webp`, `.avif`, `.jpg/.jpeg`, `.gif`) |
@@ -167,5 +168,11 @@ To enable automatic version updates:
 ```yaml
 autoupdate:
   type: tag # or "commit"
-  url: "https://github.com/user/repo/archive/$version.zip"
+  update_url: "https://github.com/user/repo"
+  url: "https://github.com/user/repo/archive/refs/tags/$version.zip"
+  icon_url: "https://raw.githubusercontent.com/user/repo/$commit_sha/icon.png"
 ```
+
+`update_url` is used to discover releases. Optional substitution templates such as
+`autoupdate.url`, `autoupdate.icon_url`, and `autoupdate.commit_sha` are applied when a
+new release is found.
diff --git a/src/schema/manifest.ts b/src/schema/manifest.ts
index e871ae2..7902310 100644
--- a/src/schema/manifest.ts
+++ b/src/schema/manifest.ts
@@ -76,6 +76,17 @@ export const AutoupdateConfig = v.looseObject({
   update_url: v.optional(
     v.string("URL to check for updates. If omitted, uses homepage."),
   ),
+  url: v.optional(
+    v.string("Template for release archive URL. Supports $version and $commit_sha substitutions."),
+  ),
+  icon_url: v.optional(
+    v.string("Template for icon URL. Supports $version and $commit_sha substitutions."),
+  ),
+  commit_sha: v.optional(
+    v.string(
+      "Template override for source.commit_sha. Supports $version and $commit_sha substitutions.",
+    ),
+  ),
   branch: v.optional(
     v.string('Branch to track when type is "commit"'),
   ),
diff --git a/src/schema/manifest_test.ts b/src/schema/manifest_test.ts
new file mode 100644
index 0000000..c8c820d
--- /dev/null
+++ b/src/schema/manifest_test.ts
@@ -0,0 +1,38 @@
+import { assertEquals } from "@std/assert"
+import * as v from "valibot"
+import { ModManifest } from "./manifest.ts"
+
+Deno.test("ModManifest parses documented autoupdate substitution fields", () => {
+  const manifest = v.parse(ModManifest, {
+    schema_version: "1.0",
+    id: "example_mod",
+    display_name: "Example Mod",
+    short_description: "Example description",
+    author: ["Example Author"],
+    license: "MIT",
+    version: "1.0.0",
+    homepage: "https://github.com/example/example-mod",
+    source: {
+      type: "github_archive",
+      url: "https://github.com/example/example-mod/archive/refs/tags/v1.0.0.zip",
+    },
+    autoupdate: {
+      type: "tag",
+      update_url: "https://github.com/example/example-mod",
+      url: "https://github.com/example/example-mod/archive/refs/tags/$version.zip",
+      icon_url: "https://raw.githubusercontent.com/example/example-mod/$commit_sha/icon.png",
+      commit_sha: "$commit_sha",
+      regex: "^v",
+    },
+  })
+
+  assertEquals(
+    manifest.autoupdate?.url,
+    "https://github.com/example/example-mod/archive/refs/tags/$version.zip",
+  )
+  assertEquals(
+    manifest.autoupdate?.icon_url,
+    "https://raw.githubusercontent.com/example/example-mod/$commit_sha/icon.png",
+  )
+  assertEquals(manifest.autoupdate?.commit_sha, "$commit_sha")
+})
diff --git a/src/scripts/check_urls.ts b/src/scripts/check_urls.ts
index aa33bf0..a329362 100644
--- a/src/scripts/check_urls.ts
+++ b/src/scripts/check_urls.ts
@@ -1,7 +1,7 @@
 #!/usr/bin/env -S deno run --allow-read --allow-net
 /**
  * Check URLs in all manifests.
- * Verifies that download URLs and icon URLs are reachable.
+ * Verifies that download, icon, and homepage URLs are reachable.
  */
 
 import { Command } from "@cliffy/command"
@@ -93,7 +93,7 @@ if (import.meta.main) {
   await new Command()
     .name("check-urls")
     .version("1.0.0")
-    .description("Check that manifest URLs (download and icon) are reachable")
+    .description("Check that manifest URLs (download, icon, and homepage) are reachable")
     .arguments("[target:string]")
     .action(async (_options, target = "registry-index/manifests") => {
       try {
diff --git a/src/utils/url_checker.ts b/src/utils/url_checker.ts
index 2317336..027944b 100644
--- a/src/utils/url_checker.ts
+++ b/src/utils/url_checker.ts
@@ -115,6 +115,7 @@ export const extractManifestUrls = (manifest: {
   [
     manifest.source?.url,
     manifest.icon_url,
+    manifest.homepage,
   ].filter((url): url is string => url !== undefined)
 
 const sleep = (ms: number): Promise<void> => new Promise((resolve) => setTimeout(resolve, ms))
diff --git a/src/utils/url_checker_test.ts b/src/utils/url_checker_test.ts
index c22e7db..527412b 100644
--- a/src/utils/url_checker_test.ts
+++ b/src/utils/url_checker_test.ts
@@ -30,6 +30,20 @@ Deno.test("extractManifestUrls - extracts icon URL", () => {
   assertEquals(urls.includes("https://example.com/icon.png"), true)
 })
 
+Deno.test("extractManifestUrls - extracts homepage URL", () => {
+  const manifest = {
+    source: {
+      url: "https://example.com/mod.zip",
+    },
+    homepage: "https://example.com/mod",
+  }
+
+  const urls = extractManifestUrls(manifest)
+  assertEquals(urls.length, 2)
+  assertEquals(urls.includes("https://example.com/mod.zip"), true)
+  assertEquals(urls.includes("https://example.com/mod"), true)
+})
+
 Deno.test("extractManifestUrls - handles missing fields", () => {
   const manifest = {}
   const urls = extractManifestUrls(manifest)