diff --git a/content/ai-agent-resources.md b/content/ai-agent-resources.md
index 74765c041f..3e30b58138 100644
--- a/content/ai-agent-resources.md
+++ b/content/ai-agent-resources.md
@@ -43,7 +43,7 @@ Each document contains:
 
 | Field | Type | Description |
 |-------|------|-------------|
-| `id` | string | URL slug identifier |
+| `id` | string | Unique identifier, the page's path without a file extension (for example `develop/clients/redis-py`) |
 | `title` | string | Page title |
 | `url` | string | Canonical URL |
 | `summary` | string | Short description |
diff --git a/layouts/_default/section.json b/layouts/_default/section.json
index 6ee91cc66d..f88dafde72 100644
--- a/layouts/_default/section.json
+++ b/layouts/_default/section.json
@@ -5,19 +5,7 @@
 {{- $content := partial "process-markdown-content.html" (dict "RawContent" .RawContent "Site" .Site "Page" .) -}}
 
 {{- /* Build the JSON object for the section itself */ -}}
-{{- /* Handle pages where .File may be nil (e.g., taxonomy pages) */ -}}
-{{- /* Also handle _index.md files where ContentBaseName is "_index" (not useful as id) */ -}}
-{{- $id := "" -}}
-{{- with .File -}}
-  {{- $baseName := .ContentBaseName -}}
-  {{- if or (not $baseName) (eq $baseName "_index") -}}
-    {{- $id = $.Title | urlize -}}
-  {{- else -}}
-    {{- $id = $baseName | urlize -}}
-  {{- end -}}
-{{- else -}}
-  {{- $id = .Title | urlize -}}
-{{- end -}}
+{{- $id := partial "page-id.html" . -}}
 {{- $summary := (.Params.description | default .Description) | plainify | replaceRE "\\s+" " " | strings.TrimSpace -}}
 {{- $tags := .Params.categories | default (slice) -}}
 {{- $lastUpdated := .Lastmod.Format "2006-01-02T15:04:05Z07:00" -}}
@@ -25,19 +13,10 @@
 {{- /* Build list of child pages */ -}}
 {{- $children := slice -}}
 {{- range .Pages -}}
-  {{- $childTitle := .Title -}}
-  {{- $childId := "" -}}
-  {{- with .File -}}
-    {{- $baseName := .ContentBaseName -}}
-    {{- if or (not $baseName) (eq $baseName "_index") -}}
-      {{- $childId = $childTitle | urlize -}}
-    {{- else -}}
-      {{- $childId = $baseName | urlize -}}
-    {{- end -}}
-  {{- else -}}
-    {{- $childId = $childTitle | urlize -}}
-  {{- end -}}
-  {{- $childSummary := (.Params.description | default .Description) | plainify | replaceRE "\\s+" " " | strings.TrimSpace -}}
+  {{- /* Same derivation as the page's own id, so children[].id resolves to the record
+         that page publishes */ -}}
+  {{- $childId := partial "page-id.html" . -}}
+  {{- $childSummary :=(.Params.description | default .Description) | plainify | replaceRE "\\s+" " " | strings.TrimSpace -}}
   {{- $child := dict "id" $childId "title" .Title "url" .Permalink "summary" $childSummary -}}
   {{- $children = $children | append $child -}}
 {{- end -}}
diff --git a/layouts/_default/single.json b/layouts/_default/single.json
index 9d815fa63f..a9325cbf43 100644
--- a/layouts/_default/single.json
+++ b/layouts/_default/single.json
@@ -5,19 +5,7 @@
 {{- $content := partial "process-markdown-content.html" (dict "RawContent" .RawContent "Site" .Site "Page" .) -}}
 
 {{- /* Build the JSON object */ -}}
-{{- /* Handle pages where .File may be nil (e.g., taxonomy pages) */ -}}
-{{- /* Also handle _index.md files where ContentBaseName is "_index" (not useful as id) */ -}}
-{{- $id := "" -}}
-{{- with .File -}}
-  {{- $baseName := .ContentBaseName -}}
-  {{- if or (not $baseName) (eq $baseName "_index") -}}
-    {{- $id = $.Title | urlize -}}
-  {{- else -}}
-    {{- $id = $baseName | urlize -}}
-  {{- end -}}
-{{- else -}}
-  {{- $id = .Title | urlize -}}
-{{- end -}}
+{{- $id := partial "page-id.html" . -}}
 {{- $summary := (.Params.description | default .Description) | plainify | replaceRE "\\s+" " " | strings.TrimSpace -}}
 {{- $tags := .Params.categories | default (slice) -}}
 {{- $lastUpdated := .Lastmod.Format "2006-01-02T15:04:05Z07:00" -}}
diff --git a/layouts/partials/page-id.html b/layouts/partials/page-id.html
new file mode 100644
index 0000000000..77a91dfd06
--- /dev/null
+++ b/layouts/partials/page-id.html
@@ -0,0 +1,41 @@
+{{- /*
+  Stable, unique id for a page record in the JSON and Markdown outputs.
+
+  Takes a Page. Returns its content path with the ".md" extension and any trailing
+  "/_index" removed, so content/develop/clients/redis-py.md becomes
+  "develop/clients/redis-py" and content/develop/clients/_index.md becomes
+  "develop/clients".
+
+  This replaces a bare filename. ContentBaseName is not unique across the corpus --
+  "message_history" named 58 different pages, "install" 42 -- so any consumer treating
+  id as a primary key silently collapsed them, with no error to notice. The content
+  path is unique by construction, because two files cannot share one path, and it is
+  stable across builds because nothing about it depends on build order. A dedup
+  suffix would not be: the page that got the plain id and the page that got "-1" could
+  swap between builds, quietly repointing anyone who had stored either.
+
+  Slashes are kept rather than flattened to hyphens. Flattening reintroduces a
+  collision risk ("a/b-c" and "a-b/c" both becoming "a-b-c") for no real gain, and the
+  path form matches how the URL is already structured.
+
+  Pages with no backing file -- generated pages, taxonomy terms -- fall back to the
+  urlized title, which is what the previous implementation did for them.
+
+  Shared by single.json, section.json and section.json's children[] entries so all
+  three agree. children[].id must equal the child page's own id or the navigation
+  graph does not resolve.
+*/ -}}
+
+{{- $id := "" -}}
+{{- with .File -}}
+  {{- /* Not ".Path | replace ..." -- piping makes .Path the LAST argument, so the
+         backslash becomes the input and every id comes out as a single backslash. */ -}}
+  {{- $path := replace .Path "\\" "/" -}}
+  {{- $path = strings.TrimSuffix ".md" $path -}}
+  {{- $path = strings.TrimSuffix "/_index" $path -}}
+  {{- $id = $path -}}
+{{- end -}}
+{{- if not $id -}}
+  {{- $id = .Title | urlize -}}
+{{- end -}}
+{{- return $id -}}