From 0b95f2e09a59ef080e073613b35742ac6017346d Mon Sep 17 00:00:00 2001
From: Claude <noreply@anthropic.com>
Date: Sat, 22 Aug 2026 02:37:38 -0400
Subject: [PATCH] Codex finding: unreadable model entries cannot prove absence
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A 200 tags response whose models array contains entries without a readable
string name is unobservable for the embed model (an unnamed entry could be
it) — never absent. Positive matches still count amid malformed siblings;
an empty, fully readable list still proves absence.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012T1XF1ZyJL7KW8AVRUJjiD
---
 src/app.js       | 17 ++++++++++++++---
 test/app.test.js | 41 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 55 insertions(+), 3 deletions(-)

diff --git a/src/app.js b/src/app.js
index 890142c..11bf3b5 100644
--- a/src/app.js
+++ b/src/app.js
@@ -84,9 +84,20 @@ export function createApp(config, { fetchImpl = fetch } = {}) {
             return null;
           }
           const found = models.some((m) => modelNamesMatch(m?.name, config.embedModel));
-          embedModelResult = probeResult(found ? OK : ABSENT, ollamaSurface, {
-            model: config.embedModel,
-          });
+          if (found) {
+            // Positive evidence stands on its own, even amid malformed entries.
+            embedModelResult = probeResult(OK, ollamaSurface, { model: config.embedModel });
+            return null;
+          }
+          // Absence is only provable from a FULLY readable list: an entry
+          // without a readable name could be the model we are looking for.
+          const allReadable = models.every((m) => typeof m?.name === "string");
+          embedModelResult = allReadable
+            ? probeResult(ABSENT, ollamaSurface, { model: config.embedModel })
+            : probeResult(UNOBSERVABLE, ollamaSurface, {
+                model: config.embedModel,
+                reason: "models list contains entries without a readable name",
+              });
           return null; // do not override the reachability verdict
         },
       }),
diff --git a/test/app.test.js b/test/app.test.js
index ee80ec9..6aa7911 100644
--- a/test/app.test.js
+++ b/test/app.test.js
@@ -234,6 +234,47 @@ test("/health: 200 tags response WITHOUT a models array is unobservable, never a
   }
 });
 
+test("/health: models list with unreadable entries cannot prove absence (unobservable)", async () => {
+  for (const badList of [
+    [{}],
+    [{ model: "nomic-embed-text" }], // wrong field name
+    [{ name: "qwen3:30b-a3b" }, { name: 42 }], // mixed: one unreadable entry
+  ]) {
+    const routes = happyRoutes();
+    routes["GET http://ollama.test:11436/api/tags"] = () => jsonResponse({ models: badList });
+    await withServer(fakeFetch(routes), async (base) => {
+      const res = await fetch(`${base}/health`);
+      const body = await res.json();
+      assert.equal(
+        body.dependencies.embed_model.status,
+        "unobservable",
+        `list ${JSON.stringify(badList)} has unreadable entries and cannot prove absence`
+      );
+    });
+  }
+});
+
+test("/health: positive evidence stands even amid malformed sibling entries", async () => {
+  const routes = happyRoutes();
+  routes["GET http://ollama.test:11436/api/tags"] = () =>
+    jsonResponse({ models: [{}, { name: "nomic-embed-text:latest" }] });
+  await withServer(fakeFetch(routes), async (base) => {
+    const res = await fetch(`${base}/health`);
+    const body = await res.json();
+    assert.equal(body.dependencies.embed_model.status, "ok");
+  });
+});
+
+test("/health: an empty models list IS readable and proves absence", async () => {
+  const routes = happyRoutes();
+  routes["GET http://ollama.test:11436/api/tags"] = () => jsonResponse({ models: [] });
+  await withServer(fakeFetch(routes), async (base) => {
+    const res = await fetch(`${base}/health`);
+    const body = await res.json();
+    assert.equal(body.dependencies.embed_model.status, "absent");
+  });
+});
+
 test("/health: non-JSON 200 tags body is unobservable", async () => {
   const routes = happyRoutes();
   routes["GET http://ollama.test:11436/api/tags"] = () => new Response("<html>proxy error</html>", { status: 200 });