diff --git a/ods/installers/lib/external-services.sh b/ods/installers/lib/external-services.sh
index 16ef70888..96564b226 100644
--- a/ods/installers/lib/external-services.sh
+++ b/ods/installers/lib/external-services.sh
@@ -1,14 +1,25 @@
 #!/bin/bash
 # External Ollama / LM Studio discovery and validation helpers.
 
+# Reduce a provider's model id to a comparable name.
+#
+# Ollama reports names as `<model>:<tag>`. The tag is the default `latest`
+# unless the user asked for a specific one, so `ollama pull qwen3-30b-a3b`
+# is listed as `qwen3-30b-a3b:latest` — the exact model ODS wants, under a
+# name that used to normalize to `qwen3-30b-a3b-latest` and match nothing.
+#
+# Tag handling therefore runs BEFORE the quantization strip: a quant that
+# arrives in the tag position (`qwen3.5-2b:q8_0`) is only recognisable once
+# the colon has become a separator the quant pattern accepts.
 external_llm_normalize_model_name() {
     local value="${1:-}"
     value="${value##*/}"
     value="${value,,}"
     value="${value%.gguf}"
     value="$(printf '%s' "$value" | sed -E \
-        -e 's/[-_.](q[0-9]+([_.][a-z0-9]+)*|iq[0-9]+([_.][a-z0-9]+)*|fp(8|16|32)|bf16)([-_.].*)?$//' \
+        -e 's/:latest$//' \
         -e 's/:/-/' \
+        -e 's/[-_.](q[0-9]+([_.][a-z0-9]+)*|iq[0-9]+([_.][a-z0-9]+)*|fp(8|16|32)|bf16)([-_.].*)?$//' \
         -e 's/[[:space:]_]+/-/g' \
         -e 's/-+/-/g' \
         -e 's/^-|-$//g')"
diff --git a/ods/tests/test-external-services.sh b/ods/tests/test-external-services.sh
index 9beac6f7c..defbf75e4 100644
--- a/ods/tests/test-external-services.sh
+++ b/ods/tests/test-external-services.sh
@@ -43,6 +43,27 @@ assert_eq "$(external_llm_normalize_model_name 'qwen3.5:9b')" \
     "qwen3.5-9b" "normalizes Ollama tags"
 assert_eq "$(external_llm_normalize_model_name 'Qwen3.5-9B-Q4_K_M.gguf')" \
     "qwen3.5-9b" "removes GGUF quantization suffixes"
+# `latest` is Ollama's default tag: `ollama pull qwen3-30b-a3b` is listed by
+# /api/tags as `qwen3-30b-a3b:latest`. Treating that as part of the name meant
+# the commonest case — the user already has exactly the model we want — never
+# matched, and the installer downloaded a duplicate copy.
+assert_eq "$(external_llm_normalize_model_name 'qwen3-30b-a3b:latest')" \
+    "qwen3-30b-a3b" "drops Ollama's default :latest tag"
+assert_eq "$(external_llm_normalize_model_name 'gemma-4-e4b-it:latest')" \
+    "gemma-4-e4b-it" "drops :latest from a hyphenated name"
+# A quantization that arrives in the tag position is still a quantization.
+assert_eq "$(external_llm_normalize_model_name 'qwen3.5-2b:q8_0')" \
+    "qwen3.5-2b" "strips a quantization supplied as an Ollama tag"
+assert_eq "$(external_llm_normalize_model_name 'qwen3.5-9b:iq4_xs')" \
+    "qwen3.5-9b" "strips an IQ quantization tag"
+# A size tag is part of the identity and must survive.
+assert_eq "$(external_llm_normalize_model_name 'qwen3.5:9b')" \
+    "qwen3.5-9b" "keeps a size tag"
+assert_eq "$(external_llm_normalize_model_name 'llama3.2:3b')" \
+    "llama3.2-3b" "keeps a size tag on another family"
+# "latest" only counts as a tag, never as part of the name.
+assert_eq "$(external_llm_normalize_model_name 'my-latest-model')" \
+    "my-latest-model" "does not strip latest from inside a name"
 assert_eq "$(external_llm_container_url 'http://localhost:11434/v1')" \
     "http://host.docker.internal:11434" "normalizes localhost for containers"
 assert_eq "$(external_llm_container_url 'http://[::1]:1234/api/v1')" \
@@ -73,6 +94,24 @@ if external_llm_model_matches "qwen3.5:9b" "llama3.2:3b"; then
 else
     pass "rejects unrelated model families"
 fi
+# The tier map's LLM_MODEL against what /api/tags actually reports for a
+# model the user pulled by bare name.
+assert_true "matches a tier target against Ollama's :latest listing" \
+    external_llm_model_matches "qwen3-30b-a3b" "qwen3-30b-a3b:latest"
+assert_true "matches a hyphenated tier target against :latest" \
+    external_llm_model_matches "gemma-4-e4b-it" "gemma-4-e4b-it:latest"
+assert_true "matches a tier target against a quantization tag" \
+    external_llm_model_matches "qwen3.5-2b" "qwen3.5-2b:q8_0"
+if external_llm_model_matches "qwen3.5-9b" "qwen3.5:4b"; then
+    fail "rejects a different size in the tag"
+else
+    pass "rejects a different size in the tag"
+fi
+if external_llm_model_matches "qwen3-30b-a3b" "qwen3-8b:latest"; then
+    fail "rejects a different model carrying :latest"
+else
+    pass "rejects a different model carrying :latest"
+fi
 
 # ── external_llm_env_value: parses .env the way lib/safe-env.sh does ─────────