diff --git a/static/ui.js b/static/ui.js
index 0fc55263..6f752f0b 100644
--- a/static/ui.js
+++ b/static/ui.js
@@ -2900,7 +2900,29 @@ function getModelLabel(modelId){
   if(STATIC_LABELS[modelId]) return STATIC_LABELS[modelId];
   // Safe Ollama-tag fallback: strip only the first slash-segment (provider
   // prefix) so multi-slash IDs preserve their vendor hierarchy (#3360).
-  let _last = modelId.includes('/') ? (modelId.slice(modelId.indexOf('/')+1) || modelId) : modelId;
+  // URI-scheme ids (e.g. `gpt://${FOLDER}/deepseek-v4-flash/latest`, provider
+  // `yandex:gpt`) must NOT be first-segment-stripped — `indexOf('/')` would
+  // land inside the `://` and leave `/${FOLDER}/...` path junk (#3429). For a
+  // `scheme://` id, drop the scheme + authority and take the last meaningful
+  // path segment (ignoring a bare version tail like `latest`/`stable`).
+  let _last;
+  const _uriMatch = /^[a-z][a-z0-9+.-]*:\/\/(.+)$/i.exec(modelId);
+  if (_uriMatch) {
+    const _segs = _uriMatch[1].split('/').filter(Boolean);
+    const _isVersionTail = (s) => /^(latest|stable|current|default|v?\d[\w.-]*)$/i.test(s);
+    let _pick = '';
+    for (let _i = _segs.length - 1; _i >= 0; _i--) {
+      // Skip env-var placeholders (${...}) and bare version tails; prefer the
+      // last segment that actually looks like a model name.
+      if (/\$\{[^}]*\}/.test(_segs[_i])) continue;
+      if (_isVersionTail(_segs[_i]) && _pick) continue;
+      if (!_pick) _pick = _segs[_i];
+      if (!_isVersionTail(_segs[_i])) { _pick = _segs[_i]; break; }
+    }
+    _last = _pick || _segs[_segs.length - 1] || modelId;
+  } else {
+    _last = modelId.includes('/') ? (modelId.slice(modelId.indexOf('/')+1) || modelId) : modelId;
+  }
   // Strip @provider: prefix if present (e.g. @ollama-cloud:kimi-k2.6)
   if (_last.startsWith('@') && _last.includes(':')) _last = _last.split(':').slice(1).join(':');
   const looksLikeOllamaTag = /^[a-z0-9][\w.-]*:[\w.-]+$/i.test(_last);
diff --git a/tests/test_issue3429_uri_scheme_model_label.py b/tests/test_issue3429_uri_scheme_model_label.py
new file mode 100644
index 00000000..fcf93e9c
--- /dev/null
+++ b/tests/test_issue3429_uri_scheme_model_label.py
@@ -0,0 +1,82 @@
+"""Regression test for #3429 — getModelLabel() mangles URI-scheme model IDs.
+
+PR #3366 (fix for #3360) changed getModelLabel() to strip only the first
+``/``-segment instead of ``split('/').pop()``. That fixed multi-slash proxy IDs
+but regressed URI-scheme IDs (e.g. Yandex ``gpt://${FOLDER}/deepseek-v4-flash/latest``)
+because ``indexOf('/')`` lands inside the ``://`` and leaves ``/${FOLDER}/...``
+path junk in the composer model chip.
+
+The fix detects a ``scheme://`` id and takes the last meaningful path segment
+(skipping ``${...}`` env-var placeholders and bare version tails like ``latest``),
+while NOT touching the #3360 multi-slash behavior for non-URI ids.
+
+Runs the live getModelLabel() via Node so drift between the test and the real
+code is caught immediately.
+"""
+import shutil
+import subprocess
+from pathlib import Path
+
+import pytest
+
+REPO_ROOT = Path(__file__).parent.parent.resolve()
+UI_JS_PATH = REPO_ROOT / "static" / "ui.js"
+NODE = shutil.which("node")
+
+pytestmark = pytest.mark.skipif(NODE is None, reason="node not on PATH")
+
+_DRIVER = r"""
+const fs = require('fs');
+const ui = fs.readFileSync(process.argv[1], 'utf8');
+// Slice getModelLabel() by function boundaries (regex literals inside it defeat
+// a naive brace counter, so bound it by the next top-level function instead).
+const start = ui.indexOf('function getModelLabel(');
+if (start < 0) throw new Error('getModelLabel not found');
+const after = ui.indexOf('\nfunction _gatewayProviderName(', start);
+if (after < 0) throw new Error('getModelLabel end boundary not found');
+const fnSrc = ui.slice(start, after);
+const _dynamicModelLabels = {};
+function _fmtOllamaLabel(s){ return s; }
+eval(fnSrc);
+const out = {};
+for (const m of JSON.parse(process.argv[2])) out[m] = getModelLabel(m);
+process.stdout.write(JSON.stringify(out));
+"""
+
+
+def _labels(model_ids):
+    import json
+    proc = subprocess.run(
+        [NODE, "-e", _DRIVER, str(UI_JS_PATH), json.dumps(model_ids)],
+        capture_output=True, text=True, timeout=30,
+    )
+    assert proc.returncode == 0, f"node driver failed: {proc.stderr}"
+    return json.loads(proc.stdout)
+
+
+def test_uri_scheme_model_id_label_is_model_name_not_path_junk():
+    """#3429: a gpt://.../model/latest id must label as the model name."""
+    out = _labels([
+        "gpt://${YANDEX_FOLDER_ID}/deepseek-v4-flash/latest",
+        "gpt://folder123/deepseek-v4-flash/latest",
+        "openrouter://acct/qwen-3-coder",
+        "gpt://${F}/qwen-3-coder",
+    ])
+    assert out["gpt://${YANDEX_FOLDER_ID}/deepseek-v4-flash/latest"] == "deepseek-v4-flash"
+    assert out["gpt://folder123/deepseek-v4-flash/latest"] == "deepseek-v4-flash"
+    assert out["openrouter://acct/qwen-3-coder"] == "qwen-3-coder"
+    assert out["gpt://${F}/qwen-3-coder"] == "qwen-3-coder"
+    # The env-var placeholder must never leak into the label.
+    for label in out.values():
+        assert "${" not in label, f"env-var placeholder leaked into label: {label!r}"
+
+
+def test_uri_fix_does_not_regress_multi_slash_or_bare_ids():
+    """#3360 multi-slash hierarchy + single-slash/bare ids stay correct."""
+    out = _labels([
+        "vendor_a/deepseek/deepseek-v4-pro",  # #3360: keep vendor hierarchy
+        "claude-sonnet-4-6",                  # bare id unchanged
+    ])
+    # Non-URI multi-slash id keeps everything after the first segment (#3360).
+    assert out["vendor_a/deepseek/deepseek-v4-pro"] == "deepseek/deepseek-v4-pro"
+    assert out["claude-sonnet-4-6"] == "claude-sonnet-4-6"