diff --git a/CHANGELOG.md b/CHANGELOG.md
index 147e0cbb..ae669234 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,13 @@
 
 ## [Unreleased]
 
+## [v0.51.211] — 2026-06-02 — Release GE (stage-batch1 — reasoning heuristics + /model shortest-match + Copilot env-token filter)
+
+### Fixed
+- Generalized reasoning-effort capability checks in `_candidate_supports_reasoning` to target whole model families (GPT-5+, Claude 4/3.7, Qwen-3, Kimi, Minimax, Mimo, GLM, Step, and DeepSeek) instead of anchoring on hardcoded version numbers or vendor formats. This prevents the thinking-level configuration selector from being hidden on custom providers, new model releases, or when names carry suffixes like `-free` or `:free` (common on integrations such as Kilo Code or OpenCode Zen). The GPT heuristic is now version-anchored (5+) to avoid falsely enabling reasoning_effort for gpt-4o/4.1/3.5 on aggregator providers (#3379, @b3nw, closes #3377).
+- The `/model` slash command no longer selects a longer model variant when a shorter name is a prefix of it (e.g. `/model mimo-v2.5` selecting `mimo-v2.5-pro`). The fuzzy fallback now prefers an exact id/label match and otherwise the shortest matching option, applied to both the main and bare-name (`provider/...`) fallbacks (#3394, @vanshaj-pahwa, closes #3368).
+- `GITHUB_TOKEN` and `GH_TOKEN` environment variables are now filtered from the Copilot credential pool alongside the seeded `gh`-CLI token, so a classic PAT (`ghp_*`) auto-detected from the environment no longer makes Copilot appear in the model picker when the Copilot API can't use it. User-specific `COPILOT_GITHUB_TOKEN` is still respected (#3382, @happy5318).
+
 ## [v0.51.210] — 2026-06-02 — Release GD (stage-batch1 — model-picker multi-slash fix + extensionless preview highlighting)
 
 ### Fixed
diff --git a/api/config.py b/api/config.py
index b474a822..014c1e91 100644
--- a/api/config.py
+++ b/api/config.py
@@ -1250,14 +1250,29 @@ _PROVIDER_MODELS = {
 
 _AMBIENT_GH_CLI_MARKERS = frozenset({"gh_cli", "gh auth token"})
 
+# Environment variable sources that are auto-detected and should be filtered
+# when the token is a classic PAT (ghp_*) that Copilot API doesn't support.
+# Note: COPILOT_GITHUB_TOKEN is NOT included here - it's user-specific config.
+_AMBIENT_GH_ENV_SOURCES = frozenset({"env:github_token", "env:gh_token"})
+
 
 def _is_ambient_gh_cli_entry(source: str, label: str, key_source: str) -> bool:
     """True when a credential-pool entry is a seeded gh-cli token rather than
     one the user added explicitly. Filter these so Copilot doesn't appear in
     the dropdown just because `gh` is installed on the system.
+
+    Also filters GITHUB_TOKEN and GH_TOKEN env var entries, which are
+    auto-detected from the environment and should not cause Copilot to appear
+    in the picker when the token is a classic PAT (ghp_*) that Copilot API
+    doesn't support.
+
+    Note: COPILOT_GITHUB_TOKEN is NOT filtered - it's user-specific config
+    that should always be respected.
     """
+    source_lower = source.strip().lower()
     return (
-        source.strip().lower() in _AMBIENT_GH_CLI_MARKERS
+        source_lower in _AMBIENT_GH_CLI_MARKERS
+        or source_lower in _AMBIENT_GH_ENV_SOURCES
         or label.strip().lower() == "gh auth token"
         or key_source.strip().lower() == "gh auth token"
     )
@@ -2136,15 +2151,44 @@ def _candidate_supports_reasoning(candidate: str) -> bool:
 
     if "thinking" in token_set or "reasoning" in token_set:
         return True
+    if "gpt" in token_set or normalized.startswith("gpt"):
+        # Restrict to GPT-5+ (exclude GPT-4o/4.1/3.5 — reasoning_effort unsupported)
+        m = re.search(r"gpt-(\d+)", normalized)
+        if m and int(m.group(1)) >= 5:
+            return True
+        return False
     if normalized in {"o1", "o3", "o4"} or normalized.startswith(("o1-", "o3-", "o4-")):
         return True
-    if normalized.startswith(("kimi-k2", "kimi-thinking", "claude-3", "claude-4")):
+    if "claude" in token_set or normalized.startswith("claude"):
+        # Restrict to Claude 4+ or Claude 3.7+ (exclude Claude 3.0/3.5)
+        match = re.search(r"claude.*?(\d+)(?:\D+(\d+))?", normalized)
+        if match:
+            major = int(match.group(1))
+            minor = int(match.group(2)) if match.group(2) else 0
+            if major >= 4 or (major == 3 and minor >= 7):
+                return True
+        return False
+    if "qwen" in token_set or normalized.startswith("qwen"):
+        # Restrict to Qwen 3+ (exclude Qwen 2/2.5)
+        match = re.search(r"qwen.*?(\d+)(?:\D+(\d+))?", normalized)
+        if match:
+            major = int(match.group(1))
+            if major >= 3:
+                return True
+        return False
+    if "kimi" in token_set or normalized.startswith("kimi"):
         return True
-    if normalized.startswith("qwen3") or "qwen3" in token_set:
+    if "minimax" in token_set or normalized.startswith("minimax"):
         return True
-    if normalized.startswith(("deepseek-v3", "deepseek-v4", "deepseek-r1", "deepseek-r2")):
+    if "mimo" in token_set or normalized.startswith("mimo"):
         return True
-    if len(tokens) >= 2 and tokens[0] == "deepseek" and tokens[1] in {"v3", "v4", "r1", "r2"}:
+    if "glm" in token_set or normalized.startswith("glm"):
+        return True
+    if "step" in token_set or normalized.startswith("step"):
+        return True
+    if normalized.startswith(("deepseek-v", "deepseek-r")):
+        return True
+    if len(tokens) >= 2 and tokens[0] == "deepseek" and tokens[1].startswith(("v", "r")):
         return True
     return False
 
diff --git a/static/commands.js b/static/commands.js
index d95529e0..e2d55249 100644
--- a/static/commands.js
+++ b/static/commands.js
@@ -322,6 +322,24 @@ function cmdClear(){
   showToast(t('conversation_cleared'));
 }
 
+// Find the best matching model <option> for a slash-command query.
+// Returns an exact id/label match if present, otherwise the shortest option
+// whose value or label contains the query. Preferring the shortest match keeps
+// a specific query like "mimo-v2.5" from being shadowed by a longer variant
+// such as "mimo-v2.5-pro". See issue #3368.
+function _bestModelMatch(options,query){
+  let best=null;
+  for(const opt of options){
+    const value=opt.value.toLowerCase();
+    const text=opt.textContent.toLowerCase();
+    if(value===query||text===query) return opt.value;
+    if(value.includes(query)||text.includes(query)){
+      if(best===null||opt.value.length<best.length) best=opt.value;
+    }
+  }
+  return best;
+}
+
 async function cmdModel(args){
   if(!args){showToast(t('model_usage'));return;}
   const sel=$('modelSelect');
@@ -348,21 +366,13 @@ async function cmdModel(args){
   let match=(typeof _findModelInDropdown==='function')?_findModelInDropdown(q,sel,preferred):null;
   // Fallback: fuzzy match across all options
   if(!match){
-    for(const opt of sel.options){
-      if(opt.value.toLowerCase().includes(q)||opt.textContent.toLowerCase().includes(q)){
-        match=opt.value;break;
-      }
-    }
+    match=_bestModelMatch(sel.options,q);
   }
   // Fallback: if q has provider/ prefix (e.g. "deepseek/deepseek-v4-flash"),
   // try the bare model name (which is how options appear for the active provider)
   if(!match && q.includes('/')){
     const bare=q.slice(q.lastIndexOf('/')+1);
-    for(const opt of sel.options){
-      if(opt.value.toLowerCase().includes(bare)||opt.textContent.toLowerCase().includes(bare)){
-        match=opt.value;break;
-      }
-    }
+    match=_bestModelMatch(sel.options,bare);
     // Cross-provider fallback: if still no match, the model is from a
     // different provider not in the dropdown. Call /api/session/update directly.
     if(!match && S&&S.session&&S.session.session_id){
diff --git a/tests/test_custom_provider_bare_model_reasoning.py b/tests/test_custom_provider_bare_model_reasoning.py
index 46fbf3f1..6d064d75 100644
--- a/tests/test_custom_provider_bare_model_reasoning.py
+++ b/tests/test_custom_provider_bare_model_reasoning.py
@@ -143,3 +143,67 @@ def test_openrouter_slash_prefix_unaffected():
         provider_id="openrouter",
     )
     assert set(efforts) >= {"low", "medium", "high"}
+
+
+def test_generalized_model_families_and_suffixed_ids():
+    test_models = [
+        # GPT
+        ("gpt-5.5", "custom:newapi"),
+        ("gpt-6-ultra", "custom:newapi"),
+        # Claude
+        ("claude-sonnet-4-6-free", "opencode-zen"),
+        ("claude-opus-4-7:free", "kilocode"),
+        ("claude-sonnet-3-7-free", "opencode-zen"),
+        # Qwen
+        ("qwen-3-coder-free", "opencode-zen"),
+        ("qwen-4-coder:free", "opencode-zen"),
+        # Minimax
+        ("minimax-m2.5-free", "opencode-zen"),
+        ("minimax-m3-pro", "custom:newapi"),
+        # Mimo
+        ("mimo-v2.5-free", "opencode-zen"),
+        ("mimo-v3-pro", "custom:newapi"),
+        # GLM
+        ("glm-5.1:free", "kilocode"),
+        ("glm-6-pro", "custom:newapi"),
+        # Step
+        ("step-1.5:free", "kilocode"),
+        ("step-2-pro", "custom:newapi"),
+        # DeepSeek
+        ("deepseek-v5-free", "custom:newapi"),
+        ("deepseek-r3:free", "kilocode"),
+        # Kimi
+        ("kimi-k2.6-free", "opencode-zen"),
+        ("kimi-k3-pro:free", "kilocode")
+    ]
+
+    for model_id, provider_id in test_models:
+        efforts = cfg.resolve_model_reasoning_efforts(model_id, provider_id=provider_id)
+        assert set(efforts) >= {"low", "medium", "high"}, (
+            f"Failed: {model_id} via {provider_id} should resolve reasoning support"
+        )
+
+
+def test_unsupported_model_families_and_versions():
+    unsupported_models = [
+        # GPT: only 5+ supports reasoning_effort — gpt-4o/4.1/3.5 must be excluded
+        ("gpt-4o", "opencode-zen"),
+        ("gpt-4o-mini", "opencode-zen"),
+        ("gpt-4.1", "kilocode"),
+        ("gpt-4-turbo", "custom:newapi"),
+        ("gpt-3.5-turbo", "opencode-zen"),
+        # Claude
+        ("claude-sonnet-3.5", "opencode-zen"),
+        ("claude-opus-3-5-free", "kilocode"),
+        # Qwen
+        ("qwen-2.5-coder-free", "opencode-zen"),
+        ("qwen-2-7b-instruct", "custom:newapi"),
+    ]
+
+    for model_id, provider_id in unsupported_models:
+        efforts = cfg.resolve_model_reasoning_efforts(model_id, provider_id=provider_id)
+        assert efforts == [], (
+            f"Failed: {model_id} via {provider_id} should NOT resolve reasoning support"
+        )
+
+