diff --git a/README.md b/README.md
index 6def2fdf..076f886a 100644
--- a/README.md
+++ b/README.md
@@ -318,6 +318,10 @@ TeacherDistillationConfig(
 )
 ```
 
+If `teacher_server.model_name` is a deployment alias rather than a tokenizer
+identifier, set `teacher_server.tokenizer_name` explicitly so the env can
+validate tokenizer compatibility.
+
 CLI shape:
 
 ```bash
diff --git a/atroposlib/envs/server_handling/vllm_server.py b/atroposlib/envs/server_handling/vllm_server.py
index aaee28d7..cc5bf9a5 100644
--- a/atroposlib/envs/server_handling/vllm_server.py
+++ b/atroposlib/envs/server_handling/vllm_server.py
@@ -281,7 +281,7 @@ class VLLMServer(APIServer):
         ), "Prompt or input_ids is required for get_logprobs!"
 
         top_k = int(kwargs.pop("top_k", kwargs.pop("top_logprobs", 1)))
-        top_k = max(1, top_k)
+        top_k = max(0, top_k)
 
         # Use input_ids if provided (from ManagedServer), otherwise tokenize prompt
         from_prompt_text = False
@@ -420,7 +420,7 @@ def resolve_openai_configs(
             ) from e
 
         if isinstance(default_server_configs, APIServerConfig):
-            server_configs = final_openai_config
+            server_configs = [final_openai_config]
         elif isinstance(default_server_configs, list):
             server_configs = [final_openai_config]
         else:
diff --git a/atroposlib/envs/teacher_distillation_env.py b/atroposlib/envs/teacher_distillation_env.py
index 85e040c7..4c8bfa75 100644
--- a/atroposlib/envs/teacher_distillation_env.py
+++ b/atroposlib/envs/teacher_distillation_env.py
@@ -33,12 +33,16 @@ class TeacherDistillationConfig(BaseEnvConfig):
     )
     teacher_server: Optional[APIServerConfig] = Field(
         default=None,
-        description="Teacher inference server configuration.",
+        description="Fallback teacher server configuration when not provided at init.",
     )
     teacher_top_k: int = Field(
-        default=1,
-        ge=1,
-        description="Top-k prompt logprobs to fetch per token position.",
+        default=0,
+        ge=-1,
+        description=(
+            "Number of extra prompt logprobs to fetch beyond the selected token. "
+            "Use 0 for selected-token-only prompt logprobs and <= -1 to disable "
+            "teacher fetching."
+        ),
     )
 
 
@@ -57,6 +61,9 @@ class TeacherDistillationEnv(BaseEnv, ABC):
         self,
         config: TeacherDistillationConfig,
         server_configs: Union[ServerBaseline, List[APIServerConfig]],
+        teacher_server_configs: Optional[
+            Union[ServerBaseline, List[APIServerConfig]]
+        ] = None,
         slurm: bool = False,
         testing: bool = False,
     ):
@@ -64,26 +71,42 @@ class TeacherDistillationEnv(BaseEnv, ABC):
         self.teacher_server: Optional[ServerManager] = None
 
         if config.teacher_enabled:
-            if config.teacher_server is None:
+            teacher_config_source = teacher_server_configs
+            if teacher_config_source is None and config.teacher_server is not None:
+                teacher_config_source = [
+                    config.teacher_server.model_copy(
+                        update={
+                            "tokenizer_name": (
+                                config.teacher_server.model_name
+                                if config.teacher_server.tokenizer_name in ("", "none")
+                                else config.teacher_server.tokenizer_name
+                            ),
+                            "timeout": 1200,
+                        }
+                    )
+                ]
+
+            if teacher_config_source is None:
                 raise ValueError(
-                    "teacher_enabled=True requires a teacher_server configuration."
+                    "teacher_enabled=True requires teacher_server_configs at init "
+                    "or a fallback teacher_server config."
                 )
-            teacher_cfg = config.teacher_server.model_copy(
-                update={
-                    "tokenizer_name": (
-                        config.teacher_server.model_name
-                        if config.teacher_server.tokenizer_name in ("", "none")
-                        else config.teacher_server.tokenizer_name
-                    ),
-                    "timeout": 1200,
-                }
-            )
             self.teacher_server = ServerManager(
-                [teacher_cfg],
+                teacher_config_source,
                 slurm=False,
                 testing=False,
             )
-            self._validate_teacher_tokenizer_compatibility(teacher_cfg.tokenizer_name)
+            if isinstance(teacher_config_source, list):
+                teacher_cfg = teacher_config_source[0]
+            else:
+                teacher_cfg = teacher_config_source
+
+            teacher_tokenizer_name = (
+                teacher_cfg.model_name
+                if getattr(teacher_cfg, "tokenizer_name", "none") in ("", "none")
+                else teacher_cfg.tokenizer_name
+            )
+            self._validate_teacher_tokenizer_compatibility(teacher_tokenizer_name)
 
     # ------------------------------------------------------------------
     # Core fetch
@@ -146,12 +169,19 @@ class TeacherDistillationEnv(BaseEnv, ABC):
             group["distill_logprobs"] = None
             return group
 
+        group_overrides = group.get("group_overrides") or {}
+        if group_overrides.get("skip_teacher_top_k", False):
+            group["distill_token_ids"] = None
+            group["distill_logprobs"] = None
+            return group
+
         top_k = int(
-            (group.get("group_overrides") or {}).get(
-                "teacher_top_k", self.config.teacher_top_k
-            )
+            group_overrides.get("teacher_top_k", self.config.teacher_top_k)
         )
-        top_k = max(1, top_k)
+        if top_k <= -1:
+            group["distill_token_ids"] = None
+            group["distill_logprobs"] = None
+            return group
 
         tasks = [self._fetch_teacher_for_sequence(seq, top_k) for seq in seqs]
         results = await asyncio.gather(*tasks, return_exceptions=True)
diff --git a/atroposlib/tests/test_teacher_distillation_env.py b/atroposlib/tests/test_teacher_distillation_env.py
index 65262984..2c0ddf17 100644
--- a/atroposlib/tests/test_teacher_distillation_env.py
+++ b/atroposlib/tests/test_teacher_distillation_env.py
@@ -69,6 +69,42 @@ async def test_attach_teacher_distillation_failure_drops_payload():
     assert out["distill_logprobs"] is None
 
 
+@pytest.mark.asyncio
+async def test_attach_teacher_distillation_negative_topk_skips_fetch():
+    env = object.__new__(_ConcreteTeacherEnv)
+    env.config = SimpleNamespace(teacher_enabled=True, teacher_top_k=-1)
+    env.teacher_server = _FakeTeacherServer()
+
+    group = {
+        "tokens": [[1, 2, 3]],
+        "group_overrides": None,
+        "masks": [[-100, 2, 3]],
+        "scores": [1.0],
+    }
+    out = await TeacherDistillationEnv._attach_teacher_distillation(env, group)
+    assert env.teacher_server.calls == 0
+    assert out["distill_token_ids"] is None
+    assert out["distill_logprobs"] is None
+
+
+@pytest.mark.asyncio
+async def test_attach_teacher_distillation_group_override_can_skip_fetch():
+    env = object.__new__(_ConcreteTeacherEnv)
+    env.config = SimpleNamespace(teacher_enabled=True, teacher_top_k=2)
+    env.teacher_server = _FakeTeacherServer()
+
+    group = {
+        "tokens": [[1, 2, 3]],
+        "group_overrides": {"skip_teacher_top_k": True},
+        "masks": [[-100, 2, 3]],
+        "scores": [1.0],
+    }
+    out = await TeacherDistillationEnv._attach_teacher_distillation(env, group)
+    assert env.teacher_server.calls == 0
+    assert out["distill_token_ids"] is None
+    assert out["distill_logprobs"] is None
+
+
 def test_teacher_tokenizer_mismatch_raises(monkeypatch):
     env = object.__new__(_ConcreteTeacherEnv)
 
diff --git a/environments/gsm8k_server_teacher_distill.py b/environments/gsm8k_server_teacher_distill.py
index 49caabec..5aa33a01 100644
--- a/environments/gsm8k_server_teacher_distill.py
+++ b/environments/gsm8k_server_teacher_distill.py
@@ -37,6 +37,7 @@ class GSM8kTeacherDistillEnv(GSM8kEnv, TeacherDistillationEnv):
                 model_name="mock-teacher",
                 api_key="",
                 server_type="vllm",
+                tokenizer_name="NousResearch/DeepHermes-3-Llama-3-3B-Preview",
             ),
             teacher_top_k=4,
         )
diff --git a/example_trainer/README.md b/example_trainer/README.md
index 8023ab73..8596a849 100644
--- a/example_trainer/README.md
+++ b/example_trainer/README.md
@@ -320,6 +320,10 @@ What to configure on the environment side:
 --env.teacher_top_k 8
 ```
 
+If `$TEACHER_MODEL` is a deployment alias instead of a tokenizer identifier,
+also set `--env.teacher_server.tokenizer_name ...` so the env can validate
+tokenizer compatibility.
+
 Why cross-tokenizer conversion is not acceptable here:
 
 - Teacher token ID `1234` and student token ID `1234` can correspond to different text.