diff --git a/python/sglang/srt/arg_groups/overrides.py b/python/sglang/srt/arg_groups/overrides.py
index e63520227..5500381d5 100644
--- a/python/sglang/srt/arg_groups/overrides.py
+++ b/python/sglang/srt/arg_groups/overrides.py
@@ -265,12 +265,8 @@ def run_post_process_pass(server_args: Any, fn: Callable[..., dict]) -> None:
 
 
 def _apply_fields(server_args: Any, fields: Dict[str, Any]) -> None:
-    """Write record fields past the guard that forbids post-resolution writes.
-
-    Resolution declares, so nothing in the pipeline calls this. It exists for
-    ``RuntimeContext.override_server_args``, the launch stand-in tests use: there
-    the caller's values are both the operator's input and resolution's answer.
-    """
+    """Write fields on behalf of the pipeline (bypasses the strict bare-
+    assignment guard that protects post-resolution mutation)."""
     object.__setattr__(server_args, "_internal_write", True)
     try:
         for field, value in fields.items():
@@ -299,7 +295,7 @@ def declare_resolution(server_args: Any, source: str, **fields: Any) -> None:
     stash = getattr(server_args, "_resolved_overrides", None)
     if stash is None:
         stash = []
-        object.__setattr__(server_args, "_resolved_overrides", stash)
+        server_args._resolved_overrides = stash
     stash.append((source, dict(fields)))
 
 
@@ -333,12 +329,12 @@ def declare_late_resolution(server_args: Any, source: str, **fields: Any) -> Non
     log = getattr(server_args, "_runtime_mutations", None)
     if log is None:
         log = []
-        object.__setattr__(server_args, "_runtime_mutations", log)
+        server_args._runtime_mutations = log
     log.append((source, dict(fields)))
     stash = getattr(server_args, "_resolved_overrides", None)
     if stash is None:
         stash = []
-        object.__setattr__(server_args, "_resolved_overrides", stash)
+        server_args._resolved_overrides = stash
     stash.append((source, dict(fields)))
 
 
@@ -376,7 +372,7 @@ def declare_direct_writes(
     stash = getattr(server_args, "_resolved_overrides", None)
     if stash is None:
         stash = []
-        object.__setattr__(server_args, "_resolved_overrides", stash)
+        server_args._resolved_overrides = stash
     # A resolver reached this way can also declare properly -- the in-tree
     # implementations of these hooks do. Those fields are already explained, and
     # recording them again would attribute them to the wrapper and bury an
diff --git a/python/sglang/srt/disaggregation/decode_kvcache_offload_manager.py b/python/sglang/srt/disaggregation/decode_kvcache_offload_manager.py
index 2ad219ab8..8eecf7e9c 100644
--- a/python/sglang/srt/disaggregation/decode_kvcache_offload_manager.py
+++ b/python/sglang/srt/disaggregation/decode_kvcache_offload_manager.py
@@ -26,7 +26,6 @@ from sglang.srt.runtime_context import (
     get_schedule,
     get_serving,
 )
-from sglang.srt.server_args import ServerArgs
 from sglang.srt.utils.common import ceil_align
 
 if TYPE_CHECKING:
@@ -44,7 +43,6 @@ class DecodeKVCacheOffloadManager:
         token_to_kv_pool_allocator: BaseTokenToKVPoolAllocator,
         tp_group: torch.distributed.ProcessGroup,
         tree_cache: BasePrefixCache,
-        server_args: ServerArgs,
     ) -> None:
         self.req_to_token_pool = req_to_token_pool
         self.token_to_kv_pool_allocator = token_to_kv_pool_allocator
@@ -64,7 +62,6 @@ class DecodeKVCacheOffloadManager:
         self.decode_host_mem_pool = build_kv_host_pool(
             kv_pool=kv_cache,
             page_size=self.page_size,
-            server_args=server_args,
             use_mla=isinstance(kv_cache, MLATokenToKVPool),
         )
 
diff --git a/python/sglang/srt/elastic_ep/elastic_ep.py b/python/sglang/srt/elastic_ep/elastic_ep.py
index 2b1b79f33..298dfa453 100644
--- a/python/sglang/srt/elastic_ep/elastic_ep.py
+++ b/python/sglang/srt/elastic_ep/elastic_ep.py
@@ -10,11 +10,11 @@ import torch
 from sglang.srt.distributed import get_world_group, parallel_state
 from sglang.srt.distributed.utils import get_global_tcp_store
 from sglang.srt.eplb.expert_location import broadcast_global_expert_location_metadata
-from sglang.srt.managers.schedule_batch import ServerArgs
 from sglang.srt.runtime_context import (
     get_exec,
     get_parallel,
 )
+from sglang.srt.server_args import ServerArgs
 from sglang.srt.utils import is_cpu, is_cuda
 
 if TYPE_CHECKING:
diff --git a/python/sglang/srt/entrypoints/http_server.py b/python/sglang/srt/entrypoints/http_server.py
index 2bd113f6d..729694b9d 100644
--- a/python/sglang/srt/entrypoints/http_server.py
+++ b/python/sglang/srt/entrypoints/http_server.py
@@ -228,13 +228,13 @@ async def init_multi_tokenizer() -> ServerArgs:
     server_args: ServerArgs
     port_args: PortArgs
 
+    publish(server_args, role="tokenizer")
+
     # API key authentication is not supported in multi-tokenizer mode
     assert (
-        server_args.api_key is None
+        get_serving().api_key is None
     ), "API key is not supported in multi-tokenizer mode"
 
-    publish(server_args, role="tokenizer")
-
     # Create a new ipc name for the current process
     port_args.tokenizer_ipc_name = (
         f"ipc://{tempfile.NamedTemporaryFile(delete=False).name}"
@@ -2754,7 +2754,7 @@ def _start_native_grpc_server_for_runtime(
         host=get_serving().host,
         port=grpc_port,
         runtime_handle=runtime_handle,
-        worker_threads=server_args.grpc_worker_threads,
+        worker_threads=get_serving().grpc_worker_threads,
     )
     logger.info(f"Native gRPC server started on {get_serving().host}:{grpc_port}")
     return grpc_handle
diff --git a/python/sglang/srt/managers/rust_server.py b/python/sglang/srt/managers/rust_server.py
index d97eb26d0..a95862e9d 100644
--- a/python/sglang/srt/managers/rust_server.py
+++ b/python/sglang/srt/managers/rust_server.py
@@ -187,7 +187,7 @@ class NativeMmHost:
         import_processors("sglang.srt.multimodal.processors")
         if mm_process_pkg := envs.SGLANG_EXTERNAL_MM_PROCESSOR_PACKAGE.get():
             import_processors(mm_process_pkg, overwrite=True)
-        self._processor = processor or get_processor_wrapper(self.server_args)
+        self._processor = processor or get_processor_wrapper()
 
     def resolve_native_spec(self) -> Optional[NativeMmSpec]:
         """The :class:`NativeMmSpec` for this model, or ``None`` when it has no
diff --git a/python/sglang/srt/managers/schedule_batch.py b/python/sglang/srt/managers/schedule_batch.py
index 399e192ee..b16d3f8ec 100755
--- a/python/sglang/srt/managers/schedule_batch.py
+++ b/python/sglang/srt/managers/schedule_batch.py
@@ -140,7 +140,6 @@ from sglang.srt.observability.req_time_stats import (
 from sglang.srt.runtime_context import get_parallel
 from sglang.srt.sampling.sampling_batch_info import SamplingBatchInfo
 from sglang.srt.sampling.sampling_params import SamplingParams
-from sglang.srt.server_args import ServerArgs
 from sglang.srt.utils import flatten_nested_list
 from sglang.srt.utils.token_sequence_matcher import TokenSequenceMatcher
 
@@ -1960,7 +1959,6 @@ def release_req(
     *,
     req: Req,
     remaing_req_count: int,
-    server_args: ServerArgs,
     req_to_token_pool: ReqToTokenPool,
     token_to_kv_pool_allocator: BaseTokenToKVPoolAllocator,
     tree_cache: BasePrefixCache,
@@ -1997,7 +1995,6 @@ def release_req(
 def retract_all(
     *,
     reqs: List[Req],
-    server_args: ServerArgs,
     req_to_token_pool: ReqToTokenPool,
     token_to_kv_pool_allocator: BaseTokenToKVPoolAllocator,
     tree_cache: BasePrefixCache,
@@ -2008,7 +2005,6 @@ def retract_all(
         release_req(
             req=reqs[idx],
             remaing_req_count=len(reqs) - idx,
-            server_args=server_args,
             req_to_token_pool=req_to_token_pool,
             token_to_kv_pool_allocator=token_to_kv_pool_allocator,
             tree_cache=tree_cache,
@@ -2877,9 +2873,7 @@ class ScheduleBatch(ScheduleBatchDisaggregationDecodeMixin):
         evict_from_tree_cache(self.tree_cache, num_tokens)
         return self.token_to_kv_pool_allocator.available_size() >= num_tokens
 
-    def retract_decode(
-        self, server_args: ServerArgs
-    ) -> Tuple[List[Req], float, List[Req]]:
+    def retract_decode(self) -> Tuple[List[Req], float, List[Req]]:
         """Retract the decoding requests when there is not enough memory."""
         sorted_indices = self._get_decode_retraction_order(self.reqs)
         sorted_indices = beam_retraction_order(sorted_indices, self.reqs)
@@ -2913,12 +2907,10 @@ class ScheduleBatch(ScheduleBatchDisaggregationDecodeMixin):
                     self.token_to_kv_pool_allocator,
                 )
                 # Aborting, so a host backup to resume from would be wasted.
-                self.release_req(
-                    idx, len(sorted_indices), server_args, offload_kv=False
-                )
+                self.release_req(idx, len(sorted_indices), offload_kv=False)
                 continue
             # release memory and don't insert into the tree because we need the space instantly
-            if self.release_req(idx, len(sorted_indices), server_args):
+            if self.release_req(idx, len(sorted_indices)):
                 retracted_reqs.append(req)
             else:
                 # The retraction host pool could not hold the backup and the
@@ -2953,7 +2945,7 @@ class ScheduleBatch(ScheduleBatchDisaggregationDecodeMixin):
                     self.req_to_token_pool,
                     self.token_to_kv_pool_allocator,
                 )
-            self.release_req(last_idx, 0, server_args, offload_kv=False)
+            self.release_req(last_idx, 0, offload_kv=False)
             logger.warning(
                 "retract_decode: aborted last request %s due to OOM", last_req.rid
             )
@@ -3012,13 +3004,11 @@ class ScheduleBatch(ScheduleBatchDisaggregationDecodeMixin):
         self,
         idx: int,
         remaing_req_count: int,
-        server_args: ServerArgs,
         offload_kv: bool = True,
     ) -> bool:
         return release_req(
             req=self.reqs[idx],
             remaing_req_count=remaing_req_count,
-            server_args=server_args,
             req_to_token_pool=self.req_to_token_pool,
             token_to_kv_pool_allocator=self.token_to_kv_pool_allocator,
             tree_cache=self.tree_cache,
diff --git a/python/sglang/srt/managers/schedule_policy.py b/python/sglang/srt/managers/schedule_policy.py
index 34472fce2..2d4a497fc 100644
--- a/python/sglang/srt/managers/schedule_policy.py
+++ b/python/sglang/srt/managers/schedule_policy.py
@@ -1498,7 +1498,7 @@ class PrefillAdder:
                 )
                 release_counter += 1
                 self.running_batch.release_req(
-                    i, len(self.running_batch.reqs) - release_counter, server_args
+                    i, len(self.running_batch.reqs) - release_counter
                 )
             else:
                 keep_indices.append(i)
diff --git a/python/sglang/srt/managers/scheduler.py b/python/sglang/srt/managers/scheduler.py
index 29bd57bb1..edc52550b 100644
--- a/python/sglang/srt/managers/scheduler.py
+++ b/python/sglang/srt/managers/scheduler.py
@@ -598,7 +598,6 @@ class Scheduler(
                     else self.tp_cpu_group
                 ),
                 tree_cache=self.tree_cache,
-                server_args=self.server_args,
             )
         else:
             self.decode_offload_manager = None
@@ -3680,9 +3679,7 @@ class Scheduler(
                 if mamba_allocator is not None
                 else None
             )
-            retracted_reqs, new_token_ratio, reqs_to_abort = batch.retract_decode(
-                self.server_args
-            )
+            retracted_reqs, new_token_ratio, reqs_to_abort = batch.retract_decode()
             new_available_tokens = self.token_to_kv_pool_allocator.available_size()
             new_token_gained = new_available_tokens - old_available_tokens
             mamba_num_gained = (
@@ -4595,9 +4592,8 @@ class Scheduler(
         if envs.SGLANG_EXPOSE_OWN_ENV_VARS.get():
             ret["env_vars"] = exportable_env_vars()
 
-        # These fields are not msgpack-serializable (a config object and a bound
-        # signal handler); no reader consumes them.
-        ret.pop("model_config", None)
+        # A bound signal handler is not msgpack-serializable, and no reader
+        # consumes it.
         ret.pop("custom_sigquit_handler", None)
 
         return GetInternalStateReqOutput(internal_state=msgspec_to_builtins(ret))
@@ -4950,7 +4946,6 @@ class Scheduler(
             # discarded. Non-decode modes ignore offload_kv (they never offload).
             retract_all(
                 reqs=retract_reqs,
-                server_args=self.server_args,
                 req_to_token_pool=self.req_to_token_pool,
                 token_to_kv_pool_allocator=self.token_to_kv_pool_allocator,
                 tree_cache=self.tree_cache,
diff --git a/python/sglang/srt/managers/tokenizer_manager.py b/python/sglang/srt/managers/tokenizer_manager.py
index 5749a066e..0277a955b 100644
--- a/python/sglang/srt/managers/tokenizer_manager.py
+++ b/python/sglang/srt/managers/tokenizer_manager.py
@@ -490,7 +490,7 @@ class TokenizerManager(TokenizerControlMixin, TokenizerManagerScoreMixin):
             import_processors("sglang.srt.multimodal.processors")
             if mm_process_pkg := envs.SGLANG_EXTERNAL_MM_PROCESSOR_PACKAGE.get():
                 import_processors(mm_process_pkg, overwrite=True)
-            _processor = get_processor_wrapper(server_args)
+            _processor = get_processor_wrapper()
             transport_mode = determine_tensor_transport_mode()
 
             # We want to parallelize the image pre-processing so we create an executor for it
@@ -3602,7 +3602,7 @@ async def print_exception_wrapper(func):
         sys.exit(1)
 
 
-def get_processor_wrapper(server_args):
+def get_processor_wrapper():
     return get_processor(
         get_serving().tokenizer_path,
         tokenizer_mode=get_serving().tokenizer_mode,
diff --git a/python/sglang/srt/mem_cache/hybrid_cache/hybrid_pool_assembler.py b/python/sglang/srt/mem_cache/hybrid_cache/hybrid_pool_assembler.py
index 2b38326b0..57e68848c 100644
--- a/python/sglang/srt/mem_cache/hybrid_cache/hybrid_pool_assembler.py
+++ b/python/sglang/srt/mem_cache/hybrid_cache/hybrid_pool_assembler.py
@@ -97,7 +97,6 @@ def build_kv_host_pool(
     *,
     kv_pool: Any,
     page_size: int,
-    server_args: ServerArgs,
     use_mla: bool,
     override_kv_cache_dim: Optional[int] = None,
     host_size: Optional[float] = None,
@@ -179,7 +178,6 @@ def build_pool_entry(
 def build_kv_only_group(
     *,
     page_size: int,
-    server_args: ServerArgs,
     kv_pool: Any,
     full_layer_mapping: dict[int, int],
     use_mla: bool,
@@ -192,7 +190,6 @@ def build_kv_only_group(
     kv_host_pool = build_kv_host_pool(
         kv_pool=kv_pool,
         page_size=page_size,
-        server_args=server_args,
         use_mla=use_mla,
         override_kv_cache_dim=override_kv_cache_dim,
         host_size=host_size,
@@ -223,7 +220,6 @@ def build_kv_only_group(
 def build_hybrid_swa_group(
     *,
     page_size: int,
-    server_args: ServerArgs,
     full_kv_pool: Any,
     swa_kv_pool: Any,
     full_layer_mapping: dict[int, int],
@@ -241,7 +237,6 @@ def build_hybrid_swa_group(
     kv_host_pool = build_kv_host_pool(
         kv_pool=full_kv_pool,
         page_size=page_size,
-        server_args=server_args,
         use_mla=use_mla,
         host_size=kv_host_size,
         pool_label="full",
@@ -249,7 +244,6 @@ def build_hybrid_swa_group(
     swa_host_pool = build_kv_host_pool(
         kv_pool=swa_kv_pool,
         page_size=page_size,
-        server_args=server_args,
         use_mla=use_mla,
         host_size=swa_host_size,
         mtp_draft_device_pools=mtp_swa_device_pools,
@@ -310,7 +304,6 @@ def build_kv_only_stack(
     transfer_layer_num = len(full_layer_mapping)
     host_pool_group = build_kv_only_group(
         page_size=params.page_size,
-        server_args=server_args,
         kv_pool=kv_pool,
         full_layer_mapping=full_layer_mapping,
         use_mla=use_mla,
@@ -371,7 +364,6 @@ def build_hybrid_swa_stack(
 
     host_pool_group = build_hybrid_swa_group(
         page_size=params.page_size,
-        server_args=server_args,
         full_kv_pool=full_kv_pool,
         swa_kv_pool=swa_kv_pool,
         full_layer_mapping=full_layer_mapping,
@@ -723,7 +715,6 @@ def build_hybrid_mamba_stack(
     kv_host_pool = build_kv_host_pool(
         kv_pool=kv_pool,
         page_size=params.page_size,
-        server_args=server_args,
         use_mla=use_mla,
         host_size=kv_host_size,
         mtp_draft_device_pools=mtp_draft_device_pools,
@@ -826,7 +817,6 @@ def build_hybrid_mamba_swa_stack(
     kv_host_pool = build_kv_host_pool(
         kv_pool=full_kv_pool,
         page_size=page_size,
-        server_args=server_args,
         use_mla=False,
         host_size=kv_host_size,
         pool_label="full",
@@ -834,7 +824,6 @@ def build_hybrid_mamba_swa_stack(
     swa_host_pool = build_kv_host_pool(
         kv_pool=swa_kv_pool,
         page_size=page_size,
-        server_args=server_args,
         use_mla=False,
         host_size=swa_host_size,
         pool_label="swa",
@@ -925,7 +914,6 @@ def build_anchor_sidecar_stack(
     kv_host_pool = build_kv_host_pool(
         kv_pool=kv_pool,
         page_size=params.page_size,
-        server_args=server_args,
         use_mla=use_mla,
         override_kv_cache_dim=override_kv_cache_dim,
         mtp_draft_device_pools=mtp_draft_device_pools,
@@ -1013,7 +1001,6 @@ def build_full_draft_pools(
     *,
     draft_kv_pool: Any,
     tree_cache: Any,
-    server_args: ServerArgs,
 ) -> tuple[list[SidecarPoolSpec], list[PoolEntry]]:
     """Build draft KV/DSA sidecars whose indices follow target full KV."""
     from sglang.srt.mem_cache.memory_pool import (
@@ -1089,7 +1076,6 @@ def build_swa_draft_pools(
     *,
     draft_kv_pool: Any,
     tree_cache: Any,
-    server_args: ServerArgs,
 ) -> tuple[list[SidecarPoolSpec], list[PoolEntry]]:
     """Build a draft SWA sidecar whose indices follow target SWA."""
     draft_swa_pool = draft_kv_pool.swa_kv_pool
@@ -1143,7 +1129,6 @@ def build_hicache_draft_sidecars(
     *,
     draft_device_pools: tuple[Any, ...],
     tree_cache: Any,
-    server_args: ServerArgs,
 ) -> tuple[list[SidecarPoolSpec], list[PoolEntry]]:
     """Compose the full and SWA draft-sidecar paths."""
     from sglang.srt.mem_cache.base_swa_memory_pool import BaseSWAKVPool
@@ -1158,7 +1143,6 @@ def build_hicache_draft_sidecars(
     return builder(
         draft_kv_pool=draft_kv_pool,
         tree_cache=tree_cache,
-        server_args=server_args,
     )
 
 
@@ -1561,7 +1545,6 @@ class _MiniMaxSparseStrategy(StackStrategy):
     ):
         host_pool_group, cache_controller = build_minimax_sparse_hicache_stack(
             params=params,
-            server_args=server_args,
             sparse_pool=kvcache,
             load_cache_event=load_cache_event,
             storage_backend=storage_backend,
@@ -1754,7 +1737,6 @@ def attach_hybrid_pool_to_unified_cache(
 def build_minimax_sparse_hicache_stack(
     *,
     params: CacheInitParams,
-    server_args: ServerArgs,
     sparse_pool: Any,
     load_cache_event,
     storage_backend: Optional[str],
@@ -1787,7 +1769,6 @@ def build_minimax_sparse_hicache_stack(
     kv_host_pool = build_kv_host_pool(
         kv_pool=main_pool,
         page_size=params.page_size,
-        server_args=server_args,
         use_mla=False,
     )
     entries = [
@@ -1892,7 +1873,6 @@ def attach_hybrid_minimax_sparse_pool_to_hiradix_cache(
         else:
             host_pool_group, cache_controller = build_minimax_sparse_hicache_stack(
                 params=params,
-                server_args=server_args,
                 sparse_pool=sparse_pool,
                 load_cache_event=load_cache_event,
                 storage_backend=get_memory().hicache_storage_backend,
diff --git a/python/sglang/srt/mem_cache/kv_cache_builder.py b/python/sglang/srt/mem_cache/kv_cache_builder.py
index 741215220..629b8247b 100644
--- a/python/sglang/srt/mem_cache/kv_cache_builder.py
+++ b/python/sglang/srt/mem_cache/kv_cache_builder.py
@@ -66,7 +66,6 @@ def maybe_register_hicache_draft(
     *,
     tree_cache,
     draft_plan: HiCacheDraftPlan,
-    server_args: ServerArgs,
 ) -> None:
     from sglang.srt.speculative.base_spec_worker import HiCacheDraftMode
 
@@ -85,7 +84,6 @@ def maybe_register_hicache_draft(
     specs, entries = build_hicache_draft_sidecars(
         draft_device_pools=draft_plan.device_pools,
         tree_cache=tree_cache,
-        server_args=server_args,
     )
     for spec, entry in zip(specs, entries, strict=True):
         tree_cache.register_sidecar_pool(spec, entry)
@@ -322,7 +320,6 @@ def build_kv_cache(
         maybe_register_hicache_draft(
             tree_cache=tree_cache,
             draft_plan=hicache_draft_plan,
-            server_args=server_args,
         )
 
     if retraction_backup == "host_pool":
diff --git a/python/sglang/srt/model_executor/model_runner.py b/python/sglang/srt/model_executor/model_runner.py
index b3c5c9f75..80a69f575 100644
--- a/python/sglang/srt/model_executor/model_runner.py
+++ b/python/sglang/srt/model_executor/model_runner.py
@@ -652,7 +652,6 @@ class ModelRunner:
         prepare_moe_topk(
             model=self.model,
             model_config=self.model_config,
-            server_args=self.server_args,
             moe_ep_size=self.ps.moe_ep_size,
             moe_ep_rank=self.ps.moe_ep_rank,
         )
@@ -1187,7 +1186,6 @@ class ModelRunner:
         # before configure_kv_cache_dtype.)
         load_kv_cache_scales(
             model=self.model,
-            server_args=self.server_args,
             kv_cache_dtype=get_model().kv_cache_dtype,
         )
 
diff --git a/python/sglang/srt/model_executor/model_runner_components/load_model_utils.py b/python/sglang/srt/model_executor/model_runner_components/load_model_utils.py
index 921817903..d7932a56b 100644
--- a/python/sglang/srt/model_executor/model_runner_components/load_model_utils.py
+++ b/python/sglang/srt/model_executor/model_runner_components/load_model_utils.py
@@ -105,9 +105,7 @@ def maybe_trigger_remote_instance_nccl_send_group(
             t.start()
 
 
-def load_kv_cache_scales(
-    *, model, server_args: ServerArgs, kv_cache_dtype: str
-) -> None:
+def load_kv_cache_scales(*, model, kv_cache_dtype: str) -> None:
     """``kv_cache_dtype`` is the caller's resolved value. Required rather than
     defaulted: a fallback to ``server_args`` would be a hidden global read for
     any future caller that forgets to pass one."""
diff --git a/python/sglang/srt/model_executor/model_runner_components/moe_ep_setup.py b/python/sglang/srt/model_executor/model_runner_components/moe_ep_setup.py
index 25cdea784..5f5b63835 100644
--- a/python/sglang/srt/model_executor/model_runner_components/moe_ep_setup.py
+++ b/python/sglang/srt/model_executor/model_runner_components/moe_ep_setup.py
@@ -18,7 +18,6 @@ from sglang.srt.utils import get_bool_env_var, is_hip, log_info_on_rank0
 
 if TYPE_CHECKING:
     from sglang.srt.configs.model_config import ModelConfig
-    from sglang.srt.server_args import ServerArgs
 
 logger = logging.getLogger(__name__)
 
@@ -29,7 +28,6 @@ def prepare_moe_topk(
     *,
     model,
     model_config: ModelConfig,
-    server_args: ServerArgs,
     moe_ep_size: int,
     moe_ep_rank: int,
 ) -> None:
diff --git a/python/sglang/srt/server_args.py b/python/sglang/srt/server_args.py
index 22bdae06b..57a49f665 100644
--- a/python/sglang/srt/server_args.py
+++ b/python/sglang/srt/server_args.py
@@ -1279,6 +1279,8 @@ class ServerArgs:
         "defaults to --port + 10000.",
         NS("serving"),
     ] = None
+    # Env-only (SGLANG_GRPC_WORKER_THREADS); a field so the projection sees it.
+    grpc_worker_threads: A[Optional[int], Arg(no_cli=True), NS("serving")] = None
     sidecar: A[
         Optional[str],
         "Start a locally managed sidecar against the native gRPC server. "
@@ -3696,7 +3698,7 @@ class ServerArgs:
         except BaseException:
             # The handlers that ran already declared, and they are not
             # idempotent over their own output.
-            object.__setattr__(self, "_resolution_failed", True)
+            self._resolution_failed = True
             raise
         # Set here too, because the dummy/absent-model path returns before the
         # end of the pipeline that normally sets it: the gate is about whether
@@ -3747,8 +3749,8 @@ class ServerArgs:
 
         # Everything outside the fields, enumerated from the instance: the raw
         # snapshot, the stash, and what resolution memoized -- including the
-        # `get_model_config()` cache, which a resolved copy can no longer fill
-        # (the read-only guard refuses the write).
+        # `get_model_config()` memo, which the copy carries over rather than
+        # rebuild.
         field_names = {field.name for field in dataclasses.fields(self)}
         for name, value in vars(self).items():
             if name in field_names or name == "_resolution_finished":
@@ -4472,7 +4474,10 @@ class ServerArgs:
 
         # Native gRPC tuning knob is env-only; --grpc-port (CLI) enables the
         # native server, falling back to SGLANG_GRPC_PORT.
-        self.grpc_worker_threads = envs.SGLANG_GRPC_WORKER_THREADS.get()
+        self._declare(
+            "_handle_deprecated_args",
+            grpc_worker_threads=envs.SGLANG_GRPC_WORKER_THREADS.get(),
+        )
 
         grpc_port_env = envs.SGLANG_GRPC_PORT.get()
         if cfg.grpc_port is None and grpc_port_env is not None:
@@ -4496,10 +4501,10 @@ class ServerArgs:
                     "--grpc-port / SGLANG_GRPC_PORT "
                     f"({cfg.grpc_port}) must be between 1 and 65535"
                 )
-            if self.grpc_worker_threads < 1:
+            if cfg.grpc_worker_threads is not None and cfg.grpc_worker_threads < 1:
                 raise ValueError(
                     "SGLANG_GRPC_WORKER_THREADS "
-                    f"({self.grpc_worker_threads}) must be >= 1"
+                    f"({cfg.grpc_worker_threads}) must be >= 1"
                 )
 
         # Native gRPC is incompatible with launch paths it doesn't wire into.
@@ -7271,7 +7276,6 @@ class ServerArgs:
             "_handle_dwdp",
             ep_size=cfg.dwdp_size,
         )
-        self.moe_ep_size = cfg.dwdp_size
         self._declare(
             "_handle_dwdp",
             moe_dp_size=1,
@@ -7290,7 +7294,7 @@ class ServerArgs:
 
         logger.info(
             f"DWDP enabled: dwdp_size={cfg.dwdp_size}, "
-            f"auto-forced dp_size={cfg.dp_size}, moe_ep_size={self.moe_ep_size}, "
+            f"auto-forced dp_size={cfg.dp_size}, ep_size={cfg.dwdp_size}, "
             f"moe_dense_tp_size=1, moe_a2a_backend=none, "
             f"dp_attention_local_control_broadcast=True, "
             f"enable_dp_lm_head=True, SCHEDULER_SKIP_ALL_GATHER=True, "
@@ -10098,7 +10102,7 @@ class ServerArgs:
         cfg = resolving_view(self)
         from sglang.srt.configs.model_config import ModelConfig
 
-        memo = getattr(self, "model_config", None)
+        memo = getattr(self, "_model_config", None)
         if memo is not None:
             # The key is the path this record carried when the cache was
             # filled. The GGUF and ModelScope handlers declare a different
@@ -10112,7 +10116,7 @@ class ServerArgs:
                 return memo
 
         model_config = ModelConfig.from_server_args(self)
-        self.model_config = model_config
+        self._model_config = model_config
         self._model_config_built_from = cfg.model_path
         if model_config.is_hybrid_swa:
             logger.info(
@@ -10147,7 +10151,6 @@ class ServerArgs:
         if (
             getattr(self, "_resolution_finished", False)
             and not getattr(self, "_internal_write", False)
-            and name not in _CACHE_SLOTS
             and (not name.startswith("_") or name in _underscore_field_names())
         ):
             raise AttributeError(
@@ -10227,7 +10230,7 @@ class ServerArgs:
             # is supported.
             result = max(candidate_steps) + 1
         if getattr(self, "_resolution_finished", False):
-            object.__setattr__(self, "_max_speculative_num_draft_tokens", result)
+            self._max_speculative_num_draft_tokens = result
         return result
 
     @property
@@ -10851,7 +10854,7 @@ class ServerArgs:
             result = json.loads(self.modelexpress_config)
         else:
             result = self.modelexpress_config
-        object.__setattr__(self, "_mx_config_cache", result)
+        self._mx_config_cache = result
         return result
 
     @property
@@ -11058,14 +11061,6 @@ def m3_fp8_attn_gemm_enabled(args) -> bool:
     )
 
 
-# Caches, which the read-only guard lets through: a value the record derived
-# from itself is not resolved configuration, and a key that can invalidate on a
-# resolved record needs the refill to be storable there. Only the public-named
-# ones are listed -- a cache key spelled with a leading underscore is already
-# exempt.
-_CACHE_SLOTS = frozenset({"model_config"})
-
-
 # NOTE: The process-wide ServerArgs is owned by the runtime context
 # (sglang.srt.runtime_context). The two functions below are LEGACY shims kept
 # for the existing call-sites; they publish/read the same live object by
diff --git a/test/registered/spec/dspark/test_dspark_draft_path_default.py b/test/registered/spec/dspark/test_dspark_draft_path_default.py
index 12b4c3621..b6bd55bf7 100644
--- a/test/registered/spec/dspark/test_dspark_draft_path_default.py
+++ b/test/registered/spec/dspark/test_dspark_draft_path_default.py
@@ -40,7 +40,7 @@ def _make_dspark_server_args(
     server_args.speculative_algorithm = "DSPARK"
     server_args.speculative_draft_model_path = None
     server_args.speculative_dspark_block_size = 5
-    server_args.model_config = SimpleNamespace(hf_config=hf_config)
+    server_args._model_config = SimpleNamespace(hf_config=hf_config)
     return server_args
 
 
diff --git a/test/registered/unit/configs/test_multimodal_piecewise_cuda_graph.py b/test/registered/unit/configs/test_multimodal_piecewise_cuda_graph.py
index b16d22a0b..5db365996 100644
--- a/test/registered/unit/configs/test_multimodal_piecewise_cuda_graph.py
+++ b/test/registered/unit/configs/test_multimodal_piecewise_cuda_graph.py
@@ -72,7 +72,7 @@ class TestMultimodalPiecewiseCudaGraph(CustomTestCase):
 
     def test_supported_multimodal_model_upgrades_default_to_tc_piecewise(self):
         args = ServerArgs(model_path="dummy")
-        args.model_config = SimpleNamespace(
+        args._model_config = SimpleNamespace(
             is_multimodal_piecewise_cuda_graph_supported=True,
             is_multimodal_breakable_cuda_graph_supported=False,
         )
@@ -101,7 +101,7 @@ class TestMultimodalPiecewiseCudaGraph(CustomTestCase):
         args = ServerArgs(model_path="dummy")
         # trtllm_mla skips the tc_piecewise upgrade and keeps breakable, which
         # now serves MLA by falling back to the flashinfer MLA impl for extend.
-        args.model_config = SimpleNamespace(
+        args._model_config = SimpleNamespace(
             is_multimodal_piecewise_cuda_graph_supported=True,
             is_multimodal=False,
             is_multimodal_breakable_cuda_graph_supported=False,
@@ -169,7 +169,7 @@ class TestMultimodalPiecewiseCudaGraph(CustomTestCase):
 
     def test_embedding_gemma_forces_breakable_prefill(self):
         args = ServerArgs(model_path="dummy")
-        args.model_config = SimpleNamespace(
+        args._model_config = SimpleNamespace(
             is_embedding_gemma=True,
             is_multimodal=False,
             context_len=2048,
@@ -183,7 +183,7 @@ class TestMultimodalPiecewiseCudaGraph(CustomTestCase):
         args.chunked_prefill_size = 2048
 
         with (
-            patch.object(args, "get_model_config", return_value=args.model_config),
+            patch.object(args, "get_model_config", return_value=args._model_config),
             patch("sglang.srt.server_args.is_cuda", return_value=True),
         ):
             args._handle_model_capability_adjustments()
@@ -202,7 +202,7 @@ class TestMultimodalPiecewiseCudaGraph(CustomTestCase):
     def test_encoder_embedding_model_enables_embedding_mode_without_flag(self):
         args = ServerArgs(model_path="dummy")
         args.is_embedding = False
-        args.model_config = SimpleNamespace(
+        args._model_config = SimpleNamespace(
             embedding_model_spec=resolve_embedding_model_spec(
                 ["BertModel"],
                 is_embedding_requested=False,
@@ -212,7 +212,7 @@ class TestMultimodalPiecewiseCudaGraph(CustomTestCase):
             hf_config=SimpleNamespace(architectures=["BertModel"]),
         )
 
-        with patch.object(args, "get_model_config", return_value=args.model_config):
+        with patch.object(args, "get_model_config", return_value=args._model_config):
             args._handle_model_capability_adjustments()
 
         self.assertTrue(resolution_result(args, "is_embedding"))
diff --git a/test/registered/unit/mem_cache/test_decode_retraction_backup.py b/test/registered/unit/mem_cache/test_decode_retraction_backup.py
index f20ea8443..4330a2bd9 100644
--- a/test/registered/unit/mem_cache/test_decode_retraction_backup.py
+++ b/test/registered/unit/mem_cache/test_decode_retraction_backup.py
@@ -116,7 +116,6 @@ class TestDecodeRetractionBackup(unittest.TestCase):
                 mode=HiCacheDraftMode.SIDECAR,
                 device_pools=(draft_pool,),
             ),
-            server_args=server_args,
         )
         self.assertIn(PoolName.DRAFT, cache.host_pool_group.entry_map)
         cache.validate_retraction_host_capacity()
diff --git a/test/registered/unit/mem_cache/test_hybrid_pool_assembler.py b/test/registered/unit/mem_cache/test_hybrid_pool_assembler.py
index 185abd5f8..1005400e4 100644
--- a/test/registered/unit/mem_cache/test_hybrid_pool_assembler.py
+++ b/test/registered/unit/mem_cache/test_hybrid_pool_assembler.py
@@ -86,7 +86,6 @@ class TestDraftSidecarPoolDispatch(CustomTestCase):
         specs, entries = build_full_draft_pools(
             draft_kv_pool=draft_kv_pool,
             tree_cache=None,
-            server_args=None,
         )
 
         self.assertEqual(specs, [])
@@ -124,7 +123,6 @@ class TestDraftSidecarPoolDispatch(CustomTestCase):
             specs, entries = build_full_draft_pools(
                 draft_kv_pool=draft_kv_pool,
                 tree_cache=tree_cache,
-                server_args=server_args,
             )
 
         self.assertEqual(build_host_pool.call_args.kwargs["host_to_device_ratio"], 1.0)
diff --git a/test/registered/unit/server_args/test_model_config_cache.py b/test/registered/unit/server_args/test_model_config_cache.py
index fa08028a9..34236dc55 100644
--- a/test/registered/unit/server_args/test_model_config_cache.py
+++ b/test/registered/unit/server_args/test_model_config_cache.py
@@ -110,7 +110,7 @@ class TestTheModelConfigCache(CustomTestCase):
         server_args = self._resolved(
             model_path=_OBJECT_STORE_URI, load_format="runai_streamer"
         )
-        cached = server_args.__dict__["model_config"]
+        cached = server_args.__dict__["_model_config"]
         self.assertIsInstance(cached, ModelConfig)
         # The record still carries the URI the operator typed, and the
         # configuration carries the directory it read the metadata from.
@@ -162,7 +162,7 @@ class TestTheModelConfigCache(CustomTestCase):
         invalidates it."""
         server_args = ServerArgs(model_path=self._checkpoint(), device="cuda")
         stand_in = SimpleNamespace(model_path="somewhere/else")
-        server_args.model_config = stand_in
+        server_args._model_config = stand_in
 
         self.assertIs(server_args.get_model_config(), stand_in)
 
diff --git a/test/registered/unit/server_args/test_no_public_non_field_slot.py b/test/registered/unit/server_args/test_no_public_non_field_slot.py
new file mode 100644
index 000000000..b962763de
--- /dev/null
+++ b/test/registered/unit/server_args/test_no_public_non_field_slot.py
@@ -0,0 +1,83 @@
+"""The record grows no attribute the projection cannot see.
+
+A publicly-named attribute that is not a dataclass field is invisible to every
+other guard here: the namespace coverage walks fields, the projection walks
+fields, and the read ratchets watch field reads. Three of them accumulated that
+way -- a `ModelConfig` cache, an `moe_ep_size` that only a log line read, and an
+env-derived `grpc_worker_threads` that one entry point read across the boundary.
+
+Leading-underscore names are the record's own bookkeeping and stay: the
+read-only guard classifies writability by that spelling, so a private name is
+already outside the config tier by construction.
+"""
+
+import ast
+import dataclasses
+import pathlib
+import unittest
+
+import sglang
+from sglang.srt.server_args import ServerArgs
+from sglang.test.ci.ci_register import register_cpu_ci
+from sglang.test.test_utils import CustomTestCase
+
+register_cpu_ci(est_time=4, suite="base-a-test-cpu")
+
+
+def _self_written_attributes() -> set:
+    """Names `ServerArgs` writes on itself, by either spelling."""
+    source = (
+        pathlib.Path(next(iter(sglang.__path__))) / "srt" / "server_args.py"
+    ).read_text(encoding="utf-8-sig")
+    tree = ast.parse(source)
+    cls = next(
+        node
+        for node in tree.body
+        if isinstance(node, ast.ClassDef) and node.name == "ServerArgs"
+    )
+    written = set()
+    for node in ast.walk(cls):
+        if isinstance(node, ast.Assign):
+            for target in node.targets:
+                if (
+                    isinstance(target, ast.Attribute)
+                    and isinstance(target.value, ast.Name)
+                    and target.value.id == "self"
+                ):
+                    written.add(target.attr)
+        if (
+            isinstance(node, ast.Call)
+            and getattr(node.func, "attr", None) == "__setattr__"
+            and getattr(getattr(node.func, "value", None), "id", None) == "object"
+            and len(node.args) >= 2
+            and isinstance(node.args[1], ast.Constant)
+        ):
+            written.add(node.args[1].value)
+    return written
+
+
+class TestNoPublicNonFieldSlot(CustomTestCase):
+    def test_every_public_attribute_is_a_field(self):
+        written = _self_written_attributes()
+        self.assertGreater(
+            len(written),
+            5,
+            f"only {len(written)} self-writes found; the scan is broken, not the "
+            "record",
+        )
+        fields = {field.name for field in dataclasses.fields(ServerArgs)}
+        stray = sorted(
+            name for name in written if not name.startswith("_") and name not in fields
+        )
+        self.assertEqual(
+            [],
+            stray,
+            "these are written on the record under a public name but are not "
+            "fields, so the projection cannot see them and no other guard "
+            "watches them: make each a field, or give it the leading underscore "
+            f"that says it is the record's own bookkeeping: {stray}",
+        )
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/test/registered/unit/server_args/test_server_args.py b/test/registered/unit/server_args/test_server_args.py
index f43ff6c64..95aad9e59 100644
--- a/test/registered/unit/server_args/test_server_args.py
+++ b/test/registered/unit/server_args/test_server_args.py
@@ -283,7 +283,7 @@ class TestImageProcessorBackend(CustomTestCase):
 class TestMultimodalFeatureTransport(CustomTestCase):
     @staticmethod
     def _set_model_type(server_args, *, is_multimodal):
-        server_args.model_config = SimpleNamespace(is_multimodal=is_multimodal)
+        server_args._model_config = SimpleNamespace(is_multimodal=is_multimodal)
 
     @patch("sglang.srt.server_args.is_cuda", return_value=True)
     def test_cuda_ipc_is_explicit_and_bounded(self, _mock_is_cuda):
@@ -920,8 +920,8 @@ class TestFa4PageSizeAutoForce(CustomTestCase):
         # use_mla_backend() (mocked) and is_sm100_supported() (mocked), not a
         # real model_config. Pre-set the attribute so get_model_config returns
         # early without touching ModelConfig.from_server_args.
-        args.model_config = MagicMock()
-        args.model_config.hf_config.dual_chunk_attention_config = None
+        args._model_config = MagicMock()
+        args._model_config.hf_config.dual_chunk_attention_config = None
         return args
 
     @patch("sglang.srt.arg_groups.overrides.is_sm100_supported", return_value=True)
@@ -1809,7 +1809,7 @@ class TestCudaGraphConfigDataclassAccess(CustomTestCase):
 class TestCudaGraphDisaggregationRoles(CustomTestCase):
     def _handled_args(self, **overrides):
         args = ServerArgs(model_path="dummy", **overrides)
-        args.model_config = SimpleNamespace(
+        args._model_config = SimpleNamespace(
             hf_config=SimpleNamespace(architectures=["LlamaForCausalLM"]),
             is_piecewise_cuda_graph_disabled_model=False,
             is_multimodal=False,
@@ -1882,7 +1882,7 @@ class TestPrefillCudaGraphLoRACompatibility(CustomTestCase):
 
     def _handled_args(self, **overrides):
         args = ServerArgs(model_path="dummy", **overrides)
-        args.model_config = SimpleNamespace(
+        args._model_config = SimpleNamespace(
             hf_config=SimpleNamespace(architectures=["LlamaForCausalLM"]),
             is_piecewise_cuda_graph_disabled_model=False,
             is_multimodal=False,
@@ -1915,7 +1915,7 @@ class TestPrefillCudaGraphLoRACompatibility(CustomTestCase):
         # Pin the tc_piecewise LoRA rule itself, with the hardware rule
         # neutralized so this runs on CPU-only CI.
         args = ServerArgs(model_path="dummy", enable_lora=True)
-        args.model_config = SimpleNamespace(
+        args._model_config = SimpleNamespace(
             hf_config=SimpleNamespace(architectures=["LlamaForCausalLM"]),
             is_piecewise_cuda_graph_disabled_model=False,
             is_multimodal=False,
@@ -1945,7 +1945,7 @@ class TestBreakableCudaGraphMultimodalAllowlist(CustomTestCase):
 
     def _handled_args(self, *, architectures, is_multimodal, allowlisted):
         args = ServerArgs(model_path="dummy")
-        args.model_config = SimpleNamespace(
+        args._model_config = SimpleNamespace(
             hf_config=SimpleNamespace(architectures=architectures),
             is_piecewise_cuda_graph_disabled_model=False,
             is_multimodal=is_multimodal,
@@ -2129,7 +2129,7 @@ class TestDeepEPv2Args(CustomTestCase):
 
     def _args(self, **overrides):
         server_args = ServerArgs(model_path="dummy", moe_a2a_backend="deepep_v2")
-        server_args.model_config = SimpleNamespace(
+        server_args._model_config = SimpleNamespace(
             hf_config=SimpleNamespace(architectures=["DeepseekV4ForCausalLM"])
         )
         # The dummy path does not initialize phase configs.
@@ -2152,7 +2152,7 @@ class TestDeepEPv2Args(CustomTestCase):
             "Qwen3MoeForCausalLM",
         ):
             args = self._args(moe_runner_backend="deep_gemm")
-            args.model_config.hf_config.architectures = [architecture]
+            args._model_config.hf_config.architectures = [architecture]
             args._handle_a2a_moe()
 
     def test_unvalidated_and_missing_architectures_rejected(self):
@@ -2163,7 +2163,7 @@ class TestDeepEPv2Args(CustomTestCase):
             None,
         ):
             args = self._args(moe_runner_backend="deep_gemm")
-            args.model_config.hf_config.architectures = architectures
+            args._model_config.hf_config.architectures = architectures
             with self.assertRaisesRegex(ValueError, "not validated"):
                 args._handle_a2a_moe()
 
@@ -2188,7 +2188,7 @@ class TestDeepEPv2Args(CustomTestCase):
             moe_runner_backend="deep_gemm",
             rl_on_policy_target="fsdp",
         )
-        args.model_config.hf_config.architectures = ["Qwen3MoeForCausalLM"]
+        args._model_config.hf_config.architectures = ["Qwen3MoeForCausalLM"]
         with (
             envs.SGLANG_VLM_CACHE_SIZE_MB.override(envs.SGLANG_VLM_CACHE_SIZE_MB.get()),
             envs.SGLANG_ENABLE_DETERMINISTIC_INFERENCE.override(
@@ -2514,7 +2514,7 @@ class TestGrpcServerArgs(CustomTestCase):
         with envs.SGLANG_GRPC_WORKER_THREADS.override(8):
             sa._handle_deprecated_args()
         self.assertEqual(resolution_result(sa, "grpc_port"), 50051)
-        self.assertEqual(sa.grpc_worker_threads, 8)
+        self.assertEqual(resolution_result(sa, "grpc_worker_threads"), 8)
 
     def test_env_grpc_port_enables_native(self):
         sa = self._args(port=30000)
@@ -2698,13 +2698,11 @@ class TestGrpcServerArgs(CustomTestCase):
 
         fake_core = SimpleNamespace(start_server=MagicMock(return_value="handle"))
         fake_bridge = SimpleNamespace(RuntimeHandle=MagicMock(return_value="rt"))
-        # The host comes from the `serving` bag; `grpc_worker_threads` is not a
-        # field (resolution sets it from the environment), so it stays on the
-        # stand-in the call site is handed.
-        override = get_context().override_server_args(host="127.0.0.1", grpc_port=50051)
-        override.install()
+        override = get_context().override_server_args(
+            host="127.0.0.1", grpc_port=50051, grpc_worker_threads=4
+        )
+        server_args = override.install()
         self.addCleanup(override.restore)
-        server_args = SimpleNamespace(grpc_worker_threads=4)
         with (
             patch(
                 "sglang.srt.rust_extensions.load_rust_extension",
@@ -2728,6 +2726,7 @@ class TestGrpcServerArgs(CustomTestCase):
         self.assertEqual(
             set(kwargs), {"host", "port", "runtime_handle", "worker_threads"}
         )
+        self.assertEqual(kwargs["worker_threads"], 4)
         self.assertNotIn("max_prefill_tokens", kwargs)
 
 
diff --git a/test/registered/unit/test_dead_server_args_parameter_ratchet.py b/test/registered/unit/test_dead_server_args_parameter_ratchet.py
new file mode 100644
index 000000000..3428bbd7d
--- /dev/null
+++ b/test/registered/unit/test_dead_server_args_parameter_ratchet.py
@@ -0,0 +1,86 @@
+"""A function does not take the record it never reads.
+
+A `server_args` parameter that the body never names keeps a reference to the
+whole record alive across a call boundary, and it reads as an invitation: the
+next person to need one value takes it off the parameter that is already there,
+instead of deciding where that value should come from. Removing one usually
+uncovers the next -- the caller that only had a record to pass it along.
+
+Class methods are exempt: a base class, an override, or one implementation of a
+strategy carries the parameter for its contract, and the body of any single one
+of them is not evidence. This walks module-level functions only.
+"""
+
+import ast
+import pathlib
+import unittest
+
+import sglang
+from sglang.test.ci.ci_register import register_cpu_ci
+from sglang.test.test_utils import CustomTestCase
+
+register_cpu_ci(est_time=6, suite="base-a-test-cpu")
+
+_PACKAGE_ROOT = pathlib.Path(next(iter(sglang.__path__)))
+
+# The resolution pipeline builds the record, so a parameter there is the subject
+# rather than a passenger. `multimodal_gen` has a different, same-named class
+# outside this contract, as the mutation ratchet also records.
+_EXCLUDED = ("srt/arg_groups", "srt/server_args.py", "multimodal_gen")
+
+_BASELINE = 0
+
+
+def _dead_parameters():
+    found = []
+    scanned = 0
+    for path in sorted(_PACKAGE_ROOT.rglob("*.py")):
+        rel = path.relative_to(_PACKAGE_ROOT).as_posix()
+        if rel.startswith(_EXCLUDED):
+            continue
+        source = path.read_text(encoding="utf-8-sig")
+        if "server_args" not in source:
+            continue
+        scanned += 1
+        try:
+            tree = ast.parse(source)
+        except SyntaxError:
+            continue
+        for node in tree.body:
+            if not isinstance(node, (ast.FunctionDef, ast.AsyncFunctionDef)):
+                continue
+            taken = [a.arg for a in node.args.args] + [
+                a.arg for a in node.args.kwonlyargs
+            ]
+            if "server_args" not in taken:
+                continue
+            named = any(
+                isinstance(inner, ast.Name) and inner.id == "server_args"
+                for inner in ast.walk(node)
+                if inner is not node
+            )
+            if not named:
+                found.append(f"{rel}:{node.lineno} {node.name}")
+    return found, scanned
+
+
+class TestNoDeadServerArgsParameter(CustomTestCase):
+    def test_no_module_level_function_takes_a_record_it_ignores(self):
+        found, scanned = _dead_parameters()
+        self.assertGreater(
+            scanned,
+            50,
+            f"only {scanned} files mention server_args; the scan is broken, not "
+            "the tree",
+        )
+        self.assertEqual(
+            _BASELINE,
+            len(found),
+            "these functions take `server_args` and never name it; drop the "
+            "parameter and the argument at every call site, then check whether "
+            f"the caller still needs its own: {found}",
+        )
+
+
+if __name__ == "__main__":
+    unittest.main()