diff --git a/llama_stack/distribution/datatypes.py b/llama_stack/distribution/datatypes.py
index e07da001e..5e48ac0ad 100644
--- a/llama_stack/distribution/datatypes.py
+++ b/llama_stack/distribution/datatypes.py
@@ -146,7 +146,9 @@ in the runtime configuration to help route to the correct provider.""",
 
 
 class Provider(BaseModel):
-    provider_id: str
+    # provider_id of None means that the provider is not enabled - this happens
+    # when the provider is enabled via a conditional environment variable
+    provider_id: str | None
     provider_type: str
     config: dict[str, Any]
 
diff --git a/llama_stack/distribution/providers.py b/llama_stack/distribution/providers.py
index f238e3bba..1d9c1f4e9 100644
--- a/llama_stack/distribution/providers.py
+++ b/llama_stack/distribution/providers.py
@@ -48,6 +48,9 @@ class ProviderImpl(Providers):
         ret = []
         for api, providers in safe_config.providers.items():
             for p in providers:
+                # Skip providers that are not enabled
+                if p.provider_id is None:
+                    continue
                 ret.append(
                     ProviderInfo(
                         api=api,
diff --git a/llama_stack/distribution/resolver.py b/llama_stack/distribution/resolver.py
index 3726bb3a5..46cd1161e 100644
--- a/llama_stack/distribution/resolver.py
+++ b/llama_stack/distribution/resolver.py
@@ -255,6 +255,10 @@ async def instantiate_providers(
     impls: dict[Api, Any] = {}
     inner_impls_by_provider_id: dict[str, dict[str, Any]] = {f"inner-{x.value}": {} for x in router_apis}
     for api_str, provider in sorted_providers:
+        # Skip providers that are not enabled
+        if provider.provider_id is None:
+            continue
+
         deps = {a: impls[a] for a in provider.spec.api_dependencies}
         for a in provider.spec.optional_api_dependencies:
             if a in impls:
diff --git a/llama_stack/providers/remote/vector_io/chroma/chroma.py b/llama_stack/providers/remote/vector_io/chroma/chroma.py
index 06d1786f0..3bef39e9c 100644
--- a/llama_stack/providers/remote/vector_io/chroma/chroma.py
+++ b/llama_stack/providers/remote/vector_io/chroma/chroma.py
@@ -137,6 +137,9 @@ class ChromaVectorIOAdapter(VectorIO, VectorDBsProtocolPrivate):
 
     async def initialize(self) -> None:
         if isinstance(self.config, RemoteChromaVectorIOConfig):
+            if not self.config.url:
+                raise ValueError("URL is a required parameter for the remote Chroma provider's config")
+
             log.info(f"Connecting to Chroma server at: {self.config.url}")
             url = self.config.url.rstrip("/")
             parsed = urlparse(url)
diff --git a/llama_stack/providers/remote/vector_io/chroma/config.py b/llama_stack/providers/remote/vector_io/chroma/config.py
index 4e893fab4..bd11d5f8c 100644
--- a/llama_stack/providers/remote/vector_io/chroma/config.py
+++ b/llama_stack/providers/remote/vector_io/chroma/config.py
@@ -10,7 +10,7 @@ from pydantic import BaseModel
 
 
 class ChromaVectorIOConfig(BaseModel):
-    url: str
+    url: str | None
 
     @classmethod
     def sample_run_config(cls, url: str = "${env.CHROMADB_URL}", **kwargs: Any) -> dict[str, Any]:
diff --git a/llama_stack/providers/remote/vector_io/pgvector/config.py b/llama_stack/providers/remote/vector_io/pgvector/config.py
index 041e864ca..92908aa8a 100644
--- a/llama_stack/providers/remote/vector_io/pgvector/config.py
+++ b/llama_stack/providers/remote/vector_io/pgvector/config.py
@@ -13,11 +13,11 @@ from llama_stack.schema_utils import json_schema_type
 
 @json_schema_type
 class PGVectorVectorIOConfig(BaseModel):
-    host: str = Field(default="localhost")
-    port: int = Field(default=5432)
-    db: str = Field(default="postgres")
-    user: str = Field(default="postgres")
-    password: str = Field(default="mysecretpassword")
+    host: str | None = Field(default="localhost")
+    port: int | None = Field(default=5432)
+    db: str | None = Field(default="postgres")
+    user: str | None = Field(default="postgres")
+    password: str | None = Field(default="mysecretpassword")
 
     @classmethod
     def sample_run_config(
diff --git a/llama_stack/templates/experimental-post-training/run.yaml b/llama_stack/templates/experimental-post-training/run.yaml
index 393cba41d..a74aa3647 100644
--- a/llama_stack/templates/experimental-post-training/run.yaml
+++ b/llama_stack/templates/experimental-post-training/run.yaml
@@ -24,7 +24,7 @@ providers:
   - provider_id: ollama
     provider_type: remote::ollama
     config:
-      url: ${env.OLLAMA_URL:http://localhost:11434}
+      url: ${env.OLLAMA_URL:=http://localhost:11434}
   eval:
   - provider_id: meta-reference
     provider_type: inline::meta-reference
@@ -32,7 +32,7 @@ providers:
       kvstore:
         type: sqlite
         namespace: null
-        db_path: ${env.SQLITE_STORE_DIR:~/.llama/distributions/meta-reference-gpu}/meta_reference_eval.db
+        db_path: ${env.SQLITE_STORE_DIR:=~/.llama/distributions/meta-reference-gpu}/meta_reference_eval.db
   scoring:
   - provider_id: basic
     provider_type: inline::basic
@@ -40,7 +40,7 @@ providers:
   - provider_id: braintrust
     provider_type: inline::braintrust
     config:
-      openai_api_key: ${env.OPENAI_API_KEY:}
+      openai_api_key: ${env.OPENAI_API_KEY:+}
   datasetio:
   - provider_id: localfs
     provider_type: inline::localfs
@@ -48,14 +48,14 @@ providers:
       kvstore:
         type: sqlite
         namespace: null
-        db_path: ${env.SQLITE_STORE_DIR:~/.llama/distributions/experimental-post-training}/localfs_datasetio.db
+        db_path: ${env.SQLITE_STORE_DIR:=~/.llama/distributions/experimental-post-training}/localfs_datasetio.db
   - provider_id: huggingface
     provider_type: remote::huggingface
     config:
       kvstore:
         type: sqlite
         namespace: null
-        db_path: ${env.SQLITE_STORE_DIR:~/.llama/distributions/huggingface}/huggingface_datasetio.db
+        db_path: ${env.SQLITE_STORE_DIR:=~/.llama/distributions/huggingface}/huggingface_datasetio.db
   telemetry:
   - provider_id: meta-reference
     provider_type: inline::meta-reference
@@ -74,7 +74,7 @@ providers:
       persistence_store:
         type: sqlite
         namespace: null
-        db_path: ${env.SQLITE_STORE_DIR:~/.llama/distributions/experimental-post-training}/agents_store.db
+        db_path: ${env.SQLITE_STORE_DIR:=~/.llama/distributions/experimental-post-training}/agents_store.db
   safety:
   - provider_id: llama-guard
     provider_type: inline::llama-guard
@@ -86,19 +86,19 @@ providers:
       kvstore:
         type: sqlite
         namespace: null
-        db_path: ${env.SQLITE_STORE_DIR:~/.llama/distributions/experimental-post-training}/faiss_store.db
+        db_path: ${env.SQLITE_STORE_DIR:=~/.llama/distributions/experimental-post-training}/faiss_store.db
   tool_runtime:
   - provider_id: brave-search
     provider_type: remote::brave-search
     config:
-      api_key: ${env.BRAVE_SEARCH_API_KEY:}
+      api_key: ${env.BRAVE_SEARCH_API_KEY:+}
       max_results: 3
 
 
 metadata_store:
   namespace: null
   type: sqlite
-  db_path: ${env.SQLITE_STORE_DIR:~/.llama/distributions/experimental-post-training}/registry.db
+  db_path: ${env.SQLITE_STORE_DIR:=~/.llama/distributions/experimental-post-training}/registry.db
 models: []
 shields: []
 vector_dbs: []
diff --git a/llama_stack/templates/meta-reference-gpu/meta_reference.py b/llama_stack/templates/meta-reference-gpu/meta_reference.py
index 57fb8f2af..4bfb4e9d8 100644
--- a/llama_stack/templates/meta-reference-gpu/meta_reference.py
+++ b/llama_stack/templates/meta-reference-gpu/meta_reference.py
@@ -46,7 +46,7 @@ def get_distribution_template() -> DistributionTemplate:
         provider_type="inline::meta-reference",
         config=MetaReferenceInferenceConfig.sample_run_config(
             model="${env.INFERENCE_MODEL}",
-            checkpoint_dir="${env.INFERENCE_CHECKPOINT_DIR:null}",
+            checkpoint_dir="${env.INFERENCE_CHECKPOINT_DIR:=null}",
         ),
     )
     embedding_provider = Provider(
@@ -112,7 +112,7 @@ def get_distribution_template() -> DistributionTemplate:
                             provider_type="inline::meta-reference",
                             config=MetaReferenceInferenceConfig.sample_run_config(
                                 model="${env.SAFETY_MODEL}",
-                                checkpoint_dir="${env.SAFETY_CHECKPOINT_DIR:null}",
+                                checkpoint_dir="${env.SAFETY_CHECKPOINT_DIR:=null}",
                             ),
                         ),
                     ],
diff --git a/llama_stack/templates/meta-reference-gpu/run-with-safety.yaml b/llama_stack/templates/meta-reference-gpu/run-with-safety.yaml
index 6b15a1e01..f60f4505f 100644
--- a/llama_stack/templates/meta-reference-gpu/run-with-safety.yaml
+++ b/llama_stack/templates/meta-reference-gpu/run-with-safety.yaml
@@ -16,7 +16,7 @@ providers:
     provider_type: inline::meta-reference
     config:
       model: ${env.INFERENCE_MODEL}
-      checkpoint_dir: ${env.INFERENCE_CHECKPOINT_DIR:null}
+      checkpoint_dir: ${env.INFERENCE_CHECKPOINT_DIR:=null}
       quantization:
         type: ${env.QUANTIZATION_TYPE:=bf16}
       model_parallel_size: ${env.MODEL_PARALLEL_SIZE:=0}
@@ -29,7 +29,7 @@ providers:
     provider_type: inline::meta-reference
     config:
       model: ${env.SAFETY_MODEL}
-      checkpoint_dir: ${env.SAFETY_CHECKPOINT_DIR:null}
+      checkpoint_dir: ${env.SAFETY_CHECKPOINT_DIR:=null}
       quantization:
         type: ${env.QUANTIZATION_TYPE:=bf16}
       model_parallel_size: ${env.MODEL_PARALLEL_SIZE:=0}
diff --git a/llama_stack/templates/meta-reference-gpu/run.yaml b/llama_stack/templates/meta-reference-gpu/run.yaml
index 1b44a0b3e..064b958c8 100644
--- a/llama_stack/templates/meta-reference-gpu/run.yaml
+++ b/llama_stack/templates/meta-reference-gpu/run.yaml
@@ -16,7 +16,7 @@ providers:
     provider_type: inline::meta-reference
     config:
       model: ${env.INFERENCE_MODEL}
-      checkpoint_dir: ${env.INFERENCE_CHECKPOINT_DIR:null}
+      checkpoint_dir: ${env.INFERENCE_CHECKPOINT_DIR:=null}
       quantization:
         type: ${env.QUANTIZATION_TYPE:=bf16}
       model_parallel_size: ${env.MODEL_PARALLEL_SIZE:=0}
diff --git a/llama_stack/templates/open-benchmark/open_benchmark.py b/llama_stack/templates/open-benchmark/open_benchmark.py
index b4cfbdb52..8d7a9dc1e 100644
--- a/llama_stack/templates/open-benchmark/open_benchmark.py
+++ b/llama_stack/templates/open-benchmark/open_benchmark.py
@@ -46,7 +46,7 @@ def get_inference_providers() -> tuple[list[Provider], dict[str, list[ProviderMo
                     model_type=ModelType.llm,
                 )
             ],
-            OpenAIConfig.sample_run_config(api_key="${env.OPENAI_API_KEY:}"),
+            OpenAIConfig.sample_run_config(api_key="${env.OPENAI_API_KEY:+}"),
         ),
         (
             "anthropic",
@@ -56,7 +56,7 @@ def get_inference_providers() -> tuple[list[Provider], dict[str, list[ProviderMo
                     model_type=ModelType.llm,
                 )
             ],
-            AnthropicConfig.sample_run_config(api_key="${env.ANTHROPIC_API_KEY:}"),
+            AnthropicConfig.sample_run_config(api_key="${env.ANTHROPIC_API_KEY:+}"),
         ),
         (
             "gemini",
@@ -66,17 +66,17 @@ def get_inference_providers() -> tuple[list[Provider], dict[str, list[ProviderMo
                     model_type=ModelType.llm,
                 )
             ],
-            GeminiConfig.sample_run_config(api_key="${env.GEMINI_API_KEY:}"),
+            GeminiConfig.sample_run_config(api_key="${env.GEMINI_API_KEY:+}"),
         ),
         (
             "groq",
             [],
-            GroqConfig.sample_run_config(api_key="${env.GROQ_API_KEY:}"),
+            GroqConfig.sample_run_config(api_key="${env.GROQ_API_KEY:+}"),
         ),
         (
             "together",
             [],
-            TogetherImplConfig.sample_run_config(api_key="${env.TOGETHER_API_KEY:}"),
+            TogetherImplConfig.sample_run_config(api_key="${env.TOGETHER_API_KEY:+}"),
         ),
     ]
     inference_providers = []
diff --git a/llama_stack/templates/open-benchmark/run.yaml b/llama_stack/templates/open-benchmark/run.yaml
index 403b0fd3d..653d76bd4 100644
--- a/llama_stack/templates/open-benchmark/run.yaml
+++ b/llama_stack/templates/open-benchmark/run.yaml
@@ -15,20 +15,20 @@ providers:
   - provider_id: openai
     provider_type: remote::openai
     config:
-      api_key: ${env.OPENAI_API_KEY:}
+      api_key: ${env.OPENAI_API_KEY:+}
   - provider_id: anthropic
     provider_type: remote::anthropic
     config:
-      api_key: ${env.ANTHROPIC_API_KEY:}
+      api_key: ${env.ANTHROPIC_API_KEY:+}
   - provider_id: gemini
     provider_type: remote::gemini
     config:
-      api_key: ${env.GEMINI_API_KEY:}
+      api_key: ${env.GEMINI_API_KEY:+}
   - provider_id: groq
     provider_type: remote::groq
     config:
       url: https://api.groq.com
-      api_key: ${env.GROQ_API_KEY:}
+      api_key: ${env.GROQ_API_KEY:+}
   - provider_id: together
     provider_type: remote::together
     config:
diff --git a/llama_stack/templates/postgres-demo/postgres_demo.py b/llama_stack/templates/postgres-demo/postgres_demo.py
index 5d42b8901..5b1a302e3 100644
--- a/llama_stack/templates/postgres-demo/postgres_demo.py
+++ b/llama_stack/templates/postgres-demo/postgres_demo.py
@@ -29,7 +29,7 @@ def get_distribution_template() -> DistributionTemplate:
             provider_id="vllm-inference",
             provider_type="remote::vllm",
             config=VLLMInferenceAdapterConfig.sample_run_config(
-                url="${env.VLLM_URL:http://localhost:8000/v1}",
+                url="${env.VLLM_URL:=http://localhost:8000/v1}",
             ),
         ),
     ]
diff --git a/llama_stack/templates/postgres-demo/run.yaml b/llama_stack/templates/postgres-demo/run.yaml
index 03b7a59fb..66253cbdb 100644
--- a/llama_stack/templates/postgres-demo/run.yaml
+++ b/llama_stack/templates/postgres-demo/run.yaml
@@ -12,7 +12,7 @@ providers:
   - provider_id: vllm-inference
     provider_type: remote::vllm
     config:
-      url: ${env.VLLM_URL:http://localhost:8000/v1}
+      url: ${env.VLLM_URL:=http://localhost:8000/v1}
       max_tokens: ${env.VLLM_MAX_TOKENS:=4096}
       api_token: ${env.VLLM_API_TOKEN:=fake}
       tls_verify: ${env.VLLM_TLS_VERIFY:=true}
diff --git a/llama_stack/templates/remote-vllm/run-with-safety.yaml b/llama_stack/templates/remote-vllm/run-with-safety.yaml
index b297f1489..e306a771b 100644
--- a/llama_stack/templates/remote-vllm/run-with-safety.yaml
+++ b/llama_stack/templates/remote-vllm/run-with-safety.yaml
@@ -15,7 +15,7 @@ providers:
   - provider_id: vllm-inference
     provider_type: remote::vllm
     config:
-      url: ${env.VLLM_URL:http://localhost:8000/v1}
+      url: ${env.VLLM_URL:=http://localhost:8000/v1}
       max_tokens: ${env.VLLM_MAX_TOKENS:=4096}
       api_token: ${env.VLLM_API_TOKEN:=fake}
       tls_verify: ${env.VLLM_TLS_VERIFY:=true}
diff --git a/llama_stack/templates/remote-vllm/run.yaml b/llama_stack/templates/remote-vllm/run.yaml
index 6bd332cc9..1dbef96a2 100644
--- a/llama_stack/templates/remote-vllm/run.yaml
+++ b/llama_stack/templates/remote-vllm/run.yaml
@@ -15,7 +15,7 @@ providers:
   - provider_id: vllm-inference
     provider_type: remote::vllm
     config:
-      url: ${env.VLLM_URL:http://localhost:8000/v1}
+      url: ${env.VLLM_URL:=http://localhost:8000/v1}
       max_tokens: ${env.VLLM_MAX_TOKENS:=4096}
       api_token: ${env.VLLM_API_TOKEN:=fake}
       tls_verify: ${env.VLLM_TLS_VERIFY:=true}
diff --git a/llama_stack/templates/remote-vllm/vllm.py b/llama_stack/templates/remote-vllm/vllm.py
index 94606e9d0..a8e1d9a58 100644
--- a/llama_stack/templates/remote-vllm/vllm.py
+++ b/llama_stack/templates/remote-vllm/vllm.py
@@ -44,7 +44,7 @@ def get_distribution_template() -> DistributionTemplate:
         provider_id="vllm-inference",
         provider_type="remote::vllm",
         config=VLLMInferenceAdapterConfig.sample_run_config(
-            url="${env.VLLM_URL:http://localhost:8000/v1}",
+            url="${env.VLLM_URL:=http://localhost:8000/v1}",
         ),
     )
     embedding_provider = Provider(
diff --git a/llama_stack/templates/starter/run.yaml b/llama_stack/templates/starter/run.yaml
index f7c53170b..00faf029e 100644
--- a/llama_stack/templates/starter/run.yaml
+++ b/llama_stack/templates/starter/run.yaml
@@ -68,7 +68,7 @@ providers:
         type: sqlite
         namespace: null
         db_path: ${env.SQLITE_STORE_DIR:=~/.llama/distributions/starter}/faiss_store.db
-  - provider_id: ${env.ENABLE_SQLITE_VEC+sqlite-vec}
+  - provider_id: ${env.ENABLE_SQLITE_VEC:+sqlite-vec}
     provider_type: inline::sqlite-vec
     config:
       db_path: ${env.SQLITE_STORE_DIR:=~/.llama/distributions/starter}/sqlite_vec.db
diff --git a/llama_stack/templates/starter/starter.py b/llama_stack/templates/starter/starter.py
index df31fed84..c0f2646d7 100644
--- a/llama_stack/templates/starter/starter.py
+++ b/llama_stack/templates/starter/starter.py
@@ -175,7 +175,7 @@ def get_distribution_template() -> DistributionTemplate:
             config=FaissVectorIOConfig.sample_run_config(f"~/.llama/distributions/{name}"),
         ),
         Provider(
-            provider_id="${env.ENABLE_SQLITE_VEC+sqlite-vec}",
+            provider_id="${env.ENABLE_SQLITE_VEC:+sqlite-vec}",
             provider_type="inline::sqlite-vec",
             config=SQLiteVectorIOConfig.sample_run_config(f"~/.llama/distributions/{name}"),
         ),