Enhance backend configurations with revision support and chat options (#16)

* fix: update Ollama backend default URL to remove /v1 suffix and set chat mode default to True

* feat: add revision support and unified chat template formatting for all backends

- Add `hf_revision`/`revision` parameter to model config, resolve, and backend constructors
- Parse and propagate revision from model spec (e.g. repo/model@main)
- Implement `format_prompt` utility to apply chat templates using tokenizer or HuggingFace model
- Use `format_prompt` in mlx-lm, llama-cpp, and openai-compat backends for consistent prompt formatting
- Add `transformers` as a required dependency

* feat: add disable_thinking option to suppress reasoning mode across backends

- Introduce `disable_thinking` flag to all backend configs and CLI, defaulting to True for consistent output comparison.
- Implement cross-backend support for disabling reasoning/thinking mode (Qwen3, DeepSeek-R1, Ollama, vLLM, OpenAI/OpenRouter).
- Strip reasoning-trigger tokens from prompts when disabled.
- Route to Ollama's native /api/chat endpoint with `think: false` when appropriate.
- Add tests for prompt formatting, payload construction, and retry logic when disabling thinking.

* feat: add disable_thinking option to suppress reasoning mode across backends

- Introduce `disable_thinking` flag to all backend configs and CLI, defaulting to True for consistent output comparison.
- Implement cross-backend support for disabling reasoning/thinking mode (Qwen3, DeepSeek-R1, Ollama, vLLM, OpenAI/OpenRouter).
- Strip reasoning-trigger tokens from prompts when disabled.
- Route to Ollama's native /api/chat endpoint with `think: false` when appropriate.
- Add tests for prompt formatting, payload construction, and retry logic when disabling thinking.

* refactor: move transformers dependency to optional http extra and cache tokenizer loading

* feat: add revision support for vllm-mlx backend and propagate resolved revision in diff command

* feat: propagate hf_revision to diff command and clarify Ollama chat handling comments

* feat: add --chat option to CLI and propagate chat mode to backend configuration

* fix: refine model spec revision parsing and tighten HF repo detection for tokenizer loading

* fix: pass revision to model loader in mlx backend

Author: NullPointerDepressiveDisorder

docs/backends.md

@@ -9,7 +9,7 @@
 | **mlx-lm**        | In-process | (local) | Local Apple Silicon inference with logprobs |
 | **llama-cpp**     | HTTP | `http://127.0.0.1:8080` | llama-server via `/completion` endpoint |
 | **vllm-mlx**      | HTTP | `http://127.0.0.1:8000` | Continuous batching on Apple Silicon |
-| **openai-compat** | HTTP | `http://127.0.0.1:11434/v1` | Any OpenAI-compatible server (vLLM, SGLang, Ollama) |
+| **openai-compat** | HTTP | `http://127.0.0.1:11434` | Any OpenAI-compatible server (vLLM, SGLang, Ollama) |
 
 ## mlx-lm
 
@@ -109,7 +109,7 @@ Generic backend for any server that implements the OpenAI API format. Works with
 
 | Model source | Default URL |
 |-------------|-------------|
-| Ollama tags (e.g., `llama3.1:8b`) | `http://127.0.0.1:11434/v1` |
+| Ollama tags (e.g., `llama3.1:8b`) | `http://127.0.0.1:11434` |
 | Custom server | Use `--base-url` |
 
 **Example with Ollama**:

pyproject.toml

@@ -37,9 +37,12 @@ dev = [
     "pytest-cov>=7.0.0",
     "ruff>=0.15.5",
 ]
-all = ["infer-check[mlx]", "infer-check[analysis]"]
+all = ["infer-check[mlx]", "infer-check[analysis]", "infer-check[http]"]
 mlx = ["mlx>=0.31.0", "mlx-lm<0.31.0"]
 analysis = ["matplotlib>=3.10.8", "scikit-learn>=1.8.0"]
+http = [
+    "transformers>=5.3.0",
+]
 
 [project.scripts]
 infer-check = "infer_check.cli:main"

src/infer_check/backends/base.py

@@ -41,7 +41,9 @@ class BackendConfig(BaseModel):
     backend_type: Literal["mlx-lm", "llama-cpp", "vllm-mlx", "openai-compat"]
     model_id: str
     quantization: str | None = None
+    hf_revision: str | None = None
     base_url: str | None = None
+    disable_thinking: bool = True
     extra: dict[str, Any] = Field(default_factory=dict)
 
 
@@ -53,33 +55,44 @@ def get_backend(config: BackendConfig) -> BackendAdapter:
         return MLXBackend(
             model_id=config.model_id,
             quantization=config.quantization,
+            revision=config.hf_revision,
+            disable_thinking=config.disable_thinking,
         )
     elif config.backend_type == "llama-cpp":
         from infer_check.backends.llama_cpp import LlamaCppBackend
 
         url = config.base_url or "http://127.0.0.1:8080"
-        return LlamaCppBackend(model_id=config.model_id, base_url=url)
+        return LlamaCppBackend(
+            model_id=config.model_id,
+            base_url=url,
+            revision=config.hf_revision,
+            disable_thinking=config.disable_thinking,
+        )
     elif config.backend_type == "vllm-mlx":
         from infer_check.backends.vllm_mlx import VLLMMLXBackend
 
         url = config.base_url or "http://127.0.0.1:8000"
         return VLLMMLXBackend(
             model_id=config.model_id,
             base_url=url,
-            chat=config.extra.get("chat", False),
+            chat=config.extra.get("chat", True),
+            revision=config.hf_revision,
+            disable_thinking=config.disable_thinking,
         )
     elif config.backend_type == "openai-compat":
         from infer_check.backends.openai_compat import OpenAICompatBackend
 
         if not config.base_url:
             raise ValueError(
-                "openai-compat backend requires --base-url. Example: --base-url http://127.0.0.1:11434/v1 (Ollama)"
+                "openai-compat backend requires --base-url. Example: --base-url http://127.0.0.1:11434 (Ollama)"
             )
         return OpenAICompatBackend(
             base_url=config.base_url,
             model_id=config.model_id,
             api_key=config.extra.get("api_key"),
-            chat=config.extra.get("chat", False),
+            chat=config.extra.get("chat", True),
+            revision=config.hf_revision,
+            disable_thinking=config.disable_thinking,
         )
     else:
         supported = ", ".join(["mlx-lm", "llama-cpp", "vllm-mlx", "openai-compat"])
@@ -91,6 +104,8 @@ def get_backend_for_model(
     backend_type: str | None = None,
     base_url: str | None = None,
     quantization: str | None = None,
+    disable_thinking: bool = True,
+    chat: bool = True,
 ) -> BackendAdapter:
     """Resolve model string to a backend and instantiate it.
 
@@ -106,6 +121,9 @@ def get_backend_for_model(
         model_id=resolved.model_id,
         base_url=base_url or resolved.base_url,
         quantization=quantization or resolved.label,
+        hf_revision=resolved.revision,
+        disable_thinking=disable_thinking,
+        extra={"chat": chat},
     )
 
     return get_backend(config)

src/infer_check/backends/llama_cpp.py

@@ -9,6 +9,7 @@
 import httpx
 
 from infer_check.types import InferenceResult, Prompt
+from infer_check.utils import format_prompt
 
 __all__ = ["LlamaCppBackend"]
 
@@ -19,9 +20,17 @@ class LlamaCppBackend:
     Communicates via the ``/completion`` endpoint.
     """
 
-    def __init__(self, model_id: str, base_url: str = "http://127.0.0.1:8080") -> None:
+    def __init__(
+        self,
+        model_id: str,
+        base_url: str = "http://127.0.0.1:8080",
+        revision: str | None = None,
+        disable_thinking: bool = True,
+    ) -> None:
         self._model_id = model_id
         self._base_url = base_url.rstrip("/")
+        self._revision = revision
+        self._disable_thinking = disable_thinking
         self._client = httpx.AsyncClient(base_url=self._base_url, timeout=120.0)
 
     # ------------------------------------------------------------------
@@ -34,9 +43,15 @@ def name(self) -> str:
 
     async def generate(self, prompt: Prompt) -> InferenceResult:
         """Send a completion request and parse the response."""
+        formatted = format_prompt(
+            prompt.text,
+            model_id=self._model_id,
+            revision=self._revision,
+            disable_thinking=self._disable_thinking,
+        )
         payload = {
             "model": self._model_id,
-            "prompt": prompt.text,
+            "prompt": formatted,
             "n_predict": prompt.max_tokens,
             "temperature": prompt.metadata.get("temperature", 0.0) if prompt.metadata else 0.0,
             "n_probs": 10,  # Request top 10 probabilities for KL divergence

src/infer_check/backends/mlx_lm.py

@@ -8,6 +8,7 @@
 from typing import Any, cast
 
 from infer_check.types import InferenceResult, Prompt
+from infer_check.utils import format_prompt
 
 __all__ = ["MLXBackend"]
 
@@ -19,9 +20,17 @@ class MLXBackend:
     importing this module alone never triggers a heavy download.
     """
 
-    def __init__(self, model_id: str, quantization: str | None = None) -> None:
+    def __init__(
+        self,
+        model_id: str,
+        quantization: str | None = None,
+        revision: str | None = None,
+        disable_thinking: bool = True,
+    ) -> None:
         self._model_id = model_id
         self._quantization = quantization
+        self._revision = revision
+        self._disable_thinking = disable_thinking
         self._model: Any = None
         self._tokenizer: Any = None
 
@@ -112,7 +121,7 @@ def _ensure_loaded(self) -> None:
 
         repo_or_path = str(model_path) if model_path.exists() else self._model_id
         try:
-            res = load(repo_or_path)
+            res = load(repo_or_path, revision=self._revision)
         except Exception as exc:
             msg = str(exc)
             if "404" in msg or "Repository Not Found" in msg:
@@ -132,25 +141,19 @@ def _ensure_loaded(self) -> None:
         self._model = res[0]
         self._tokenizer = res[1]
 
-    def _format_prompt(self, text: str) -> str:
-        """Apply chat template if the tokenizer has one (Instruct models).
-
-        Raw prompts sent to Instruct models produce undefined behavior that
-        varies across quantization levels, making comparisons meaningless.
-        """
-        if hasattr(self._tokenizer, "apply_chat_template") and self._tokenizer.chat_template is not None:
-            messages = [{"role": "user", "content": text}]
-            return str(self._tokenizer.apply_chat_template(messages, tokenize=False, add_generation_prompt=True))
-        return text
-
     def _generate_simple(self, prompt: Prompt) -> InferenceResult:
         """Generate using the high-level ``mlx_lm.generate`` API."""
         from mlx_lm import generate as mlx_generate
         from mlx_lm.sample_utils import make_sampler
 
         temp = prompt.metadata.get("temperature", 0.0) if prompt.metadata else 0.0
         sampler = make_sampler(temp=temp)
-        formatted = self._format_prompt(prompt.text)
+        formatted = format_prompt(
+            prompt.text,
+            tokenizer=self._tokenizer,
+            revision=self._revision,
+            disable_thinking=self._disable_thinking,
+        )
         start = time.perf_counter()
         text: str = mlx_generate(
             self._model,
@@ -184,7 +187,12 @@ def _generate_with_logprobs(self, prompt: Prompt) -> InferenceResult:
 
         temp = prompt.metadata.get("temperature", 0.0) if prompt.metadata else 0.0
         sampler = make_sampler(temp=temp)
-        formatted = self._format_prompt(prompt.text)
+        formatted = format_prompt(
+            prompt.text,
+            tokenizer=self._tokenizer,
+            revision=self._revision,
+            disable_thinking=self._disable_thinking,
+        )
         input_ids = mx.array(self._tokenizer.encode(formatted))
 
         # Configurable top-K to avoid memory explosion. Default to 10.