feat(providers): add Cheaper Inference as an OpenAI-compatible gateway

core/config.py

@@ -317,6 +317,7 @@ class ProvidersConfig(_Base):
     openrouter: ProviderConfig = Field(default_factory=ProviderConfig)
     forge: ProviderConfig = Field(default_factory=ProviderConfig)
     requesty: ProviderConfig = Field(default_factory=ProviderConfig)
+    cheaperinference: ProviderConfig = Field(default_factory=ProviderConfig)
     bedrock: ProviderConfig = Field(default_factory=ProviderConfig)
     anthropic: ProviderConfig = Field(default_factory=ProviderConfig)
     openai: ProviderConfig = Field(default_factory=ProviderConfig)

core/providers/registry.py

@@ -233,6 +233,19 @@ def _matches_declared_endpoint(self, api_base: str | None) -> bool:
         # OpenRouter-style gateways above.
         strip_model_prefix=True,
     ),
+    ProviderSpec(
+        name="cheaperinference",
+        keywords=("cheaperinference",),
+        env_key="CHEAPER_INFERENCE_API_KEY",
+        display_name="Cheaper Inference",
+        backend="openai_compat",
+        is_gateway=True,
+        endpoint_class="gateway",
+        detect_by_base_keyword="cheaperinference.com",
+        default_api_base="https://api.cheaperinference.com/v1",
+        # Cheaper Inference resolves bare model ids, like Forge.
+        strip_model_prefix=True,
+    ),
     ProviderSpec(
         name="bedrock",
         keywords=("bedrock",),

docs/guide/models.md

@@ -105,6 +105,25 @@ This first integration sends the configured value as a bearer token through
 Bedrock's OpenAI-compatible Chat Completions API. It does **not** implement AWS
 SigV4 signing, IAM role/profile discovery, SSO, or the native Converse API.
 
+### Cheaper Inference
+
+[Cheaper Inference](https://cheaperinference.com) is an OpenAI-compatible
+gateway to models from several labs. Each model costs 15–60% less than the
+list price of its lab. Create a key at
+[cheaperinference.com/signup](https://cheaperinference.com/signup) and expose
+it through `CHEAPER_INFERENCE_API_KEY`:
+
+```console
+deepcode provider set my-cheaperinference --template cheaperinference \
+  --api-key-env CHEAPER_INFERENCE_API_KEY
+deepcode provider models my-cheaperinference --refresh
+deepcode provider test my-cheaperinference --model gpt-5.4-mini --agent
+```
+
+The template uses `https://api.cheaperinference.com/v1`. Model IDs are bare,
+for example `gpt-5.4-mini`, `gpt-5.4` or `claude-sonnet-5`. Cheaper Inference
+serves chat models only; it has no embeddings endpoint.
+
 ## Declared models and capacities
 
 If your server's model is missing from the list, add it manually. You can also

tests/test_cheaperinference_provider.py

@@ -0,0 +1,71 @@
+"""Cheaper Inference gateway registration.
+
+Cheaper Inference is an OpenAI-compatible gateway on the generic
+``openai_compat`` backend. Like Forge, it resolves bare model ids.
+"""
+
+from __future__ import annotations
+
+import sys
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parents[1]
+if str(ROOT) not in sys.path:
+    sys.path.insert(0, str(ROOT))
+
+from core.config import DeepCodeConfig, ProvidersConfig  # noqa: E402
+from core.providers.credentials import CredentialStore  # noqa: E402
+from core.providers.model_compat import resolve_model_compat  # noqa: E402
+from core.providers.profiles import ConnectionResolver  # noqa: E402
+from core.providers.registry import find_by_name  # noqa: E402
+
+
+def test_cheaperinference_is_registered_as_a_gateway():
+    spec = find_by_name("cheaperinference")
+    assert spec is not None
+    assert spec.display_name == "Cheaper Inference"
+    assert spec.is_gateway is True
+    assert spec.endpoint_class == "gateway"
+    assert spec.backend == "openai_compat"
+    assert spec.env_key == "CHEAPER_INFERENCE_API_KEY"
+    assert spec.default_api_base == "https://api.cheaperinference.com/v1"
+
+
+def test_cheaperinference_strips_the_vendor_prefix():
+    """Cheaper Inference resolves bare model ids, like Forge."""
+
+    spec = find_by_name("cheaperinference")
+    assert spec.strip_model_prefix is True
+    compat = resolve_model_compat(
+        model_name="openai/gpt-5.4-mini", spec=spec, reasoning_effort=None
+    )
+    assert compat.model_name == "gpt-5.4-mini"
+
+
+def test_cheaperinference_does_not_collide_with_other_gateway_detection():
+    spec = find_by_name("cheaperinference")
+    assert spec.detect_by_base_keyword == "cheaperinference.com"
+    assert spec.detect_by_key_prefix == ""
+
+
+def test_providers_config_exposes_cheaperinference():
+    """``config.py`` reads providers via ``getattr(..., spec.name)``, so a
+    missing field silently disables the provider everywhere."""
+
+    assert hasattr(ProvidersConfig(), "cheaperinference")
+
+
+def test_cheaperinference_profile_uses_the_default_base(tmp_path: Path):
+    credentials = CredentialStore(tmp_path / "credentials.json")
+    credentials.set("my-ci", "ci-test-secret")
+    config = DeepCodeConfig.model_validate(
+        {"providers": {"profiles": {"my-ci": {"template": "cheaperinference"}}}}
+    )
+    connection = ConnectionResolver(config, credentials).resolve_connection("my-ci")
+
+    assert connection.provider_name == "cheaperinference"
+    assert connection.adapter == "openai_compat"
+    assert connection.api_base == "https://api.cheaperinference.com/v1"
+    assert connection.api_key == "ci-test-secret"
+    assert connection.model_catalog == "openai"
+    assert connection.is_usable is True

tests/test_provider_egress.py

@@ -201,6 +201,7 @@ def test_invalid_policy_entry_fails_closed():
         ("openrouter", "gateway"),
         ("requesty", "gateway"),
         ("forge", "gateway"),
+        ("cheaperinference", "gateway"),
         ("zhipu", "aggregator"),
         ("dashscope", "aggregator"),
         ("minimax", "aggregator"),