feat: Add reported context offset functionality and update related configurations

README.md

@@ -25,6 +25,7 @@ The application is configured via `src/main/resources/application.properties`.
 | `server.port` | `11434` | The port on which the bridge runs. |
 | `bridge.upstream-base-url` | `http://localhost:5001` | The base URL of the upstream LLM server. |
 | `bridge.version` | `0.24.0` | The ollama version to report. |
+| `bridge.reported-context-offset` | `0` | Tokens to subtract from the downstream context length before reporting it to clients. |
 
 ## API Endpoints
 
@@ -68,11 +69,23 @@ This project is licensed under the Apache License 2.0. See the `LICENSE` file fo
     ./mvnw spring-boot:run
     ```
 
+    You can also override any of the bridge settings with JVM system properties, for example:
+    ```bash
+    java -Dserver.port=11435 -Dbridge.upstream-base-url=http://localhost:5002 -Dbridge.version=0.24.1 -Dbridge.reported-context-offset=5000 -jar target/ollama-oai-bridge.jar
+    ```
+
+    If you use VS Code GitHub Copilot BYOK, configure the Ollama provider to point at the bridge endpoint and keep the upstream server behind it.
+
     Or, after building, you can use the provided `start.sh` script. Copy the generated `.jar` file from the `target/` directory and `start.sh` into the same directory, then run:
     ```bash
     ./start.sh
     ```
 
+    The `start.sh` launcher also accepts JVM `-D` options directly, so this works too:
+    ```bash
+    ./start.sh -Dserver.port=11435 -Dbridge.upstream-base-url=http://localhost:5002 -Dbridge.version=0.24.1 -Dbridge.reported-context-offset=5000
+    ```
+
 ## Architecture
 
 - **`GatewayProxyConfiguration`**: Sets up the Spring Cloud Gateway routes to proxy requests.

src/main/java/de/extio/ollama_oai_bridge/BridgeProperties.java

@@ -11,6 +11,8 @@ public class BridgeProperties {
 
 	private String version = "0.24.0";
 
+	private long reportedContextOffset = 0L;
+
 	public URI getUpstreamBaseUrl() {
 		return this.upstreamBaseUrl;
 	}
@@ -27,4 +29,12 @@ public class BridgeProperties {
 		this.version = version;
 	}
 
+	public long getReportedContextOffset() {
+		return this.reportedContextOffset;
+	}
+
+	public void setReportedContextOffset(final long reportedContextOffset) {
+		this.reportedContextOffset = reportedContextOffset;
+	}
+
 }

src/main/java/de/extio/ollama_oai_bridge/OllamaDiscoveryService.java

@@ -24,10 +24,13 @@ public class OllamaDiscoveryService {
 
 	private final LlamaServerClient llamaServerClient;
 
+	private final BridgeProperties bridgeProperties;
+
 	private final ObjectMapper objectMapper;
 
-	public OllamaDiscoveryService(LlamaServerClient llamaServerClient, ObjectMapper objectMapper) {
+	public OllamaDiscoveryService(LlamaServerClient llamaServerClient, BridgeProperties bridgeProperties, ObjectMapper objectMapper) {
 		this.llamaServerClient = llamaServerClient;
+		this.bridgeProperties = bridgeProperties;
 		this.objectMapper = objectMapper;
 	}
 
@@ -63,12 +66,13 @@ public class OllamaDiscoveryService {
 
 		ObjectNode response = this.objectMapper.createObjectNode();
 		response.put("license", "");
-		response.put("modelfile", buildModelfile(model, snapshot.props(), snapshot.slots()));
-		response.put("parameters", buildParameters(snapshot.props()));
+		long reportedContextLength = reportedContextLength(model, snapshot.props(), snapshot.slots());
+		response.put("modelfile", buildModelfile(model, snapshot.props(), reportedContextLength));
+		response.put("parameters", buildParameters(snapshot.props(), reportedContextLength));
 		response.put("template", text(snapshot.props(), "chat_template"));
 		response.put("system", "");
 		response.set("details", detailsNode(resolveDetails(model, snapshot.props())));
-		response.set("model_info", buildModelInfo(model, snapshot.props(), snapshot.slots()));
+		response.set("model_info", buildModelInfo(model, snapshot.props(), snapshot.slots(), reportedContextLength));
 		response.set("capabilities", capabilitiesNode(resolveCapabilities(model, snapshot.props())));
 		response.put("modified_at", defaultString(model.modifiedAt()));
 		return response;
@@ -150,7 +154,7 @@ public class OllamaDiscoveryService {
 		return List.copyOf(capabilities);
 	}
 
-	private String buildModelfile(LlamaModelDescriptor model, JsonNode props, JsonNode slots) {
+	private String buildModelfile(LlamaModelDescriptor model, JsonNode props, long reportedContextLength) {
 		StringBuilder modelfile = new StringBuilder("# Modelfile generated by ollama-oai-bridge\n");
 		modelfile.append("FROM ")
 			.append(firstNonBlank(text(props, "model_path"), model.model(), model.name()))
@@ -163,7 +167,7 @@ public class OllamaDiscoveryService {
 				.append("\"\"\"\n");
 		}
 
-		appendNumericModelfileParameter(modelfile, "num_ctx", contextLength(model, props, slots));
+		appendNumericModelfileParameter(modelfile, "num_ctx", reportedContextLength);
 		appendTextModelfileParameter(modelfile, "temperature", text(props.path("default_generation_settings").path("params"), "temperature"));
 		appendTextModelfileParameter(modelfile, "top_k", text(props.path("default_generation_settings").path("params"), "top_k"));
 		appendTextModelfileParameter(modelfile, "top_p", text(props.path("default_generation_settings").path("params"), "top_p"));
@@ -176,9 +180,9 @@ public class OllamaDiscoveryService {
 		return modelfile.toString().trim();
 	}
 
-	private String buildParameters(JsonNode props) {
+	private String buildParameters(JsonNode props, long reportedContextLength) {
 		StringBuilder parameters = new StringBuilder();
-		appendParameterLine(parameters, "num_ctx", text(props.path("default_generation_settings"), "n_ctx"));
+		appendParameterLine(parameters, "num_ctx", String.valueOf(reportedContextLength));
 		appendParameterLine(parameters, "temperature", text(props.path("default_generation_settings").path("params"), "temperature"));
 		appendParameterLine(parameters, "top_k", text(props.path("default_generation_settings").path("params"), "top_k"));
 		appendParameterLine(parameters, "top_p", text(props.path("default_generation_settings").path("params"), "top_p"));
@@ -191,7 +195,7 @@ public class OllamaDiscoveryService {
 		return parameters.toString().trim();
 	}
 
-	private ObjectNode buildModelInfo(LlamaModelDescriptor model, JsonNode props, JsonNode slots) {
+	private ObjectNode buildModelInfo(LlamaModelDescriptor model, JsonNode props, JsonNode slots, long reportedContextLength) {
 		LlamaModelDetails details = resolveDetails(model, props);
 		ObjectNode modelInfo = this.objectMapper.createObjectNode();
 
@@ -201,7 +205,7 @@ public class OllamaDiscoveryService {
 		putLongIfPositive(modelInfo, "general.parameter_count", longValue(model.meta(), "n_params"));
 		putStringIfPresent(modelInfo, "general.size_label", details.parameterSize());
 		putStringIfPresent(modelInfo, "general.quantization", details.quantizationLevel());
-		putStringIfPresent(modelInfo, architecture + ".context_length", String.valueOf(contextLength(model, props, slots)));
+		putStringIfPresent(modelInfo, architecture + ".context_length", String.valueOf(reportedContextLength));
 		putLongIfPositive(modelInfo, architecture + ".embedding_length", longValue(model.meta(), "n_embd"));
 		putLongIfPositive(modelInfo, architecture + ".vocab_size", longValue(model.meta(), "n_vocab"));
 		putLongIfPositive(modelInfo, architecture + ".trained_context_length", longValue(model.meta(), "n_ctx_train"));
@@ -228,7 +232,13 @@ public class OllamaDiscoveryService {
 		return busySlots;
 	}
 
-	private long contextLength(LlamaModelDescriptor model, JsonNode props, JsonNode slots) {
+	private long reportedContextLength(LlamaModelDescriptor model, JsonNode props, JsonNode slots) {
+		long downstreamContextLength = downstreamContextLength(model, props, slots);
+		long offset = Math.max(0L, this.bridgeProperties.getReportedContextOffset());
+		return Math.max(0L, downstreamContextLength - offset);
+	}
+
+	private long downstreamContextLength(LlamaModelDescriptor model, JsonNode props, JsonNode slots) {
 		long metaContext = longValue(model.meta(), "n_ctx");
 		if (metaContext > 0) {
 			return metaContext;

src/main/resources/application.properties

@@ -3,3 +3,4 @@ server.port=11434
 
 bridge.upstream-base-url=http://localhost:5001
 bridge.version=0.24.0
+bridge.reported-context-offset=0

src/test/java/de/extio/ollama_oai_bridge/OllamaDiscoveryServiceContextOffsetTests.java

@@ -0,0 +1,46 @@
+package de.extio.ollama_oai_bridge;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+import org.junit.jupiter.api.Test;
+
+import tools.jackson.databind.ObjectMapper;
+import tools.jackson.databind.node.ObjectNode;
+
+class OllamaDiscoveryServiceContextOffsetTests {
+
+	private final ObjectMapper objectMapper = new ObjectMapper();
+
+	@Test
+	void reportedContextLengthIsReducedBeforeBeingReturnedToClients() throws Exception {
+		final LlamaServerClient llamaServerClient = mock(LlamaServerClient.class);
+		final BridgeProperties bridgeProperties = new BridgeProperties();
+		bridgeProperties.setReportedContextOffset(5000);
+		final OllamaDiscoveryService service = new OllamaDiscoveryService(llamaServerClient, bridgeProperties, this.objectMapper);
+
+		when(llamaServerClient.fetchSnapshot()).thenReturn(new LlamaServerClient.LlamaServerSnapshot(
+			this.objectMapper.readTree("""
+				{"default_generation_settings":{"n_ctx":16128,"params":{"temperature":1.0}},"model_path":"/models/gemma.gguf","chat_template":"","eos_token":"","bos_token":"","model_alias":""}
+				"""),
+			this.objectMapper.createArrayNode(),
+			java.util.List.of(new LlamaServerClient.LlamaModelDescriptor(
+				"gemma-4-E4B-it-Q6_K.gguf",
+				"gemma-4-E4B-it-Q6_K.gguf",
+				"",
+				0L,
+				"",
+				new LlamaServerClient.LlamaModelDetails("", "", "gemma4", java.util.List.of("gemma4"), "", ""),
+				java.util.List.of(),
+				this.objectMapper.createObjectNode(),
+				"llamacpp"))));
+
+		final ObjectNode response = service.show("gemma-4-E4B-it-Q6_K.gguf");
+
+		assertThat(response.path("model_info").path("gemma4.context_length").asLong()).isEqualTo(11_128L);
+		assertThat(response.path("parameters").asText()).contains("num_ctx 11128");
+		assertThat(response.path("modelfile").asText()).contains("PARAMETER num_ctx 11128");
+	}
+
+}

start.sh

@@ -20,4 +20,12 @@ if [[ -n "${OLLAMA_OAI_BRIDGE_OPTS:-}" ]]; then
   read -r -a app_opts <<<"${OLLAMA_OAI_BRIDGE_OPTS}"
 fi
 
-exec java "${java_opts[@]}" "${app_opts[@]}" -jar "$jar_file" "$@"
+for arg in "$@"; do
+  if [[ "$arg" == -D* ]]; then
+    java_opts+=("$arg")
+  else
+    app_opts+=("$arg")
+  fi
+done
+
+exec java "${java_opts[@]}" -jar "$jar_file" "${app_opts[@]}"