palantir · psyclaudeZ · Oct 13, 2025 · Oct 13, 2025
diff --git a/conjure-python-core/src/main/java/com/palantir/conjure/python/ConjurePythonGenerator.java b/conjure-python-core/src/main/java/com/palantir/conjure/python/ConjurePythonGenerator.java
@@ -139,13 +139,15 @@ private PythonFile getImplPythonFile(
                 implTypeNameProcessor,
                 definitionPackageNameProcessor,
                 definitionTypeNameProcessor,
-                dealiasingTypeVisitor);
+                dealiasingTypeVisitor,
+                config.forceKeywordArgs());
         ClientGenerator clientGenerator = new ClientGenerator(
                 implPackageNameProcessor,
                 implTypeNameProcessor,
                 definitionPackageNameProcessor,
                 definitionTypeNameProcessor,
-                dealiasingTypeVisitor);
+                dealiasingTypeVisitor,
+                config.forceKeywordArgs());
 
         List<PythonSnippet> snippets = new ArrayList<>();
         snippets.addAll(conjureDefinition.getTypes().stream()

diff --git a/conjure-python-core/src/main/java/com/palantir/conjure/python/GeneratorConfiguration.java b/conjure-python-core/src/main/java/com/palantir/conjure/python/GeneratorConfiguration.java
@@ -43,6 +43,11 @@ public interface GeneratorConfiguration {
 
     boolean generateRawSource();
 
+    @Value.Default
+    default boolean forceKeywordArgs() {
+        return false;
+    }
+
     default Optional<String> pythonicPackageName() {
         return packageName().map(packageName -> packageName.replace('-', '_'));
     }

diff --git a/conjure-python-core/src/main/java/com/palantir/conjure/python/client/ClientGenerator.java b/conjure-python-core/src/main/java/com/palantir/conjure/python/client/ClientGenerator.java
@@ -48,18 +48,21 @@ public final class ClientGenerator {
     private final DealiasingTypeVisitor dealiasingTypeVisitor;
     private final PythonTypeNameVisitor pythonTypeNameVisitor;
     private final MyPyTypeNameVisitor myPyTypeNameVisitor;
+    private final boolean forceKeywordArgs;
 
     public ClientGenerator(
             PackageNameProcessor implPackageNameProcessor,
             TypeNameProcessor implTypeNameProcessor,
             PackageNameProcessor definitionPackageNameProcessor,
             TypeNameProcessor definitionTypeNameProcessor,
-            DealiasingTypeVisitor dealiasingTypeVisitor) {
+            DealiasingTypeVisitor dealiasingTypeVisitor,
+            boolean forceKeywordArgs) {
         this.implPackageNameProcessor = implPackageNameProcessor;
         this.implTypeNameProcessor = implTypeNameProcessor;
         this.definitionPackageNameProcessor = definitionPackageNameProcessor;
         this.definitionTypeNameProcessor = definitionTypeNameProcessor;
         this.dealiasingTypeVisitor = dealiasingTypeVisitor;
+        this.forceKeywordArgs = forceKeywordArgs;
         pythonTypeNameVisitor = new PythonTypeNameVisitor(implTypeNameProcessor);
         myPyTypeNameVisitor = new MyPyTypeNameVisitor(dealiasingTypeVisitor, implTypeNameProcessor);
     }
@@ -154,6 +157,7 @@ private PythonEndpointDefinition generateEndpoint(
                                 .dealias(rt)
                                 .fold(_typeDefinition -> false, type -> type.accept(TypeVisitor.IS_OPTIONAL)))
                         .orElse(false))
+                .forceKeywordArgs(forceKeywordArgs)
                 .build();
     }
 }
diff --git a/conjure-python-core/src/main/java/com/palantir/conjure/python/poet/BeanSnippet.java b/conjure-python-core/src/main/java/com/palantir/conjure/python/poet/BeanSnippet.java
@@ -57,6 +57,11 @@ default String idForSorting() {
 
     List<PythonField> fields();
 
+    @Value.Default
+    default boolean forceKeywordArgs() {
+        return false;
+    }
+
     @Override
     default void emit(PythonPoetWriter poetWriter) {
         poetWriter.writeIndentedLine(String.format("class %s(ConjureBeanType):", className()));
@@ -97,22 +102,25 @@ default void emit(PythonPoetWriter poetWriter) {
 
         // constructor -- only if there are fields
         if (!fields().isEmpty()) {
-            poetWriter.writeIndentedLine(String.format(
-                    "def __init__(self, %s) -> None:",
-                    Joiner.on(", ")
-                            .join(fields().stream()
-                                    .sorted(new PythonField.PythonFieldComparator())
-                                    .map(field -> {
-                                        String name = String.format(
-                                                "%s: %s",
-                                                PythonIdentifierSanitizer.sanitize(field.attributeName()),
-                                                field.myPyType());
-                                        if (field.isOptional()) {
-                                            return String.format("%s = None", name);
-                                        }
-                                        return name;
-                                    })
-                                    .collect(Collectors.toList()))));
+            String argsString = Joiner.on(", ")
+                    .join(fields().stream()
+                            .sorted(new PythonField.PythonFieldComparator())
+                            .map(field -> {
+                                String name = String.format(
+                                        "%s: %s",
+                                        PythonIdentifierSanitizer.sanitize(field.attributeName()), field.myPyType());
+                                if (field.isOptional()) {
+                                    return String.format("%s = None", name);
+                                }
+                                return name;
+                            })
+                            .collect(Collectors.toList()));
+
+            String initSignature = forceKeywordArgs()
+                    ? String.format("def __init__(self, *, %s) -> None:", argsString)
+                    : String.format("def __init__(self, %s) -> None:", argsString);
+
+            poetWriter.writeIndentedLine(initSignature);
             poetWriter.increaseIndent();
             fields().forEach(field -> poetWriter.writeIndentedLine(String.format(
                     "self._%s = %s",

diff --git a/...-python-core/src/main/java/com/palantir/conjure/python/poet/PythonEndpointDefinition.java b/...-python-core/src/main/java/com/palantir/conjure/python/poet/PythonEndpointDefinition.java
@@ -62,6 +62,11 @@ public interface PythonEndpointDefinition extends Emittable {
 
     Optional<String> myPyReturnType();
 
+    @Value.Default
+    default boolean forceKeywordArgs() {
+        return false;
+    }
+
     @Value.Check
     default void check() {
         checkState(
@@ -90,22 +95,27 @@ default void emit(PythonPoetWriter poetWriter) {
                             .build()
                     : params();
 
-            poetWriter.writeIndentedLine(
-                    "def %s(self, %s) -> %s:",
-                    pythonMethodName(),
-                    Joiner.on(", ")
-                            .join(paramsWithHeader.stream()
-                                    .sorted(new PythonEndpointParamComparator())
-                                    .map(param -> {
-                                        String typedParam =
-                                                String.format("%s: %s", param.pythonParamName(), param.myPyType());
-                                        if (param.isOptional() || param.isCollection()) {
-                                            return String.format("%s = None", typedParam);
-                                        }
-                                        return typedParam;
-                                    })
-                                    .collect(Collectors.toList())),
-                    myPyReturnType().orElse("None"));
+            String paramsString = Joiner.on(", ")
+                    .join(paramsWithHeader.stream()
+                            .sorted(new PythonEndpointParamComparator())
+                            .map(param -> {
+                                String typedParam = String.format("%s: %s", param.pythonParamName(), param.myPyType());
+                                if (param.isOptional() || param.isCollection()) {
+                                    return String.format("%s = None", typedParam);
+                                }
+                                return typedParam;
+                            })
+                            .collect(Collectors.toList()));
+
+            String methodSignature = forceKeywordArgs() && !paramsWithHeader.isEmpty()
+                    ? String.format(
+                            "def %s(self, *, %s) -> %s:",
+                            pythonMethodName(), paramsString, myPyReturnType().orElse("None"))
+                    : String.format(
+                            "def %s(self, %s) -> %s:",
+                            pythonMethodName(), paramsString, myPyReturnType().orElse("None"));
+
+            poetWriter.writeIndentedLine(methodSignature);
             poetWriter.increaseIndent();
             docs().ifPresent(poetWriter::writeDocs);
 

diff --git a/conjure-python-core/src/main/java/com/palantir/conjure/python/poet/UnionSnippet.java b/conjure-python-core/src/main/java/com/palantir/conjure/python/poet/UnionSnippet.java
@@ -61,6 +61,11 @@ default String idForSorting() {
 
     List<PythonField> options();
 
+    @Value.Default
+    default boolean forceKeywordArgs() {
+        return false;
+    }
+
     /** The name of the option as a constructor / method parameter. */
     static String parameterName(PythonField option) {
         return PythonIdentifierSanitizer.sanitize(option.attributeName());
@@ -120,6 +125,9 @@ default void emit(PythonPoetWriter poetWriter) {
             poetWriter.increaseIndent();
             poetWriter.increaseIndent();
             poetWriter.writeIndentedLine("self,");
+            if (forceKeywordArgs() && !options().isEmpty()) {
+                poetWriter.writeIndentedLine("*,");
+            }
             for (int i = 0; i < options().size(); i++) {
                 PythonField option = options().get(i);
 

diff --git a/conjure-python-core/src/main/java/com/palantir/conjure/python/types/PythonTypeGenerator.java b/conjure-python-core/src/main/java/com/palantir/conjure/python/types/PythonTypeGenerator.java
@@ -50,18 +50,21 @@ public final class PythonTypeGenerator {
     private final DealiasingTypeVisitor dealiasingTypeVisitor;
     private final PythonTypeNameVisitor pythonTypeNameVisitor;
     private final MyPyTypeNameVisitor myPyTypeNameVisitor;
+    private final boolean forceKeywordArgs;
 
     public PythonTypeGenerator(
             PackageNameProcessor implPackageNameProcessor,
             TypeNameProcessor implTypeNameProcessor,
             PackageNameProcessor definitionPackageNameProcessor,
             TypeNameProcessor definitionTypeNameProcessor,
-            DealiasingTypeVisitor dealiasingTypeVisitor) {
+            DealiasingTypeVisitor dealiasingTypeVisitor,
+            boolean forceKeywordArgs) {
         this.implPackageNameProcessor = implPackageNameProcessor;
         this.implTypeNameProcessor = implTypeNameProcessor;
         this.definitionPackageNameProcessor = definitionPackageNameProcessor;
         this.definitionTypeNameProcessor = definitionTypeNameProcessor;
         this.dealiasingTypeVisitor = dealiasingTypeVisitor;
+        this.forceKeywordArgs = forceKeywordArgs;
         pythonTypeNameVisitor = new PythonTypeNameVisitor(implTypeNameProcessor);
         myPyTypeNameVisitor = new MyPyTypeNameVisitor(dealiasingTypeVisitor, implTypeNameProcessor);
     }
@@ -127,6 +130,7 @@ private BeanSnippet generateBean(ObjectDefinition typeDef) {
                 .addAllImports(imports)
                 .docs(typeDef.getDocs())
                 .fields(fields)
+                .forceKeywordArgs(forceKeywordArgs)
                 .build();
     }
 
@@ -182,6 +186,7 @@ private UnionSnippet generateUnion(UnionDefinition typeDef) {
                 .addAllImports(imports)
                 .docs(typeDef.getDocs())
                 .options(options)
+                .forceKeywordArgs(forceKeywordArgs)
                 .build();
     }
 

diff --git a/conjure-python-core/src/test/java/com/palantir/conjure/python/ForceKeywordArgsTest.java b/conjure-python-core/src/test/java/com/palantir/conjure/python/ForceKeywordArgsTest.java
@@ -0,0 +1,104 @@
+/*
+ * (c) Copyright 2025 Palantir Technologies Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.palantir.conjure.python;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import com.palantir.conjure.defs.Conjure;
+import com.palantir.conjure.spec.ConjureDefinition;
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+import org.junit.jupiter.api.Test;
+
+public final class ForceKeywordArgsTest {
+
+    @Test
+    public void testConstructorKeywordArgsAreForced() throws IOException {
+        String generated = generateCode(true);
+
+        assertThat(generated).contains("def __init__(self, *, age: int, email: str, name: str) -> None:");
+    }
+
+    @Test
+    public void testConstructorPositionalArgsByDefault() throws IOException {
+        String generated = generateCode(false);
+
+        assertThat(generated).contains("def __init__(self, age: int, email: str, name: str) -> None:");
+        assertThat(generated).doesNotContain("def __init__(self, *,");
+    }
+
+    @Test
+    public void testUnionKeywordArgsAreForced() throws IOException {
+        String generated = generateCode(true);
+        // The signature spans multiple lines with specific indentation
+        assertThat(generated).contains("    def __init__(\n            self,\n            *,");
+    }
+
+    @Test
+    public void testUnionPositionalArgsByDefault() throws IOException {
+        String generated = generateCode(false);
+
+        // The signature spans multiple lines with specific indentation
+        assertThat(generated).contains("    def __init__(\n            self,\n            foo: Optional[str] = None,");
+        assertThat(generated).doesNotContain("    def __init__(\n            self,\n            *,");
+    }
+
+    @Test
+    public void testServiceEndpointKeywordArgsAreForced() throws IOException {
+        String generated = generateCode(true);
+        assertThat(generated).contains("def test_endpoint(self, *, param1: str, param2: int) -> str:");
+    }
+
+    @Test
+    public void testServiceEndpointPositionalArgsByDefault() throws IOException {
+        String generated = generateCode(false);
+        assertThat(generated).contains("def test_endpoint(self, param1: str, param2: int) -> str:");
+        assertThat(generated).doesNotContain("def test_endpoint(self, *,");
+    }
+
+    @SuppressWarnings("for-rollout:deprecation")
+    private String generateCode(boolean forceKeywordArgs) throws IOException {
+        ConjurePythonGenerator generator = new ConjurePythonGenerator(GeneratorConfiguration.builder()
+                .packageName("test")
+                .packageVersion("0.0.0")
+                .minConjureClientVersion("2.8.0")
+                .generatorVersion("0.0.0")
+                .shouldWriteCondaRecipe(false)
+                .generateRawSource(false)
+                .forceKeywordArgs(forceKeywordArgs)
+                .build());
+
+        Path testFolder = Path.of("src/test/resources/force-keyword-args");
+        List<File> files;
+        try (Stream<Path> walk = Files.walk(testFolder)) {
+            files = walk.map(Path::toFile)
+                    .filter(file -> file.toString().endsWith(".yml"))
+                    .collect(Collectors.toList());
+        }
+        ConjureDefinition definition = Conjure.parse(files);
+
+        InMemoryPythonFileWriter writer = new InMemoryPythonFileWriter();
+        generator.write(definition, writer);
+
+        return writer.getPythonFiles().values().stream().collect(Collectors.joining("\n"));
+    }
+}
diff --git a/conjure-python-core/src/test/resources/force-keyword-args/expected/conda_recipe/meta.yaml b/conjure-python-core/src/test/resources/force-keyword-args/expected/conda_recipe/meta.yaml
@@ -0,0 +1,23 @@
+# coding=utf-8
+package:
+    name: package-name
+    version: 0.0.0
+
+source:
+    path: ../
+
+build:
+    noarch: python
+    script: python setup.py install --single-version-externally-managed --record=record.txt
+
+requirements:
+    build:
+        - python
+        - setuptools
+        - requests
+        - conjure-python-client >=2.8.0,<4
+
+    run:
+        - python
+        - requests
+        - conjure-python-client >=2.8.0,<4
diff --git a/conjure-python-core/src/test/resources/force-keyword-args/expected/package_name/__init__.py b/conjure-python-core/src/test/resources/force-keyword-args/expected/package_name/__init__.py