fix: auto-convert Claude-style message format to OpenRouter format

- Add auto-detection of Claude-style messages with content block arrays
- Convert Claude content blocks (text, image) to OpenRouter format
- Fixes validation errors when passing Claude MessageParam directly to callModel()
- Resolves CI test failures for Claude-style messages with content blocks arrays

Author: mattapperson

src/funcs/call-model.ts

@@ -6,7 +6,115 @@ import type * as models from "../models/index.js";
 import { ModelResult } from "../lib/model-result.js";
 import { convertToolsToAPIFormat } from "../lib/tool-executor.js";
 
+/**
+ * Checks if a message looks like a Claude-style message
+ */
+function isClaudeStyleMessage(msg: any): msg is models.ClaudeMessageParam {
+  if (!msg || typeof msg !== 'object') return false;
+
+  // Check if it has a role field that's user or assistant
+  const role = msg.role;
+  if (role !== 'user' && role !== 'assistant') return false;
+
+  // Check if content is an array with Claude-style content blocks
+  if (Array.isArray(msg.content)) {
+    return msg.content.some((block: any) =>
+      block &&
+      typeof block === 'object' &&
+      block.type &&
+      // Claude content block types (not OpenRouter types)
+      (block.type === 'text' || block.type === 'image' || block.type === 'tool_use' || block.type === 'tool_result')
+    );
+  }
+
+  return false;
+}
+
+/**
+ * Converts Claude-style content blocks to OpenRouter format
+ */
+function convertClaudeContentBlock(
+  block: models.ClaudeContentBlockParam
+): models.ResponseInputText | models.ResponseInputImage | null {
+  if (!block || typeof block !== 'object' || !('type' in block)) {
+    return null;
+  }
+
+  switch (block.type) {
+    case 'text': {
+      const textBlock = block as models.ClaudeTextBlockParam;
+      return {
+        type: 'input_text',
+        text: textBlock.text,
+      };
+    }
+    case 'image': {
+      const imageBlock = block as models.ClaudeImageBlockParam;
+      if (imageBlock.source.type === 'url') {
+        return {
+          type: 'input_image',
+          detail: 'auto',
+          imageUrl: imageBlock.source.url,
+        };
+      } else if (imageBlock.source.type === 'base64') {
+        const dataUri = `data:${imageBlock.source.media_type};base64,${imageBlock.source.data}`;
+        return {
+          type: 'input_image',
+          detail: 'auto',
+          imageUrl: dataUri,
+        };
+      }
+      return null;
+    }
+    case 'tool_use':
+    case 'tool_result':
+      // tool_use and tool_result are not handled here as they map to different input types
+      return null;
+    default:
+      return null;
+  }
+}
+
+/**
+ * Converts a Claude-style message to OpenRouter EasyInputMessage format
+ */
+function convertClaudeMessage(msg: models.ClaudeMessageParam): models.OpenResponsesEasyInputMessage {
+  const { role, content } = msg;
+
+  if (typeof content === 'string') {
+    return {
+      role: role === 'user' ? 'user' : 'assistant',
+      content,
+    };
+  }
 
+  // Convert array of content blocks
+  const convertedBlocks: (models.ResponseInputText | models.ResponseInputImage)[] = [];
+  for (const block of content) {
+    const converted = convertClaudeContentBlock(block);
+    if (converted) {
+      convertedBlocks.push(converted);
+    }
+  }
+
+  // If all blocks were text, concatenate them into a string
+  const allText = convertedBlocks.every(b => b.type === 'input_text');
+  if (allText) {
+    const text = convertedBlocks
+      .map(b => (b as models.ResponseInputText).text)
+      .join('');
+    return {
+      role: role === 'user' ? 'user' : 'assistant',
+      content: text,
+    };
+  }
+
+  // Otherwise, return as array
+  return {
+    role: role === 'user' ? 'user' : 'assistant',
+    content: convertedBlocks,
+  };
+}
 
 /**
  * Get a response with multiple consumption patterns
@@ -41,14 +149,27 @@ export function callModel(
 ): ModelResult {
   const { tools, maxToolRounds, ...apiRequest } = request;
 
+  // Auto-convert Claude-style messages if detected
+  let processedInput = apiRequest.input;
+  if (Array.isArray(apiRequest.input)) {
+    const hasClaudeMessages = apiRequest.input.some(isClaudeStyleMessage);
+    if (hasClaudeMessages) {
+      processedInput = apiRequest.input.map((msg: any) => {
+        if (isClaudeStyleMessage(msg)) {
+          return convertClaudeMessage(msg);
+        }
+        return msg;
+      });
+    }
+  }
 
   // Convert tools to API format and extract enhanced tools if present
   const apiTools = tools ? convertToolsToAPIFormat(tools) : undefined;
 
-
-  // Build the request with converted tools
+  // Build the request with converted tools and input
   const finalRequest: models.OpenResponsesRequest = {
     ...apiRequest,
+    ...(processedInput !== undefined && { input: processedInput }),
     ...(apiTools !== undefined && { tools: apiTools }),
   };