change claude model defaults for create-magnitude-app and implicit client to haiku 4.5

Author: anerli

packages/create-magnitude-app/src/cli.ts

@@ -240,7 +240,7 @@ async function createProject(tempDir: string, projectDir: string, project: Proje
 
     let clientSnippet;
     if (project.provider === 'anthropic') {
-        const model = 'claude-sonnet-4-20250514';
+        const model = 'claude-haiku-4-5-20251001';
         clientSnippet = `llm: {
             provider: 'anthropic',
             options: {
@@ -249,7 +249,7 @@ async function createProject(tempDir: string, projectDir: string, project: Proje
             }
         },`;
     } else if (project.provider === 'openrouter') {
-        const model = project.model === 'claude' ? 'anthropic/claude-sonnet-4' : 'qwen/qwen2.5-vl-72b-instruct';
+        const model = project.model === 'claude' ? 'anthropic/claude-haiku-4.5' : 'qwen/qwen2.5-vl-72b-instruct';
         clientSnippet = `llm: {
             provider: 'openai-generic',
             options: {
@@ -260,7 +260,7 @@ async function createProject(tempDir: string, projectDir: string, project: Proje
         },`;
     } else {
         // claude code
-        const model = 'claude-sonnet-4-20250514';
+        const model = 'claude-haiku-4-5-20251001';
         clientSnippet = `llm: {
             provider: 'claude-code',
             options: {

packages/magnitude-core/src/ai/modelHarness.ts

@@ -121,6 +121,7 @@ export class ModelHarness {
             'claude-3.5-sonnet': { inputTokens: 3.00, outputTokens: 15.00, cacheWriteInputTokens: 3.75, cacheReadInputTokens: 0.30 },
             'claude-3.7-sonnet': { inputTokens: 3.00, outputTokens: 15.00, cacheWriteInputTokens: 3.75, cacheReadInputTokens: 0.30 },
             'claude-sonnet-4': { inputTokens: 3.00, outputTokens: 15.00, cacheWriteInputTokens: 3.75, cacheReadInputTokens: 0.30 },
+            'claude-haiku-4-5': { inputTokens: 1.00, outputTokens: 5.00, cacheWriteInputTokens: 1.25, cacheReadInputTokens: 0.10 },
             'claude-opus-4': { inputTokens: 15.00, outputTokens: 75.00, cacheWriteInputTokens: 18.75, cacheReadInputTokens: 1.50 },
             'gpt-4.1': { inputTokens: 2.00, outputTokens: 8.00 },
             'gpt-4.1-mini': { inputTokens: 0.40, outputTokens: 1.60 },

packages/magnitude-core/src/ai/util.ts

@@ -120,7 +120,8 @@ export function tryDeriveUIGroundedClient(): LLMClient | null {
                 // model: 'claude-3-5-sonnet-20240620', // <- definitely not, pre computer use
                 // model: 'claude-3-5-sonnet-20241022', // <- not great on rescaling res
                 //model: 'claude-3-7-sonnet-latest', // <- underplans
-                model: 'claude-sonnet-4-20250514', // <- underplans, also supposedly worse at visual reasoning
+                // model: 'claude-sonnet-4-20250514', // <- underplans, also supposedly worse at visual reasoning
+                model: 'claude-haiku-4-5-20251001', // <- fast, cost-effective, good performance
                 apiKey: process.env.ANTHROPIC_API_KEY
             }
         }