Anthropic Advanced Troubleshooting

Overview

Debug complex Claude integration issues that go beyond basic error handling — inconsistent outputs, tool use failures where Claude calls nonexistent tools, streaming connection drops, max_tokens truncation, and image/vision format problems.

Inconsistent Outputs

Symptom: Same prompt gives different answers each time. Cause: temperature defaults to 1.0 (maximum randomness).

// Fix: Set temperature to 0 for deterministic outputs
const message = await client.messages.create({
  model: 'claude-sonnet-4-20250514',
  max_tokens: 1024,
  temperature: 0, // Deterministic
  messages,
});

Tool Use Failures

Symptom: Claude calls a tool that doesn't exist or sends wrong parameters.

// Always validate tool calls before executing
const toolUse = response.content.find(b => b.type === 'tool_use');
if (toolUse) {
  const validTools = tools.map(t => t.name);
  if (!validTools.includes(toolUse.name)) {
    console.error(`Claude requested unknown tool: ${toolUse.name}`);
    // Send error back as tool_result
    messages.push({ role: 'assistant', content: response.content });
    messages.push({ role: 'user', content: [{
      type: 'tool_result',
      tool_use_id: toolUse.id,
      is_error: true,
      content: `Tool "${toolUse.name}" does not exist. Available: ${validTools.join(', ')}`,
    }]});
  }
}

Streaming Connection Drops

Symptom: Stream stops mid-response without message_stop event.

// Detect incomplete streams
const stream = client.messages.stream({ ... });
let gotStop = false;

for await (const event of stream) {
  if (event.type === 'message_stop') gotStop = true;
  // ... process events
}

if (!gotStop) {
  console.error('Stream ended without message_stop — connection dropped');
  // Retry the request
}

max_tokens Truncation

Response cuts off mid-sentence.