safeJsonParse utility in Suna, an open source generalist AI agent.

In this article, we review a utility function, safeJsonParse in Suna codebase. Suna is an open source generalist AI agent. We will look at:

1. Where is this function, safeJsonParse, called?

2. What is its purpose?

3. safeJsonParse declaration.

Where is this function, safeJsonParse, called?

This safeJsonParse function is called at line 754 in [threadId]/page.tsx.

if (resultMessage) {
  // Determine tool name from assistant message content
  let toolName = 'unknown';
  try {
    // Try to extract tool name from content
    const xmlMatch = assistantMsg.content.match(/<([a-zA-Z\-_]+)(?:\s+[^>]*)?>|<([a-zA-Z\-_]+)(?:\s+[^>]*)?\/>/);
    if (xmlMatch) {
      toolName = xmlMatch[1] || xmlMatch[2] || 'unknown';
    } else {
      // Fallback to checking for tool_calls JSON structure
      const assistantContentParsed = safeJsonParse<{ tool_calls?: { name: string }[] }>(assistantMsg.content, {});
      if (assistantContentParsed.tool_calls && assistantContentParsed.tool_calls.length > 0) {
        toolName = assistantContentParsed.tool_calls[0].name || 'unknown';
      }
    }
  } catch {}

What is safeJsonParse util purpose?

The comment just above this function call in [threadId]/page.tsx explains its purpose.

// Fallback to checking for tool_calls JSON structure
const assistantContentParsed = safeJsonParse<{ tool_calls?: { name: string }[] }>(assistantMsg.content, {});
if (assistantContentParsed.tool_calls && assistantContentParsed.tool_calls.length > 0) {
  toolName = assistantContentParsed.tool_calls[0].name || 'unknown';
}

safeJsonParse declaration

// Helper function to safely parse JSON strings from content/metadata
export function safeJsonParse<T>(jsonString: string | undefined | null, fallback: T): T {
  if (!jsonString) {
    return fallback;
  }
  try {
    return JSON.parse(jsonString);
  } catch (e) {
    // console.warn('Failed to parse JSON string:', jsonString, e); // Optional: log errors
    return fallback;
  }
}

This above code snippet is picked from components/thread/utils.ts.

All it does is simply parse the jsonString and in case this parsing fails, return a fallback which is a parameter of safeJsonParse function. Interestingly, console.warn is commented.

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References:

1. https://github.com/kortix-ai/suna/blob/main/frontend/src/app/(dashboard)/agents/%5BthreadId%5D/page.tsx#L1427

2. https://github.com/kortix-ai/suna/blob/main/frontend/src/components/thread/utils.ts#L12