TrafficLog class

Prints HTTP request/response traffic in a human-readable form.

The logger is not const because it holds a small mutable flag (_promptPrintedOnce). The first call to systemPrompt prints the prompt in full; later calls truncate it, so the console remains readable while still showing the entire security contract at least once.

When to use

Anywhere a reader needs to audit the interaction between the demo and the AI. The logger is the "show me the bytes on the wire" tool: every prompt, every request body, every response body, every usage block.

How it works

The interpreters call the logger's methods in this order for each complete:

1. systemPrompt — the system prompt that will be sent.
2. request — the HTTP envelope (endpoint, model, sentence, body).
3. response — the HTTP status and raw body.
4. parsed or refused — the classified reply.

If the port throws, error is called instead of steps 3–4.

Non-obvious

• The logger writes to stdout directly. It has no buffer, no flush, no file target. For a demo, that is what we want. For a production system, replace _out with a structured logger call.
• The prompt is printed in full the first time, then truncated. The first call prints all lines. Every subsequent call prints the first 12 lines and appends ... (N more lines — same prompt as scenario 1). That keeps the console readable while guaranteeing the reader sees the full security contract at least once.
• silent: true suppresses all output. Useful for tests. The logger still runs its truncation logic so the first non-silent call behaves correctly.

Example

final log = TrafficLog();
log.systemPrompt(systemPrompt({'add', 'remove', 'clear'}));
log.request(
  endpoint: 'https://api.deepseek.com/chat/completions',
  model: 'deepseek-flash',
  sentence: 'add 3',
  body: '{"model":"deepseek-flash",...}',
);