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Advanced — 0.0.x primitives

You don't need this page for a normal integration. Use the quickstarts and createMythos() instead. These low-level functions remain exported for custom setups.

Idempotency

Prevent double-billing when users retry or double-click billable actions.

info

Related: Usage metering · reportUsage

How charge_id works today​

Each reportUsage / report_usage call sends a charge_id to Mythos /meter. By default, the SDK generates a fresh UUID on every call (see Caller-supplied idempotency key below to override this):

typescript
// Internal behavior — SDK generates charge_id automatically
await reportUsage(sessionJti, { credits: 1, reason: 'post' });

If the user double-clicks a billable button, two calls produce two different charge_id values and two charges.

App-level deduplication​

Prevent duplicate calls before they reach the SDK:

typescript
let billingInFlight = false;

async function onGeneratePost() {
  if (billingInFlight) return;
  billingInFlight = true;
  try {
    await generatePost();
    await reportMythosUsage(1, 'instagram-post');
  } finally {
    billingInFlight = false;
  }
}

Disable the button after first click. Use a per-action ID (post ID, request ID) as a client-side dedup key.

Caller-supplied idempotency key​

Pass an optional idempotency key so retries send the same charge_id:

typescript
// Same idempotencyKey on retry dedupes at the backend
await reportUsage(sessionJti, { credits: 1, reason: 'post', idempotencyKey: postId });
python
# idempotency_key is keyword-only
await report_usage(session.sessionJti, credits=1, reason="post", idempotency_key=post_id)

Generate the key once per billable action, not per HTTP retry. Use a stable identifier tied to the action (e.g. generated post UUID), not a random value per click.

Backend SQS dedup​

Mythos uses charge_id for SQS metering job deduplication. Same charge_id + same session = one debit. Different charge_id = separate charges.

Next steps​