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JWT Token Expires Mid-Session — Silent 401 Errors After 1 Hour

Symptom

• Agent works for ~60 minutes then starts failing
• API calls return 401 Unauthorized
• Error message: {"error": "token_expired"} or {"error": "invalid_token"}
• Agent retries same call multiple times — all fail with same 401
• Session started fine; nothing changed except time
• Problem always appears at the same interval (usually 1 hour or 24 hours)

Root Cause

JWT access tokens have short expiry (typically 1 hour). When the token expires, all API calls using it get 401. Without automatic token refresh, the agent is stuck with an expired credential for the remainder of the session.

Fix

Option 1: Automatic refresh on 401

import httpx, time
from functools import wraps

class AuthenticatedClient:
    def __init__(self, access_token, refresh_token, token_url):
        self.access_token = access_token
        self.refresh_token = refresh_token
        self.token_url = token_url
        self.token_expires_at = time.time() + 3600  # Default 1hr

    def _is_expired(self):
        return time.time() >= self.token_expires_at - 60  # Refresh 60s early

    async def refresh(self):
        async with httpx.AsyncClient() as client:
            resp = await client.post(self.token_url, json={
                "grant_type": "refresh_token",
                "refresh_token": self.refresh_token
            })
            resp.raise_for_status()
            data = resp.json()
            self.access_token = data["access_token"]
            self.token_expires_at = time.time() + data.get("expires_in", 3600)

    async def request(self, method, url, **kwargs):
        if self._is_expired():
            await self.refresh()

        kwargs.setdefault("headers", {})["Authorization"] = f"Bearer {self.access_token}"
        async with httpx.AsyncClient() as client:
            response = await client.request(method, url, **kwargs)

        if response.status_code == 401:
            # Token may have expired between check and use — refresh and retry once
            await self.refresh()
            kwargs["headers"]["Authorization"] = f"Bearer {self.access_token}"
            async with httpx.AsyncClient() as client:
                response = await client.request(method, url, **kwargs)

        return response

Option 2: Token expiry detection from JWT payload

import base64, json, time

def get_jwt_expiry(token):
    """Decode JWT payload without verification to get exp claim"""
    payload_b64 = token.split('.')[1]
    # Add padding if needed
    payload_b64 += '=' * (4 - len(payload_b64) % 4)
    payload = json.loads(base64.urlsafe_b64decode(payload_b64))
    return payload.get('exp', 0)

def is_token_valid(token, buffer_seconds=60):
    """Return True if token is valid for at least buffer_seconds more"""
    exp = get_jwt_expiry(token)
    return time.time() < exp - buffer_seconds

Option 3: Proactive refresh before expiry

import asyncio

async def token_refresh_loop(client, interval_seconds=1800):
    """Refresh token every 30 minutes (before 1hr expiry)"""
    while True:
        await asyncio.sleep(interval_seconds)
        try:
            await client.refresh()
            print("Token refreshed proactively")
        except Exception as e:
            print(f"Token refresh failed: {e}")
            # Alert here — session will expire soon

# Start in background
asyncio.create_task(token_refresh_loop(client))

Option 4: OpenClaw config — auto token refresh

# openclaw.config.yaml
auth:
  jwt:
    auto_refresh: true
    refresh_buffer_seconds: 300    # Refresh 5 minutes before expiry
    on_refresh_failure: retry_with_reauth
  oauth:
    token_url: ${OAUTH_TOKEN_URL}
    client_id: ${OAUTH_CLIENT_ID}
    client_secret: ${OAUTH_CLIENT_SECRET}

Detection Pattern

def detect_token_expiry_pattern(error_log):
    """Check if 401s correlate with session duration"""
    import re
    from datetime import datetime

    first_request = None
    errors = []

    for line in error_log:
        if "401" in line or "token_expired" in line:
            # Extract timestamp and check if ~1hr after session start
            timestamp = extract_timestamp(line)
            if first_request and (timestamp - first_request).seconds > 3000:
                errors.append(timestamp)

    return len(errors) > 0, f"Token expiry pattern detected — {len(errors)} 401s after session hour"

Expected Token Savings

Agent stuck in 401 retry loop for 30 minutes: ~40,000 tokens wasted Proactive refresh: 0 extra tokens, seamless

Environment

• Any agent using JWT-based authentication
• Most common: OAuth2 access tokens (Google, GitHub, Slack, etc.)
• Source: direct experience, standard JWT expiry pattern

Wasting tokens on this error?

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