Error 529, overloaded: what Claude is telling you
A red message appears in the middle of your work. Error 529. You cannot tell whether it is your computer, your connection, your subscription, or something you did wrong. You reload, you try again, and you lose twenty minutes wondering whether paying more would make it stop.
The first digit of the code answers it. A 4xx error comes from your request — key, billing, limit, size. A 5xx error comes from their servers, and 529 in particular simply means the service is temporarily overloaded. You have broken nothing.
The first-digit rule
There is one thing to take from this whole article, and it fits into a single digit.
Error codes start with 4 or with 5. That first digit tells you whose problem it is.
An error starting with 4 concerns your request: your key, your billing, your limit, the size of what you sent. There is something to fix on your side.
An error starting with 5 concerns their servers. Your request was valid, it simply could not be handled. There is nothing to fix on your side.
That distinction alone settles 90% of the anxiety. Before hunting for what you broke, look at the first digit.
The errors that come from them
529 — overloaded. The documentation names it overloaded_error and defines it plainly: the service is temporarily overloaded. It occurs when traffic is high across all users, not when your project is at fault.
It is the most common at peak hours, and the most unnerving because it lands without warning in the middle of your work. It says nothing about you.
500 — internal error. Named api_error, it signals an unexpected problem inside their systems. The official recommendation is to retry, spacing attempts out progressively.
504 — timed out. The request took too long to process. It mostly affects very long jobs.
In all three cases, you have nothing to repair. You have to wait.
The errors that come from you
429 — rate limit reached. This one stands apart, because it is frequent and often misread. It does not mean the service is down: it means your account hit a limit. It is a pacing constraint, and it is handled by slowing down — the subject of what “usage limit reached” actually means.
401 — authentication problem. Your key is malformed, revoked or expired. If you have just changed it, it is almost always this one. Note that a revoked key never becomes valid again, you have to create a new one.
402 — billing problem. A payment method to update. Nothing technical.
403 — permission denied. The key is valid but is not allowed to reach what you asked for.
413 — request too large. You are sending more than the maximum allowed size. In practice: an oversized attachment, or a conversation that has grown enormous.
400 — malformed request. The catch-all for format problems. If you go through a tool rather than your own code, it usually comes from the tool, not from you.
What to do, in order
Look at the first digit. Five minutes of panic avoided.
If it is a 5, open the status page. It is public and lives at status.claude.com. A declared incident saves you every other check. If the page is green and the error keeps coming back, only then suspect your side.
If it is a 5, do not retry in a loop. It is the natural instinct and the wrong one: on a saturated service, hammering adds to the saturation. Wait, then space your attempts out.
If it is a 4, read the error’s name, not just its number. Each code has a name saying exactly what is wrong: authentication, billing, permission, size. The name is more useful than the digit.
What not to do
Ask the AI to fix the error. On a 529 there is nothing to fix, and the tool answering you is the very one that is saturated. On a 401 it cannot see your key. Either way you are adding round trips to a problem that needs none.
Change your code because an error appeared. That is the surest way to break something that worked, over a problem that came from elsewhere and would have cleared on its own. If you already did, go back before anything else.
Create a new key “just in case”. Outside a confirmed 401 it fixes nothing, and it forces you to replace the key everywhere it was already installed.