Zukko Blog
Guides to Claude Code, Cursor, Codex and the Claude and GPT APIs: setup, token savings and troubleshooting.
OpenAI API Keys in the Open: Why You Should Not Use Them
6 min · · API keys
Where free keys on GitHub come from, why using them is dangerous for you and for the owner, and how to protect your own key from the same leak.
GLM API Errors: Why the Request Fails and How to Fix It
5 min · · errors
A wrong model id, an overflowing 128K context, the key, the balance, limits: the typical causes of GLM API errors and a quick way to find yours.
This organization has been disabled in the Claude API: What to Do
5 min · · errors
An Anthropic key suddenly answers "organization has been disabled". What the error is, what to check, and how to move the SDK and Claude Code to another provider.
JetBrains AI Assistant not working: causes and workarounds
6 min · · IDE
AI Assistant will not activate, stays silent or is off for some files. We go through the causes in the JetBrains docs and connect your own models via a gateway.
Gemini API not working: region, key, limits and model name
6 min · · errors
Step-by-step Gemini API diagnostics: from checking status and region to a leaked key, 429 and 503 errors and a typo in the model name.
Invalid API key in opencode: why the key is rejected and how to check
5 min · · errors
The Invalid API key error in opencode almost always comes down to four causes. We test the key outside opencode and find where the chain breaks.
The API key header: Authorization Bearer or x-api-key and where each goes
5 min · · errors
OpenAI clients send the key in Authorization, Anthropic clients in x-api-key. What the gateway accepts and how to tell from the response where the key got lost.
Codex error 403: causes and how to keep working
5 min · · errors
A 403 in Codex comes in three kinds: a region refusal, an account problem and gateway key restrictions. How to tell them apart by the error text and what to fix.
Cline "hit repeated tool call failures": causes and fixes
6 min · · errors
The message means the agent failed several tool calls in a row. Causes and a checking order, from the base URL to context size.
Qwen Code: error 401 invalid access token or token expired
5 min · · errors
A 401 in Qwen Code often means a stale Qwen OAuth login or a key sent to the wrong address. Step-by-step diagnosis and a switch to your own key.
Unable to connect to API (ConnectionRefused) in Claude: causes and fixes
6 min · · errors
Claude Code cannot open a connection to the API. We check the address, proxy, DNS and network with three curl commands and find the cause from the result.
Cursor not working: common problems and how to fix them
6 min · · errors
Cursor froze, shows Reconnecting or does not answer. We go from simple causes to complex ones and cover problems with your own key and a gateway separately.
"Your card was declined" in OpenRouter: why a card gets rejected
6 min · · errors
Why a card payment can be rejected on a foreign service, what you can check yourself and how to connect models when payment does not go through.
Cursor AI limits: how they work and what to do when you run out
6 min · · errors
A Cursor limit is consumption of an included amount of usage, not a message counter. What eats it and four ways to keep working when it runs out.
Codex limits: why they run out and how to keep working
6 min · · errors
Codex subscription limits are consumed by OpenAI's rules and cannot be reset. What drives usage, and how to continue on a key with a dollar limit.
Codex in Russia: installation and use without a ChatGPT subscription
5 min · · IDE
Codex CLI can be pointed at a gateway through a single config file. Installation, config.toml and a breakdown of the typical access and authorization errors.
Copilot: Language model unavailable and other errors, what to do
6 min · · errors
What to do when Copilot says Language model unavailable or "We are having troubles", and how to keep working on your own key.
How to update Claude Code, roll back a version or remove it completely
6 min · · development
Commands to update, roll back and remove Claude Code by install method, and how to keep your gateway connection settings when reinstalling.
Claude API error: Anthropic-format error types and what to do
5 min · · errors
A table of Messages API errors: what each type means, which HTTP code arrives through the gateway, what to retry with a pause and what to fix in the request.
DeepSeek not working in Russia: what to check and how to keep working
5 min · · errors
The chat will not open or the API is silent. How to tell a service outage from a network or key problem, and how to avoid stopping work.
Roo Code not working or hanging on API Request: what to check
6 min · · errors
Roo Code stays silent, hangs on API Request or throws errors. We go from simple to complex: key, address, model, context, timeouts and limits.
ChatGPT does not work in Russia: what the errors mean and what to do
5 min · · errors
Access errors for ChatGPT and the OpenAI API explained, with their causes and a way to use GPT models through a gateway in chat and via the API.
OpenAI Python SDK: timeouts, retries, errors and raw responses
5 min · · development
The openai client for Python does more than create(). We cover timeouts, retries, exceptions, raw responses and streaming, using a gateway as the example.
Gemini API key: how to get one and what to do if it does not work
6 min · · API keys
Two ways to a Gemini API key: a Google AI Studio key and a Zukko gateway key. Steps, request examples, safe storage and common problems.