Zukko Blog
Guides to Claude Code, Cursor, Codex and the Claude and GPT APIs: setup, token savings and troubleshooting.
The Codex extension for VS Code: features and your own provider
6 min · · IDE
The Codex extension lives in the VS Code sidebar and uses the same config.toml as the CLI. Features, connecting a gateway and the limits.
Claude Opus 4.6: what it is and how to move to Opus 5.5 safely
5 min · · models
Opus 4.6, 4.7 and 4.8 are the previous generation, and the catalogue now has Opus 5 and 5.5. A four-step migration plan: model id, your own prompts, cost comparison, rollback.
AI for C++ code: CMake builds, compiler errors and sanitizers
5 min · · development
C++ forgives a model a lot at compile time and punishes it later. How to build a build, test and sanitizer loop for an agent and what it costs on different models.
Claude Code in Russian: replies, comments and commit messages
6 min · · агенты
Claude Code understands Russian but answers in whatever language your instructions set. Where to put the language rule, what not to translate and what it costs in tokens.
"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.
Claude Sonnet 5.5 via API: connection, prices and cache at October 18, 2026
6 min · · models
How to call claude-sonnet-5-5 from Python and curl, what a typical request costs with and without cache, and how it differs from Sonnet 5 and Sonnet 4.6.
AI for SQL: how to write and optimize queries with a model
6 min · · development
Schema, sample data and a query plan in the request to the model, an EXPLAIN check and read-only access. Working Python code and a cost estimate.
LangChainGo: connecting a Go application to an OpenAI-compatible API
5 min · · development
The langchaingo library accepts any OpenAI-compatible address. We show the client, a request, streaming and a templated chain in Go, and estimate call costs.
AI for accounting: where it helps and where it must not be trusted
5 min · · бизнес
Where a model really saves an accountant's time and where it cannot be trusted unchecked. Code to extract fields from a document with an arithmetic check, and a cost estimate.
Chat PDF: asking questions about a PDF through an AI API
6 min · · автоматизация
Two ways to question a PDF with a model: put the document in context and cache it, or retrieve the relevant parts. Python code and the price of twenty questions.
Documents from a template with AI: filling templates from data
4 min · · автоматизация
A Word template, a data table and a script: hundreds of standard documents in one run. What to give the model, what to compute in code and how to verify fields.
Cursor for 1C: writing BSL code with an AI agent
6 min · · IDE
How to open a 1C configuration dump in Cursor, write rules for BSL, give the agent metadata and avoid accepting invented code. With a session cost estimate.
AI for teachers: lesson plans, assignments and checking student work
5 min · · бизнес
How a teacher can prepare materials with a model: tiered assignments, criteria, draft feedback. What to check, what not to delegate and what it costs.
AI for SMM: a content plan and batches of posts via API
5 min · · автоматизация
A monthly content plan and thirty posts in one voice from a single script. How to describe the brand voice, generate in batches and check the output.
AI for marketers: research, copy and analysis without made-up facts
5 min · · бизнес
Where a model really saves a marketer's time and where it invents numbers. Code for review analysis, fact-checking rules and a cost estimate.
Comparing documents with AI: finding the meaningful differences
5 min · · автоматизация
Combine an ordinary text diff with a model's semantic review to see which edits change the terms and which are cosmetic. Code, report format and cost.
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.
Roo Code Ollama: local models in Cline and Aider, an honest look
6 min · · агенты
We connect Ollama to Roo Code, Cline, Aider and OpenCode per each tool's documentation, cover the limits and show when it is simpler to return to a cloud API.
LangChain with_structured_output: a typed model response
5 min · · development
How to get a Pydantic object instead of text from a model: with_structured_output, three methods, include_raw, retries on errors and testing several models on your data.
Gemini API billing: how to pay for Gemini by the token from Russia
6 min · · payments
How Google bills the Gemini API, where setup gets stuck on payment, and how to call Gemini from a single dollar balance instead.
Claude CLI on Linux and macOS: Install and Connect to the Gateway
5 min · · development
Install Claude Code on Linux and macOS, put the address and key into your shell profile and verify the connection with curl. PATH and permission errors included.
Website analysis with AI: auditing pages, texts and structure via API
4 min · · автоматизация
Collect page data with a script, send the model compact JSON and get a report on headings, meta tags and text structure. With a cost estimate and honest limits.
Skills in Claude Code: what they are and how to write your own
7 min · · агенты
A skill is a folder with a SKILL.md file that Claude Code loads only when needed. We compare it with CLAUDE.md and write one of our own.
Grok API price: cost of Grok 4.7, 4.6 and 4.5 with examples
6 min · · экономия
We price requests to Grok 4.7, 4.6 and 4.5 in Zukko on three scenarios and compare with official xAI prices. Formulas are shown and the arithmetic can be checked.