Sphinx is a Git hook that stops pushes on designated branches and asks questions about the diff, such as how the code will behave when errors occur—for example, retrying after a Stripe timeout—to check that we truly understand the code before releasing it.
It works with Codex, Claude Code, Cursor, OpenCode, and Pi, or directly with Git. Answers are not sent back to the coding agent, and Sphinx does not open .env files or keys.
See Sphinx in action before code is pushed
When Git stops the push, Sphinx asks about the diff: if a retry occurs or charge() fails, what will the code do next? The author must answer correctly before the push can proceed.
When the code looks correct, but you cannot explain how it fails
Consider a webhook that records the event ID before calling charge(). When Stripe times out and sends the same event again, the system finds the existing ID and returns 200 without charging again. This appears to solve the problem, but there is still a gap.
If charge() fails after the ID has been recorded, the next retry will skip the charge, so the customer will never be charged. This example shows that simply having an agent write code is not enough—the author must also understand what the code will do when an error occurs.
Where Sphinx fits in an agent-driven development workflow
Sphinx is a Git hook inserted before code is pushed. It reads the diff and asks the developer what the code changes and what will happen when things go wrong.
It works with Codex, Claude Code, Cursor, OpenCode, Pi, or regular Git, making it suitable for teams that use agents to write code but still want people to verify their understanding before pushing.
From reading the diff yourself to answering questions that confirm understanding
The source does not provide details about an earlier product version or a specific legacy system, so the comparison can only cover the workflows described.
| Factor | Reading the diff yourself | Sphinx |
|---|---|---|
| Checkpoint | Developer or reviewer reads the diff | Git stops the protected branch |
| How understanding is verified | Interpret the code yourself | Answer questions about what the code does |
| When problems occur | No details provided in the source | Learn the reasoning and try a new scenario |
Sphinx’s approach fits the moment before a push because it requires people to answer questions based on the actual diff before the code moves forward.
What real-world situations do Sphinx’s questions address?
A clear example is a webhook that records the event ID before calling charge(), followed by Stripe sending the same event again after a timeout: the retry finds the existing ID and returns 200 without charging again. But if charge() fails after the ID has been recorded, the retry will skip the charge, leaving the customer uncharged.
If you answer incorrectly, Sphinx explains the reasoning and lets you try a new scenario until you better understand the diff. When you are in a hurry, use sphinx yolo to let the push go through; the system still records every time questions were skipped.
How is Sphinx different from the tools you already use?
Sphinx does not replace Codex, Claude Code, Cursor, OpenCode, or Pi. Instead, it works with these coding agents, as well as plain Git, by adding questions based on the diff before a push.
| Factor | Sphinx | Codex, Claude Code, Cursor, OpenCode, Pi, or plain Git |
|---|---|---|
| Role | Git hook that asks about understanding before code is sent out | Coding agents or environments used to write code |
| How they work together | Connects Git with coding agents | Tools or environments that Sphinx works alongside |
| Competitor details | Provides information about asking questions based on the diff | The source does not provide direct details about their operation |
Strengths and limitations identified by the source
Sphinx checks understanding of the code before a push using the diff and explains the reasoning when we answer incorrectly, making it suitable for work where behavior during errors must be carefully considered.
Pros
- +Uses few tokens
- +Supports OpenRouter and OpenAI-compatible endpoints
- +Does not open .env files or keys
- +Does not send answers to the coding agent
Cons
- −Requires answering questions before pushing
- −Details about other aspects of its operation must be read in the documentation
Costs and overhead beyond the installation command
Although the installation command is short, the machine must use Node 22.19 or later and support macOS, Linux, or WSL. You must also configure Sphinx to connect with Git and your coding agent, and choose a model for review.
The main cost is the time spent answering questions before each push. This is especially true when you answer incorrectly, because the system explains the reasoning and asks you to try a new scenario. It suits teams that want to understand the diff before code goes live, but if you are always in a hurry, this process adds another moment to pause and think during your work.
Who is Sphinx for, and who may not need it?
Made for
- Developers who use coding agents and want to understand the diff before pushing
- Users of Codex, Claude Code, Cursor, OpenCode, or Pi
Think twice
- Teams willing to add a question-and-answer step to review cases where the code behaves incorrectly
Skip this one
- People who do not want Git to stop and ask questions before pushing—use Git without installing Sphinx
Short questions that might help prevent code from causing the same damage again
Sphinx does not claim to write code for users. Instead, it stops Git to ask what the diff will do when an error occurs and gives users a chance to understand the outcome before sending the code.
A few short questions may reveal unexpected behavior before the code goes live. Consider whether pausing for a few minutes to explain failure cases is worth preventing a problem that could happen again.