Errors

Every NullRun exception carries a docs_url. The SDK sets it to this page, because one page holds the whole vocabulary and a per-code page for every code would be a worse place to send a reader.

The reference itself lives in one place: Error codes → reference.

You have	Go to
An NR-* code	NR-* error code catalog
A gateway wire code, such as BUDGET_HARD_BLOCKED	Gateway wire error codes
A Python exception class	SDK exception hierarchy
A generic API error with an error slug	Generic API errors
A failure you need to classify, not just name	Decision vs. infrastructure

To branch in your own code, read exc.error_code. To show the user a message, call nullrun.format_user_message(exc). To decide whether to retry, read exc.retryable.

See Concepts → Error handling for the exception → hook → message flow, and SDK API for the fields each exception carries.