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# Architecture

Tracer runs as a short pipeline:

1. register handlers
2. convert runtime PHP errors to exceptions
3. route uncaught throwables to CLI or web flow
4. print or render the final error output

## Registration

`ErrorHandler::setup()` registers both error and exception handlers on the same instance. Call it once during bootstrap so the same handler owns both flows.

## CLI flow

For `PHP_SAPI === 'cli'`:

* output goes to the injected CLI output, or to Symfony `ConsoleOutput` when you do not provide one
* production prints the exception message for compact terminal output
* debug prints the exception class, message, file/line, and trace

## Web flow

For non-CLI runtime:

* severity is resolved from the throwable before logging
* production requests log through the matching logger method when available, with `error()` as the fallback method
* renderer returns an HTTP 500 response by rendering `errors/trace` in debug mode or `errors/500` in production
* when view rendering is unavailable, Tracer sends a plain `Internal Server Error` response

## Trace formatting

`StackTraceFormatter` builds source excerpts around trace lines for the debug view.

Notes:

* Handler-owned frames are skipped so the trace starts closer to application code.
* Source snippets appear when `fs()` is backed by a local filesystem adapter.


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