# Specifications

This document is *not* a full system spec, it's instead intended to be a brief description of externally-facing behavior that is useful for application developers.

## Consensus parameters <a href="#consensus-parameters" id="consensus-parameters"></a>

<table><thead><tr><th width="373"></th><th></th></tr></thead><tbody><tr><td><strong>Block time</strong></td><td>5 seconds</td></tr><tr><td><strong>Block gas limit</strong></td><td>36,000,000</td></tr><tr><td><strong>EVM Chain ID</strong></td><td>8150</td></tr></tbody></table>

These numbers will change in the future as Alpen's design evolves.

## Upstream precompiles <a href="#upstream-precompiles" id="upstream-precompiles"></a>

All upstream precompiles supported as of Prague, except `0x0a` for KZG proofs.

See [execution-specs](https://github.com/ethereum/execution-specs?tab=readme-ov-file#ethereum-protocol-releases) or [evm.codes/precompiled](https://www.evm.codes/precompiled?fork=prague) for more information.

## Other notable addresses <a href="#other-notable-addresses" id="other-notable-addresses"></a>

* `0x5400000000000000000000000000000000000001`: Bridge withdrawal precompile. See the [bridge documentation](/how-alpen-works/bitcoin-bridge.md) for more information.
* `0x5400000000000000000000000000000000000002`: Schnorr signature verification precompile.&#x20;


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.alpenlabs.io/how-alpen-works/specifications.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.