chore: add CLAUDE.md guidance file

Author: LesnyRumcajs

AGENTS.md

@@ -0,0 +1,399 @@
+# CLAUDE.md
+
+This file provides guidance to AI coding assistants (such as Claude Code, Cursor, Copilot, etc.) when working with code in this repository.
+
+## Project Overview
+
+Forest is a Rust implementation of a Filecoin node that can transfer FIL, host a high-performance RPC API, validate the Filecoin blockchain, and generate blockchain snapshots. It aims to be faster and easier-to-use than the canonical Filecoin node (Lotus).
+
+## Development Commands
+
+### Building and Installing
+
+```bash
+# Install Forest binaries with release profile (recommended)
+mise install
+
+# Install with different profiles
+mise install quick          # Faster build, less optimization
+mise install release-lto-fat # Maximum optimization (slower build)
+mise install dev            # Debug build
+
+# Install slim version (minimal features)
+mise install --slim
+
+# Build without installing
+cargo build --release
+cargo build --profile quick  # Faster compile time
+
+# Run binaries directly (for development)
+cargo daemon --chain calibnet  # Alias for: cargo run --bin forest --
+cargo cli info show            # Alias for: cargo run --bin forest-cli --
+cargo forest-tool --help       # Alias for: cargo run --bin forest-tool --release --
+```
+
+### Testing
+
+```bash
+# Run all tests (requires cargo-nextest: cargo install cargo-nextest --locked)
+mise test           # Uses 'quick' profile by default
+mise test release   # Run with release profile
+mise test dev       # Run with dev profile
+
+# Run only Rust tests (no doctests)
+mise test:rust
+mise test:rust release
+
+# Run only doctests
+mise test:docs
+mise test:docs release
+
+# Run specific test
+cargo nextest run --cargo-profile quick <test_name>
+
+# Run tests in a specific file/module
+cargo nextest run --cargo-profile quick state_manager::
+
+# Run single test with full output
+cargo nextest run --cargo-profile quick --no-capture <test_name>
+
+# Run doctests for private items
+cargo test --doc --profile quick --features doctest-private
+```
+
+### Linting and Formatting
+
+```bash
+# Install all linting tools
+mise install-lint-tools
+
+# Run all linters
+mise lint
+
+# Run specific linters
+mise lint:rust-fmt    # Rust formatting check
+mise lint:clippy      # Rust linter
+mise lint:toml        # TOML formatting/linting
+mise lint:spellcheck  # Spell checking
+mise lint:deny        # Check licenses and security
+mise lint:unused-deps # Check for unused dependencies
+mise lint:dockerfile  # Lint Dockerfiles
+mise lint:shellcheck  # Lint shell scripts
+mise lint:golang      # Lint Go code (F3 sidecar)
+
+# Format code
+mise fmt              # Format Rust, TOML, markdown, YAML
+
+# Check specific issues
+cargo fmt --all -- --check
+cargo clippy --all-targets --no-deps -- --deny=warnings
+taplo fmt --check && taplo lint
+```
+
+### Code Coverage
+
+```bash
+# Generate coverage report (requires cargo-llvm-cov: cargo install cargo-llvm-cov)
+mise codecov
+```
+
+### Cleaning
+
+```bash
+# Clean all build artifacts and dependencies
+mise clean
+```
+
+## High-Level Architecture
+
+### Core Modules
+
+- **`daemon/`** - Node startup, initialization, and service orchestration
+- **`chain/`** - Blockchain storage (`ChainStore`) and index management
+- **`chain_sync/`** - Chain synchronization, consensus (`ChainFollower`, `ChainMuxer`)
+- **`state_manager/`** - State tree management and FVM execution coordinator
+- **`rpc/`** - JSON-RPC API server with authentication and filtering middleware
+- **`libp2p/`** - P2P networking (peer discovery, chain exchange, gossipsub)
+- **`message_pool/`** - Transaction pool for pending messages
+- **`db/`** - Database abstraction layer (ParityDb, MemoryDB, CAR format)
+- **`interpreter/`** - Filecoin Virtual Machine (FVM) integration (multi-version)
+- **`blocks/`** - Block and tipset structures
+- **`shim/`** - Filecoin protocol primitives (actors, crypto, addresses, state tree)
+- **`eth/`** - Ethereum compatibility layer (EVM transactions, address mapping)
+- **`wallet/`** - Key management and transaction signing
+- **`networks/`** - Network configurations (mainnet, calibnet, devnet)
+
+### Key Architectural Patterns
+
+**Blockstore Pattern**: Generic database trait (`fvm_ipld_blockstore::Blockstore`) allows swapping storage implementations. Most core structures are generic over `DB: Blockstore`:
+
+```rust
+pub struct StateManager<DB> where DB: Blockstore { ... }
+pub struct ChainStore<DB> where DB: Blockstore { ... }
+```
+
+**Publisher/Subscriber**: `HeadChange` events (new tipsets, reorg reverts) are broadcast via `Publisher` to multiple subscribers (RPC, message pool, chain indexer).
+
+**State Management**: `StateManager` is the central coordinator for state transitions, actor queries, and FVM execution. It caches state roots and receipts in `TipsetStateCache`.
+
+**Multi-version FVM**: Supports FVM2, FVM3, and FVM4 for different network versions. Stack size management with `stacker::grow()` is required for WASM execution.
+
+### Daemon Startup Flow
+
+1. `startup_init()` - Increase file descriptor limits, initialize proof cache
+2. `AppContext::init()` - Initialize database, state manager, keystore, JWT
+3. `create_p2p_service()` - Start libp2p networking stack
+4. `create_mpool()` - Initialize message pool
+5. `create_chain_follower()` - Start chain synchronization
+6. `maybe_start_rpc_service()` - Start JSON-RPC server
+7. `maybe_start_metrics_service()` - Start Prometheus metrics endpoint
+8. `maybe_start_health_check_service()` - Start health check service
+9. `maybe_start_f3_service()` - Start F3 sidecar (Fast Finality, optional)
+
+### Chain Synchronization
+
+**ChainFollower** orchestrates synchronization:
+
+- Receives tipsets from network peers
+- Validates blocks via `TipsetSyncer` and `TipsetValidator`
+- Resolves forks via `ChainMuxer` (heaviest chain wins)
+- Updates chain head through `StateManager`
+- Maintains `BadBlockCache` for invalid blocks
+- Reports `SyncStatus` to RPC clients
+
+### RPC Server Architecture
+
+Multi-layer middleware stack:
+
+```
+Request → AuthLayer → FilterLayer → SegregationLayer →
+SetExtensionLayer → LogLayer → MetricsLayer → RpcHandler
+```
+
+Major RPC namespaces: `auth::`, `chain::`, `state::`, `mpool::`, `eth::`, `net::`, `sync::`, `wallet::`
+
+### FVM Integration
+
+**Version Selection**: Network version determines FVM version (FVM2 for v1-v15, FVM3 for v16-v20, FVM4 for v21+)
+
+**VM Execution Flow**:
+
+```
+StateManager::call_with_gas()
+  → VM::new(ExecutionContext)
+  → vm.apply_message() / apply_implicit_message()
+  → VM::flush() → new_state_root
+```
+
+**Key Concepts**:
+
+- **State Tree** - IPLD-based Merkle tree of actor states
+- **Actors** - Smart contracts (System, Init, Power, Market, Miner, etc.)
+- **Messages** - Transactions that execute actor methods
+- **Receipts** - Execution results (gas used, exit code, return value)
+- **Randomness** - Provided by Drand beacon (via `ChainRand`)
+- **State Migrations** - Automatic upgrades at network version boundaries
+
+### P2P Networking
+
+Libp2p protocols:
+
+- **Chain Exchange** - Fetch blocks and messages during sync
+- **Hello** - Exchange peer info and genesis CID
+- **Gossipsub** - Broadcast new blocks and messages
+- **Bitswap** - IPLD block exchange (legacy)
+- **Kademlia DHT** - Peer discovery
+- **mDNS** - Local network discovery
+
+**Peer Manager** tracks peer quality, manages connections, and scores peers based on message validity.
+
+### Database Organization
+
+Storage layers:
+
+```
+Application (StateManager, ChainStore)
+  ↓
+IPLD Blockstore (LogicalDB)
+  ↓
+Write Buffer / Read Cache (optional)
+  ↓
+ParityDb (embedded KV store)
+```
+
+Special stores:
+
+- **Settings Store** - Configuration persistence (chain head, message pool config)
+- **Eth Mappings Store** - ETH ↔ Filecoin address mappings
+- **Indices Store** - Message and event indices
+- **CAR DB** - Snapshot import/export (v1, v2 with F3 data)
+
+### Ethereum Compatibility
+
+Supports legacy transactions, EIP-155, and EIP-1559. Provides standard Ethereum RPC methods (`eth_call`, `eth_sendTransaction`, `eth_getTransactionReceipt`, `eth_subscribe`, etc.)
+
+**Address Mapping**: EVM addresses map to Filecoin f4 (delegated) addresses. Precompiles provide Filecoin-specific operations.
+
+## Project-Specific Patterns
+
+### Error Handling
+
+Use `anyhow::Result<T>` for most operations. Add context with `.context()`:
+
+```rust
+some_operation().context("Failed to execute VM")?
+```
+
+### Async/Await
+
+- Tokio runtime for async execution
+- Use `tokio::task::spawn_blocking` for CPU-intensive work (VM execution, cryptography)
+- Channel-based communication between tasks (flume, tokio channels)
+
+### Module Organization
+
+Each module has:
+
+- `mod.rs` - Public API exports
+- Private submodules for implementation details
+- Clear trait boundaries for extensibility
+
+### Code Style
+
+- **No indexing** - Use `.get()` instead of `[index]` (enforced by clippy)
+- **No unwrap in production** - Use `?` or `expect()` with descriptive messages
+- **No dbg! or todo!** - Enforced in non-test code
+- Use `strum` for enum string conversions
+- Use `derive_more` for common trait implementations
+
+### Testing Utilities
+
+- `test_utils/` provides fixtures and helpers
+- Use `#[cfg(test)]` or `#[cfg(feature = "doctest-private")]` for test-only code
+- Serial tests (database tests) use `#[serial_test::serial]`
+
+### Network-Specific Configuration
+
+Networks defined in `networks/`:
+
+- **mainnet** - Production Filecoin network
+- **calibnet** - Public testnet (recommended for development)
+- **devnet** - Lightweight local network
+- **butterflynet** - Alternative testnet
+
+Each network has its own genesis, bootstrap peers, actor bundles, and upgrade epochs.
+
+## Common Development Workflows
+
+### Running a Local Node
+
+```bash
+# Mainnet (requires snapshot download)
+forest --encrypt-keystore false
+
+# Calibnet (testnet, auto-download snapshot)
+forest --chain calibnet --auto-download-snapshot --encrypt-keystore false
+
+# Using Docker
+docker run --init -it --rm ghcr.io/chainsafe/forest:latest --chain calibnet --auto-download-snapshot
+```
+
+### Using the CLI
+
+```bash
+# Set admin token for privileged operations
+export FULLNODE_API_INFO="<token>:/ip4/127.0.0.1/tcp/2345/http"
+
+# Or use --token flag
+forest-cli --token <ADMIN_TOKEN> info show
+
+# Common commands
+forest-cli info show           # Node status
+forest-cli chain head          # Current chain head
+forest-cli sync status         # Sync progress
+forest-cli net peers           # Connected peers
+forest-cli wallet list         # List wallets
+forest-cli mpool pending       # Pending messages
+```
+
+### Working with Snapshots
+
+```bash
+# Fetch snapshot
+forest-tool snapshot fetch --chain calibnet
+
+# Export snapshot
+forest-tool snapshot export --output snapshot.car
+
+# Import snapshot
+forest --import-snapshot snapshot.car --encrypt-keystore false
+```
+
+### Debugging
+
+```bash
+# Enable debug logging
+RUST_LOG=debug forest --chain calibnet
+
+# Filter specific modules
+RUST_LOG="debug,forest_libp2p::service=info" forest
+
+# Use tokio-console (requires tokio-console feature)
+tokio-console  # In separate terminal
+forest         # With RUSTFLAGS="--cfg tokio_unstable"
+
+# Profile with debugging symbols
+FOREST_F3_SIDECAR_FFI_BUILD_OPT_OUT=1 cargo build --profile debugging
+lldb target/debugging/forest
+```
+
+## Important Environment Variables
+
+- `FOREST_KEYSTORE_PHRASE` - Passphrase for encrypted keystore (headless mode)
+- `FOREST_CONFIG_PATH` - Path to config file (overrides default locations)
+- `RUST_LOG` - Logging configuration (e.g., `debug`, `forest=trace`)
+- `FULLNODE_API_INFO` - RPC endpoint and authentication token
+- `FOREST_F3_SIDECAR_FFI_BUILD_OPT_OUT` - Disable F3 sidecar build (for debugging profile)
+
+## Cargo Features
+
+- **`default`** - `jemalloc`, `tokio-console`, `tracing-loki`, `tracing-chrome`
+- **`slim`** - Minimal feature set (uses rustalloc)
+- **`jemalloc`** - Use jemalloc allocator (production default)
+- **`rustalloc`** - Use Rust standard allocator
+- **`system-alloc`** - Use system allocator (for memory profiling)
+- **`tokio-console`** - Enable tokio-console integration
+- **`tracing-loki`** - Send telemetry to Loki
+- **`tracing-chrome`** - Chrome tracing support
+- **`no-f3-sidecar`** - Disable F3 sidecar build
+- **`doctest-private`** - Enable doctests for private items
+- **`benchmark-private`** - Enable benchmark suite
+- **`interop-tests-private`** - Enable interop tests
+
+## Build Profiles
+
+- **`dev`** - Fast compile, line-table-only debug info, opt-level=1 for deps
+- **`quick`** - Inherits from release, opt-level=1, no LTO (good for testing)
+- **`release`** - Optimized, stripped, thin LTO, panic=abort
+- **`release-lto-fat`** - Maximum optimization with fat LTO
+- **`debugging`** - Full debug info (requires `FOREST_F3_SIDECAR_FFI_BUILD_OPT_OUT=1`)
+- **`profiling`** - For profiling tools
+
+## Key Dependencies
+
+- **Rust**: Version specified in `rust-toolchain.toml`
+- **Go**: Version specified in `go.work` (required for F3 sidecar)
+- **OS packages**: `build-essential` (Ubuntu), `clang`, `clang-devel` (Fedora)
+- **mise-en-place**: Task runner and tool installer (`mise.jdx.dev`)
+
+## Contributing Guidelines
+
+From CONTRIBUTING.md:
+
+- Use conventional commits (e.g., `feat: add Filecoin.RuleTheWorld RPC method`)
+- Run linters before submitting: `mise lint`
+- Format code: `mise fmt`
+- Ensure tests pass: `mise test`
+- Fill PR template exhaustively
+- First-time contributors sign CLA when opening PR
+- Document public functions and structs (see [Documentation practices](https://github.com/ChainSafe/forest/wiki/Documentation-practices))