From 12952d070f10fba51afbbcfbfa1b782d0d2fed3a Mon Sep 17 00:00:00 2001
From: Sergei Tikhomirov <sergey.s.tikhomirov@gmail.com>
Date: Tue, 9 Dec 2025 10:45:06 +0100
Subject: [PATCH] Add text file for coding LLMs with high-level nwaku info and
 style guide advice (#3624)

* add CLAUDE.md first version

* extract style guide advice

* use AGENTS.md instead of CLAUDE.md for neutrality

* chore: update AGENTS.md w.r.t. master developments

* Apply suggestions from code review

Co-authored-by: Ivan FB <128452529+Ivansete-status@users.noreply.github.com>

* remove project tree from AGENTS.md; minor editx

* Apply suggestions from code review

Co-authored-by: NagyZoltanPeter <113987313+NagyZoltanPeter@users.noreply.github.com>

---------

Co-authored-by: Ivan FB <128452529+Ivansete-status@users.noreply.github.com>
Co-authored-by: NagyZoltanPeter <113987313+NagyZoltanPeter@users.noreply.github.com>
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+# AGENTS.md - AI Coding Context
+
+This file provides essential context for LLMs assisting with Logos Messaging development.
+
+## Project Identity
+
+Logos Messaging is designed as a shared public network for generalized messaging, not application-specific infrastructure.
+
+This project is a Nim implementation of a libp2p protocol suite for private, censorship-resistant P2P messaging. It targets resource-restricted devices and privacy-preserving communication.
+
+Logos Messaging was formerly known as Waku. Waku-related terminology remains within the codebase for historical reasons.
+
+### Design Philosophy
+
+Key architectural decisions:
+
+Resource-restricted first: Protocols differentiate between full nodes (relay) and light clients (filter, lightpush, store). Light clients can participate without maintaining full message history or relay capabilities. This explains the client/server split in protocol implementations.
+
+Privacy through unlinkability: RLN (Rate Limiting Nullifier) provides DoS protection while preserving sender anonymity. Messages are routed through pubsub topics with automatic sharding across 8 shards. Code prioritizes metadata privacy alongside content encryption.
+
+Scalability via sharding: The network uses automatic content-topic-based sharding to distribute traffic. This is why you'll see sharding logic throughout the codebase and why pubsub topic selection is protocol-level, not application-level.
+
+See [documentation](https://docs.waku.org/learn/) for architectural details.
+
+### Core Protocols
+- Relay: Pub/sub message routing using GossipSub
+- Store: Historical message retrieval and persistence
+- Filter: Lightweight message filtering for resource-restricted clients
+- Lightpush: Lightweight message publishing for clients
+- Peer Exchange: Peer discovery mechanism
+- RLN Relay: Rate limiting nullifier for spam protection
+- Metadata: Cluster and shard metadata exchange between peers
+- Mix: Mixnet protocol for enhanced privacy through onion routing
+- Rendezvous: Alternative peer discovery mechanism
+
+### Key Terminology
+- ENR (Ethereum Node Record): Node identity and capability advertisement
+- Multiaddr: libp2p addressing format (e.g., `/ip4/127.0.0.1/tcp/60000/p2p/16Uiu2...`)
+- PubsubTopic: Gossipsub topic for message routing (e.g., `/waku/2/default-waku/proto`)
+- ContentTopic: Application-level message categorization (e.g., `/my-app/1/chat/proto`)
+- Sharding: Partitioning network traffic across topics (static or auto-sharding)
+- RLN (Rate Limiting Nullifier): Zero-knowledge proof system for spam prevention
+
+### Specifications
+All specs are at [rfc.vac.dev/waku](https://rfc.vac.dev/waku). RFCs use `WAKU2-XXX` format (not legacy `WAKU-XXX`).
+
+## Architecture
+
+### Protocol Module Pattern
+Each protocol typically follows this structure:
+```
+waku_<protocol>/
+├── protocol.nim       # Main protocol type and handler logic
+├── client.nim         # Client-side API
+├── rpc.nim           # RPC message types
+├── rpc_codec.nim     # Protobuf encoding/decoding
+├── common.nim        # Shared types and constants
+└── protocol_metrics.nim  # Prometheus metrics
+```
+
+### WakuNode Architecture
+- WakuNode (`waku/node/waku_node.nim`) is the central orchestrator
+- Protocols are "mounted" onto the node's switch (libp2p component)
+- PeerManager handles peer selection and connection management
+- Switch provides libp2p transport, security, and multiplexing
+
+Example protocol type definition:
+```nim
+type WakuFilter* = ref object of LPProtocol
+  subscriptions*: FilterSubscriptions
+  peerManager: PeerManager
+  messageCache: TimedCache[string]
+```
+
+## Development Essentials
+
+### Build Requirements
+- Nim 2.x (check `waku.nimble` for minimum version)
+- Rust toolchain (required for RLN dependencies)
+- Build system: Make with nimbus-build-system
+
+### Build System
+The project uses Makefile with nimbus-build-system (Status's Nim build framework):
+```bash
+# Initial build (updates submodules)
+make wakunode2
+
+# After git pull, update submodules
+make update
+
+# Build with custom flags
+make wakunode2 NIMFLAGS="-d:chronicles_log_level=DEBUG"
+```
+
+Note: The build system uses `--mm:refc` memory management (automatically enforced). Only relevant if compiling outside the standard build system.
+
+### Common Make Targets
+```bash
+make wakunode2          # Build main node binary
+make test               # Run all tests
+make testcommon         # Run common tests only
+make libwakuStatic      # Build static C library
+make chat2              # Build chat example
+make install-nph        # Install git hook for auto-formatting
+```
+
+### Testing
+```bash
+# Run all tests
+make test
+
+# Run specific test file
+make test tests/test_waku_enr.nim
+
+# Run specific test case from file
+make test tests/test_waku_enr.nim "check capabilities support"
+
+# Build and run test separately (for development iteration)
+make test tests/test_waku_enr.nim
+```
+
+Test structure uses `testutils/unittests`:
+```nim
+import testutils/unittests
+
+suite "Waku ENR - Capabilities":
+  test "check capabilities support":
+    ## Given
+    let bitfield: CapabilitiesBitfield = 0b0000_1101u8
+    
+    ## Then
+    check:
+      bitfield.supportsCapability(Capabilities.Relay)
+      not bitfield.supportsCapability(Capabilities.Store)
+```
+
+### Code Formatting
+Mandatory: All code must be formatted with `nph` (vendored in `vendor/nph`)
+```bash
+# Format specific file
+make nph/waku/waku_core.nim
+
+# Install git pre-commit hook (auto-formats on commit)
+make install-nph
+```
+The nph formatter handles all formatting details automatically, especially with the pre-commit hook installed. Focus on semantic correctness.
+
+### Logging
+Uses `chronicles` library with compile-time configuration:
+```nim
+import chronicles
+
+logScope:
+  topics = "waku lightpush"
+
+info "handling request", peerId = peerId, topic = pubsubTopic
+error "request failed", error = msg
+```
+
+Compile with log level:
+```bash
+nim c -d:chronicles_log_level=TRACE myfile.nim
+```
+
+
+## Code Conventions
+
+Common pitfalls:
+- Always handle Result types explicitly
+- Avoid global mutable state: Pass state through parameters
+- Keep functions focused: Under 50 lines when possible
+- Prefer compile-time checks (`static assert`) over runtime checks
+
+### Naming
+- Files/Directories: `snake_case` (e.g., `waku_lightpush`, `peer_manager`)
+- Procedures: `camelCase` (e.g., `handleRequest`, `pushMessage`)
+- Types: `PascalCase` (e.g., `WakuFilter`, `PubsubTopic`)
+- Constants: `PascalCase` (e.g., `MaxContentTopicsPerRequest`)
+- Constructors: `func init(T: type Xxx, params): T`
+- For ref types: `func new(T: type Xxx, params): ref T`
+- Exceptions: `XxxError` for CatchableError, `XxxDefect` for Defect
+- ref object types: `XxxRef` suffix
+
+### Imports Organization
+Group imports: stdlib, external libs, internal modules:
+```nim
+import
+  std/[options, sequtils],      # stdlib
+  results, chronicles, chronos,  # external
+  libp2p/peerid
+import
+  ../node/peer_manager,          # internal (separate import block)
+  ../waku_core,
+  ./common
+```
+
+### Async Programming
+Uses chronos, not stdlib `asyncdispatch`:
+```nim
+proc handleRequest(
+    wl: WakuLightPush, peerId: PeerId
+): Future[WakuLightPushResult] {.async.} =
+  let res = await wl.pushHandler(peerId, pubsubTopic, message)
+  return res
+```
+
+### Error Handling
+The project uses both Result types and exceptions:
+
+Result types from nim-results are used for protocol and API-level errors:
+```nim
+proc subscribe(
+    wf: WakuFilter, peerId: PeerID
+): Future[FilterSubscribeResult] {.async.} =
+  if contentTopics.len > MaxContentTopicsPerRequest:
+    return err(FilterSubscribeError.badRequest("exceeds maximum"))
+  
+  # Handle Result with isOkOr
+  (await wf.subscriptions.addSubscription(peerId, criteria)).isOkOr:
+    return err(FilterSubscribeError.serviceUnavailable(error))
+  
+  ok()
+```
+
+Exceptions still used for:
+- chronos async failures (CancelledError, etc.)
+- Database/system errors
+- Library interop
+
+Most files start with `{.push raises: [].}` to disable exception tracking, then use try/catch blocks where needed.
+
+### Pragma Usage
+```nim
+{.push raises: [].}  # Disable default exception tracking (at file top)
+
+proc myProc(): Result[T, E] {.async.} =  # Async proc
+```
+
+### Protocol Inheritance
+Protocols inherit from libp2p's `LPProtocol`:
+```nim
+type WakuLightPush* = ref object of LPProtocol
+  rng*: ref rand.HmacDrbgContext
+  peerManager*: PeerManager
+  pushHandler*: PushMessageHandler
+```
+
+### Type Visibility
+- Public exports use `*` suffix: `type WakuFilter* = ...`
+- Fields without `*` are module-private
+
+## Style Guide Essentials
+
+This section summarizes key Nim style guidelines relevant to this project. Full guide: https://status-im.github.io/nim-style-guide/
+
+### Language Features
+
+Import and Export
+- Use explicit import paths with std/ prefix for stdlib
+- Group imports: stdlib, external, internal (separate blocks)
+- Export modules whose types appear in public API
+- Avoid include
+
+Macros and Templates
+- Avoid macros and templates - prefer simple constructs
+- Avoid generating public API with macros
+- Put logic in templates, use macros only for glue code
+
+Object Construction
+- Prefer Type(field: value) syntax
+- Use Type.init(params) convention for constructors
+- Default zero-initialization should be valid state
+- Avoid using result variable for construction
+
+ref object Types
+- Avoid ref object unless needed for:
+  - Resource handles requiring reference semantics
+  - Shared ownership
+  - Reference-based data structures (trees, lists)
+  - Stable pointer for FFI
+- Use explicit ref MyType where possible
+- Name ref object types with Ref suffix: XxxRef
+
+Memory Management
+- Prefer stack-based and statically sized types in core code
+- Use heap allocation in glue layers
+- Avoid alloca
+- For FFI: use create/dealloc or createShared/deallocShared
+
+Variable Usage
+- Use most restrictive of const, let, var (prefer const over let over var)
+- Prefer expressions for initialization over var then assignment
+- Avoid result variable - use explicit return or expression-based returns
+
+Functions
+- Prefer func over proc
+- Avoid public (*) symbols not part of intended API
+- Prefer openArray over seq for function parameters
+
+Methods (runtime polymorphism)
+- Avoid method keyword for dynamic dispatch
+- Prefer manual vtable with proc closures for polymorphism
+- Methods lack support for generics
+
+Miscellaneous
+- Annotate callback proc types with {.raises: [], gcsafe.}
+- Avoid explicit {.inline.} pragma
+- Avoid converters
+- Avoid finalizers
+
+Type Guidelines
+
+Binary Data
+- Use byte for binary data
+- Use seq[byte] for dynamic arrays
+- Convert string to seq[byte] early if stdlib returns binary as string
+
+Integers
+- Prefer signed (int, int64) for counting, lengths, indexing
+- Use unsigned with explicit size (uint8, uint64) for binary data, bit ops
+- Avoid Natural
+- Check ranges before converting to int
+- Avoid casting pointers to int
+- Avoid range types
+
+Strings
+- Use string for text
+- Use seq[byte] for binary data instead of string
+
+### Error Handling
+
+Philosophy
+- Prefer Result, Opt for explicit error handling
+- Use Exceptions only for legacy code compatibility
+
+Result Types
+- Use Result[T, E] for operations that can fail
+- Use cstring for simple error messages: Result[T, cstring]
+- Use enum for errors needing differentiation: Result[T, SomeErrorEnum]
+- Use Opt[T] for simple optional values
+- Annotate all modules: {.push raises: [].} at top
+
+Exceptions (when unavoidable)
+- Inherit from CatchableError, name XxxError
+- Use Defect for panics/logic errors, name XxxDefect
+- Annotate functions explicitly: {.raises: [SpecificError].}
+- Catch specific error types, avoid catching CatchableError
+- Use expression-based try blocks
+- Isolate legacy exception code with try/except, convert to Result
+
+Common Defect Sources
+- Overflow in signed arithmetic
+- Array/seq indexing with []
+- Implicit range type conversions
+
+Status Codes
+- Avoid status code pattern
+- Use Result instead
+
+### Library Usage
+
+Standard Library
+- Use judiciously, prefer focused packages
+- Prefer these replacements:
+  - async: chronos
+  - bitops: stew/bitops2
+  - endians: stew/endians2
+  - exceptions: results
+  - io: stew/io2
+
+Results Library
+- Use cstring errors for diagnostics without differentiation
+- Use enum errors when caller needs to act on specific errors
+- Use complex types when additional error context needed
+- Use isOkOr pattern for chaining
+
+Wrappers (C/FFI)
+- Prefer native Nim when available
+- For C libraries: use {.compile.} to build from source
+- Create xxx_abi.nim for raw ABI wrapper
+- Avoid C++ libraries
+
+Miscellaneous
+- Print hex output in lowercase, accept both cases
+
+### Common Pitfalls
+
+- Defects lack tracking by {.raises.}
+- nil ref causes runtime crashes
+- result variable disables branch checking
+- Exception hierarchy unclear between Nim versions
+- Range types have compiler bugs
+- Finalizers infect all instances of type
+
+## Common Workflows
+
+### Adding a New Protocol
+1. Create directory: `waku/waku_myprotocol/`
+2. Define core files:
+   - `rpc.nim` - Message types
+   - `rpc_codec.nim` - Protobuf encoding
+   - `protocol.nim` - Protocol handler
+   - `client.nim` - Client API
+   - `common.nim` - Shared types
+3. Define protocol type in `protocol.nim`:
+   ```nim
+   type WakuMyProtocol* = ref object of LPProtocol
+     peerManager: PeerManager
+     # ... fields
+   ```
+4. Implement request handler
+5. Mount in WakuNode (`waku/node/waku_node.nim`)
+6. Add tests in `tests/waku_myprotocol/`
+7. Export module via `waku/waku_myprotocol.nim`
+
+### Adding a REST API Endpoint
+1. Define handler in `waku/rest_api/endpoint/myprotocol/`
+2. Implement endpoint following pattern:
+   ```nim
+   proc installMyProtocolApiHandlers*(
+       router: var RestRouter, node: WakuNode
+   ) =
+     router.api(MethodGet, "/waku/v2/myprotocol/endpoint") do () -> RestApiResponse:
+       # Implementation
+       return RestApiResponse.jsonResponse(data, status = Http200)
+   ```
+3. Register in `waku/rest_api/handlers.nim`
+
+### Adding Database Migration
+For message_store (SQLite):
+1. Create `migrations/message_store/NNNNN_description.up.sql`
+2. Create corresponding `.down.sql` for rollback
+3. Increment version number sequentially
+4. Test migration locally before committing
+
+For PostgreSQL: add in `migrations/message_store_postgres/`
+
+### Running Single Test During Development
+```bash
+# Build test binary
+make test tests/waku_filter_v2/test_waku_client.nim
+
+# Binary location
+./build/tests/waku_filter_v2/test_waku_client.nim.bin
+
+# Or combine
+make test tests/waku_filter_v2/test_waku_client.nim "specific test name"
+```
+
+### Debugging with Chronicles
+Set log level and filter topics:
+```bash
+nim c -r \
+  -d:chronicles_log_level=TRACE \
+  -d:chronicles_disabled_topics="eth,dnsdisc" \
+  tests/mytest.nim
+```
+
+## Key Constraints
+
+### Vendor Directory
+- Never edit files directly in vendor - it is auto-generated from git submodules
+- Always run `make update` after pulling changes
+- Managed by `nimbus-build-system`
+
+### Chronicles Performance
+- Log levels are configured at compile time for performance
+- Runtime filtering is available but should be used sparingly: `-d:chronicles_runtime_filtering=on`
+- Default sinks are optimized for production
+
+### Memory Management
+- Uses `refc` (reference counting with cycle collection)
+- Automatically enforced by the build system (hardcoded in `waku.nimble`)
+- Do not override unless absolutely necessary, as it breaks compatibility
+
+### RLN Dependencies
+- RLN code requires a Rust toolchain, which explains Rust imports in some modules
+- Pre-built `librln` libraries are checked into the repository
+
+## Quick Reference
+
+Language: Nim 2.x | License: MIT or Apache 2.0
+
+### Important Files
+- `Makefile` - Primary build interface
+- `waku.nimble` - Package definition and build tasks (called via nimbus-build-system)
+- `vendor/nimbus-build-system/` - Status's build framework
+- `waku/node/waku_node.nim` - Core node implementation
+- `apps/wakunode2/wakunode2.nim` - Main CLI application
+- `waku/factory/waku_conf.nim` - Configuration types
+- `library/libwaku.nim` - C bindings entry point
+
+### Testing Entry Points
+- `tests/all_tests_waku.nim` - All Waku protocol tests
+- `tests/all_tests_wakunode2.nim` - Node application tests
+- `tests/all_tests_common.nim` - Common utilities tests
+
+### Key Dependencies
+- `chronos` - Async framework
+- `nim-results` - Result type for error handling
+- `chronicles` - Logging
+- `libp2p` - P2P networking
+- `confutils` - CLI argument parsing
+- `presto` - REST server
+- `nimcrypto` - Cryptographic primitives
+
+Note: For specific version requirements, check `waku.nimble`.
+
+