Shared models

rustygpt-shared centralises the data structures consumed by the server, web client, and CLI. Keeping these DTOs in one crate prevents drift between components and allows serde + utoipa derives to stay consistent.

Configuration loader

src/config/server.rs defines the Config struct and associated sub-structures (ServerConfig, RateLimitConfig, SseConfig, etc.). Every binary loads configuration through Config::load_config, which merges defaults, optional files, and environment overrides. Feature flags such as features.auth_v1 gate server subsystems without requiring code changes.

API payloads

The src/models directory contains strongly typed request/response structs:

• models/chat.rs – conversations, threads, message payloads, and streaming events
• models/oauth.rs – GitHub/Apple OAuth exchanges
• models/setup.rs – first-time setup contract (SetupRequest, SetupResponse)
• models/limits.rs – rate limit admin DTOs (CreateRateLimitProfileRequest, RateLimitAssignment, ...)
• models/session.rs – session summaries returned by /api/auth/*

All types derive Serialize, Deserialize, and when relevant utoipa::ToSchema so the OpenAPI generator stays in sync.

LLM abstractions

src/llms exposes traits (LLMProvider, LLMModel) and helpers for llama.cpp integration. The server’s AssistantService uses these traits to stream responses and emit metrics (llm_model_cache_hits_total, llm_model_load_seconds). When you add a new provider, implement the traits here and update the configuration schema.

Why it matters

• Type safety – clients compile against the same structs the server uses, catching breaking changes early.
• Single-source documentation – OpenAPI docs and mdBook pages pull names directly from these types.
• Testing – shared fixtures in shared::models make it easier to write integration tests that cover both server handlers and CLI commands.

Whenever you extend the API, add or update the relevant struct in rustygpt-shared first, then regenerate the OpenAPI spec with cargo run -p rustygpt-cli -- spec.