chore: introduce AI-assisted development to the project

.claude/settings.json

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+{
+  "permissions": {
+    "allow": [
+      "Bash(tsc --noEmit)",
+      "Bash(uv run dmypy*)",
+      "Bash(uv run pytest*)",
+      "Bash(uv run ruff*)",
+      "Bash(uv run scripts/*)",
+      "Bash(pnpm install*)",
+      "Bash(pnpm run build*)",
+      "Bash(pnpm run lint*)",
+      "Bash(pnpm run format*)",
+      "Bash(pnpm test*)",
+      "Bash(pnpm run test*)"
+    ]
+  }
+}

.serena/.gitignore

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+/cache
+/project.local.yml

.serena/project.yml

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+# the name by which the project can be referenced within Serena
+project_name: "chainlit"
+
+
+# list of languages for which language servers are started; choose from:
+#   al                  bash                clojure             cpp                 csharp
+#   csharp_omnisharp    dart                elixir              elm                 erlang
+#   fortran             fsharp              go                  groovy              haskell
+#   java                julia               kotlin              lua                 markdown
+#   matlab              nix                 pascal              perl                php
+#   php_phpactor        powershell          python              python_jedi         r
+#   rego                ruby                ruby_solargraph     rust                scala
+#   swift               terraform           toml                typescript          typescript_vts
+#   vue                 yaml                zig
+#   (This list may be outdated. For the current list, see values of Language enum here:
+#   https://github.com/oraios/serena/blob/main/src/solidlsp/ls_config.py
+#   For some languages, there are alternative language servers, e.g. csharp_omnisharp, ruby_solargraph.)
+# Note:
+#   - For C, use cpp
+#   - For JavaScript, use typescript
+#   - For Free Pascal/Lazarus, use pascal
+# Special requirements:
+#   Some languages require additional setup/installations.
+#   See here for details: https://oraios.github.io/serena/01-about/020_programming-languages.html#language-servers
+# When using multiple languages, the first language server that supports a given file will be used for that file.
+# The first language is the default language and the respective language server will be used as a fallback.
+# Note that when using the JetBrains backend, language servers are not used and this list is correspondingly ignored.
+languages:
+- typescript
+- python
+- bash
+- markdown
+- toml
+- yaml
+
+# the encoding used by text files in the project
+# For a list of possible encodings, see https://docs.python.org/3.11/library/codecs.html#standard-encodings
+encoding: "utf-8"
+
+# line ending convention to use when writing source files.
+# Possible values: unset (use global setting), "lf", "crlf", or "native" (platform default)
+# This does not affect Serena's own files (e.g. memories and configuration files), which always use native line endings.
+line_ending:
+
+# The language backend to use for this project.
+# If not set, the global setting from serena_config.yml is used.
+# Valid values: LSP, JetBrains
+# Note: the backend is fixed at startup. If a project with a different backend
+# is activated post-init, an error will be returned.
+language_backend:
+
+# whether to use project's .gitignore files to ignore files
+ignore_all_files_in_gitignore: true
+
+# advanced configuration option allowing to configure language server-specific options.
+# Maps the language key to the options.
+# Have a look at the docstring of the constructors of the LS implementations within solidlsp (e.g., for C# or PHP) to see which options are available.
+# No documentation on options means no options are available.
+ls_specific_settings: {}
+
+# list of additional paths to ignore in this project.
+# Same syntax as gitignore, so you can use * and **.
+# Note: global ignored_paths from serena_config.yml are also applied additively.
+ignored_paths: []
+
+# whether the project is in read-only mode
+# If set to true, all editing tools will be disabled and attempts to use them will result in an error
+# Added on 2025-04-18
+read_only: false
+
+# list of tool names to exclude.
+# This extends the existing exclusions (e.g. from the global configuration)
+#
+# Below is the complete list of tools for convenience.
+# To make sure you have the latest list of tools, and to view their descriptions, 
+# execute `uv run scripts/print_tool_overview.py`.
+#
+#  * `activate_project`: Activates a project by name.
+#  * `check_onboarding_performed`: Checks whether project onboarding was already performed.
+#  * `create_text_file`: Creates/overwrites a file in the project directory.
+#  * `delete_lines`: Deletes a range of lines within a file.
+#  * `delete_memory`: Deletes a memory from Serena's project-specific memory store.
+#  * `execute_shell_command`: Executes a shell command.
+#  * `find_referencing_code_snippets`: Finds code snippets in which the symbol at the given location is referenced.
+#  * `find_referencing_symbols`: Finds symbols that reference the symbol at the given location (optionally filtered by type).
+#  * `find_symbol`: Performs a global (or local) search for symbols with/containing a given name/substring (optionally filtered by type).
+#  * `get_current_config`: Prints the current configuration of the agent, including the active and available projects, tools, contexts, and modes.
+#  * `get_symbols_overview`: Gets an overview of the top-level symbols defined in a given file.
+#  * `initial_instructions`: Gets the initial instructions for the current project.
+#     Should only be used in settings where the system prompt cannot be set,
+#     e.g. in clients you have no control over, like Claude Desktop.
+#  * `insert_after_symbol`: Inserts content after the end of the definition of a given symbol.
+#  * `insert_at_line`: Inserts content at a given line in a file.
+#  * `insert_before_symbol`: Inserts content before the beginning of the definition of a given symbol.
+#  * `list_dir`: Lists files and directories in the given directory (optionally with recursion).
+#  * `list_memories`: Lists memories in Serena's project-specific memory store.
+#  * `onboarding`: Performs onboarding (identifying the project structure and essential tasks, e.g. for testing or building).
+#  * `prepare_for_new_conversation`: Provides instructions for preparing for a new conversation (in order to continue with the necessary context).
+#  * `read_file`: Reads a file within the project directory.
+#  * `read_memory`: Reads the memory with the given name from Serena's project-specific memory store.
+#  * `remove_project`: Removes a project from the Serena configuration.
+#  * `replace_lines`: Replaces a range of lines within a file with new content.
+#  * `replace_symbol_body`: Replaces the full definition of a symbol.
+#  * `restart_language_server`: Restarts the language server, may be necessary when edits not through Serena happen.
+#  * `search_for_pattern`: Performs a search for a pattern in the project.
+#  * `summarize_changes`: Provides instructions for summarizing the changes made to the codebase.
+#  * `switch_modes`: Activates modes by providing a list of their names
+#  * `think_about_collected_information`: Thinking tool for pondering the completeness of collected information.
+#  * `think_about_task_adherence`: Thinking tool for determining whether the agent is still on track with the current task.
+#  * `think_about_whether_you_are_done`: Thinking tool for determining whether the task is truly completed.
+#  * `write_memory`: Writes a named memory (for future reference) to Serena's project-specific memory store.
+excluded_tools: []
+
+# list of tools to include that would otherwise be disabled (particularly optional tools that are disabled by default).
+# This extends the existing inclusions (e.g. from the global configuration).
+included_optional_tools: []
+
+# fixed set of tools to use as the base tool set (if non-empty), replacing Serena's default set of tools.
+# This cannot be combined with non-empty excluded_tools or included_optional_tools.
+fixed_tools: []
+
+# list of mode names to that are always to be included in the set of active modes
+# The full set of modes to be activated is base_modes + default_modes.
+# If the setting is undefined, the base_modes from the global configuration (serena_config.yml) apply.
+# Otherwise, this setting overrides the global configuration.
+# Set this to [] to disable base modes for this project.
+# Set this to a list of mode names to always include the respective modes for this project.
+base_modes:
+
+# list of mode names that are to be activated by default.
+# The full set of modes to be activated is base_modes + default_modes.
+# If the setting is undefined, the default_modes from the global configuration (serena_config.yml) apply.
+# Otherwise, this overrides the setting from the global configuration (serena_config.yml).
+# This setting can, in turn, be overridden by CLI parameters (--mode).
+default_modes:
+
+# initial prompt for the project. It will always be given to the LLM upon activating the project
+# (contrary to the memories, which are loaded on demand).
+initial_prompt: ""
+
+# time budget (seconds) per tool call for the retrieval of additional symbol information
+# such as docstrings or parameter information.
+# This overrides the corresponding setting in the global configuration; see the documentation there.
+# If null or missing, use the setting from the global configuration.
+symbol_info_budget:
+
+# list of regex patterns which, when matched, mark a memory entry as read‑only.
+# Extends the list from the global configuration, merging the two lists.
+read_only_memory_patterns: []
+
+# list of regex patterns for memories to completely ignore.
+# Matching memories will not appear in list_memories or activate_project output
+# and cannot be accessed via read_memory or write_memory.
+# To access ignored memory files, use the read_file tool on the raw file path.
+# Extends the list from the global configuration, merging the two lists.
+# Example: ["_archive/.*", "_episodes/.*"]
+ignored_memory_patterns: []

AGENTS.md

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+# AGENTS.md
+
+This file provides guidance to AI agents when working with code in this repository.
+
+## Backward Compatibility (CRITICAL)
+
+All changes MUST be backward-compatible. If a refactor or breaking change is unavoidable, notify the user and stop — do not proceed without explicit approval. When approved, prefer adding a compatibility layer over keeping legacy code in place.
+
+## Overview
+
+Chainlit is a Python framework for building production-ready conversational AI applications. It consists of a Python/FastAPI backend and a React frontend, with a pnpm monorepo for the JS packages.
+
+## Prerequisites
+
+- Python: **3.13** (3.10+ is the framework's minimum, but development targets 3.13)
+- Node.js: **24+**
+- [uv](https://docs.astral.sh/uv/) — Python package manager
+- [pnpm 9](https://pnpm.io/) — Node.js package manager (Corepack)
+
+## Quick Start
+
+### Install
+
+| | Command | Directory |
+|---|---|---|
+| Backend  | `uv sync --all-extras` | `backend/` |
+| Frontend | `pnpm install` | repo root |
+
+### Build
+
+| | Command | Directory | What it does |
+|---|---|---|---|
+| Backend | `uv build` | `backend/` | Build Python package — runs `pnpm buildUi`, then copies assets into `backend/chainlit/frontend/dist/` and `backend/chainlit/copilot/dist/` |
+| Frontend | `pnpm run buildUi` | repo root | Build libs + frontend JS assets |
+| Frontend (libs only) | `pnpm run build:libs` | repo root | Build only `react-client` and `copilot` libs |
+
+### Dev servers
+
+| | Command | Directory | URL |
+|---|---|---|---|
+| Backend | `uv run chainlit run chainlit/sample/hello.py -h` | `backend/` | http://localhost:8000 |
+| Frontend | `pnpm run dev` | `frontend/` | http://localhost:5173 (proxies to :8000) |
+
+### Tests
+
+| | Command | Directory |
+|---|---|---|
+| Backend (all) | `uv run pytest --cov=chainlit/` | `backend/` |
+| Backend (single file) | `uv run pytest tests/test_file.py` | `backend/` |
+| Frontend unit | `pnpm test` | `frontend/` |
+| E2E (Cypress) | `pnpm test` | repo root |
+
+### Lint & Format
+
+| | Command | Directory |
+|---|---|---|
+| Lint all | `pnpm run lint` | repo root |
+| Lint frontend only | `pnpm run lintUi` | repo root |
+| Format Python | `uv run ruff format chainlit/ tests/` | `backend/` |
+| Format JS/TS | `pnpm run formatUi` | repo root |
+
+### Type checking
+
+| | Command | Directory |
+|---|---|---|
+| Python (mypy) | `uv run dmypy run -- chainlit/ tests/` | `backend/` |
+| TypeScript | `tsc --noemit` | `frontend/` |
+
+Run `pnpm run lint` before committing — CI enforces this.
+
+### Commits
+
+This project uses [Conventional Commits](https://www.conventionalcommits.org/). Format: `<type>(<optional scope>): <description>`.
+
+Common types: `feat`, `fix`, `chore`, `docs`, `refactor`, `test`, `ci`. Scope is optional but encouraged (e.g. `fix(data): ...`, `feat(i18n): ...`).
+
+All commits made with AI assistance **must** include a `Co-Authored-By` trailer identifying the AI agent. Add it as the last line of the commit message body:
+
+```
+Co-Authored-By: <Agent Name> <agent-email-or-noreply>
+```
+
+Examples:
+- `Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>`
+- `Co-Authored-By: GitHub Copilot <noreply@github.com>`
+- `Co-Authored-By: Gemini CLI <noreply@google.com>`
+
+## Tech Stack
+
+| Layer | Stack |
+|---|---|
+| **Frontend** | React 18, TypeScript 5.2, Vite 5, Tailwind CSS 3, Vitest, Zod 3 |
+| **Frontend (state & routing)** | Recoil, React Router 6, react-hook-form, socket.io-client, SWR |
+| **Frontend (rendering)** | react-markdown + remark-gfm/math + rehype-katex/raw, highlight.js, lucide-react (icons), Radix UI (primitives), Plotly.js |
+| **Backend** | Python 3.13, FastAPI, Starlette, Uvicorn, python-socketio, Pydantic 2, PyJWT, httpx |
+| **LLM integrations** | MCP, LangChain, LlamaIndex, OpenAI SDK, Semantic Kernel, MistralAI |
+| **Infra / persistence** | SQLAlchemy (PostgreSQL/SQLite), DynamoDB + S3 (boto3), Azure Blob / Data Lake, Google Cloud Storage, LiteralAI |
+| **DX** | Husky (pre-commit), ESLint, Prettier, ruff, mypy (dmypy), pytest, Cypress |
+
+## Architecture
+
+### Monorepo structure
+
+```
+backend/          # Python package (published to PyPI as "chainlit")
+frontend/         # React app (built output served by backend)
+libs/
+  react-client/   # @chainlit/react-client — published npm package with React hooks
+  copilot/        # Copilot widget (embedded chat bubble)
+cypress/          # E2E tests
+```
+
+The pnpm workspace includes `frontend/`, `libs/react-client/`, and `libs/copilot/`. The built frontend assets are copied into `backend/chainlit/frontend/dist/` and served as static files.
+
+### Backend (`backend/chainlit/`)
+
+**Entry point for user apps**: `__init__.py` re-exports all public API decorators and classes.
+
+**Key files:**
+- `server.py` — FastAPI app, all REST routes (auth, elements, threads, file upload), serves the built frontend SPA, mounts the SocketIO app
+- `socket.py` — SocketIO event handlers for real-time WebSocket communication (connect, message, audio, etc.)
+- `callbacks.py` — Decorator functions registered via `@cl.on_message`, `@cl.on_chat_start`, `@cl.on_audio_chunk`, etc. These store functions on `config.code.*`
+- `config.py` — Reads `.chainlit/config.toml` from `APP_ROOT`. `ChainlitConfig` holds both static TOML config and runtime user-registered callbacks. `APP_ROOT` defaults to `os.getcwd()`.
+- `session.py` — `WebsocketSession` (per-connection state: user, files, MCP connections, message queue) and `HTTPSession`
+- `context.py` — `ChainlitContext` per-coroutine context variable (similar to thread-local), providing access to the current session and emitter
+- `emitter.py` — Sends events back to the frontend through the SocketIO session
+- `data/base.py` — `BaseDataLayer` ABC for persistence (threads, steps, elements, users, feedback). Implementations: `sql_alchemy.py`, `dynamodb.py`, `literalai.py`
+- `auth/` — JWT creation/validation (`jwt.py`), OAuth state cookies (`cookie.py`)
+- `types.py` — Shared Pydantic models for API request/response types
+
+**Data layer pattern**: The data layer is optional (no persistence by default). Register a custom implementation with `@cl.data_layer` decorator or use the built-in SQLAlchemy/DynamoDB/LiteralAI implementations. The `@queue_until_user_message()` decorator on `BaseDataLayer` methods queues write operations until the first user message arrives.
+
+**Integrations**: `langchain/`, `llama_index/`, `openai/`, `semantic_kernel/`, `mistralai/` — each provides callback handlers that bridge those frameworks into Chainlit steps/messages.
+
+### Frontend (`frontend/src/`)
+
+React 18 + TypeScript + Vite, styled with Tailwind CSS and Radix UI primitives.
+
+- `main.tsx` — React root, wraps app in `RecoilRoot` and `ChainlitContext.Provider`
+- `App.tsx` — Handles auth readiness, chat profile selection, and WebSocket connection lifecycle
+- `router.tsx` — Client-side routes: `/` (Home), `/thread/:id`, `/element/:id`, `/login`, `/login/callback`, `/share/:id`, `/env`
+- `state/` — Recoil atoms: `chat.ts` (messages, elements, tasks), `project.ts` (config, session), `user.ts` (env vars)
+- `components/chat/` — Core chat UI (message list, input bar, elements, audio)
+- `components/header/` — Top navigation bar
+- `components/LeftSidebar/` — Thread history sidebar
+
+### `@chainlit/react-client` (`libs/react-client/src/`)
+
+Publishable npm package — the bridge between the React UI and the backend WebSocket.
+
+- `api.ts` — `ChainlitAPI` class: HTTP calls to backend REST endpoints
+- `useChatSession.ts` — Manages socket.io connection lifecycle
+- `useChatMessages.ts` — Exposes message tree state
+- `useChatData.ts` — Exposes elements, actions, tasklists, connection status
+- `useChatInteract.ts` — `sendMessage`, `replyMessage`, `callAction`, `stopTask`, `clear`
+- `state.ts` — Recoil atoms shared between the lib and consuming apps
+
+State is managed via Recoil; consuming apps must wrap the tree in `<RecoilRoot>` and provide a `ChainlitAPI` instance via `ChainlitContext.Provider`.
+
+### Communication flow
+
+1. User sends a message → `useChatInteract.sendMessage` → emits `client_message` over SocketIO
+2. Backend `socket.py` handler receives it → calls `config.code.on_message(message)`
+3. User's app calls `cl.Message(...).send()` → `emitter.py` emits `new_message` back over SocketIO
+4. Frontend `useChatMessages` updates Recoil state → component re-renders
+
+### App configuration
+
+Apps configure Chainlit via `.chainlit/config.toml` (created automatically on first run). Key sections: `[project]` (auth, session timeouts, CORS), `[UI]` (name, theme, layout).
+
+---
+
+## Documentation Verification Requirements
+
+Before writing/modifying code, verify against official docs.
+
+**Lookup order**: Context7 MCP (preferred) → WebFetch → WebSearch.
+
+Pre-resolved Context7 library IDs: [docs/context7.md](docs/context7.md)
+
+Cross-reference API signatures and patterns during implementation. When uncertain, always check docs rather than relying on training data.

CLAUDE.md

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+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+@AGENTS.md

docs/README.md

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+# Documentation for Chainlit developers, contributors, and AI coding assistants.
+
+See also:
+- [CONTRIBUTING.md](../CONTRIBUTING.md) — contribution guidelines
+- [CHANGELOG.md](../CHANGELOG.md) — release history