feat: add Claude Agent SDK implementation

.claude/CLAUDE.md

@@ -4,19 +4,20 @@ This file provides guidance to Claude Code (claude.ai/code) when working with co
 
 ## What This Is
 
-A monorepo containing two parallel implementations of **Casey**, an AI-powered IT helpdesk agent for Slack built with Bolt for Python. Both implementations are functionally identical from the Slack user's perspective but use different AI agent frameworks:
+A monorepo containing three parallel implementations of **Casey**, an AI-powered IT helpdesk agent for Slack built with Bolt for Python. All implementations are functionally identical from the Slack user's perspective but use different AI agent frameworks:
 
 - `pydantic-ai/` — Built with **Pydantic AI**
 - `openai-agents-sdk/` — Built with **OpenAI Agents SDK**
+- `claude-agent-sdk/` — Built with **Claude Agent SDK**
 
 All tool data (knowledge base, tickets, password resets, system status, permissions) is hardcoded for demo purposes.
 
 ## Commands
 
-All commands must be run from within the respective project directory (`pydantic-ai/` or `openai-agents-sdk/`).
+All commands must be run from within the respective project directory (`pydantic-ai/`, `openai-agents-sdk/`, or `claude-agent-sdk/`).
 
 ```sh
-# Run the app (requires .env with OPENAI_API_KEY; Slack tokens optional with CLI)
+# Run the app (requires .env with OPENAI_API_KEY or ANTHROPIC_API_KEY; Slack tokens optional with CLI)
 slack run          # via Slack CLI
 python3 app.py     # directly
 
@@ -34,9 +35,10 @@ pytest
 .github/              # Shared CI workflows and dependabot config
 pydantic-ai/         # Pydantic AI implementation
 openai-agents-sdk/   # OpenAI Agents SDK implementation
+claude-agent-sdk/    # Claude Agent SDK implementation
 ```
 
-CI runs ruff lint/format checks against both directories via a matrix strategy in `.github/workflows/ruff.yml`. Dependabot monitors `requirements.txt` in both directories independently.
+CI runs ruff lint/format checks against all directories via a matrix strategy in `.github/workflows/ruff.yml`. Dependabot monitors `requirements.txt` in all directories independently.
 
 ## Architecture (shared across both implementations)
 
@@ -59,15 +61,16 @@ Each sub-package has a `register(app)` function called from `listeners/__init__.
 
 ## Key Differences Between Implementations
 
-| Aspect | Pydantic AI | OpenAI Agents SDK |
-|--------|-------------|-------------------|
-| Agent file | `agent/casey.py` | `agent/support_agent.py` |
-| Agent definition | `Agent(deps_type=CaseyDeps)` | `Agent[CaseyDeps](model="gpt-4o-mini")` |
-| Model config | Passed at runtime via `run_sync(model=DEFAULT_MODEL)` | Set directly on agent constructor |
-| Tool definition | Plain async functions | `@function_tool` decorated functions |
-| Tool context param | `RunContext[CaseyDeps]` | `RunContextWrapper[CaseyDeps]` |
-| Execution | `casey_agent.run_sync(text, model=..., deps=..., message_history=...)` | `Runner.run_sync(casey_agent, input=..., context=...)` |
-| Result output | `result.output` | `result.final_output` |
-| Result messages | `result.all_messages()` | `result.to_input_list()` |
-| History type | `list[ModelMessage]` (framework-native) | `list` (generic, manually constructed) |
-| Feedback blocks | Native `FeedbackButtonsElement` | Native `FeedbackButtonsElement` |
+| Aspect | Pydantic AI | OpenAI Agents SDK | Claude Agent SDK |
+|--------|-------------|-------------------|-----------------|
+| Agent file | `agent/casey.py` | `agent/support_agent.py` | `agent/casey.py` |
+| App type | `App` (sync) | `App` (sync) | `AsyncApp` (fully async) |
+| Agent definition | `Agent(deps_type=CaseyDeps)` | `Agent[CaseyDeps](model="gpt-4o-mini")` | `ClaudeSDKClient` with `ClaudeAgentOptions` |
+| Model config | Passed at runtime via `run_sync(model=DEFAULT_MODEL)` | Set directly on agent constructor | Managed by SDK (Claude models) |
+| Tool definition | Plain async functions | `@function_tool` decorated functions | `@tool` decorated functions via MCP server |
+| Tool context param | `RunContext[CaseyDeps]` | `RunContextWrapper[CaseyDeps]` | `args` dict (no context param) |
+| Execution | `casey_agent.run_sync(text, model=..., deps=..., message_history=...)` | `Runner.run_sync(casey_agent, input=..., context=...)` | `await run_casey_agent(text, session_id=...)` |
+| Result output | `result.output` | `result.final_output` | `response_text` from collected `TextBlock.text` |
+| Conversation history | `list[ModelMessage]` stored locally | `list` stored locally | Session-based via `resume` (server-side) |
+| API key env var | `OPENAI_API_KEY` | `OPENAI_API_KEY` | `ANTHROPIC_API_KEY` |
+| Feedback blocks | Native `FeedbackButtonsElement` | Native `FeedbackButtonsElement` | Native `FeedbackButtonsElement` |

.github/dependabot.yml

@@ -5,6 +5,7 @@ updates:
       - "/"
       - "/openai-agents-sdk"
       - "/pydantic-ai"
+      - "/claude-agent-sdk"
     schedule:
       interval: "weekly"
     labels:

.github/workflows/ruff.yml

@@ -14,6 +14,7 @@ jobs:
         directory:
           - openai-agents-sdk
           - pydantic-ai
+          - claude-agent-sdk
     defaults:
       run:
         working-directory: ${{ matrix.directory }}

README.md

@@ -6,14 +6,14 @@ Built with [Bolt for Python](https://docs.slack.dev/tools/bolt-python/).
 
 ## Choose Your Framework
 
-This repo contains the same app built with two different AI agent frameworks. Pick the one that fits your stack:
+This repo contains the same app built with three different AI agent frameworks. Pick the one that fits your stack:
 
-| | [Pydantic AI](./pydantic-ai/) | [OpenAI Agents SDK](./openai-agents-sdk/) |
-|---|---|---|
-| **Framework** | [pydantic-ai](https://ai.pydantic.dev/) | [openai-agents](https://openai.github.io/openai-agents-python/) |
-| **Get started** | [View README](./pydantic-ai/README.md) | [View README](./openai-agents-sdk/README.md) |
+| | [Pydantic AI](./pydantic-ai/) | [OpenAI Agents SDK](./openai-agents-sdk/) | [Claude Agent SDK](./claude-agent-sdk/) |
+|---|---|---|---|
+| **Framework** | [pydantic-ai](https://ai.pydantic.dev/) | [openai-agents](https://openai.github.io/openai-agents-python/) | [claude-agent-sdk](https://docs.anthropic.com/en/docs/agents/claude-agent-sdk) |
+| **Get started** | [View README](./pydantic-ai/README.md) | [View README](./openai-agents-sdk/README.md) | [View README](./claude-agent-sdk/README.md) |
 
-Both implementations share the same Slack listener layer, the same five simulated IT tools, and the same user experience. The only difference is how the agent is defined and executed under the hood.
+All implementations share the same Slack listener layer, the same five simulated IT tools, and the same user experience. The only difference is how the agent is defined and executed under the hood.
 
 ## What Casey Can Do
 

claude-agent-sdk/.claude/CLAUDE.md

@@ -0,0 +1,19 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+See the root `../.claude/CLAUDE.md` for monorepo-wide architecture, commands, and a comparison of all implementations.
+
+## Claude Agent SDK Specifics
+
+**App (`app.py`)** uses `AsyncApp` from Bolt for Python. All listeners and Slack API calls are fully async (`await`).
+
+**Agent (`agent/casey.py`)** uses `ClaudeSDKClient` from the Claude Agent SDK. Tools are registered via `create_sdk_mcp_server()` and passed as `mcp_servers` in `ClaudeAgentOptions`. The `run_casey_agent()` function is async and returns `(response_text, session_id)`.
+
+**Tools (`agent/tools/`)** are defined with the `@tool` decorator from `claude_agent_sdk`. Each tool returns `{"content": [{"type": "text", "text": ...}]}`. Tools are registered into a single MCP server via `create_sdk_mcp_server()`.
+
+**Conversation history** is managed server-side by the Claude Agent SDK via sessions. The local `SessionStore` (`conversation/store.py`) only maps `(channel_id, thread_ts)` to session IDs. Sessions are resumed via `ClaudeAgentOptions(resume=session_id)`.
+
+**Feedback blocks** use the native `FeedbackButtonsElement` from `slack_sdk.models.blocks`. A single `feedback` action ID is registered.
+
+**Dependencies** (`agent/deps.py`) use `AsyncWebClient` from `slack_sdk.web.async_client` instead of the sync `WebClient`.

claude-agent-sdk/.env.sample

@@ -0,0 +1,9 @@
+# Optional, uncomment and set when running without the Slack CLI (python3 app.py).
+# SLACK_APP_TOKEN=YOUR_SLACK_APP_TOKEN
+# SLACK_BOT_TOKEN=YOUR_SLACK_BOT_TOKEN
+
+# Optional, uncomment and set when using a custom Slack instance.
+# SLACK_API_URL=YOUR_SLACK_API_URL
+
+# Required, set your Anthropic API key.
+ANTHROPIC_API_KEY=YOUR_ANTHROPIC_API_KEY

claude-agent-sdk/.gitignore

@@ -0,0 +1,43 @@
+# general things to ignore
+build/
+dist/
+docs/_sources/
+docs/.doctrees
+.eggs/
+*.egg-info/
+*.egg
+*.py[cod]
+__pycache__/
+*.so
+*~
+
+# virtualenv
+env*/
+venv/
+.venv*
+.env*
+!.env.sample
+
+# codecov / coverage
+.coverage
+cov_*
+coverage.xml
+
+# due to using tox and pytest
+.tox
+.cache
+.pytest_cache/
+.python-version
+pip
+.mypy_cache/
+
+# misc
+tmp.txt
+.DS_Store
+logs/
+*.db
+.pytype/
+.idea/
+
+# claude
+.claude/*.local.json

claude-agent-sdk/.slack/.gitignore

@@ -0,0 +1,2 @@
+apps.dev.json
+cache/

claude-agent-sdk/.slack/config.json

@@ -0,0 +1,6 @@
+{
+  "manifest": {
+    "source": "local"
+  },
+  "project_id": "c189134c-231e-4c96-b800-ea39c055aa77"
+}

claude-agent-sdk/.slack/hooks.json

@@ -0,0 +1,5 @@
+{
+  "hooks": {
+    "get-hooks": "python3 -m slack_cli_hooks.hooks.get_hooks"
+  }
+}