LangGraph support

agentstack/__init__.py

@@ -7,15 +7,34 @@
 from pathlib import Path
 from agentstack import conf
 from agentstack.utils import get_framework
+from agentstack.agents import get_agent
+from agentstack.tasks import get_task
 from agentstack.inputs import get_inputs
 
 ___all___ = [
     "conf", 
+    "agent", 
+    "task", 
     "get_tags", 
     "get_framework", 
+    "get_agent", 
+    "get_task", 
     "get_inputs", 
 ]
 
+def agent():
+    """
+    The `agent` decorator is used to mark a method that implements an Agent. 
+    """
+    pass
+
+
+def task():
+    """
+    The `task` decorator is used to mark a method that implements a Task.
+    """
+    pass
+
 
 def get_tags() -> list[str]:
     """

agentstack/agents.py

@@ -9,6 +9,7 @@
 
 
 AGENTS_FILENAME: Path = Path("src/config/agents.yaml")
+AGENTS_PROMPT_TPL: str = "You are {role}. {backstory}\nYour personal goal is: {goal}"
 
 yaml = YAML()
 yaml.preserve_quotes = True  # Preserve quotes in existing data
@@ -67,6 +68,25 @@ def __init__(self, name: str):
                 error_str += f"{' '.join([str(loc) for loc in error['loc']])}: {error['msg']}\n"
             raise ValidationError(f"Error loading agent {name} from {filename}.\n{error_str}")
 
+    @property
+    def provider(self) -> str:
+        from agentstack import frameworks
+        return frameworks.parse_llm(self.llm)[0]
+
+    @property
+    def model(self) -> str:
+        from agentstack import frameworks
+        return frameworks.parse_llm(self.llm)[1]
+
+    @property
+    def prompt(self) -> str:
+        """Concatenate the prompts for role, goal, and backstory."""
+        return AGENTS_PROMPT_TPL.format(**{
+            'role': self.role,
+            'goal': self.goal,
+            'backstory': self.backstory,
+        })
+
     def model_dump(self, *args, **kwargs) -> dict:
         dump = super().model_dump(*args, **kwargs)
         dump.pop('name')  # name is the key, so keep it out of the data
@@ -104,3 +124,9 @@ def get_all_agent_names() -> list[str]:
 
 def get_all_agents() -> list[AgentConfig]:
     return [AgentConfig(name) for name in get_all_agent_names()]
+
+
+def get_agent(name: str) -> Optional[AgentConfig]:
+    """Get an agent configuration by name."""
+    return AgentConfig(name)
+

agentstack/cli/agentstack_data.py

@@ -58,6 +58,7 @@ def __init__(
     ):
         self.agents = []
         self.tasks = []
+        self.graph = []
         self.inputs = {}
         self.method = method
         self.manager_agent = manager_agent
@@ -68,6 +69,9 @@ def add_agent(self, agent):
     def add_task(self, task):
         self.tasks.append(task)
 
+    def add_edge(self, edge):
+        self.graph.append(edge)
+
     def set_inputs(self, inputs):
         self.inputs = inputs
 
@@ -77,6 +81,7 @@ def to_dict(self):
             'manager_agent': self.manager_agent,
             'agents': self.agents,
             'tasks': self.tasks,
+            'graph': self.graph,
             'inputs': self.inputs,
         }
 

agentstack/cli/cli.py

@@ -43,6 +43,7 @@
 def init_project_builder(
     slug_name: Optional[str] = None,
     template: Optional[str] = None,
+    framework: Optional[str] = None,
     use_wizard: bool = False,
 ):
     if not slug_name and not use_wizard:
@@ -77,10 +78,12 @@ def init_project_builder(
             "author": "Name <Email>",
             "license": "MIT",
         }
-        framework = template_data.framework
+        if framework is None:
+            framework = template_data.framework
         design = {
             'agents': [agent.model_dump() for agent in template_data.agents],
             'tasks': [task.model_dump() for task in template_data.tasks],
+            'graph': [[node[0].model_dump(), node[1].model_dump()] for node in template_data.graph],
             'inputs': template_data.inputs,
         }
         tools = [tools.model_dump() for tools in template_data.tools]
@@ -102,10 +105,12 @@ def init_project_builder(
             "author": "Name <Email>",
             "license": "MIT",
         }
-        framework = default_project.framework
+        if framework is None:
+            framework = default_project.framework
         design = {
             'agents': [agent.model_dump() for agent in default_project.agents],
             'tasks': [task.model_dump() for task in default_project.tasks],
+            'graph': [[node[0].model_dump(), node[1].model_dump()] for node in default_project.graph],
             'inputs': default_project.inputs,
         }
         tools = [tools.model_dump() for tools in default_project.tools]
@@ -387,6 +392,7 @@ def insert_template(
     project_structure.agents = design["agents"]
     project_structure.tasks = design["tasks"]
     project_structure.inputs = design["inputs"]
+    project_structure.graph = design.get("graph", [])
 
     cookiecutter_data = CookiecutterData(
         project_metadata=project_metadata,

agentstack/cli/init.py

@@ -3,6 +3,7 @@
 from pathlib import Path
 from agentstack import conf
 from agentstack import packaging
+from agentstack import frameworks
 from agentstack.cli import welcome_message, init_project_builder
 from agentstack.utils import term_color
 
@@ -28,6 +29,7 @@ def require_uv():
 def init_project(
     slug_name: Optional[str] = None,
     template: Optional[str] = None,
+    framework: Optional[str] = None,
     use_wizard: bool = False,
 ):
     """
@@ -55,8 +57,14 @@ def init_project(
     print(term_color("🦾 Creating a new AgentStack project...", 'blue'))
     print(f"Using project directory: {conf.PATH.absolute()}")
 
+    if framework:
+        if not framework in frameworks.SUPPORTED_FRAMEWORKS:
+            print(f"Error: Framework '{framework}' is not supported.")
+            sys.exit(1)
+        print(f"Using framework: {framework}")
+
     # copy the project skeleton, create a virtual environment, and install dependencies
-    init_project_builder(slug_name, template, use_wizard)
+    init_project_builder(slug_name, template, framework, use_wizard)
     packaging.create_venv()
     packaging.install_project()
 

agentstack/frameworks/__init__.py

@@ -11,12 +11,18 @@
 
 
 CREWAI = 'crewai'
-SUPPORTED_FRAMEWORKS = [CREWAI, ]
+LANGGRAPH = 'langgraph'
+SUPPORTED_FRAMEWORKS = [
+    CREWAI,
+    LANGGRAPH,
+]
+
 
 class FrameworkModule(Protocol):
     """
     Protocol spec for a framework implementation module.
     """
+
     ENTRYPOINT: Path
     """
     Relative path to the entrypoint file for the framework in the user's project.
@@ -30,6 +36,12 @@ def validate_project(self) -> None:
         """
         ...
 
+    def parse_llm(self, llm: str) -> tuple[str, str]:
+        """
+        Parse a language model string into a provider and model.
+        """
+        ...
+
     def get_tool_names(self) -> list[str]:
         """
         Get a list of tool names in the user's project.
@@ -88,59 +100,78 @@ def get_framework_module(framework: str) -> FrameworkModule:
     except ImportError:
         raise Exception(f"Framework {framework} could not be imported.")
 
+
 def get_entrypoint_path(framework: str) -> Path:
     """
     Get the path to the entrypoint file for a framework.
     """
     return conf.PATH / get_framework_module(framework).ENTRYPOINT
 
+
 def validate_project():
     """
     Validate that the user's project is ready to run.
     """
     return get_framework_module(get_framework()).validate_project()
 
+
+def parse_llm(llm: str) -> tuple[str, str]:
+    """
+    Parse a language model string into a provider and model.
+    """
+    return get_framework_module(get_framework()).parse_llm(llm)
+
+
 def add_tool(tool: ToolConfig, agent_name: str):
     """
-    Add a tool to the user's project. 
+    Add a tool to the user's project.
     The tool will have aready been installed in the user's application and have
     all dependencies installed. We're just handling code generation here.
     """
     return get_framework_module(get_framework()).add_tool(tool, agent_name)
 
+
 def remove_tool(tool: ToolConfig, agent_name: str):
     """
     Remove a tool from the user's project.
     """
     return get_framework_module(get_framework()).remove_tool(tool, agent_name)
 
+
 def get_agent_names() -> list[str]:
     """
     Get a list of agent names in the user's project.
     """
     return get_framework_module(get_framework()).get_agent_names()
 
+
 def get_agent_tool_names(agent_name: str) -> list[str]:
     """
     Get a list of tool names in the user's project.
     """
     return get_framework_module(get_framework()).get_agent_tool_names(agent_name)
 
+
 def add_agent(agent: AgentConfig):
     """
     Add an agent to the user's project.
     """
+    if agent.name in get_agent_names():
+        raise ValidationError(f"Agent `{agent.name}` already exists in {get_entrypoint_path()}")
     return get_framework_module(get_framework()).add_agent(agent)
 
+
 def add_task(task: TaskConfig):
     """
     Add a task to the user's project.
     """
+    if task.name in get_task_names():
+        raise ValidationError(f"Task `{task.name}` already exists in {get_entrypoint_path()}")
     return get_framework_module(get_framework()).add_task(task)
 
+
 def get_task_names() -> list[str]:
     """
     Get a list of task names in the user's project.
     """
     return get_framework_module(get_framework()).get_task_names()
-

agentstack/frameworks/crewai.py

@@ -55,9 +55,6 @@ def get_task_methods(self) -> list[ast.FunctionDef]:
     def add_task_method(self, task: TaskConfig):
         """Add a new task method to the CrewAI entrypoint."""
         task_methods = self.get_task_methods()
-        if task.name in [method.name for method in task_methods]:
-            # TODO this should check all methods in the class for duplicates
-            raise ValidationError(f"Task `{task.name}` already exists in {ENTRYPOINT}")
         if task_methods:
             # Add after the existing task methods
             _, pos = self.get_node_range(task_methods[-1])
@@ -71,6 +68,7 @@ def {task.name}(self) -> Task:
         return Task(
             config=self.tasks_config['{task.name}'],
         )"""
+
         if not self.source[:pos].endswith('\n'):
             code = '\n\n' + code
         if not self.source[pos:].startswith('\n'):
@@ -85,9 +83,6 @@ def add_agent_method(self, agent: AgentConfig):
         """Add a new agent method to the CrewAI entrypoint."""
         # TODO do we want to pre-populate any tools?
         agent_methods = self.get_agent_methods()
-        if agent.name in [method.name for method in agent_methods]:
-            # TODO this should check all methods in the class for duplicates
-            raise ValidationError(f"Agent `{agent.name}` already exists in {ENTRYPOINT}")
         if agent_methods:
             # Add after the existing agent methods
             _, pos = self.get_node_range(agent_methods[-1])
@@ -103,6 +98,7 @@ def {agent.name}(self) -> Agent:
             tools=[], # add tools here or use `agentstack tools add <tool_name>
             verbose=True,
         )"""
+
         if not self.source[:pos].endswith('\n'):
             code = '\n\n' + code
         if not self.source[pos:].startswith('\n'):
@@ -238,6 +234,15 @@ def validate_project() -> None:
         )
 
 
+def parse_llm(llm: str) -> tuple[str, str]:
+    """
+    Parse the llm string into a `LLM` dataclass.
+    Crew separates providers and models with a forward slash.
+    """
+    provider, model = llm.split('/')
+    return provider, model
+
+
 def get_task_names() -> list[str]:
     """
     Get a list of task names (methods with an @task decorator).