fred-sdk 2.0.3

Authoring SDK for Fred agents — graph, ReAct, and team agent primitives.

fred-sdk

fred-sdk is the authoring library for Fred agents.
It provides everything needed to define agents, tools, workflows, and multi-agent compositions — with no dependency on any running platform service.

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Where fred-sdk fits

fred-core          Pure utilities — model factories, embeddings, logging
     │
fred-sdk           Execution engine + authoring surface  ← this package
     │              ReAct, Graph, Team, Deep agent types
     │              Tool authoring, HITL, MCP references
     │
fred-runtime       Platform adapters + pod factory
                    SQL checkpointer, LLM routing, FastAPI app factory

Agent logic belongs in fred-sdk.
Infrastructure wiring (DB, MCP server, Keycloak, object store) belongs in fred-runtime.
fred-sdk must stay importable on a bare laptop with no services running.

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Installation

pip install fred-sdk

Requires Python 3.12.

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Agent types

ReAct agent

Tool-calling assistant backed by a ReAct loop. The most common agent type.

from fred_sdk import ReActAgent, tool, ToolContext, ToolOutput

class WeatherAgent(ReActAgent):
    agent_id = "my.weather.agent"
    role = "Weather assistant"
    description = "Answers weather questions using the get_weather tool."
    system_prompt_template = "You are a helpful weather assistant."

    @tool("Get current weather for a city")
    async def get_weather(self, city: str, ctx: ToolContext) -> ToolOutput:
        # call external API here
        return ToolOutput.text(f"It is sunny in {city}.")

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Graph agent

Deterministic workflow with typed state. Nodes are Python functions; edges and conditional routes are declared in GraphWorkflow.

from fred_sdk import GraphAgent, GraphWorkflow, typed_node, StepResult
from pydantic import BaseModel

class MyState(BaseModel):
    message: str = ""
    result: str = ""

@typed_node(MyState)
async def process(state: MyState, ctx) -> StepResult:
    return StepResult(update={"result": f"processed: {state.message}"})

class MyGraphAgent(GraphAgent):
    agent_id = "my.graph.agent"
    role = "Processing pipeline"
    description = "Runs a deterministic processing workflow."
    state_schema = MyState
    workflow = GraphWorkflow(
        entry="process",
        nodes={"process": process},
    )

Graph workflow primitives available from fred_sdk:

Primitive	What it does
typed_node	Decorator — turns a function into a typed graph node
GraphWorkflow	Declares nodes, edges, and conditional routes
choice_step	Built-in node for HITL choice gates
finalize_step	Built-in node that sets final_text and ends the graph
intent_router_step	Built-in LLM-powered intent classifier node
model_text_step	Built-in node that calls the LLM and stores the result
structured_model_step	Built-in node that calls the LLM and parses structured output
StepResult	Return type for typed nodes

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Team agent

Multi-agent composition. A coordinator routes or sequences work across members.

from fred_sdk import TeamAgent, AgentSpec

class SupportRouter(TeamAgent):
    agent_id = "my.support.router"
    role = "Support request router"
    description = "Routes support requests to the right specialist."
    mode = "route"
    coordinator_instructions = "Pick the right specialist based on user intent."
    members = (
        AgentSpec(name="Billing", role="Billing questions", agent_ref="my.billing.agent"),
        AgentSpec(name="Technical", role="Technical issues", agent_ref="my.technical.agent"),
    )

Three modes:

Mode	Behaviour
sequential	Members run in order; each is an inline LLM call
dynamic	A coordinator LLM decides who runs next after each member
route	A coordinator LLM picks exactly one registered agent and delegates the full request

Child agents used as agent_ref targets should set public = False so they are not exposed as top-level models in Open WebUI or other OpenAI-compatible frontends.

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Deep agent

Extended ReAct variant with a built-in planning step. Inherits the full ReAct authoring surface; the planning engine is wired by the runtime.

from fred_sdk import DeepAgentDefinition

class MyDeepAgent(DeepAgentDefinition):
    agent_id = "my.deep.agent"
    role = "Deep research assistant"
    description = "Plans and executes multi-step research tasks."
    ...

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Tool authoring

Tools are async methods decorated with @tool on a ReActAgent subclass.

from fred_sdk import tool, ToolContext, ToolOutput, ToolInvocationError

@tool("Search internal documents for a query")
async def search_docs(self, query: str, ctx: ToolContext) -> ToolOutput:
    token = ctx.access_token          # bearer token from the request
    user_id = ctx.user_id             # current user
    results = await my_search_api(query, token=token)
    if not results:
        raise ToolInvocationError("No documents found.")
    return ToolOutput.text("\n".join(results))

ToolContext gives the tool access to the runtime context: user_id, team_id, session_id, language, access_token, and invoke_agent() for sub-agent calls.

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Human-in-the-loop (HITL)

Pause a graph at a node and wait for user input. Use choice_step for menu-driven flows or emit HumanInputRequest directly for free-text prompts.

from fred_sdk import choice_step, HumanChoiceOption

approve_step = choice_step(
    title="Confirm transfer",
    question="Do you want to proceed with this bank transfer?",
    choices=[
        HumanChoiceOption(id="confirm", label="Yes, confirm"),
        HumanChoiceOption(id="cancel",  label="No, cancel"),
    ],
    routes={"confirm": "execute", "cancel": "abort"},
)

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MCP server references

Declare which MCP servers an agent needs. The runtime wires the actual connection.

from fred_sdk import MCPServerRef, MCP_SERVER_KNOWLEDGE_FLOW_CORPUS

class MyRagAgent(ReActAgent):
    agent_id = "my.rag.agent"
    ...
    default_mcp_servers = (MCP_SERVER_KNOWLEDGE_FLOW_CORPUS,)

Built-in MCP server constants:

Constant	Connects to
MCP_SERVER_KNOWLEDGE_FLOW_CORPUS	Document search and retrieval
MCP_SERVER_KNOWLEDGE_FLOW_FS	Workspace file system
MCP_SERVER_KNOWLEDGE_FLOW_TABULAR	Tabular data / CSV
MCP_SERVER_KNOWLEDGE_FLOW_STATISTICS	Statistical analysis
MCP_SERVER_KNOWLEDGE_FLOW_OPENSEARCH_OPS	OpenSearch operations

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Built-in tool references

Pre-built platform tools declared by reference (no implementation needed in the agent):

from fred_sdk import TOOL_REF_KNOWLEDGE_SEARCH, TOOL_REF_ARTIFACTS_PUBLISH_TEXT

class MyAgent(ReActAgent):
    declared_tool_refs = (TOOL_REF_KNOWLEDGE_SEARCH, TOOL_REF_ARTIFACTS_PUBLISH_TEXT)

Constant	What it does
TOOL_REF_KNOWLEDGE_SEARCH	Semantic/hybrid search over indexed documents
TOOL_REF_RESOURCES_FETCH_TEXT	Fetch document content as text
TOOL_REF_ARTIFACTS_PUBLISH_TEXT	Publish a text artifact to the workspace
TOOL_REF_GEO_RENDER_POINTS	Render geographic points on a map
TOOL_REF_LOGS_QUERY	Query audit logs
TOOL_REF_TRACES_SUMMARIZE_CONVERSATION	Summarize conversation traces

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Running an agent

fred-sdk defines agents; fred-runtime executes them. A minimal pod:

# main.py
from fred_runtime.app import create_agent_app, load_agent_pod_config
from myapp.registry import REGISTRY

config = load_agent_pod_config()
app = create_agent_app(registry=REGISTRY, config=config)

See fred-runtime on PyPI for the full pod setup guide.

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Related packages

Package	PyPI	Role
fred-core	pypi	Pure utilities — logging, model factories, embeddings, portable observability
fred-sdk	pypi	This package
fred-runtime	pypi	Platform adapters + pod factory

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License

Apache 2.0 — see LICENSE.