Choose a harness

A harness is the agent framework your code runs inside. Tanomis supports two Python harnesses, and they share everything that is not your code: the manifest, the build, versions, tenant enablement, the session runtime, governed tools, and evidence. Pick by how you want to express the agent.

At a glance

• Claude Agent SDK: your entrypoint returns a prompt and options. The smallest entrypoint, Claude’s tools, hooks, subagents, and permission callbacks.
• Deep Agents: your entrypoint returns a compiled LangGraph graph. Typed LangChain tools, middleware, structured output, checkpoint-aware state.
• Both are declared with one line in agent.yaml, framework, and scaffolded by tanomis agent new.
• Switching harness is a new agent, not a new version; framework is part of the contract.

The choice

	claude-agents-sdk	deepagents
Best fit	A system prompt plus tools, or an existing Claude Agent SDK agent	Tool-heavy or graph-shaped work, or existing LangGraph code
Entrypoint returns	(prompt, options)	A graph from create_deep_agent
Tools	Claude Agent SDK tools, hooks, subagents	Typed LangChain tools and middleware
State between turns	Claude SDK session continuity	LangGraph checkpoints in the session workspace
Approvals and questions	permission_mode: "default" plus the manifest’s list	Manifest list composed with author interrupt_on

Choose Claude Agent SDK when the behaviour is naturally a prompt with options and you want the least code. Choose Deep Agents when the agent is a graph of typed tools, needs structured output or middleware, or already exists as LangGraph code.

What does not change

The runtime owns tenant isolation, the working directory, the resolved model and provider credentials, session identifiers, governed connectors, and persistence. You own the instructions, the tool implementations, and the behaviour the manifest permits. The entrypoint contract is the same shape for both.

List the harnesses your installed CLI supports rather than copying a value from memory:

Terminal

tanomis agent harnesses

Where to go next

• Claude Agent SDK: the entrypoint, the ownership boundary, approvals.
• Deep Agents: the graph entrypoint, dependencies, tool interrupts.
• Write your agent: what comes in and what you return.