langchain-ai/deepagents · critical · RuntimeError

Agent backend did not publish its offload operation; /offloa

Error message

Agent backend did not publish its offload operation; /offload has no server implementation.

What it means

RuntimeError raised while building the CLI server graphs when the composite agent backend does not expose an offload operation. /offload is a built-in command that needs a server-side implementation; if the backend never published one, the runtime cannot be constructed and startup fails fast.

Source

Thrown at libs/code/deepagents_code/server_graph.py:422

            cwd=project_context.user_cwd if project_context is not None else config.cwd,
            project_context=project_context,
            async_subagents=async_subagents,
            goal_criteria_tools=read_only_context_tools,
            rubric_grader_tools=read_only_context_tools,
            model_retries=result.model_retries,
            cli_max_retries=result.cli_max_retries,
            summarization_model=config.summarization_model,
            extension_registry=extension_registry,
        )
        from deepagents_code.offload_middleware import offload_operation_from

        offload = offload_operation_from(composite_backend)
        if offload is None:
            msg = (
                "Agent backend did not publish its offload operation; "
                "/offload has no server implementation."
            )
            raise RuntimeError(msg)
        return ServerRuntime(
            agent=agent,
            backend=composite_backend,
            offload=offload,
        )

    from deepagents_code._env_vars import EXPERIMENTAL, is_env_truthy

    if is_env_truthy(EXPERIMENTAL):
        from deepagents_code.extensions import ExtensionMode, load_extensions
        from deepagents_code.extensions.runtime import bind_server_extensions

        extension_result = await load_extensions(
            cwd=(
                project_context.user_cwd
                if project_context is not None
                else Path(config.cwd)
                if config.cwd is not None

View on GitHub (pinned to a1af029e6e)

Solutions

1. Use a backend factory/builder that includes the offload operation layer
2. Check the backend composition code for a missing layer that publishes the offload operation
3. Pin/upgrade backend packages so CLI and backend capabilities match
4. If only testing graphs, provide a stub backend that registers a no-op offload operation

Example fix

// before
backend = create_backend(model)  # no offload layer

// after
backend = create_backend(model, include_offload=True)  # publishes offload op

from deepagents_code.server_graph import offload_operation_from
if offload_operation_from(backend) is None:
    raise RuntimeError("backend lacks offload op; fix backend composition before building graphs")

def has_offload(backend: object) -> bool:
    return offload_operation_from(backend) is not None

try:
    runtime = build_cli_graphs(backend)
except RuntimeError as e:
    if "offload" in str(e):
        runtime = build_cli_graphs(with_offload_layer(backend))
    else:
        raise

When it happens

Trigger: Calling _create_cli_graphs_sync (indirectly at startup/runtime construction) with a backend assembled such that offload_operation_from(composite_backend) returns None — e.g. a custom or partial backend missing the offload capability.

Common situations: Swapping in a custom backend for testing that omits the offload operation; mis-ordered backend composition where the offload-publishing layer is missing; version drift between the CLI and backend packages.

Related errors

• Local filesystem backend is unavailable.
• archive backend returned no response for {path}
• archive read failed for {path}: {response.error}
• Offload operation must use the agent's composite backend
• dcode: {message}

AI-assisted analysis of langchain-ai/deepagents@a1af029e6e (2026-08-29). Data as JSON: /api/errors/8de770fa661308dc. Report an issue: GitHub.