Runtime

The runtime determines how an agent’s inner loop runs — how each turn calls the model, interprets intent, and invokes tools. The default runtime is built on Google ADK’s execution flow and works out of the box; you can also switch the execution backend or inject shared processing logic into the flow, without changing the agent itself.

Default runtime

The ADK runtime is the default and needs no extra configuration:

from veadk import Agent

agent = Agent(name="assistant")  # uses the ADK runtime by default

Switch the execution backend

Use runtime to select the inner-loop execution backend: Install the Codex Python SDK before selecting the Codex runtime:

pip install openai-codex

The Codex runtime in VeADK 1.0.1 allows command execution, host file access, and network access by default, without interactive approval. Run trusted tasks in an isolated environment and restrict the credentials and data available to the process.

agent = Agent(name="assistant", runtime="codex")

Value	Description
`adk` (default)	Google ADK’s built-in execution flow; suitable for most cases.
`codex`	Runs the agent’s inner loop with the Codex SDK; requires `openai-codex`.

Skills and tools in the Codex runtime

VeADK 1.0.1 makes skills loaded through ADK SkillToolset or the legacy skills entry point available to the Codex runtime. The runtime can also call an agent’s function and MCP tools:

from google.adk.tools.mcp_tool.mcp_toolset import MCPToolset
from google.adk.tools.mcp_tool.mcp_session_manager import StdioServerParameters
from veadk import Agent

mcp_tools = MCPToolset(
    connection_params=StdioServerParameters(
        command="python",
        args=["mcp_server.py"],
    )
)

agent = Agent(runtime="codex", tools=[mcp_tools])

The MCP server process and its tools receive the permissions allowed by the current environment. Connect only trusted servers and restrict their access to files, networks, and credentials.

Codex backend requests

Environment variable	Default	Description
`CODEX_SHIM_NUM_RETRIES`	`2`	Retry count for rate limits, server errors, overload, and timeouts; values below `0` are treated as `0`.
`CODEX_SHIM_TIMEOUT`	`0`	Per-request backend timeout in seconds; `0` does not add a timeout.

Enable web search

Web search is disabled by default when the Codex runtime calls models through Volcengine Ark. Set CODEX_SHIM_MAX_TOOL_ITERS to an integer greater than 0 to let the runtime call VeADK’s web_search and web_fetch tools and return their results to the model for a bounded number of rounds:

export CODEX_SHIM_MAX_TOOL_ITERS=6

Environment variable	Default	Description
`CODEX_SHIM_MAX_TOOL_ITERS`	`0`	Maximum web-tool rounds per request; `0` disables them. Start with `6`, then adjust for task complexity and latency.

Web search requires outbound network access and any credentials required by the selected tools. See Web search for configuration. Web content comes from external sources; validate it in production and do not execute search results as trusted instructions.

Request processing

Without touching business logic, you can inject shared cross-cutting processing into each run. Pass a processor to run_processor, for example to enforce login via identity authentication:

from veadk import Agent
from veadk.integrations.ve_identity import AuthRequestProcessor

agent = Agent(name="assistant", run_processor=AuthRequestProcessor())

When unset, the default processor is used and behavior is unchanged. VeADK ships AuthRequestProcessor as a ready-made implementation for identity authentication.

Custom processors

Every processor subclasses the abstract base BaseRunProcessor and implements its process_run(runner, message) method. That method returns a decorator wrapping the run’s event stream, letting you:

inject logic before and after the whole run (auth, logging, monitoring);
intercept, rewrite, or inject events produced during the run;
build control logic such as retries on top of that.

from veadk.processors.base_run_processor import BaseRunProcessor

class LoggingProcessor(BaseRunProcessor):
    def process_run(self, runner, message, **kwargs):
        def decorator(event_generator):
            async def wrapper():
                # Before: record start, validate, ...
                async for event in event_generator():
                    yield event  # intercept or rewrite events here
                # After: summarize, report, ...
            return wrapper
        return decorator

Overview

Get started

Core components

Observability

Extensions

Frontend

Security

Default runtime

Switch the execution backend

Skills and tools in the Codex runtime

Codex backend requests

Enable web search

Request processing

Custom processors

​Default runtime

​Switch the execution backend

​Skills and tools in the Codex runtime

​Codex backend requests

​Enable web search

​Request processing

​Custom processors

Default runtime

Switch the execution backend

Skills and tools in the Codex runtime

Codex backend requests

Enable web search

Request processing

Custom processors