Google ADK - Sakshi Documentation

Google’s Agent Development Kit runs agents through a Runner, and the Runner invokes registered plugins around every agent, model, and tool step. Sakshi ships such a plugin. Register SakshiAdkPlugin once on the Runner and every model call and tool call in the whole agent tree is witnessed on the active decision. Turn on enforce and each tool call is routed through the agent’s autonomy envelope before it runs. The plugin does not import google-adk at module load, so it degrades cleanly and carries no version lock.

Install

pip install sakshi-sdk google-adk

Register the plugin

Pass SakshiAdkPlugin to the Runner’s plugins list, and open a witness session around the run. Every model and tool call inside lands on that decision.

from google.adk.runners import Runner

runner = Runner(
    agent=root_agent,
    app_name="loans",
    session_service=session_service,
)

async for event in runner.run_async(user_id="u1", session_id="s1",
                                     new_message=message):
    ...

from google.adk.runners import Runner
from sakshi import SakshiClient
from sakshi.middleware import SakshiAdkPlugin

client = SakshiClient("https://sakshi.your-company.internal", api_key="sks_...")

runner = Runner(
    agent=root_agent,
    app_name="loans",
    session_service=session_service,
    plugins=[SakshiAdkPlugin(client, "loan-decision-agent")],
)

with client.witness("loan-decision-agent", client_ref="APP-2026-04471") as decision:
    async for event in runner.run_async(user_id="u1", session_id="s1",
                                        new_message=message):
        ...
    decision.action(outcome="approved", mode="auto")

What gets witnessed

The plugin records onto the active witness session as the agent runs:

Model calls become llm_call steps with latency, token usage, the finish reason, and the served model identity (RBI draft MRM para 56). ADK agents usually run on Gemini, but the plugin reads the model generically, so LiteLLM-backed models are recorded too.
Tool calls become tool_call steps with the tool name, the argument keys (never the values, which are tokenized at ingest anyway), the latency, and the result status. A tool that raises is recorded as an error, since failures are evidence too.
Agents are bracketed with agent_start and agent_end steps, so a multi-agent tree reads as nested control flow on the chain.

Enforce in the tool path

With enforce=True, the plugin routes each tool call through the agent’s autonomy envelope in before_tool_callback, before the tool runs. An auto outcome lets the tool proceed. Anything else (review or block) stops the tool and returns a structured “parked for review” result to the agent instead of executing it. This is the same tool-path boundary as the MCP proxy, applied inside ADK.

plugin = SakshiAdkPlugin(
    client,
    "loan-decision-agent",
    enforce=True,
    exempt_tools=("check_credit", "lookup_customer"),   # read-only, never gated
    stakes_fields=("amount", "stakes", "value"),         # read stakes from tool args
    confidence_fields=("confidence", "score"),
)

The stakes and confidence signals are read from the tool’s own arguments by the field names you configure, and passed to the envelope. A read-only tool listed in exempt_tools is never gated.

Enforcement is fail-closed: if Sakshi is unreachable, a governed tool is blocked rather than run ungoverned. Witnessing is fail-open: a recording problem never breaks the agent, and with no active witness session the plugin is a no-op. enforce=True requires the client and the agent id.

Combine with MCP tools

If your ADK agent reaches tools over the Model Context Protocol, you can also govern that layer with the MCP integration, which detects tool-manifest poisoning. The two compose: the ADK plugin governs the agent’s own tool calls, and the MCP surface governs the MCP tool boundary.

Full SDK reference

The client, the witness session, and enforcement.

​Install

​Register the plugin

​What gets witnessed

​Enforce in the tool path

​Combine with MCP tools

Full SDK reference

Install

Register the plugin

What gets witnessed

Enforce in the tool path

Combine with MCP tools