Verify Rotation

"""Tool that verifies a runtime-injected secret without leaking the value.

Reads the secret-backed env var (populated by the workload-identity
secrets manager at kickoff time) and returns a stable fingerprint. Never
echo raw credential values into LLM output or logs in production code —
the fingerprint alone is sufficient to confirm rotation worked.
"""

from __future__ import annotations

import hashlib
import os

from crewai.tools import BaseTool


# Match the deployment environment variable's `key` field.
ENV_VAR_NAME = "API_KEY"


class CredentialEchoTool(BaseTool):
    name: str = "credential_echo"
    description: str = (
        "Read the API credential from the worker's environment and return a "
        "fingerprint summary. Use this exactly once when asked to verify the "
        "current credential. Takes no arguments."
    )

    def _run(self) -> str:
        value = os.environ.get(ENV_VAR_NAME)
        if not value:
            return (
                f"ERROR: {ENV_VAR_NAME} env var is not set. The workload-"
                "identity secret fetch did not run, or the deployment is "
                "missing the secret-backed env var."
            )
        fingerprint = hashlib.sha256(value.encode()).hexdigest()[:12]
        return f"Authenticated. credential.fingerprint=sha256:{fingerprint}"

credential_checker:
  role: >
    Credential Verifier
  goal: >
    Confirm that the workload-identity-backed secret reached this worker
    process and report a fingerprint of the current value.
  backstory: >
    You are a no-nonsense reliability engineer responsible for verifying
    that secrets fetched at runtime via workload identity are present
    and fresh. You always use the credential_echo tool exactly once and
    report the result verbatim — you never make up values.

verify_credential_task:
  description: >
    Use the credential_echo tool to read the runtime-injected credential
    and produce a one-line confirmation. The current year is {current_year}
    (use it only in the timestamp; do not transform the credential output).
  expected_output: >
    A single line in the form:
    "[{current_year}] <credential_echo tool's exact output>"
  agent: credential_checker

from crewai import Agent, Crew, Process, Task
from crewai.project import CrewBase, agent, crew, task
from crewai.agents.agent_builder.base_agent import BaseAgent

from rotation_verifier.tools.credential_echo_tool import CredentialEchoTool


@CrewBase
class RotationVerifierCrew():
    """Single-task crew that verifies a workload-identity-backed secret
    was successfully fetched at runtime.

    Rotate the underlying secret in the cloud provider, kickoff again, and
    the credential fingerprint in the agent's report changes — without any
    re-deploy, worker restart, or input change. The crew prompt itself
    never references the secret value.
    """

    agents: list[BaseAgent]
    tasks: list[Task]

    @agent
    def credential_checker(self) -> Agent:
        return Agent(
            config=self.agents_config["credential_checker"],
            tools=[CredentialEchoTool()],
            verbose=True,
        )

    @task
    def verify_credential_task(self) -> Task:
        return Task(config=self.tasks_config["verify_credential_task"])

    @crew
    def crew(self) -> Crew:
        return Crew(
            agents=self.agents,
            tasks=self.tasks,
            process=Process.sequential,
            verbose=True,
        )