microsoft/semantic-kernel · error · AgentInvokeException

No token received.

Error message

No token received.

What it means

An AgentInvokeException from the fallback (no bot_secret) branch: GET to token_endpoint returned 200 but the JSON body lacked a 'token' field. Functionally the same malformed-response condition as the bot_secret branch, just reached via the alternate token_endpoint path.

Source

Thrown at python/samples/demos/copilot_studio_agent/src/direct_line_agent.py:75

                headers = {"Authorization": f"Bearer {self.bot_secret}"}
                async with self.session.post(url, headers=headers) as resp:
                    if resp.status == 200:
                        data = await resp.json()
                        self.directline_token = data.get("token")
                        if not self.directline_token:
                            logger.error("Token generation response missing token: %s", data)
                            raise AgentInvokeException("No token received from token generation.")
                    else:
                        logger.error("Token generation endpoint error status: %s", resp.status)
                        raise AgentInvokeException("Failed to generate token using bot_secret.")
            else:
                async with self.session.get(self.token_endpoint) as resp:
                    if resp.status == 200:
                        data = await resp.json()
                        self.directline_token = data.get("token")
                        if not self.directline_token:
                            logger.error("Token endpoint returned no token: %s", data)
                            raise AgentInvokeException("No token received.")
                    else:
                        logger.error("Token endpoint error status: %s", resp.status)
                        raise AgentInvokeException("Failed to fetch token from token endpoint.")
        except Exception as ex:
            logger.exception("Exception fetching token: %s", ex)
            raise AgentInvokeException("Exception occurred while fetching token.") from ex

    @trace_agent_get_response
    @override
    async def get_response(
        self,
        history: ChatHistory,
        arguments: dict[str, Any] | None = None,
        **kwargs: Any,
    ) -> ChatMessageContent:
        """
        Get a response from the DirectLine Bot.
        """

View on GitHub (pinned to c028a0c7dc)

Solutions

1. Inspect the logged body (logger.error) to find the real token key.
2. Confirm token_endpoint is the actual token-issuing URL, not a generic service base URL.
3. Switch to the bot_secret flow if the token_endpoint path is unsupported for your setup.

Example fix

// before
self.directline_token = data.get("token")  # body had different key

// after
logger.error("Token endpoint body: %s", data)
self.directline_token = data.get("token") or data.get("access_token")

try:
    await fetch_token()
except AgentInvokeException as e:
    if "No token received" in str(e):
        logger.error("Token endpoint 200 without token; inspect body schema.")
    raise

When it happens

Trigger: self.bot_secret is unset, so the agent GETs self.token_endpoint; it returns 200 with a body that does not contain 'token'.

Common situations: token_endpoint points at an endpoint returning a different schema; a gateway returns a health-check 200 without token data; the endpoint URL is correct but the service isn't a token issuer.

Related errors

• No token received from token generation.
• Failed to generate token using bot_secret.
• Failed to fetch token from token endpoint.
• Exception occurred while fetching token.
• Failed to start conversation.

AI-assisted analysis of microsoft/semantic-kernel@c028a0c7dc (2026-08-13). Data as JSON: /api/errors/ee3bc648aa2f0549. Report an issue: GitHub.