The LangGraph process holds the public key. The caller holds the access token and, if it minted that token, the client secret. `POST /invoke` expects `Authorization: Bearer`.

The exchange is in [Agent frameworks](/docs/agent-frameworks#mint-the-bearer). This server does not take `AUTHDOG_CLIENT_SECRET`.

## Which credential

| Credential | Use it when |
| --- | --- |
| Agent identity | A named agent inside a project that already has users. [Agents](/docs/console/agents) is sales-gated until access is approved. |
| M2M application | The caller is a job or another backend, or Agents access is not approved yet. Same `client_credentials` grant. |
| Personal access token | One person's script. Keep it off an unattended caller. |
| Service account | Authdog REST automation. Not the bearer `require_auth` checks here. |

## Where each value goes

| Variable | Process | Purpose |
| --- | --- | --- |
| `PK_AUTHDOG` | The process that serves `/invoke` | `Authdog(public_key=...)`. Selects the identity host. |
| `AUTHDOG_CLIENT_ID` / `AUTHDOG_CLIENT_SECRET` | The process that calls the token endpoint | Mint the access token. |
| Access token | `Authorization` header | What `require_auth` sends to userinfo. |

There is no refresh token. Repeat the exchange before `expires_in`. `PK_AUTHDOG` does not mint tokens. A vault API key is not this bearer.

To act for a person, keep the same route and put an [RFC 8693 token](/guides/agent-delegation) in the header. `sub` stays the user. `act` names the agent. The sample mints a token whose subject is the agent client.

## Related

| Read | To learn how to |
| --- | --- |
| [Custom channel auth for LangGraph](/docs/ai/langgraph/channel-auth) | Keep `ainvoke` behind `require_auth` |
| [Machine identity](/docs/machine-identity) | Choose the credential |
| [LangGraph](/docs/agent-frameworks/langgraph) | Call `/invoke` and read `subject:` |
| [OpenAI Agents SDK](/docs/agent-frameworks/openai-agents) | Present this same token from a tool |