Skip to main content

Credential Tools

GPTScript supports credential provider tools. These tools can be used to fetch credentials from a secure location (or directly from user input) and conveniently set them in the environment before running a script.

Writing a Credential Provider Tool​

A credential provider tool looks just like any other GPTScript, with the following caveats:

  • It cannot call the LLM and must run a command.
  • It must print contents to stdout in the format {"env":{"ENV_VAR_1":"value1","ENV_VAR_2":"value2"}}.

Here is a simple example of a credential provider tool that uses the builtin sys.prompt to ask the user for some input:

# my-credential-tool.gpt
Name: my-credential-tool

#!/usr/bin/env bash

output=$(gptscript -q --disable-cache sys.prompt '{"message":"Please enter your fake credential.","fields":"credential","sensitive":"true"}')
credential=$(echo $output | jq -r '.credential')
echo "{\"env\":{\"MY_ENV_VAR\":\"$credential\"}}"

Using a Credential Provider Tool​

Continuing with the above example, this is how you can use it in a script:

Credentials: my-credential-tool.gpt as myCred

#!/usr/bin/env bash

echo "The value of MY_ENV_VAR is $MY_ENV_VAR"
note

GPTScript accepts Cred:, Creds:, Credential:, and Credentials: as valid directives.

When you run the script, GPTScript will call the credential provider tool first, set the environment variables from its output, and then run the script body. The credential provider tool is called by GPTScript itself. GPTScript does not ask the LLM about it or even tell the LLM about the tool.

If GPTScript has called the credential provider tool in the same context (more on that later), then it will use the stored credential instead of fetching it again.

To delete the credential that just got stored, run gptscript credential delete myCred.

You can also specify multiple credential tools for the same script, but they must be on separate lines:

Credentials: credential-tool-1.gpt
Credentials: credential-tool-2.gpt

(tool stuff here)

Generic Credential Tool​

GPTScript also provides a generic credential tool (github.com/gptscript-ai/credential) that is ideal for cases where you only need to set one environment variable. Here is an example of how to use it:

Credentials: github.com/gptscript-ai/credential as myCredentialName with MY_ENV_VAR as env and "this message will be displayed to the user" as message and key as field

(tool stuff here)

When this tool is run, the user will be shown the message and prompted to enter a key. The value entered will be set as the environment variable MY_ENV_VAR and stored in a credential called myCredentialName.

See the repo for more information.

Credential Tool Parameters​

A credential tool may define parameters. Here is an example:

Name: my-credential-tool
Parameter: env: the environment variable to set
Parameter: val: the value to set it to

#!/usr/bin/env bash

echo "{\"env\":{\"$ENV\":\"$VAL\"}}"

When you reference this credential tool in another file, you can use syntax like this to set both parameters:

Credential: my-credential-tool.gpt with MY_ENV_VAR as env and "my value" as val

(tool stuff here)

In this example, the tool's output would be {"env":{"MY_ENV_VAR":"my value"}}

Storing Credentials​

By default, credentials are automatically stored in the credential store. Read the main credentials page for more information about the credential store.

note

Credentials received from credential provider tools that are not on GitHub (such as a local file) and do not have an alias will not be stored in the credentials store.

Credential Aliases​

When you reference a credential tool in your script, you can give it an alias using the as keyword like this:

Credentials: my-credential-tool.gpt as myAlias

(tool stuff here)

This will store the resulting credential with the name myAlias. This is useful when you want to reference the same credential tool in scripts that need to handle different credentials, or when you want to store credentials that were provided by a tool that is not on GitHub.

Credential Contexts​

Each stored credential is uniquely identified by the name of its provider tool (or alias, if one was specified) and the name of its context. A credential context is basically a namespace for credentials. If you have multiple credentials from the same provider tool, you can switch between them by defining them in different credential contexts. The default context is called default, and this is used if none is specified.

You can set the credential context to use with the --credential-context flag when running GPTScript. For example:

gptscript --credential-context my-azure-workspace my-azure-script.gpt

Any credentials fetched for that script will be stored in the my-azure-workspace context. If you were to call it again with a different context, you would be able to give it a different set of credentials.

Listing and Deleting Stored Credentials​

The gptscript credential command can be used to list and delete stored credentials. Running the command with no --credential-context set will use the default credential context. You can also specify that it should list credentials in all contexts with --all-contexts.

You can delete a credential by running the following command:

gptscript credential delete --credential-context <credential context> <credential name>

The --show-env-vars argument will also display the names of the environment variables that are set by the credential. This is useful when working with credential overrides.

Credential Overrides (Advanced)​

You can bypass credential tools and stored credentials by setting the --credential-override argument (or the GPTSCRIPT_CREDENTIAL_OVERRIDE environment variable) when running GPTScript. To set up a credential override, you need to be aware of which environment variables the credential tool sets. You can find this out by running the gptscript credential --show-env-vars command.

To override multiple credentials, specify the --credential-override argument multiple times.

Format​

info

In the examples that follow, toolA, toolB, etc. are the names of credentials. By default, a credential has the same name as the tool that created it. This can be overridden with a credential alias, i.e. credential: my-cred-tool.gpt as myAlias. If the credential has an alias, use it instead of the tool name when you specify an override.

The --credential-override argument must be formatted in one of the following two ways:

1. Key-Value Pairs​

toolA:ENV_VAR_1=value1,ENV_VAR_2=value2

In this example, both toolA provides the variables ENV_VAR_1 and ENV_VAR_2. This will set the environment variables ENV_VAR_1 and ENV_VAR_2 to the specific values value1 and value2.

2. Environment Variables​

toolA:ENV_VAR_1,ENV_VAR_2

In this example, toolA provides the variables ENV_VAR_1 and ENV_VAR_2, This will read the values of ENV_VAR_1 through ENV_VAR_4 from the current environment and set them for the credential. This is a direct mapping of environment variable names. This is not recommended when overriding credentials for multiple tools that use the same environment variable names.

Credential Refresh (Advanced)​

Some use cases (such as OAuth) may involve the need to refresh expired credentials. To support this, your credential tool can return other fields besides env in its JSON output. This is the full list of supported fields in the credential tool output:

  • env (type: object) - The environment variables to set.
  • expiresAt (type: string, timestamp in RFC3339 format) - The time when the credential expires.
  • refreshToken (type: string) - The refresh token to use to refresh the credential.

When GPTScript tries to use a credential that has a defined expiresAt time, it will check if the credential has expired. If the credential has expired, it will run the credential tool again, and the current value of the credential will be set to the environment variable GPTSCRIPT_EXISTING_CREDENTIAL as a JSON string. This way, the credential tool can check for that environment variable, and if it is set, get the refresh token from the existing credential and use it to refresh and return a new credential, typically without user interaction.

For an example of a tool that uses the refresh feature, see the Gateway OAuth2 tool.

GPTSCRIPT_CREDENTIAL_EXPIRATION environment variable​

When a tool references a credential tool, GPTScript will add the environment variables from the credential to the tool's environment before executing the tool. If at least one of the credentials has an expiresAt field, GPTScript will also set the environment variable GPTSCRIPT_CREDENTIAL_EXPIRATION, which contains the nearest expiration time out of all credentials referenced by the tool, in RFC 3339 format. That way, it can be referenced in the tool body if needed. Here is an example:

Credential: my-credential-tool.gpt as myCred

#!python3

import os

print("myCred expires at " + os.getenv("GPTSCRIPT_CREDENTIAL_EXPIRATION", ""))