Instructions for handling API keys and credentials safely, verifying their presence, and prompting the user to add them if missing using a safe protocol.
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tessl review fix ./skills/credentials/SKILL.mdMany skills require API keys or other credentials to function or to access higher rate limits. This skill defines the standard safe credentials protocol for verifying and prompting for these credentials without leaking sensitive keys into the agent context or the conversation history.
As soon as a skill that requires a credential or API key looks relevant to the
user's request, you MUST immediately verify if the credential is present in
the .env file (typically located in your home directory ~/.env or the
project root) — before doing any other work for that skill.
CRITICAL: You must verify the presence of the credential without printing its value to the terminal or reading it into your context.
Use grep in quiet and suppress-errors mode (-sq) to check if the variable is
defined in ~/.env. The -s flag ensures the command works cleanly even if
~/.env does not exist yet.
grep -sq "^CREDENTIAL_NAME=" ~/.envReplace CREDENTIAL_NAME with the actual credential name required by the
calling skill (e.g., ALPHAGENOME_API_KEY or USER_EMAIL).
.env file does not exist yet), the credential is missing.
You MUST IMMEDIATELY stop and prompt the user to add it using the
instructions in
Prompting the User to Add Credentials
before attempting to run any scripts or tools. Do not conclude the turn by
simply stating that the key is missing.[!CRITICAL] If verification fails (any non-zero exit code), you MUST NOT attempt to execute any tools or scripts from the calling skill, nor should you conclude the turn by simply reporting the missing key. You MUST IMMEDIATELY generate the appropriate terminal command from the templates below and prompt the user to run it. The template command will create the
.envfile if it does not already exist.
NEVER run cat ~/.env, grep "VAR" ~/.env (without -q), echo $VAR, or
printenv to check for credentials.
If a credential is missing, do NOT ask the user to paste it into the chat. This would leak the value into the agent's context and the conversation history.
Instead, you MUST generate a specific command for the user to run in their terminal by replacing the placeholders in one of the templates below.
CRITICAL: Before presenting the command to the user, you MUST replace:
CREDENTIAL_NAME with the actual variable name needed (e.g.,
ALPHAGENOME_API_KEY, USER_EMAIL).ENV_FILE with the resolved literal path to the .env file (usually
~/.env).All credentials are treated as sensitive. The read -s flag hides the user's
typing. You MUST inform the user that their typing will be hidden.
CRITICAL: When requesting a credential, you MUST also provide the user with the appropriate registration link or instructions provided by the calling skill so they know how to obtain the value if they do not have one.
printf "Enter CREDENTIAL_NAME (typing hidden): " && read -s val && echo && echo "CREDENTIAL_NAME=$val" >> "ENV_FILE" && echo "Saved."All helper scripts inside the calling skills load these credentials
automatically from the .env file using dotenv.
You do NOT need to manually read the keys, export them to the shell
environment, or pass them as CLI arguments, when calling the helper scripts that
require them. As long as you have verified the key is present in .env using
the safe protocol above, simply run the script directly — the script will load
the credential automatically.
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