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Clear out junk files and repair common Windows errorsFree Scan →Fix the driver behind crashes, sound loss and screen glitchesFind Drivers →Keep raw API keys out of agent-readable configuration, prompts, source code, reusable plugin packages, and logs. Put only non-secret settings in files you share or commit. If the agent process can read a key—whether it comes from an environment variable or a vault injection—assume code running in that process can expose it. When the agent must use a credential without seeing it, have a trusted backend or proxy attach it to approved requests.
Why API keys do not belong in agent configuration
Agent definitions and tool-connection files are easy to copy, commit, package, or include in logs. A credential placed inline can travel with them. OpenAI’s MCP connections guidance says to keep secrets out of reusable agent definitions, plugin archives, and logs.
Use configuration files for settings that are safe to share, such as a service name or a non-secret endpoint. Do not include a raw key in a prompt, code sample, MCP authorization field, plugin archive, or debugging output. A reference to a secret is safer than its value only when the target runtime supports that reference and resolves it securely.
Choose the right place for the credential
| Pattern | What it protects | Limitation | Best fit |
|---|---|---|---|
| Environment variable | Keeps the literal key out of source code and checked-in configuration. | The process and code able to read its environment can read the key. | Local development or a trusted process where process-level access is acceptable. |
| Platform vault or secret store | Stores the real credential outside reusable agent configuration and can supply it through a supported integration. | Availability and isolation depend on the platform, credential type, and injection mechanism. Direct injection into an agent-readable environment still exposes the value to that process. | Hosted agent and MCP integrations that document vault support. |
| Trusted backend or proxy | Keeps the raw key outside agent-generated code; the trusted service authenticates approved outbound requests. | Requires operating and securing an intermediary, including constraints on its destinations and capabilities. | Untrusted agent execution or stronger separation between agent code and credentials. |
OpenAI’s sandbox security guidance puts the environment-variable limitation plainly: “Injecting a stored secret into the environment still exposes it to agent-generated code.” Environment variables improve configuration hygiene, but they are not an isolation boundary.
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Keep MCP credentials out of reusable configuration
MCP setups may specify authorization inline or use a matching vault credential, depending on the platform. Prefer the documented vault mechanism when the runtime supports it; do not assume a placeholder syntax from one SDK or platform works elsewhere. OpenAI documents vault credentials for MCP and sandbox use, including a placeholder environment variable for cases where the real secret stays outside an OpenAI-hosted sandbox.
For details, follow the platform’s documentation for MCP connections and vaults. If the credential must remain inaccessible to agent-generated code, a trusted proxy or server should hold it and add it only to approved requests.
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Restrict which tools an agent can discover and call. In OpenAI’s MCP connection setup, allowed_tools can limit tool access. That reduces available actions, but it does not protect a key already readable by the process.
Set up an environment variable without exposing its value
- Remove the literal key from the config and source. Replace it with a non-secret setting or a runtime-supported secret reference. Check that the key is not in prompts, plugin packages, or example files either.
- Supply the key through the trusted runtime. For local development, use an environment variable that is not committed to source control. For a hosted agent, use its documented secret-store integration if available.
- Check presence without printing the secret. Verify that the required variable is set using a presence-only check or the platform’s secret-status indicator. Do not echo the value to a terminal, log, or agent transcript.
- Review what can read it. Determine whether the agent process, generated code, tools, or subprocesses can inspect the environment. If they can, the variable does not keep the key secret from them; use a proxy or other documented isolation boundary instead.
- Keep logs and traces free of credential values. Avoid logging authorization headers, environment contents, or full request data that may contain secrets.
OpenAI recommends environment variables as an API-key safety measure in its API key safety guidance. That protects against accidental inclusion in source control; it does not make a key inaccessible to software running with permission to read it.
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Limit what an exposed credential can do
Storage is only one part of the security boundary. Assess each setup by asking:
- Can the agent or its generated code read the raw credential?
- Where does the real secret reside, and which component injects or uses it?
- Which hosts and actions can the credential authorize?
- Can you scope, revoke, or replace it independently of the agent configuration?
- Could logs, traces, or error reports capture the secret?
Grant only the tool access and credential scope the task needs. OWASP’s MCP01:2025 guidance on token mismanagement and secret exposure identifies hard-coded MCP credentials and poor token handling as exposure risks, and recommends using secret-storage controls.
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If a key may have been exposed
- Revoke or rotate the credential. Do not wait to confirm whether someone used it if exposure is credible.
- Remove it from active configuration and source. Replace it with a supported secret reference or move credential use behind a trusted service.
- Check relevant repositories, logs, and traces. Look for copies of the value or requests that may have included it; do not reproduce the secret in remediation notes.
- Review access and usage. Check the provider’s available activity records for unexpected use, and narrow the credential’s permissions if needed.
OpenAI’s sandbox security guidance advises rotation or revocation when exposure is suspected.
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