How should security teams connect Antigravity to authenticated MCP tools without exposing downstream credentials?

Use a gateway pattern rather than placing third-party secrets in the editor. Point Antigravity at a managed MCP gateway, authenticate the client with a narrow gateway credential, and pass a verified end user identity on each request. That keeps downstream authorization, token storage, refresh, and tool execution outside local configs and reduces the chance of credential sprawl or prompt exposure.

Why a gateway pattern is the right integration boundary

The safe integration point is not the editor itself, but a managed MCP gateway that sits between Antigravity and downstream tools. That boundary lets security teams centralise authentication, token issuance, request validation, and authorization decisions in one controlled service, instead of scattering third-party secrets across local developer settings or promptable environments.

Using a gateway also preserves a cleaner trust model. Antigravity needs only a narrow client credential to reach the gateway, while the gateway can exchange that for the right downstream access on each request. The result is less secret sprawl, easier rotation, and a much smaller blast radius if the editor, workstation, or prompt context is exposed.

For teams working with authenticated tool chains, this is materially different from embedding downstream credentials directly in the client. Once the editor holds long-lived secrets, the control plane and the execution plane collapse into the same place, which makes revocation, auditing, and incident containment much harder.

How verified end user identity changes the control model

The other essential design choice is to pass a verified end user identity on every request, rather than letting the editor act as an all-powerful proxy. That allows the gateway and the MCP server to distinguish who initiated the action, apply per-user policy, and avoid granting the editor blanket authority over every tool it can reach.

This matters because tool access is usually not a single permission. A user may be allowed to read one system, run a narrow command in another, or trigger an action only under specific conditions. If the gateway cannot see the user identity, downstream authorization becomes coarse, and the safest fallback is often to overgrant the client.

In practice, the identity passed to the gateway should be suitable for policy enforcement, logging, and troubleshooting. That means the gateway should receive a stable assertion or session context that it can evaluate, not a vague application label that hides which human or workflow is actually using the tool.

What should stay out of local configs and editor settings

Local configuration should hold only what the editor needs to reach the gateway, and nothing that can directly authenticate to downstream systems. Downstream refresh tokens, API keys, service credentials, and tool-specific secrets belong behind the gateway so they can be stored, refreshed, scoped, and revoked without depending on the developer environment.

This separation also reduces accidental disclosure paths. Editor configs are often copied, synced, backed up, inspected by extensions, or exposed in support workflows. If those files contain downstream credentials, any compromise of the workstation or prompt surface can become a broader credential leak.

A well-designed gateway can also enforce short-lived access and request-by-request mediation. That is the practical way to prevent one compromised editor session from turning into reusable access across multiple tools and environments.

Risk and Threat Considerations

Directly embedding downstream credentials in an editor creates an attractive theft target, because the attacker only needs access to the local environment or the prompt stream to reach valuable secrets. Once exposed, those credentials can often be replayed outside the editor and used for tool access, data exfiltration, or lateral movement.

Failure mechanism: Long-lived secrets stored in local configs are easy to copy, cache, leak, or reuse, and the editor becomes a privileged secret container instead of a thin client.

Impact: A single compromise can expose downstream systems, make revocation slower, and enlarge blast radius across every tool that trusted the same credential.

Standards & Framework Alignment

This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.

OWASP Non-Human Identity Top 10 and OWASP Agentic AI Top 10 address the attack and risk surface, while NIST SP 800-53 Rev 5 sets the governance and control requirements practitioners need to meet.

Framework	Control / Reference	Relevance
OWASP Non-Human Identity Top 10	NHI-02 — Secret Leakage	Local editor secret exposure is the core risk in this MCP pattern.
	NHI-05 — Overprivileged NHI	A gateway credential and downstream tool access both need tight scoping.
	NHI-07 — Long-Lived Secrets	The question is about avoiding persistent downstream credentials in the editor.
Recommendation — Keep downstream secrets out of the client and store them only in managed server-side secret handling. Scope the gateway and tool credentials to the minimum actions and resources required. Replace persistent downstream secrets with short-lived, centrally issued credentials.
OWASP Agentic AI Top 10	ASI03 — Identity & Privilege Abuse	Antigravity-style tool access must preserve identity context and least privilege.
Recommendation — Pass verified user identity through the gateway and enforce per-request authorization.
NIST SP 800-53 Rev 5	IA-9 — Identification and Authentication (Non-Organizational Users)	The gateway mediates tool access for an external or user-bound client identity.
	AC-6 — Least Privilege	The pattern depends on limiting the editor and gateway to only necessary permissions.
Recommendation — Authenticate the client through the gateway before allowing tool access. Grant the editor and gateway only the permissions required for each tool request.

Practitioner Guidance

What to prioritise: Put the gateway in front of any authenticated MCP tool before you harden prompt handling or editor policy. If the downstream credential can reach production data or privileged actions, it should never be resident in the client.

What to verify: Confirm that Antigravity only receives a narrow gateway credential, that downstream secrets never appear in local config files, and that every tool call carries a verifiable user context the gateway can enforce and log.

Common mistake: Treating an MCP client as if it were the trust boundary. The client should request access, not store the access it is requesting.

Practitioner takeaway: The safest design is a thin editor, a policy-enforcing gateway, and downstream credentials that never leave the controlled server side of the trust boundary.