October 20, 2026

AI agent authentication platforms: compare per-user credential support

AI agent authentication platforms qualify for a no-shared-credentials policy when the agent’s tool call reaches the target service with the initiating user’s…

A security team selecting an agent platform needs to prove which user authorizes each tool call at the destination service. Trace the initiating user, delegated credential, target scopes, and logged attribution through normal calls and revocation cases. MCP connectivity and platform API keys are separate evidence from user-specific delegation.

This comparison has one named, documented delegated-identity example—Google Cloud Agent Identity—alongside architecture categories. The low-code and CRM categories are unverified in the reviewed evidence; that is a limit of this comparison, not evidence that those products lack support.

Key takeaways

Short answer: choose an agent tool flow that delegates each caller’s identity to the target service.

Require delegated identity: Each tool call must use the initiating user’s authorization, rather than a shared service account or creator’s connection.
Start with documented user OAuth: Google Cloud's Agent Identity overview describes 3-legged OAuth for agents accessing external tools on an individual user's behalf.
Test the full path: Verify user attribution, authorization scopes, credential isolation, revocation and audit records with the actual target tool.
Separate MCP from identity: MCP supports tool discovery and invocation; verify separately which identity and authorization the target service receives.
Place Seahorse accurately: Seahorse Cloud's Managed Agent supports MCP-standard tool calling, and the Seahorse Database component lists API-key authentication.

What per-user credentials mean in an agent tool call

Per-user credentials let an agent act at a connected service under the authority of the person who requested the action. In OAuth 2.0, the user authorizes a client to access protected resources, and the authorization server issues an access token for that delegated access. The OAuth 2.0 Authorization Framework illustrates this with a printing service accessing a user’s stored photos without receiving the user’s password.

The security question is which identity the destination service sees when the tool runs. A delegated flow should carry the initiating user’s authorization to the service that owns the data or action.

The OAuth 2.0 Authorization Framework says client credentials are typically used when a client acts on its own behalf or requests access based on a prior arrangement. That model can suit scheduled or organization-owned tasks when policy approves an application identity. The no-shared-user-credentials requirement in this comparison applies to user-specific actions; it is not a universal rule for every agent task. For actions that must use a specific person’s authority, verify delegated user identity at the target service.

The MCP tools specification defines tools/list for discovering a server’s tools and tools/call for invoking one. These functions cover tool discovery and invocation; the security team still needs to verify which identity the tool or downstream service receives.

For HTTP-based transports, the reviewed November 25, 2025 MCP authorization specification defines optional transport-level authorization for MCP clients accessing restricted servers on resource owners’ behalf. This transport authorization does not by itself establish the identity the downstream service applies to a tool call.

OAuth delegation does not mean forwarding the same token through every hop. Validate the token’s audience or resource, scopes, issuer and association with the correct user at each boundary, and use credentials appropriate to the target service. Never pass an MCP-server token to a downstream API merely because it authenticates the first hop.

A practical eligibility test asks: does the target service authorize this call as Alice, Bob or another named user, and does it enforce that user’s own permissions? The flow must identify the caller, obtain the right authorization and carry it to the resource that performs the action.

How documented and conditional credential paths compare

The named managed example in this review is Google Cloud Agent Identity. Its overview separates an agent's own application identity from delegated user authority, and documents three-legged OAuth for external tools accessed on a person's behalf. This establishes a supported design to test, not blanket qualification for every connector or deployment.

Approach	Identity used for the tool request	Documented credential path	Conditions and team responsibility
Managed cloud agent identity/runtime	The individual user, through delegated OAuth 2.0 3LO.	Agent Identity auth manager manages user consent and tokens for delegated access.	Configure an OAuth provider and redirect URIs, then bind it to the orchestrator agent in Agent Registry. The documented setup also requires a frontend application for user sign-in and consent redirects. Confirm the target tool supports the required OAuth flow and scopes.
Developer-built agent or framework	The identity implemented by the development team.	OAuth provides delegated authorization, while the team connects the user session to the token used for each tool.	The team owns the authorization handoff, token storage and refresh, target-service integration, permission enforcement and audit trail. Test each tool endpoint.
MCP-enabled managed RAG or agent platform	The product’s separately configured authorization path determines the identity used at the target.	MCP defines tool discovery and invocation; it does not itself establish per-user delegation.	Evaluate the product’s separate authorization flow and test which principal the target service receives.
Other candidate platforms: low-code builders, CRM-native agents and similar products	No specific qualifying implementation is established for these categories in the sources used for this comparison.	The reviewed evidence does not establish a named candidate’s per-user delegated flow.	Require current product documentation for the covered actions, connectors, channels or rollout conditions, and delegated-user flow; then test the principal recorded by the target service.

Google Cloud’s Agent Identity overview lists API keys, OAuth client credentials and delegated end-user access tokens as authentication options for the auth manager. For the documented 3-legged OAuth setup, the setup guide says to enable the Agent Identity Connector API if it is not already enabled. Select delegated-user access for user-specific work, then verify consent, scopes, configuration and the exact production tool path.

A developer-owned flow is a valid architecture when the team plans to own the complete credential lifecycle. The OAuth 2.0 authorization-code grant uses a redirection flow in which the client interacts with the user’s browser and receives a redirect from the authorization server. In an agent product, developers still connect that standards-based flow to the agent session, preserve the user-to-token association, select the correct token for each tool and protect credentials throughout runtime operations.

What the security team should prove before approving a platform

Run an acceptance test through the same agent, tool connection and target service planned for production. Use at least two test users whose permissions differ, and exercise the same agent task under each identity. The results should show the target service applying each person’s own access rights.

Trace the caller: Capture the authenticated user at agent entry, the identity selected for the tool call and the principal recorded by the target service. Record opaque connection or token IDs and relevant metadata for correlation; never log access tokens, refresh tokens or secrets.
Prove permission separation: Give two test users different access to the same resource or action. Run the same prompt and compare retrieval and tool results.
Inspect authorization scope and consent: Record the resources and permissions requested during authorization. Confirm that the user or approved administrator can understand and grant the access required for the task. Match the granted scope to the specific tools the agent uses.
Test revocation and account changes: Revoke consent or disable a test user, then repeat the same tool call. Measure the time until the service rejects access and verify that the agent does not continue through a fallback credential.
Check credential isolation: Sign in two users and test session switching, parallel calls and retry behavior. Confirm that tokens and cached connections remain associated with the right user throughout those cases.
Review token protection: Record where tokens are stored and which runtime components can read them. RFC 9700, OAuth 2.0 Security Best Current Practice recommends sender-constrained access tokens to reduce misuse of stolen or leaked tokens, and requires public clients to sender-constrain refresh tokens or rotate them.
Keep an attributable audit trail: Record the user, agent, tool, target resource, authorization outcome, time, and opaque connection or token IDs with relevant metadata for each sensitive action. Never record access tokens, refresh tokens or secrets. Limit log access and retention to the operational and security purpose, and remove unnecessary personal data.
Record availability conditions: Capture the product edition, enabled feature, connected tool, target service and deployment channel used in the test.

Score retrieval results, answer support, permission behavior and operating effort separately. Retrieval tests establish whether the agent finds the right user-authorized material. Answer-support tests check whether the response follows from the material. Permission tests establish whether user-level access boundaries hold. Operating-effort tests show what the team must maintain across provider setup, consent, tool changes and credential lifecycle.

A platform passes the policy gate when the test demonstrates user attribution at the target, least-privilege access, isolation between users and the team’s required revocation and audit behavior. Record any unsupported tool, channel or permission behavior as a deployment constraint, then test a supported alternative path before approval.

Does MCP tool calling make Seahorse Cloud a per-user-credential platform?

MCP support and per-user credential support answer different questions. MCP provides a standard way to expose, discover and invoke tools. The authorization flow determines whether a restricted server accepts a connection and which user or application identity the service applies to the request.

Seahorse Cloud’s Managed Agent is built on its Vector Database and RAG and supports MCP-standard tool calling. Seahorse Database combines API-key authentication with table and schema management, multi-tenant isolation and monitoring. These capabilities describe managed agent and database functions; the team should evaluate a connected tool’s user-delegated identity flow as a separate part of its credential test.

Trace the identity through each hop to the service that reads or changes the protected resource.

Which approach fits the team after it passes the credential test

Choose a managed delegated-identity service when its documented user-OAuth flow supports the team’s tools and its managed provider setup, consent and token handling fit the team. Google Cloud Agent Identity is the comparison’s named documented 3LO example; eligibility remains conditional on configuration and target-tool testing.

Choose a developer-owned flow when the team needs control over identity propagation, target-specific policy and runtime behavior, and can maintain token issuance, secure storage, renewal, revocation handling, per-user caching and audit events. Test each target service so changes cannot silently shift requests to an application credential; log only opaque connection or token IDs and relevant metadata, never access tokens, refresh tokens or secrets.

Consider Seahorse Cloud for managed RAG, a managed agent and MCP-standard tool calling. These capabilities do not establish per-user delegated identity: test the selected tool path against the same credential gate before treating it as eligible for a no-shared-credentials policy.

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