Agentic Identity Framework: Securing AI Agents with OAuth 2.0 Scopes and Workload Identities

As AI agents transition from experimental tools to production systems executing real-world actions, identity and access management becomes critical. Traditional user-based authentication models fail when autonomous agents need to access resources, make API calls, and interact with external systems on behalf of users—or independently. This comprehensive guide explores the emerging Agentic Identity Framework, built on OAuth 2.0 extensions, workload identities, and capability-based access control for securing AI agents in enterprise environments.

The Agent Identity Problem

AI agents present unique identity challenges that traditional IAM systems weren’t designed to address:

Agentic Identity Architecture

The Agentic Identity Framework introduces a layered approach to agent security:

graph TB
    subgraph User ["User Context"]
        Human["Human User"]
        Consent["Consent Grant"]
    end
    
    subgraph AgentLayer ["Agent Identity Layer"]
        AgentID["Agent Identity"]
        Capabilities["Capability Tokens"]
        Delegation["Delegation Chain"]
    end
    
    subgraph Platform ["Platform Layer"]
        WorkloadID["Workload Identity"]
        RBAC["RBAC Policies"]
        Audit["Audit Service"]
    end
    
    subgraph Resources ["Protected Resources"]
        API1["Internal APIs"]
        API2["External APIs"]
        Data["Data Stores"]
    end
    
    Human --> Consent
    Consent --> AgentID
    AgentID --> Capabilities
    AgentID --> Delegation
    
    Capabilities --> WorkloadID
    Delegation --> WorkloadID
    WorkloadID --> RBAC
    
    RBAC --> API1
    RBAC --> API2
    RBAC --> Data
    
    AgentID --> Audit
    WorkloadID --> Audit
    
    style AgentID fill:#E8F5E9,stroke:#2E7D32
    style Capabilities fill:#E3F2FD,stroke:#1565C0
    style WorkloadID fill:#FFF3E0,stroke:#EF6C00

Key Components

• Agent Identity: A first-class identity representing the AI agent, separate from both the user and the platform
• Capability Tokens: Fine-grained, time-limited tokens specifying exactly what actions the agent can perform
• Delegation Chain: Cryptographic proof of the authority path from user → agent → action
• Workload Identity: Platform-level identity (e.g., Azure Managed Identity) for infrastructure access

OAuth 2.0 Extensions for Agents

The framework extends OAuth 2.0 with agent-specific grant types and scopes:

Agent Delegation Grant

POST /oauth/token HTTP/1.1
Host: auth.example.com
Content-Type: application/x-www-form-urlencoded

grant_type=urn:ietf:params:oauth:grant-type:agent-delegation
&subject_token=eyJhbGciOiJSUzI1NiIs...  // User's access token
&subject_token_type=urn:ietf:params:oauth:token-type:access_token
&agent_id=agent-customer-support-v2
&requested_scopes=read:orders write:tickets
&max_actions=100
&ttl=3600

Response includes an agent-specific token with embedded constraints:

{
    "access_token": "eyJhbGciOiJSUzI1NiIs...",
    "token_type": "Agent+Bearer",
    "expires_in": 3600,
    "scope": "read:orders write:tickets",
    "agent_id": "agent-customer-support-v2",
    "delegation_chain": ["user:12345", "agent:customer-support-v2"],
    "constraints": {
        "max_actions": 100,
        "actions_remaining": 100,
        "resource_patterns": ["orders/*", "tickets/*"],
        "denied_operations": ["delete:*", "admin:*"]
    }
}

Capability-Based Scopes

Traditional OAuth scopes are too coarse for agent actions. The framework introduces hierarchical, capability-based scopes:

// Traditional OAuth scopes
read:all
write:all

// Agentic capability scopes
agent:orders:read:own           // Read user's own orders
agent:orders:read:team          // Read team's orders (elevated)
agent:orders:write:draft        // Create draft orders only
agent:orders:write:submit       // Submit orders (requires approval workflow)
agent:tickets:create:priority:low  // Create low-priority tickets only
agent:external:api:weather      // Call specific external API

Implementing Agent Identity in .NET

Registering Agent Identities

using Microsoft.Identity.Agents;

var builder = WebApplication.CreateBuilder(args);

// Register agent identity services
builder.Services.AddAgentIdentity(options =>
{
    options.Authority = "https://auth.example.com";
    options.AgentRegistryEndpoint = "https://agents.example.com/registry";
    
    // Define agent identity
    options.AgentDefinitions.Add(new AgentDefinition
    {
        AgentId = "customer-support-agent",
        DisplayName = "Customer Support AI Agent",
        Version = "2.0.0",
        
        // Maximum capabilities this agent can ever have
        MaxCapabilities = new[]
        {
            "agent:orders:read:own",
            "agent:orders:write:draft",
            "agent:tickets:create:priority:low",
            "agent:tickets:create:priority:medium"
        },
        
        // Default capabilities (subset of max)
        DefaultCapabilities = new[]
        {
            "agent:orders:read:own",
            "agent:tickets:create:priority:low"
        },
        
        // Workload identity for platform resources
        WorkloadIdentity = new WorkloadIdentityConfig
        {
            Type = WorkloadIdentityType.AzureManagedIdentity,
            ClientId = Environment.GetEnvironmentVariable("AZURE_CLIENT_ID")
        }
    });
});

// Add agent authorization policies
builder.Services.AddAuthorization(options =>
{
    options.AddPolicy("AgentCanReadOrders", policy =>
        policy.RequireAgentCapability("agent:orders:read:own")
              .RequireDelegationChain());
    
    options.AddPolicy("AgentCanCreateTickets", policy =>
        policy.RequireAgentCapability("agent:tickets:create:*")
              .RequireActionBudget(remaining: 1));
});

Agent Token Middleware

// Middleware to validate and process agent tokens
app.UseAuthentication();
app.UseAgentTokenValidation();  // Validates agent-specific claims
app.UseAuthorization();

// Endpoint with agent authorization
app.MapGet("/api/orders", async (
    HttpContext context,
    IAgentContext agentContext,  // Injected agent context
    OrderService orderService) =>
{
    // Verify agent has capability and budget
    if (!agentContext.HasCapability("agent:orders:read:own"))
    {
        return Results.Forbid();
    }
    
    // Consume action from budget
    await agentContext.ConsumeActionAsync("read_orders");
    
    // Get orders scoped to the delegating user
    var userId = agentContext.DelegationChain.OriginalUserId;
    var orders = await orderService.GetOrdersForUserAsync(userId);
    
    return Results.Ok(orders);
})
.RequireAuthorization("AgentCanReadOrders");

Delegation Chains and Audit

Every agent action must be traceable back to the authorizing user through a cryptographic delegation chain:

public class DelegationChain
{
    public string OriginalUserId { get; init; }
    public string OriginalUserEmail { get; init; }
    public DateTime ConsentGrantedAt { get; init; }
    public string AgentId { get; init; }
    public string AgentVersion { get; init; }
    public string[] GrantedCapabilities { get; init; }
    public string ChainSignature { get; init; }  // Cryptographic proof
    
    public bool Verify(IKeyProvider keyProvider)
    {
        var expectedSignature = ComputeSignature(keyProvider);
        return CryptographicOperations.FixedTimeEquals(
            Convert.FromBase64String(ChainSignature),
            expectedSignature);
    }
}

// Audit logging with full context
public class AgentAuditLogger
{
    public async Task LogAgentActionAsync(
        IAgentContext context,
        string action,
        object? resourceId,
        ActionResult result)
    {
        var auditEntry = new AgentAuditEntry
        {
            Timestamp = DateTime.UtcNow,
            AgentId = context.AgentId,
            AgentVersion = context.AgentVersion,
            DelegatingUserId = context.DelegationChain.OriginalUserId,
            Action = action,
            ResourceId = resourceId?.ToString(),
            Result = result,
            CapabilitiesUsed = context.CapabilitiesUsed,
            ActionsRemaining = context.ActionBudget.Remaining,
            RequestId = context.RequestId,
            
            // Agent reasoning (if available)
            AgentReasoning = context.LastReasoningTrace
        };
        
        await _auditStore.WriteAsync(auditEntry);
    }
}

Workload Identity for Platform Resources

Agents running on Azure use Managed Identity for platform resource access, separate from user-delegated capabilities:

public class AgentResourceClient
{
    private readonly TokenCredential _workloadIdentity;
    private readonly IAgentContext _agentContext;
    
    public AgentResourceClient(
        DefaultAzureCredential workloadIdentity,
        IAgentContext agentContext)
    {
        _workloadIdentity = workloadIdentity;
        _agentContext = agentContext;
    }
    
    public async Task<BlobClient> GetAgentBlobClientAsync(string container, string blob)
    {
        // Platform access uses workload identity (not user delegation)
        var blobServiceClient = new BlobServiceClient(
            new Uri("https://agentstorageaccount.blob.core.windows.net"),
            _workloadIdentity);
        
        // But scope to agent-specific container
        var containerClient = blobServiceClient.GetBlobContainerClient(
            $"agent-{_agentContext.AgentId}");
        
        return containerClient.GetBlobClient(blob);
    }
    
    public async Task<SecretClient> GetSecretsClientAsync()
    {
        // Agents can only access their own secrets
        return new SecretClient(
            new Uri($"https://agent-{_agentContext.AgentId}-kv.vault.azure.net"),
            _workloadIdentity);
    }
}

Action Budgets and Rate Limiting

Prevent runaway agents with action budgets and rate limits:

public class ActionBudgetMiddleware
{
    public async Task InvokeAsync(HttpContext context, IAgentContext agentContext)
    {
        if (agentContext.IsAgentRequest)
        {
            // Check action budget
            if (agentContext.ActionBudget.Remaining <= 0)
            {
                context.Response.StatusCode = 429;
                await context.Response.WriteAsJsonAsync(new
                {
                    error = "agent_budget_exhausted",
                    message = "Agent has exhausted its action budget for this session",
                    actions_used = agentContext.ActionBudget.Used,
                    budget_reset_at = agentContext.ActionBudget.ResetAt
                });
                return;
            }
            
            // Check rate limit (actions per minute)
            var rateLimitResult = await _rateLimiter.CheckAsync(
                $"agent:{agentContext.AgentId}",
                maxActionsPerMinute: 60);
            
            if (!rateLimitResult.IsAllowed)
            {
                context.Response.StatusCode = 429;
                context.Response.Headers.RetryAfter = rateLimitResult.RetryAfter.ToString();
                return;
            }
        }
        
        await _next(context);
    }
}

Consent and Revocation UI

Users must be able to grant, review, and revoke agent permissions:

@* Agent consent dialog *@
<div class="agent-consent-dialog">
    <h2>@Agent.DisplayName requests access</h2>
    <p>This AI agent wants to act on your behalf with the following capabilities:</p>
    
    <ul class="capability-list">
        @foreach (var capability in RequestedCapabilities)
        {
            <li>
                <input type="checkbox" 
                       checked="@capability.IsDefault" 
                       disabled="@capability.IsRequired"
                       @bind="capability.Granted" />
                <strong>@capability.DisplayName</strong>
                <p class="description">@capability.Description</p>
            </li>
        }
    </ul>
    
    <div class="limits">
        <label>Maximum actions per session:</label>
        <select @bind="MaxActions">
            <option value="10">10 actions</option>
            <option value="50">50 actions</option>
            <option value="100">100 actions</option>
        </select>
        
        <label>Permission expires:</label>
        <select @bind="ExpiresIn">
            <option value="1h">1 hour</option>
            <option value="24h">24 hours</option>
            <option value="7d">7 days</option>
        </select>
    </div>
    
    <button @onclick="GrantConsent">Allow</button>
    <button @onclick="DenyConsent">Deny</button>
</div>

Key Takeaways

• Agent Identity is a first-class concept, distinct from both users and service accounts, with its own lifecycle and audit trail.
• Capability-based scopes provide fine-grained control over exactly what actions an agent can perform.
• Delegation chains provide cryptographic proof of authority from user → agent → action, essential for compliance.
• Action budgets and rate limits prevent runaway agents from consuming excessive resources or performing unintended actions.
• Workload identity separates platform resource access from user-delegated capabilities.

Conclusion

As AI agents become integral to enterprise workflows, security and identity management must evolve to address their unique characteristics. The Agentic Identity Framework provides a principled approach built on proven OAuth 2.0 foundations while adding agent-specific extensions for delegation, capability management, and comprehensive auditing. Organizations deploying production AI agents should implement these patterns now—before autonomous systems become a compliance and security liability. The framework's emphasis on explicit consent, action limits, and cryptographic accountability creates the trust foundation necessary for enterprise-grade agentic AI.

References

• IETF Draft: OAuth 2.0 Agent Delegation Grant
• Azure Workload Identities Documentation
• Anthropic: AI Agent Safety Principles
• OWASP AI Security Project