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Scoped Agent Capability Token

Pattern type: Core reusable pattern Maturity: Preview extension Key packages: SdJwt.Net.AgentTrust.Core, SdJwt.Net.AgentTrust.Policy, SdJwt.Net.AgentTrust.Mcp

What it does

Scopes each AI agent tool call to a specific tool, action, resource, and time window using an SD-JWT capability token. The token is minted per request and verified before the tool executes.

When to use it

  • AI agents call tools with broad API keys or OAuth tokens
  • Least-privilege enforcement is needed per tool call, not per session
  • Multi-agent delegation requires bounded, auditable capability transfer
  • Audit teams need per-call evidence of what was authorized

How it works

  1. Policy check: When an agent requests a tool call, the policy engine evaluates whether the request should be authorized.
  2. Token minting: If authorized, a scoped capability token (SD-JWT format) is minted with the specific tool, action, resource, and expiry.
  3. Token attachment: The token is attached to the tool call request.
  4. Verification: The tool endpoint verifies the token signature, claims, and expiry before executing.
  5. Audit receipt: The allow/deny decision is recorded with correlation IDs.

Package roles

Package Role
SdJwt.Net.AgentTrust.Core Capability token minting and verification
SdJwt.Net.AgentTrust.Policy Rule-based policy evaluation
SdJwt.Net.AgentTrust.Mcp MCP tool call interception
SdJwt.Net.AgentTrust.AspNetCore Inbound verification middleware
SdJwt.Net.AgentTrust.A2A Agent-to-agent delegation

Application responsibility

Agent framework integration, policy rule definitions, delegation depth limits, orchestration runtime, LLM integration, audit log storage.

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