Use Cases

This chapter stays close to current product use, not roadmap integrations.

1. Secure A Local MCP Tool Server

Use this when: Claude Desktop, Codex, or another MCP client is calling tools that should not run on blind trust.

Recommended JACS path:

What JACS adds:

  • Signed JSON-RPC messages
  • Fail-closed verification by default
  • Agent identity and auditability for tool calls

2. Add Provenance To LangChain Or LangGraph

Use this when: your model already runs inside LangChain or LangGraph and you want signed tool outputs without introducing MCP.

Recommended JACS path:

What JACS adds:

  • Signed tool results
  • Optional strict mode at the adapter boundary
  • Minimal changes to existing framework code

3. Exchange Signed Artifacts Across Organizations

Use this when: one agent produces work that another organization, service, or team must verify before acting on it.

Recommended JACS path:

What JACS adds:

  • Agent Cards with JACS provenance metadata
  • Signed A2A artifacts
  • Trust policies for admission control

4. Sign HTTP Or API Boundaries Without MCP

Use this when: the boundary is an API route, not an MCP transport.

Recommended JACS path:

What JACS adds:

  • Signed JSON responses
  • Verified inbound requests
  • A clean upgrade path to A2A discovery on the same app boundary

5. Run Multi-Agent Approval Workflows

Use this when: multiple agents must sign off on the same document, deployment, or decision.

Recommended JACS path:

What JACS adds:

  • M-of-N quorum
  • Timeout and algorithm constraints
  • Verifiable signature chain across signers

6. Keep Signed Files Or JSON As Durable Artifacts

Use this when: you need an artifact to stay verifiable after it leaves the process that created it.

Recommended JACS path:

What JACS adds:

  • Self-contained signed envelopes
  • Re-verification at read time
  • Cross-language interoperability

7. Publish Public Identity Without A Central Auth Service

Use this when: external systems need to verify your agent identity but you do not want a shared auth server in the middle.

Recommended JACS path:

What JACS adds:

  • Public key fingerprint anchoring
  • DNS-based verification flows
  • Local private-key custody