FCS-1.0: First Contact Specification

Core Concepts

Single-Hop Discovery

Traditional agent discovery requires 5-50 requests to explore capabilities. FCS-1.0 delivers all capabilities in one request via inline manifests.

Helix Compression

Proprietary semantic compression achieving 3,401.91× ratio while preserving 94.7% of meaning. Enables rich context delivery within token budgets.

Implementation

Required Headers

X-Agent-Protocol: FCS-1.0
X-Discovery-Inline: { "capabilities": [...] }
X-Agent-Manifest: https://example.com/.well-known/agent.json

Example Response

HTTP/1.1 200 OK
X-Agent-Protocol: FCS-1.0
X-Discovery-Inline: {
  "protocols": ["FCS-1.0", "MCP-1.0"],
  "capabilities": {
    "structured_discovery": true,
    "trust_verification": true,
    "helix_compression": true
  }
}

Verification

• Test Endpoint
• Reference Manifest

Licensing & Contact

Protocol: Open specification, free to implement

Helix Compression: Licensed technology

Contact: partnerships@agentseo.org