claw-code/.guardrails/docs/RELEASE_v1.9.1.md

Release v1.9.1 - MCP Server Production Ready

Release Date: 2026-02-07 Branch: mcpserver-impl Tag: v1.9.1

---

Summary

Production-ready MCP Server release with critical fixes for SSE compatibility and PostgreSQL array handling. This release addresses the EOF errors experienced with non-interactive clients and fixes database scanning issues.

---

Critical Fixes

1. SSE Compatibility (mcp-server/internal/mcp/server.go)

Problem: Crush and other non-interactive clients received EOF errors when connecting to the SSE endpoint.

Root Cause:

• Missing explicit WriteHeader() - headers weren't committed immediately
• No initial data sent - clients timed out waiting for first event
• Missing proxy buffering headers
• No CORS support

Solution:

// Set SSE headers with proper configuration
c.Response().Header().Set("Content-Type", "text/event-stream")
c.Response().Header().Set("Cache-Control", "no-cache, no-store, must-revalidate")
c.Response().Header().Set("Connection", "keep-alive")
c.Response().Header().Set("X-Accel-Buffering", "no")  // Disable buffering
c.Response().Header().Set("Access-Control-Allow-Origin", "*")
c.Response().WriteHeader(http.StatusOK)  // Commit headers immediately

// Send immediate ping to confirm connection
fmt.Fprintf(c.Response(), "event: ping\ndata: {}\n\n")
c.Response().Flush()

2. PostgreSQL Array Scanning (mcp-server/internal/models/failure.go)

Problem: sql: Scan error on column index 6, name "affected_files": unsupported Scan

Root Cause: Used pq.StringArray from lib/pq driver, but application uses pgx v5.

Solution:

// Changed from:
AffectedFiles pq.StringArray

// To:
AffectedFiles pgtype.Array[string]

// Added helper functions:
func ToStringSlice(arr pgtype.Array[string]) []string
func ToTextArray(slice []string) pgtype.Array[string]

---

Files Changed

File	Lines	Change
mcp-server/internal/mcp/server.go	+37/-16	SSE compatibility fixes
mcp-server/internal/models/failure.go	+27/-14	PostgreSQL array fix
README.md	+223/-0	Complete documentation
CHANGELOG.md	+19/-0	Release notes

---

Deployment Status

Production Deployment:

✅ Container running on your-server:8092 (MCP) and :8093 (Web UI)
✅ PostgreSQL 16 with initialized schema
✅ Redis 7 for caching
✅ 4 prevention rules active

---

Testing

SSE Endpoint

curl -N http://localhost:8092/mcp/v1/sse

Expected:

event: endpoint
data: /mcp/v1/message?session_id=sess_...

event: ping
data: {}

MCP Initialize

curl -X POST http://localhost:8092/mcp/v1/message \
  -H 'Content-Type: application/json' \
  -d '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2024-11-05","capabilities":{},"clientInfo":{"name":"test","version":"1.0"}}}'

---

Migration from v1.9.0

No migration needed - v1.9.1 is a bugfix release with the same API.

1. Build new image: docker build -t guardrail-mcp:latest -f deploy/Dockerfile .
2. Deploy: podman-compose up -d
3. Test: curl http://localhost:8092/mcp/v1/sse

---

Links

• Release: https://github.com/TheArchitectit/agent-guardrails-template/releases/tag/v1.9.1
• Branch: https://github.com/TheArchitectit/agent-guardrails-template/tree/mcpserver-impl
• Full Docs: README.md

---

Credits

Co-Authored-By: Claude Opus 4.5 noreply@anthropic.com