In-depth architectural comparison of the Opa Mcp Server and Scopeblind Gateway MCP servers. Compare execution transports, security boundaries, tool capabilities, quality scores, and ready-to-paste client installation snippets for Claude, Cursor, Windsurf, and VS Code.
At a Glance & Executive Verdict
Opa Mcp Server
Security · Local stdio
Quality: 55/100 (Good) | Auth: No auth required
Scopeblind Gateway
Security · Local stdio
Quality: 48/100 (Fair) | Auth: No auth required
Verdict Summary: Choose Opa Mcp Server if you need specialized Security tools running via a local process. Choose Scopeblind Gateway if your workspace requires Security integration with local subprocess execution. Both servers can be configured concurrently in your client's mcpServers manifest.
Which MCP Server Should You Choose?
Choose Opa Mcp Server when:
You need dedicated capabilities in the Security domain.
You prefer local stdio subprocess transport architecture.
Your security boundary fits: No auth required (Free / Open Source).
You have access to required keys: OPA_BINARY, REGAL_BINARY, OPA_URL, OPA_MCP_ALLOWED_PATHS.
Open Policy Agent (OPA) and Rego policy toolkit. 32 tools spanning authoring (format, lint, check, deps), evaluation (eval, test, bench, coverage), and OPA REST control (policies, data, decisions, compile). Wraps the OPA CLI and the Regal linter, with AI-assisted helpers for explaining decisions, generating test skeletons, and suggesting fixes.
Security gateway that wraps any MCP server with per-tool policies, approval gates, and optional Ed25519-signed receipts. Shadow mode logs every tool call; enforce mode blocks, rate-limits, or requires approval.
Category & Scope
Tools & Capabilities Breakdown
Opa Mcp Server Tools (52)
rego_format
Format Rego source. Wraps `opa fmt`. Idempotent.
rego_check
Type-check and validate Rego. Wraps `opa check`.
rego_lint
Run Regal across a file or directory. Returns findings grouped by category. **Requires `regal` on `PATH` or `REGAL_BINARY` set.
rego_parse_ast
Parse Rego to AST JSON. Wraps `opa parse`.
rego_inspect
Inspect a bundle or directory: packages, rules, annotations. Wraps `opa inspect`.
rego_capabilities
Ready-to-Paste Client Configurations
Paste either (or both) of these JSON server blocks into your client config file (e.g. claude_desktop_config.json or ~/.cursor/mcp.json).
Opa Mcp Server is categorized under Security and uses a local stdio subprocess. In contrast, Scopeblind Gateway belongs to Security using local stdio subprocess. Select Opa Mcp Server when you need capabilities focused on security and Scopeblind Gateway when you require tools for security.
Return the capabilities (built-ins, future keywords) understood by the bundled OPA.
rego_deps
Static dependency analysis: rule-level data references and cross-package calls.
rego_migrate_v1
Migrate Rego v0 source to v1 syntax. Runs `opa fmt --rego-v1` then validates with `opa check --v1-compatible`. Returns `{ original, migrated, changed, valid, errors }`.
rego_check_schema
Check Rego against a JSON Schema. Validates that every `input.*` field the policy reads exists in the schema using `opa check --schema`. Accepts inline schema or a path to a JSON Schema file on disk.
rego_eval
Evaluate a query against a policy and input. The bread-and-butter tool.
rego_eval_with_explain
Evaluate with `--explain=full` and return a structured trace.
rego_eval_with_profile
Evaluate with `--profile` and return per-rule timing and evaluation counts.
+40 more tools listed on main page
Scopeblind Gateway Tools (6)
Per-tool policy enforcement (block, rate limit, min tier)
Shadow mode logs all tool calls without blocking
Enforce mode applies policies to tool calls
Ed25519-signed receipts for tool call decisions
Offline-verifiable audit bundle export
Local key generation and signing without external accounts