orygn/opa-mcp repository overview

⁠OPA MCP Server

Model Context Protocol (MCP) server for Open Policy Agent (OPA) and the Rego policy language.

Wraps the OPA CLI, the OPA REST API, and the Regal linter behind 49 schema-validated tools so any MCP-compatible client (Claude Desktop, Claude Code, Cursor, VS Code, Zed, Windsurf) can author, evaluate, and debug Rego policies through a structured tool surface instead of free-form CLI text.

• Product page: https://orygn.tech/products/opa-mcp⁠
• OPA Ecosystem: https://www.openpolicyagent.org/ecosystem/entry/opa-mcp⁠
• Source: https://github.com/OrygnsCode/opa-mcp-server⁠
• npm: https://www.npmjs.com/package/@orygn/opa-mcp⁠
• Releases (incl. signed .mcpb bundle): https://github.com/OrygnsCode/opa-mcp-server/releases⁠

⁠Why use this image

This image is multi-arch (linux/amd64, linux/arm64), runs as a non-root user, and bundles pinned versions of opa and regal inside the container. No host install of OPA or Regal is required.

That is the main reason to use this image over npm install -g @orygn/opa-mcp -- you get a reproducible, self-contained runtime with no version-skew risk.

⁠Quick start

docker pull orygn/opa-mcp:latest

docker run --rm -i \
  -v /path/to/your/policies:/policies:ro \
  -e OPA_MCP_ALLOWED_PATHS=/policies \
  orygn/opa-mcp

The container speaks MCP over stdio. Wire it into your client by pointing it at docker run --rm -i ... orygn/opa-mcp as the launch command.

⁠Tags

Versioned tags follow Semantic Versioning. The public surface for SemVer purposes is the set of registered tools, prompts, and resources, their input/output schemas, and the recognized environment variables.

⁠Configuration

All configuration is via environment variables. Every variable is optional.

OPA_BINARY and REGAL_BINARY are not used in this image -- both binaries ship at known paths inside the container.

⁠What's inside

49 tools across six categories:

• Authoring -- rego_format, rego_lint, rego_check, rego_check_schema, rego_parse, rego_deps, rego_inspect, rego_capabilities
• Evaluation -- rego_eval, rego_test, rego_bench, rego_profile, rego_coverage_gaps, rego_compile
• Bundles -- rego_bundle_build, rego_bundle_sign, rego_bundle_verify, rego_bundle_inspect
• OPA REST -- opa_list_policies, opa_get_policy, opa_put_policy, opa_delete_policy, opa_get_data, opa_put_data, opa_patch_data, opa_delete_data, opa_query_decision, opa_compile_query, opa_health, opa_status, opa_config
• Helpers -- rego_explain_decision, rego_describe_policy, rego_generate_test_skeleton, rego_suggest_fix, rego_fix, rego_format_write, rego_security_audit, rego_coverage_gaps, rego_infer_input_schema, rego_policy_diff, rego_verify, mcp_server_info
• Conftest -- conftest_test, conftest_verify, conftest_pull, conftest_push (requires conftest binary -- not bundled; see note above)

Three MCP prompts and three resources (built-in function catalog, Rego style guide, curated pattern library).

Stable error codes (INVALID_REGO, OPA_UNREACHABLE, PATH_NOT_ALLOWED, TIMEOUT, CANCELLED, etc.) and a structured { ok, data | error } envelope on every response.

⁠Security

• Subprocesses run with shell: false and a hard timeout.
• File tools refuse paths outside OPA_MCP_ALLOWED_PATHS.
• OPA_TOKEN is never echoed in tool responses or log output.
• Image is built reproducibly from the committed Dockerfile.

⁠License

MIT © Orygn LLC⁠

@orygn/opa-mcp is an independent project. It is not affiliated with, endorsed by, or sponsored by the Open Policy Agent project, the Cloud Native Computing Foundation, Styra, or Anthropic. "Open Policy Agent" and "Rego" are trademarks of their respective owners. "Model Context Protocol" is a trademark of Anthropic, PBC.