streamnative-mcp-server: Instructions file for GitHub Copilot

Copilot instructions

Use the repo's concrete workflow and architecture, not generic Go defaults. The codebase targets Go 1.25.12 from go.mod.

Build, test, and lint

go mod verify
go mod download
go fmt ./...
go mod tidy
golangci-lint run --timeout=3m
go test -race ./...
go test -race ./pkg/mcp/builders/...
go test -v -run TestName ./pkg/...
make build

• CI expects go fmt ./... and go mod tidy to leave no diff behind.
• make build writes bin/snmcp from cmd/streamnative-mcp-server/main.go.
• If you add files or touch license headers, run make license-check and make license-fix.
• If you touch charts/**, cmd/snmcp-e2e/**, or scripts/e2e-test.sh, also run ./scripts/e2e-test.sh all.
• If you change release or packaging flow, also run go generate ./... and goreleaser release --snapshot --clean.

High-level architecture

• cmd/streamnative-mcp-server/main.go defines the snmcp Cobra CLI, adds shared config flags, and attaches the stdio and sse subcommands.
• pkg/cmd/mcp/mcp.go resolves config and selects one runtime mode:
  • --key-file enables StreamNative Cloud mode, defaults to all features, and ensures streamnative-cloud is present if features were set explicitly.
  • --use-external-kafka enables Kafka-only mode, rejects extra feature flags, and infers Kafka admin, client, and schema registry features.
  • --use-external-pulsar enables Pulsar-only mode, rejects extra feature flags, and infers all-pulsar.
• pkg/cmd/mcp/server.go is the server bootstrap and tool-registration hub. It creates backend sessions and wires every Kafka, Pulsar, and StreamNative tool family into one MCP server.
• pkg/mcp/server.go is the thin wrapper around mark3labs/mcp-go; it applies default resource capabilities, recovery, and logging.
• Request-scoped sessions are passed through pkg/mcp/internal/context/ctx.go. Tool handlers are expected to retrieve Kafka, Pulsar, and StreamNative Cloud sessions from there.
• pkg/mcp/*_tools.go files are mostly registration wrappers. The actual Kafka and Pulsar tool schemas and handler logic belong in pkg/mcp/builders/{kafka,pulsar}.
• StreamNative Cloud context, resource, and log tools still register from pkg/mcp/streamnative_*_tools.go; pkg/mcp/builders/streamnative/ is not the primary implementation path today.
• pkg/cmd/mcp/sse.go owns SSE transport, auth middleware, and health endpoints at <httpPath>/sse, <httpPath>/message, <httpPath>/healthz, and <httpPath>/readyz.
• Multi-session Pulsar exists only in SSE plus external Pulsar mode. pkg/mcp/session/ caches per-token sessions, and requests must send Authorization: Bearer <token>.
• pkg/mcp/pftools/ plus pkg/mcp/pulsar_functions_as_tools.go dynamically expose deployed Pulsar Functions as MCP tools, so changes there alter the runtime tool surface.
• docs/tools/ content is surfaced to MCP clients at runtime, so docs changes can be behavior-visible.