refactor: remove the unnecessary tool and parameter, implement unit tests

.github/workflows/CI.yaml

@@ -67,6 +67,9 @@ jobs:
       - name: Lint
         run: make lint
 
+      - name: Test
+        run: make test
+
       - name: Build Docker images
         run: make docker
 

CLAUDE.md

@@ -32,7 +32,7 @@ make build-image      # Build Docker image skywalking-mcp:latest
 make clean            # Remove build artifacts
 ```
 
-No unit tests exist yet. CI runs license checks, lint, and docker build.
+Unit tests exist for selected transport/context behavior. CI runs license checks, lint, and docker build.
 
 ## Architecture
 
@@ -41,12 +41,11 @@ No unit tests exist yet. CI runs license checks, lint, and docker build.
 Three MCP transport modes as cobra subcommands: `stdio`, `sse`, `streamable`.
 
 The SkyWalking OAP URL is resolved in priority order:
-- **stdio**: `set_skywalking_url` session tool > `--sw-url` flag > `http://localhost:12800/graphql`
-- **SSE/HTTP**: `SW-URL` HTTP header > `--sw-url` flag > `http://localhost:12800/graphql`
+- **All transports**: `--sw-url` flag > `http://localhost:12800/graphql`
 
-The `set_skywalking_url` tool is only available in stdio mode (single client, well-defined session). SSE and HTTP transports use per-request headers instead.
+SSE and HTTP transports always use the configured server URL.
 
-Basic auth is configured via `--sw-username` / `--sw-password` flags. Both flags (and the `set_skywalking_url` tool) support `${ENV_VAR}` syntax to resolve credentials from environment variables (e.g. `--sw-password ${MY_SECRET}`).
+Basic auth is configured via `--sw-username` / `--sw-password` flags. The startup flags support `${ENV_VAR}` syntax to resolve credentials from environment variables (e.g. `--sw-password ${MY_SECRET}`).
 
 Each transport injects the OAP URL and auth into the request context via `WithSkyWalkingURLAndInsecure()` and `WithSkyWalkingAuth()`. Tools extract them downstream using `skywalking-cli`'s `contextkey.BaseURL{}`, `contextkey.Username{}`, and `contextkey.Password{}`.
 
@@ -99,4 +98,4 @@ Tool handlers should return `(mcp.NewToolResultError(...), nil)` for expected qu
 
 ## CI & Merge Policy
 
-Squash-merge only. PRs to `main` require 1 approval and passing `Required` status check (license + lint + docker build). Go 1.25.
+Squash-merge only. PRs to `main` require 1 approval and passing `Required` status check (license + lint + docker build). Go 1.25.

Makefile

@@ -31,6 +31,8 @@ PLATFORMS ?= linux/amd64
 MULTI_PLATFORMS ?= linux/amd64,linux/arm64
 OUTPUT ?= --load
 IMAGE_TAGS ?= -t $(IMAGE):$(VERSION) -t $(IMAGE):latest
+GO_TEST_FLAGS ?=
+GO_TEST_PKGS ?= ./...
 
 .PHONY: all
 all: build ;
@@ -48,6 +50,14 @@ build: ## Build the binary.
 		-X ${VERSION_PATH}.date=${BUILD_DATE}" \
 		-o bin/swmcp cmd/skywalking-mcp/main.go
 
+.PHONY: test
+test: ## Run unit tests.
+	go test $(GO_TEST_FLAGS) $(GO_TEST_PKGS)
+
+.PHONY: test-cover
+test-cover: ## Run unit tests with coverage output in coverage.txt.
+	go test $(GO_TEST_FLAGS) -coverprofile=coverage.txt $(GO_TEST_PKGS)
+
 $(GO_LINT):
 	@$(GO_LINT) version > /dev/null 2>&1 || go install github.com/golangci/golangci-lint/cmd/golangci-lint@v1.64.0
 $(LICENSE_EYE):
@@ -139,7 +149,7 @@ PUSH_RELEASE_SCRIPTS := ./scripts/push-release.sh
 release-push-candidate:
 	${PUSH_RELEASE_SCRIPTS}
 
-.PHONY: lint fix-lint
+.PHONY: lint fix-lint test test-cover
 .PHONY: license-header fix-license-header dependency-license fix-dependency-license
 .PHONY: release-binary release-source release-sign release-assembly
 .PHONY: release-push-candidate docker-build-multi

README.md

@@ -65,6 +65,11 @@ bin/swmcp stdio --sw-url http://localhost:12800 --sw-username admin --sw-passwor
 bin/swmcp sse --sse-address localhost:8000 --base-path /mcp --sw-url http://localhost:12800
 ```
 
+Transport URL behavior:
+
+- `stdio`, `sse`, and `streamable` all use the configured `--sw-url` value (or the default `http://localhost:12800/graphql`).
+- `sse` and `streamable` ignore request-level URL override headers.
+
 ### Usage with Cursor, Copilot, Claude Code
 
 ```json
@@ -128,7 +133,6 @@ SkyWalking MCP provides the following tools to query and analyze SkyWalking OAP
 
 | Category     | Tool Name                      | Description                                                                                       |
 |--------------|--------------------------------|---------------------------------------------------------------------------------------------------|
-| **Session**  | `set_skywalking_url`           | Set the SkyWalking OAP server URL and optional basic auth credentials for the current session (stdio mode only). Supports `${ENV_VAR}` syntax for credentials. |
 | **Trace**    | `query_traces`                 | Query traces with multi-condition filtering (service, endpoint, state, tags, and time range via start/end/step). Supports `full`, `summary`, and `errors_only` views with performance insights. |
 | **Log**      | `query_logs`                   | Query logs with filters for service, instance, endpoint, trace ID, tags, and time range. Supports cold storage and pagination. |
 | **MQE**      | `execute_mqe_expression`       | Execute MQE (Metrics Query Expression) to query and calculate metrics data. Supports calculations, aggregations, TopN, trend analysis, and multiple result types. |
@@ -176,4 +180,4 @@ SkyWalking MCP provides the following prompts for guided analysis workflows:
 
 [Apache 2.0 License.](/LICENSE)
 
-[mcp]: https://modelcontextprotocol.io/
+[mcp]: https://modelcontextprotocol.io/

internal/swmcp/server.go

@@ -37,18 +37,13 @@ import (
 )
 
 // newMCPServer creates a new MCP server with all tools, resources, and prompts registered.
-// When stdio is true, session management tools (set_skywalking_url) are also registered,
-// since stdio has a single client and session semantics are well-defined.
-func newMCPServer(stdio bool) *server.MCPServer {
+func newMCPServer() *server.MCPServer {
 	s := server.NewMCPServer(
 		"skywalking-mcp", "0.1.0",
 		server.WithResourceCapabilities(true, true),
 		server.WithPromptCapabilities(true),
 		server.WithLogging(),
 	)
-	if stdio {
-		AddSessionTools(s)
-	}
 	tools.AddTraceTools(s)
 	tools.AddLogTools(s)
 	tools.AddMQETools(s)
@@ -131,63 +126,31 @@ func withConfiguredAuth(ctx context.Context) context.Context {
 	return ctx
 }
 
-// urlFromHeaders extracts URL for a request.
-// URL is sourced from Header > configured value > Default.
-func urlFromHeaders(req *http.Request) string {
-	urlStr := req.Header.Get("SW-URL")
-	if urlStr == "" {
-		return configuredSkyWalkingURL()
-	}
-
-	return tools.FinalizeURL(urlStr)
-}
-
-// applySessionOverrides checks for a session in the context and applies any
-// URL or auth overrides that were set via the set_skywalking_url tool.
-func applySessionOverrides(ctx context.Context) context.Context {
-	session := SessionFromContext(ctx)
-	if session == nil {
-		return ctx
-	}
-	if url := session.URL(); url != "" {
-		ctx = context.WithValue(ctx, contextkey.BaseURL{}, url)
-	}
-	if username := session.Username(); username != "" {
-		ctx = WithSkyWalkingAuth(ctx, username, session.Password())
-	}
-	return ctx
-}
-
 // EnhanceStdioContextFunc returns a StdioContextFunc that enriches the context
-// with SkyWalking settings from the global configuration and a per-session store.
+// with SkyWalking settings from the global configuration.
 func EnhanceStdioContextFunc() server.StdioContextFunc {
-	session := &Session{}
 	return func(ctx context.Context) context.Context {
-		ctx = WithSession(ctx, session)
 		ctx = WithSkyWalkingURLAndInsecure(ctx, configuredSkyWalkingURL(), false)
 		ctx = withConfiguredAuth(ctx)
-		ctx = applySessionOverrides(ctx)
 		return ctx
 	}
 }
 
 // EnhanceSSEContextFunc returns a SSEContextFunc that enriches the context
-// with SkyWalking settings from SSE request headers and CLI-configured auth.
+// with SkyWalking settings from the CLI configuration and configured auth.
 func EnhanceSSEContextFunc() server.SSEContextFunc {
-	return func(ctx context.Context, req *http.Request) context.Context {
-		urlStr := urlFromHeaders(req)
-		ctx = WithSkyWalkingURLAndInsecure(ctx, urlStr, false)
+	return func(ctx context.Context, _ *http.Request) context.Context {
+		ctx = WithSkyWalkingURLAndInsecure(ctx, configuredSkyWalkingURL(), false)
 		ctx = withConfiguredAuth(ctx)
 		return ctx
 	}
 }
 
 // EnhanceHTTPContextFunc returns a HTTPContextFunc that enriches the context
-// with SkyWalking settings from HTTP request headers and CLI-configured auth.
+// with SkyWalking settings from the CLI configuration and configured auth.
 func EnhanceHTTPContextFunc() server.HTTPContextFunc {
-	return func(ctx context.Context, req *http.Request) context.Context {
-		urlStr := urlFromHeaders(req)
-		ctx = WithSkyWalkingURLAndInsecure(ctx, urlStr, false)
+	return func(ctx context.Context, _ *http.Request) context.Context {
+		ctx = WithSkyWalkingURLAndInsecure(ctx, configuredSkyWalkingURL(), false)
 		ctx = withConfiguredAuth(ctx)
 		return ctx
 	}