Merge branch 'main' into feature/es-datastream-support

Author: SoumyaRaikwar

.gitignore

@@ -25,6 +25,8 @@ cmd/agent/agent
 cmd/agent/agent-*
 cmd/anonymizer/anonymizer
 cmd/anonymizer/anonymizer-*
+cmd/jaeger/jaeger
+cmd/jaeger/jaeger-*
 cmd/jaeger/internal/integration/results
 cmd/remote-storage/remote-storage
 cmd/remote-storage/remote-storage-*

CONTRIBUTING.md

@@ -72,19 +72,13 @@ We are currently using `gofumpt`, which is installed automatically by `make inst
 ### Running local build with the UI
 
 ```
-$ make run-all-in-one
+$ go run ./cmd/jaeger --config ./cmd/jaeger/config.yaml
 ```
 
 #### What does this command do?
 
-The `jaeger-ui` submodule, which was added from the Pre-requisites step above, contains
-the source code for the UI assets (requires Node.js 6+).
-
-The assets must be compiled first with `make build-ui`, which runs Node.js build and then
-packages the assets into a Go file that is `.gitignore`-ed.
-
-`make run-all-in-one` essentially runs Jaeger all-in-one by combining both of the above
-steps into a single `make` command.
+The Jaeger binary runs with the default configuration file (config.yaml) that includes 
+the UI configuration via the `jaeger_query` extension. The `jaeger-ui` submodule, which was added from the Pre-requisites step above, contains the source code for the UI assets (requires Node.js 24+). The assets must be compiled first with `make build-ui`, which normally downloads them from the latest UI release, but can also build them from source.
 
 ## Project Structure
 

cmd/jaeger/config.yaml

@@ -1,5 +1,5 @@
 service:
-  extensions: [jaeger_storage, jaeger_query, remote_sampling, healthcheckv2, pprof]
+  extensions: [jaeger_storage, jaeger_query, jaeger_mcp, remote_sampling, healthcheckv2, pprof]
   pipelines:
     traces:
       receivers: [otlp, jaeger, zipkin]
@@ -41,6 +41,12 @@ extensions:
     # Defaults to 0 seconds, which means it's disabled.
     max_clock_skew_adjust: 0s
 
+  jaeger_mcp:
+    # MCP (Model Context Protocol) server for LLM integration
+    # Depends on jaeger_query extension
+    http:
+      endpoint: 0.0.0.0:16687
+
   jaeger_storage:
     backends:
       some_store:

cmd/jaeger/internal/all-in-one.yaml

@@ -1,5 +1,5 @@
 service:
-  extensions: [jaeger_storage, jaeger_query, remote_sampling, healthcheckv2, expvar, zpages]
+  extensions: [jaeger_storage, jaeger_query, jaeger_mcp, remote_sampling, healthcheckv2, expvar, zpages]
   pipelines:
     traces:
       receivers: [otlp, jaeger, zipkin]
@@ -26,6 +26,12 @@ extensions:
     storage:
       traces: some_storage
 
+  jaeger_mcp:
+    # MCP (Model Context Protocol) server for LLM integration
+    # Depends on jaeger_query extension
+    http:
+      endpoint: "${env:JAEGER_LISTEN_HOST:-localhost}:16687"
+
   jaeger_storage:
     backends:
       some_storage:

cmd/jaeger/internal/components.go

@@ -38,6 +38,7 @@ import (
 
 	"github.com/jaegertracing/jaeger/cmd/jaeger/internal/exporters/storageexporter"
 	"github.com/jaegertracing/jaeger/cmd/jaeger/internal/extension/expvar"
+	"github.com/jaegertracing/jaeger/cmd/jaeger/internal/extension/jaegermcp"
 	"github.com/jaegertracing/jaeger/cmd/jaeger/internal/extension/jaegerquery"
 	"github.com/jaegertracing/jaeger/cmd/jaeger/internal/extension/jaegerstorage"
 	"github.com/jaegertracing/jaeger/cmd/jaeger/internal/extension/remotesampling"
@@ -79,6 +80,7 @@ func (b builders) build() (otelcol.Factories, error) {
 		// add-ons
 		basicauthextension.NewFactory(),
 		sigv4authextension.NewFactory(),
+		jaegermcp.NewFactory(),
 		jaegerquery.NewFactory(),
 		jaegerstorage.NewFactory(),
 		remotesampling.NewFactory(),

cmd/jaeger/internal/extension/jaegermcp/README.md

@@ -0,0 +1,59 @@
+# jaeger_mcp
+
+This extension implements a Model Context Protocol (MCP) server for Jaeger, enabling LLM-based assistants to query and analyze distributed traces efficiently.
+
+## Overview
+
+The MCP server provides a structured way for AI agents to interact with Jaeger's trace data using progressive disclosure:
+- **Search** → Find traces matching specific criteria
+- **Map** → Visualize trace structure without loading full attribute data  
+- **Diagnose** → Identify critical execution paths that contributed to latency or errors
+- **Inspect** → Load full details only for specific, suspicious spans
+
+This approach prevents context-window exhaustion in LLMs and enables more efficient trace analysis.
+
+**Note:** The current implementation uses Streamable HTTP transport only. MCP stdio transport is not supported.
+
+## Status
+
+✅ **Phase 1: Foundation (Complete)** - Extension scaffold, lifecycle management, and MCP SDK integration
+
+Future phases will add:
+- Phase 2: Basic MCP tools (search, span details, errors)
+- Phase 3: Advanced tools (topology, critical path)
+- Phase 4: Documentation and observability
+
+See [ADR-002](../../../../docs/adr/002-mcp-server.md) for full design details.
+
+## Configuration
+
+```yaml
+extensions:
+  jaeger_mcp:
+    # HTTP endpoint for MCP protocol (Streamable HTTP transport)
+    http:
+      endpoint: "0.0.0.0:16687"
+    
+    # Server identification for MCP protocol
+    server_name: "jaeger"
+    # server_version will default to the build version
+    
+    # Limits
+    max_span_details_per_request: 20
+    max_search_results: 100
+```
+
+## Dependencies
+
+This extension depends on the [jaeger_query](../jaegerquery/) extension to access trace data. The `jaeger_query` extension must be configured in the service extensions list.
+
+## Development Status
+
+Phase 1 implements:
+- ✅ Extension directory structure
+- ✅ Configuration validation
+- ✅ Factory implementation
+- ✅ Server lifecycle management
+- ✅ MCP SDK integration
+- ✅ Streamable HTTP transport
+- ✅ Basic health tool (placeholder for Phase 2)

cmd/jaeger/internal/extension/jaegermcp/config.go

@@ -0,0 +1,39 @@
+// Copyright (c) 2026 The Jaeger Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package jaegermcp
+
+import (
+	"github.com/asaskevich/govalidator"
+	"go.opentelemetry.io/collector/config/confighttp"
+	"go.opentelemetry.io/collector/confmap/xconfmap"
+)
+
+// Config represents the configuration for the Jaeger MCP server extension.
+type Config struct {
+	// HTTP contains the HTTP server configuration for the MCP protocol endpoint.
+	HTTP confighttp.ServerConfig `mapstructure:"http"`
+
+	// ServerName is the name of the MCP server for protocol identification.
+	ServerName string `mapstructure:"server_name"`
+
+	// ServerVersion is the version of the MCP server.
+	ServerVersion string `mapstructure:"server_version" valid:"required"`
+
+	// MaxSpanDetailsPerRequest limits the number of spans that can be fetched in a single request.
+	MaxSpanDetailsPerRequest int `mapstructure:"max_span_details_per_request" valid:"range(1|100)"`
+
+	// MaxSearchResults limits the number of trace search results.
+	MaxSearchResults int `mapstructure:"max_search_results" valid:"range(1|1000)"`
+}
+
+// Validate checks if the configuration is valid.
+func (cfg *Config) Validate() error {
+	// if cfg.ServerVersion == "" {
+	// 	cfg.ServerVersion = version.Get().GitVersion
+	// }
+	_, err := govalidator.ValidateStruct(cfg)
+	return err
+}
+
+var _ xconfmap.Validator = (*Config)(nil)

cmd/jaeger/internal/extension/jaegermcp/config_test.go

@@ -0,0 +1,57 @@
+// Copyright (c) 2026 The Jaeger Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package jaegermcp
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestValidate(t *testing.T) {
+	tests := []struct {
+		name        string
+		config      *Config
+		expectError bool
+	}{
+		{
+			name: "Valid config with ServerVersion",
+			config: &Config{
+				ServerVersion:            "1.0.0",
+				MaxSpanDetailsPerRequest: 20,
+				MaxSearchResults:         100,
+			},
+			expectError: false,
+		},
+		{
+			name: "Invalid MaxSpanDetailsPerRequest (too high)",
+			config: &Config{
+				ServerVersion:            "1.0.0",
+				MaxSpanDetailsPerRequest: 101,
+				MaxSearchResults:         100,
+			},
+			expectError: true,
+		},
+		{
+			name: "Invalid MaxSearchResults (too high)",
+			config: &Config{
+				ServerVersion:            "1.0.0",
+				MaxSpanDetailsPerRequest: 20,
+				MaxSearchResults:         1001,
+			},
+			expectError: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			err := tt.config.Validate()
+			if tt.expectError {
+				require.Error(t, err)
+			} else {
+				require.NoError(t, err)
+			}
+		})
+	}
+}

cmd/jaeger/internal/extension/jaegermcp/factory.go

@@ -0,0 +1,53 @@
+// Copyright (c) 2026 The Jaeger Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package jaegermcp
+
+import (
+	"context"
+
+	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/config/confighttp"
+	"go.opentelemetry.io/collector/extension"
+
+	"github.com/jaegertracing/jaeger/internal/version"
+	"github.com/jaegertracing/jaeger/ports"
+)
+
+// componentType is the name of this extension in configuration.
+var componentType = component.MustNewType("jaeger_mcp")
+
+// ID is the identifier of this extension.
+var ID = component.NewID(componentType)
+
+// NewFactory creates a factory for the Jaeger MCP extension.
+func NewFactory() extension.Factory {
+	return extension.NewFactory(
+		componentType,
+		createDefaultConfig,
+		createExtension,
+		component.StabilityLevelAlpha,
+	)
+}
+
+// createDefaultConfig creates the default configuration for the extension.
+func createDefaultConfig() component.Config {
+	ver := version.Get().GitVersion
+	if ver == "" {
+		ver = "dev"
+	}
+	return &Config{
+		HTTP: confighttp.ServerConfig{
+			Endpoint: ports.PortToHostPort(ports.MCPHTTP),
+		},
+		ServerName:               "jaeger",
+		ServerVersion:            ver,
+		MaxSpanDetailsPerRequest: 20,
+		MaxSearchResults:         100,
+	}
+}
+
+// createExtension creates the extension based on this config.
+func createExtension(_ context.Context, set extension.Settings, cfg component.Config) (extension.Extension, error) {
+	return newServer(cfg.(*Config), set.TelemetrySettings), nil
+}

cmd/jaeger/internal/extension/jaegermcp/factory_test.go

@@ -0,0 +1,44 @@
+// Copyright (c) 2026 The Jaeger Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package jaegermcp
+
+import (
+	"context"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"go.opentelemetry.io/collector/extension"
+)
+
+func TestNewFactory(t *testing.T) {
+	factory := NewFactory()
+	assert.Equal(t, componentType, factory.Type())
+	assert.Equal(t, factory.CreateDefaultConfig(), createDefaultConfig())
+}
+
+func TestCreateExtension(t *testing.T) {
+	set := extension.Settings{
+		ID: ID,
+	}
+	cfg := createDefaultConfig()
+	ext, err := createExtension(context.Background(), set, cfg)
+
+	require.NoError(t, err)
+	assert.NotNil(t, ext)
+}
+
+func TestCreateDefaultConfig(t *testing.T) {
+	cfg := createDefaultConfig()
+	assert.NotNil(t, cfg)
+
+	mcpCfg, ok := cfg.(*Config)
+	require.True(t, ok)
+
+	assert.Equal(t, ":16687", mcpCfg.HTTP.Endpoint)
+	assert.Equal(t, "jaeger", mcpCfg.ServerName)
+	// server_version will be empty in tests since it's set at build time
+	assert.Equal(t, 20, mcpCfg.MaxSpanDetailsPerRequest)
+	assert.Equal(t, 100, mcpCfg.MaxSearchResults)
+}