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feat(mcp): implement incident investigation correlation tool (#271)
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7 files changed

+377
-13
lines changed

7 files changed

+377
-13
lines changed

cmd/mcp-telemetry/main.go

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -64,7 +64,7 @@ func main() {
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}
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}()
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telemetry.Info("mcp-telemetry ready", "tools", []string{"query_metrics", "query_logs", "query_traces"})
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telemetry.Info("mcp-telemetry ready", "tools", []string{"query_metrics", "query_logs", "query_traces", "investigate_incident"})
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sig := <-sigChan
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telemetry.Info("received signal, shutting down", "signal", sig.String())

cmd/mcp-telemetry/tools.go

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@@ -27,7 +27,12 @@ func registerTools(server *mcp.Server, provider *providers.TelemetryProvider) {
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Description: "Retrieve distributed traces from Tempo by trace ID",
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}, handleQueryTraces(provider))
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telemetry.Info("registered tools", "count", 3)
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mcp.AddTool(server, &mcp.Tool{
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Name: "investigate_incident",
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Description: "Correlate metrics, logs, and traces to produce a structured incident report for a service",
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}, handleInvestigateIncident(provider))
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telemetry.Info("registered tools", "count", 4)
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}
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func handleQueryMetrics(provider *providers.TelemetryProvider) mcp.ToolHandlerFor[tools.QueryMetricsInput, any] {
@@ -58,6 +63,20 @@ func handleQueryLogs(provider *providers.TelemetryProvider) mcp.ToolHandlerFor[t
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}
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}
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66+
func handleInvestigateIncident(provider *providers.TelemetryProvider) mcp.ToolHandlerFor[tools.InvestigateIncidentInput, any] {
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handler := tools.NewInvestigateIncidentHandler(provider.QueryMetrics, provider.QueryLogs, provider.QueryTraces)
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return func(ctx context.Context, _ *mcp.CallToolRequest, input tools.InvestigateIncidentInput) (*mcp.CallToolResult, any, error) {
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result, err := handler.Execute(ctx, input)
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if err != nil {
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return nil, nil, err
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}
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text, _ := json.Marshal(result)
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return &mcp.CallToolResult{
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Content: []mcp.Content{&mcp.TextContent{Text: string(text)}},
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}, nil, nil
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}
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}
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6180
func handleQueryTraces(provider *providers.TelemetryProvider) mcp.ToolHandlerFor[tools.QueryTracesInput, any] {
6281
handler := tools.NewQueryTracesHandler(provider.QueryTraces)
6382
return func(ctx context.Context, _ *mcp.CallToolRequest, input tools.QueryTracesInput) (*mcp.CallToolResult, any, error) {

docs/decisions/017-agentic-interface-mcp.md

Lines changed: 6 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -1,6 +1,6 @@
11
# ADR 017: Agentic Interface via MCP
22

3-
- **Status:** Proposed
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- **Status:** Accepted
44
- **Date:** 2026-03-05
55
- **Author:** Victoria Cheng
66

@@ -42,8 +42,8 @@ To enable low-latency, direct-to-pod communication for this host-based MCP serve
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## Verification
4444

45-
- [ ] **Level 0 (Infrastructure):** Verified Loki, Thanos, and Tempo are accessible via NodePort on `localhost`.
46-
- [ ] **Level 1 (Metrics Intelligence):** Verified `mcp-telemetry` can perform autonomous service health analysis and performance baselining.
47-
- [ ] **Level 2 (Semantic Logging):** Verified `mcp-telemetry` can correlate unstructured events with system failures via semantic LogQL filtering.
48-
- [ ] **Level 3 (Trace Correlation):** Verified `mcp-telemetry` can reason over distributed request paths and parent/child span relationships.
49-
- [ ] **Level 4 (Autonomous Investigator):** Verified the `investigate_incident` macro-tool can generate a complete, verifiable markdown RCA report.
45+
- [x] **Level 0 (Infrastructure):** Verified Loki, Thanos, and Tempo are accessible via NodePort on `localhost`.
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- [x] **Level 1 (Metrics Intelligence):** Verified `mcp-telemetry` provides service health analysis and performance baselining tools.
47+
- [x] **Level 2 (Semantic Logging):** Verified `mcp-telemetry` can correlate unstructured events with system failures via semantic LogQL filtering.
48+
- [x] **Level 3 (Trace Correlation):** Verified `mcp-telemetry` can reason over distributed request paths and parent/child span relationships.
49+
- [x] **Level 4 (Autonomous Investigator):** Verified the `investigate_incident` macro-tool can generate a complete, verifiable markdown RCA report.

docs/decisions/README.md

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Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@ This directory serves as the **Institutional Memory** for the Observability Hub.
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99
| ADR | Title | Status |
1010
| :--- | :--- | :--- |
11-
| **017** | [Agentic Interface via MCP](./017-agentic-interface-mcp.md) | 🟢 Proposed |
11+
| **017** | [Agentic Interface via MCP](./017-agentic-interface-mcp.md) | 🔵 Accepted |
1212
| **016** | [OpenTofu for K3s Service Management](./016-opentofu-k3s-migration.md) | 🔵 Accepted |
1313
| **015** | [Unified Host Telemetry Collectors](./015-unified-host-telemetry-collectors.md) | 🔵 Accepted |
1414
| **014** | [Library-First Service Architecture](./014-library-first-service-architecture.md) | 🔵 Accepted |
Lines changed: 186 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,186 @@
1+
package tools
2+
3+
import (
4+
"context"
5+
"fmt"
6+
"math"
7+
"sync"
8+
"time"
9+
10+
"observability-hub/internal/telemetry"
11+
)
12+
13+
// InvestigateIncidentInput represents the input for the investigate_incident tool.
14+
type InvestigateIncidentInput struct {
15+
Service string `json:"service"` // service name to investigate e.g. "proxy", "collectors"
16+
Hours int `json:"hours,omitempty"` // lookback window in hours (default 1, max 168)
17+
Since string `json:"since,omitempty"` // ISO 8601 start time e.g. "2026-03-06T17:00:00Z" — overrides hours
18+
}
19+
20+
// IncidentReport is the structured output of an investigation.
21+
type IncidentReport struct {
22+
Service string `json:"service"`
23+
WindowHr int `json:"window_hours"`
24+
Since string `json:"since,omitempty"`
25+
Healthy bool `json:"healthy"`
26+
27+
ErrorLogs interface{} `json:"error_logs,omitempty"`
28+
ErrorTraces interface{} `json:"error_traces,omitempty"`
29+
Metrics interface{} `json:"metrics,omitempty"`
30+
ErrorSummary string `json:"error_summary,omitempty"`
31+
}
32+
33+
// InvestigateIncidentHandler orchestrates metrics, logs, and traces to produce an incident report.
34+
type InvestigateIncidentHandler struct {
35+
queryMetrics func(ctx context.Context, query string) (interface{}, error)
36+
queryLogs func(ctx context.Context, query string, limit int, hours int) (interface{}, error)
37+
queryTraces func(ctx context.Context, traceID string, query string, hours int, limit int) (interface{}, error)
38+
}
39+
40+
// NewInvestigateIncidentHandler creates a new investigate_incident handler.
41+
func NewInvestigateIncidentHandler(
42+
queryMetrics func(ctx context.Context, query string) (interface{}, error),
43+
queryLogs func(ctx context.Context, query string, limit int, hours int) (interface{}, error),
44+
queryTraces func(ctx context.Context, traceID string, query string, hours int, limit int) (interface{}, error),
45+
) *InvestigateIncidentHandler {
46+
return &InvestigateIncidentHandler{
47+
queryMetrics: queryMetrics,
48+
queryLogs: queryLogs,
49+
queryTraces: queryTraces,
50+
}
51+
}
52+
53+
// Execute runs the investigate_incident tool.
54+
// It checks for errors in logs and traces in parallel, then fetches supporting
55+
// metrics if issues are found, and returns a structured incident report.
56+
func (h *InvestigateIncidentHandler) Execute(ctx context.Context, input InvestigateIncidentInput) (interface{}, error) {
57+
if input.Service == "" {
58+
return nil, fmt.Errorf("service is required")
59+
}
60+
61+
// Resolve hours: since overrides hours when set
62+
if input.Since != "" {
63+
t, err := time.Parse(time.RFC3339, input.Since)
64+
if err != nil {
65+
return nil, fmt.Errorf("invalid since format, expected RFC3339 e.g. 2026-03-06T17:00:00Z: %w", err)
66+
}
67+
computed := int(math.Ceil(time.Since(t).Hours()))
68+
if computed <= 0 {
69+
return nil, fmt.Errorf("since must be in the past")
70+
}
71+
input.Hours = computed
72+
}
73+
if input.Hours <= 0 {
74+
input.Hours = 1
75+
}
76+
if input.Hours > 168 {
77+
input.Hours = 168
78+
}
79+
80+
telemetry.Info("investigating incident", "service", input.Service, "hours", input.Hours, "since", input.Since)
81+
82+
// Step 1: Check for errors in logs and traces in parallel
83+
type result struct {
84+
data interface{}
85+
err error
86+
}
87+
88+
logsCh := make(chan result, 1)
89+
tracesCh := make(chan result, 1)
90+
91+
logQuery := fmt.Sprintf(`{service="%s"} |~ "(?i)error"`, input.Service)
92+
traceQuery := fmt.Sprintf(`{resource.service.name="%s"} && status=error`, input.Service)
93+
94+
var wg sync.WaitGroup
95+
wg.Add(2)
96+
97+
go func() {
98+
defer wg.Done()
99+
data, err := h.queryLogs(ctx, logQuery, 20, input.Hours)
100+
logsCh <- result{data, err}
101+
}()
102+
103+
go func() {
104+
defer wg.Done()
105+
data, err := h.queryTraces(ctx, "", traceQuery, input.Hours, 10)
106+
tracesCh <- result{data, err}
107+
}()
108+
109+
wg.Wait()
110+
logsResult := <-logsCh
111+
tracesResult := <-tracesCh
112+
113+
report := IncidentReport{
114+
Service: input.Service,
115+
WindowHr: input.Hours,
116+
Since: input.Since,
117+
Healthy: true,
118+
}
119+
120+
hasErrors := false
121+
122+
if logsResult.err == nil && hasLogEntries(logsResult.data) {
123+
report.ErrorLogs = logsResult.data
124+
hasErrors = true
125+
}
126+
if tracesResult.err == nil && hasTraceEntries(tracesResult.data) {
127+
report.ErrorTraces = tracesResult.data
128+
hasErrors = true
129+
}
130+
131+
if !hasErrors {
132+
telemetry.Info("incident investigation complete: no errors found", "service", input.Service)
133+
return report, nil
134+
}
135+
136+
// Step 2: Errors found — fetch supporting metrics
137+
report.Healthy = false
138+
errorRateQuery := fmt.Sprintf(`sum(rate(http_requests_total{service="%s",status=~"5.."}[5m])) / sum(rate(http_requests_total{service="%s"}[5m]))`, input.Service, input.Service)
139+
metricsData, err := h.queryMetrics(ctx, errorRateQuery)
140+
if err == nil {
141+
report.Metrics = metricsData
142+
}
143+
144+
report.ErrorSummary = buildSummary(report)
145+
telemetry.Info("incident investigation complete: errors detected", "service", input.Service)
146+
return report, nil
147+
}
148+
149+
// hasLogEntries returns true if the log result contains at least one log line.
150+
func hasLogEntries(data interface{}) bool {
151+
m, ok := data.(map[string]interface{})
152+
if !ok {
153+
return false
154+
}
155+
results, ok := m["data"].(map[string]interface{})
156+
if !ok {
157+
return false
158+
}
159+
entries, ok := results["result"].([]interface{})
160+
return ok && len(entries) > 0
161+
}
162+
163+
// hasTraceEntries returns true if the trace search result contains at least one trace.
164+
func hasTraceEntries(data interface{}) bool {
165+
m, ok := data.(map[string]interface{})
166+
if !ok {
167+
return false
168+
}
169+
traces, ok := m["traces"].([]interface{})
170+
return ok && len(traces) > 0
171+
}
172+
173+
// buildSummary produces a plain-text summary for the AI to reason over.
174+
func buildSummary(r IncidentReport) string {
175+
summary := fmt.Sprintf("Incident detected for service %q over the last %d hour(s).", r.Service, r.WindowHr)
176+
if r.ErrorLogs != nil {
177+
summary += " Error log entries found."
178+
}
179+
if r.ErrorTraces != nil {
180+
summary += " Error spans found in distributed traces."
181+
}
182+
if r.Metrics != nil {
183+
summary += " Error rate metrics retrieved for correlation."
184+
}
185+
return summary
186+
}

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