Claude code mon

README.md

@@ -9,6 +9,7 @@ _Another attempt of blogging or personal knowledge base_
 
 ## 2026
 
+- 2026-02-24 - [How to Monitor Claude Code with OpenTelemetry](docs/blog/2026/2026-02-24-claude-code-mon.md)
 - 2026-02-18 - [How Node.js Embeds Built-in JS Modules](docs/blog/2026/2026-02-18-nodejs-embed-std-lib.md)
 - 2026-02-16 - [The "Silent Watcher" Regression in MkDocs 1.6.1](docs/blog/2026/2026-02-16-mkdocs-livereload-bug.md)
 - 2026-01-31 - [Git Doesn't Track File Renames (And How It Fakes It)](docs/blog/2026/2026-01-31-git-content-similarity.md)

docs/blog/2025/2025-10-29-claude-code-cli-notes.md

@@ -1,5 +1,5 @@
 # Claude Code CLI Prompts
-<!-- tags: genai -->
+<!-- tags: claude code -->
 
 ![thumbnail](2025-10-29-claude-code-cli-notes/pic0.png)
 

docs/blog/2026/2026-02-24-claude-code-mon.md

@@ -0,0 +1,110 @@
+# How to Monitor Claude Code with OpenTelemetry
+<!-- tags: claude code, otel, grafana, prometheus, observability, monitoring  -->
+
+![thumbnail](2026-02-24-claude-code-mon/pic0.jpg)
+
+**TL;DR**: Claude Code is powerful but you have minimal visibility into costs, token usage, or development patterns. I pre-configured a 5-minute OpenTelemetry monitoring stack (Prometheus + Loki + Grafana) that shows exactly where your money goes and how effective prompt caching really is.
+
+## The Problem
+
+Claude Code gives you no built-in visibility into:
+
+- Which models are eating your budget
+- Whether prompt caching is actually saving you money
+- How many tokens you're burning through daily
+- Development velocity metrics (lines changed, commits, PRs)
+
+## The Solution
+
+I configured an observability stack using industry-standard tools:
+
+![pic1](2026-02-24-claude-code-mon/pic1-arch.png)
+
+**Architecture:**
+
+- **Claude Code** exports telemetry via OpenTelemetry Protocol (OTLP)
+- **OTel Collector** receives metrics and logs, routes them appropriately
+- **Prometheus** stores time-series metrics (costs, tokens, cache rates)
+- **Loki** stores logs (session logs, real-time activity)
+- **Grafana** visualizes everything with pre-built dashboards
+
+All configuration, automation, and dashboards are in the GitHub repo: [halyph/claude-mon](https://github.com/halyph/claude-mon).
+
+## Quick Demo
+
+One command:
+
+```bash
+git clone https://github.com/halyph/claude-mon.git
+cd claude-mon
+./setup.sh
+```
+
+![setup_sh](2026-02-24-claude-code-mon/setup_sh.jpg)
+
+Wait 2 minutes for setup to complete, then open `http://localhost:3000`. Default credentials: `admin/admin`.
+
+## What You Get
+
+### Two Grafana Dashboards
+
+**Metrics Dashboard**
+
+![pic2](2026-02-24-claude-code-mon/pic2_cc_monitoring.png)
+
+16 panels:
+
+- **Cost tracking**: Total spend by model, cost distribution pie chart
+- **Token usage**: Input/output/cache tokens over time
+- **Cache effectiveness**: Hit rate gauge showing cache read/write ratios
+- **Development activity**: Lines changed, commits created, PRs opened
+- **Code edits**: Accept/reject decisions by tool and language
+
+**Logs Dashboard**
+
+![pic3](2026-02-24-claude-code-mon/pic3_cc_logs.png)
+
+Real-time log streaming with:
+
+- Live session activity (refreshes every 5 seconds)
+- Log volume over time
+- Per-session filtering
+- Model-based categorization
+
+**NOTE**: Dashboards are pre-configured templates. Customize as needed.
+
+## Key Metrics Reference
+
+Claude Code exports these metrics (converted to Prometheus format):
+
+| Metric | What It Measures | Why It Matters |
+|--------|-----------------|----------------|
+| `claude_code_cost_usage_total` | Cost in USD by model/session | Budget tracking, model comparison |
+| `claude_code_token_usage_total` | Tokens by type (input/output/cache) | Optimize prompts, track cache effectiveness |
+| `claude_code_active_time_total` | Session duration (user/cli) | Understand usage patterns |
+| `claude_code_lines_of_code_count` | Lines added/removed | Development velocity |
+| `claude_code_commit_count` | Git commits created | Productivity metric |
+| `claude_code_code_edit_tool_decision` | Accept/reject by tool/language | Quality tracking |
+
+All metrics include standard labels: `model`, `session_id`, `terminal_type`, `user_id`, `type`.
+
+## Data Persistence
+
+Docker volumes preserve all historical data:
+
+- `prometheus-data`: Metrics time-series
+- `loki-data`: Log streams
+- `grafana-data`: Dashboards and settings
+
+```bash
+docker-compose down      # Stops services, keeps data
+docker-compose down -v   # Stops services, deletes data
+```
+
+## References
+
+- **GitHub Repo**: [halyph/claude-mon](https://github.com/halyph/claude-mon) - Full setup, configuration, and dashboards
+- **Claude Code Docs**: [Monitoring & Usage](https://code.claude.com/docs/en/monitoring-usage) - Official telemetry documentation
+- [**OpenTelemetry**](https://opentelemetry.io/) - OTLP protocol and collectors
+- [**Prometheus**](https://prometheus.io/) - Time-series metrics database
+- [**Grafana**](https://grafana.com/) - Visualization and dashboards