WIP note: The goal is to track coding model interactions so I can annotate good vs bad ones and use that data to improve coding CLIs and models over time; I’m using Vector as a local OTLP sink for CLI tools. I plan to add more configurability for other tools and explore the data format in a bit. There are existing tools for this (e.g., https://langfuse.com, https://phoenix.arize.com), but I want a lightweight, single-tool setup that captures all traces and stores them as compressed JSONL for later analysis instead of standing up a larger stack.

Install Vector

• Follow the Vector docs for your OS.
• macOS (Homebrew):

  brew tap vectordotdev/brew && brew install vector
  

• Debian/Ubuntu:

  bash -c "$(curl -L https://setup.vector.dev)"
  sudo apt-get install vector
  

Vector config

Save a config like this (e.g. config.yaml):

sources:
  otlp:
    type: opentelemetry
    grpc:
      address: 0.0.0.0:4317
    http:
      address: 0.0.0.0:4318

sinks:
  file:
    type: file
    inputs: [otlp.logs, otlp.traces, otlp.metrics]
    path: ./vector-%Y-%m-%d.jsonl.zstd
    compression: zstd
    encoding:
      codec: json
    framing:
      method: newline_delimited

Run locally

• Be mindful of the bind IP. Don’t use 0.0.0.0 on a public server.
• Adjust the output path to a location you want to keep long-term.
• Run locally with:

  vector -c ./config.yaml
  

Explore logs

• Install zstd tools for zstdcat:

  brew install zstd
  

Codex CLI

Add this to ~/.codex/config.toml:

[otel]
log_user_prompt=true
exporter = { otlp-grpc = { endpoint = "http://localhost:4317/", headers = { "x-otlp-meta" = "codex-cli" } }}

Claude Code

Set environment variables:

export CLAUDE_CODE_ENABLE_TELEMETRY=1
export OTEL_METRICS_EXPORTER=otlp
export OTEL_LOGS_EXPORTER=otlp
export OTEL_EXPORTER_OTLP_PROTOCOL=grpc
export OTEL_EXPORTER_OTLP_ENDPOINT=http://localhost:4317
export OTEL_EXPORTER_OTLP_HEADERS=".." # if necessary
export OTEL_METRIC_EXPORT_INTERVAL=10000
export OTEL_LOGS_EXPORT_INTERVAL=5000

Docs

• Vector quickstart: https://vector.dev/docs/setup/quickstart/
• Codex CLI config: https://developers.openai.com/codex/config-reference/
• Codex CLI observability: https://developers.openai.com/codex/config-advanced#observability-and-telemetry
• Claude Code monitoring: https://code.claude.com/docs/en/monitoring-usage