Dash0 Agent Plugin

Claude Code plugin that captures all agent activity and logs hook events to a newline-delimited JSON file for observability.

Installation

# Add the Dash0 marketplace
/plugin marketplace add dash0hq/claude-marketplace

# Install the plugin
/plugin install dash0-agent-plugin@dash0

Local development

# Test locally without marketplace
claude --plugin-dir /path/to/dash0-agent-plugin

# Build the binary locally (instead of downloading from GitHub Releases)
go build -o ~/.claude/plugins/data/dash0-agent-plugin-inline/bin/on-event-0.1.0-$(uname -s | tr '[:upper:]' '[:lower:]')-$(uname -m | sed 's/x86_64/amd64/') ./cmd/on-event/

What it does

The plugin registers a hook for every supported Claude Code event. Each event's payload is written as a single JSON line (with a timestamp field added) to:

~/.claude/plugins/data/dash0-agent-plugin/events.jsonl

Hooked events

Category	Events
Session	SessionStart, SessionEnd
Turn	UserPromptSubmit, Stop, StopFailure
Tool	PreToolUse, PostToolUse, PostToolUseFailure
Permission	PermissionRequest, PermissionDenied
Subagent	SubagentStart, SubagentStop
Task	TaskCreated, TaskCompleted, TeammateIdle
Config	ConfigChange, CwdChanged, FileChanged, InstructionsLoaded
Compaction	PreCompact, PostCompact
Worktree	WorktreeCreate, WorktreeRemove
Elicitation	Elicitation, ElicitationResult
Notification	Notification

Configuration

Create .claude/dash0-agent-plugin.local.md in your project root:

---
enabled: true
otlp_url: "https://ingress.us1.dash0.com"
auth_token: "your-dash0-auth-token"
dataset: "your-dataset"
agent_name: "my-coding-agent"
---

Setting	Description	Required
enabled	Enable or disable the plugin for this project (true/false)	No (defaults to true)
otlp_url	Dash0 OTLP endpoint URL	Yes
auth_token	Dash0 authentication token	Yes
dataset	Dash0 dataset to send data to	No
agent_name	Name for this agent, used as service.name and gen_ai.agent.name resource attributes	No (defaults to claude-code)

Environment variables

These can also be set as environment variables instead of (or in addition to) the configuration file:

Variable	Description
DASH0_OTLP_URL	Dash0 OTLP endpoint URL — must include scheme (e.g. https://ingress.us1.dash0.com)
DASH0_AUTH_TOKEN	Dash0 authentication token
DASH0_DATASET	Dash0 dataset
DASH0_AGENT_NAME	Agent name
DASH0_OMIT_USER_INFO	Omit user.name and user.email from telemetry (true/false)
DASH0_OMIT_IO	Omit tool inputs/outputs and prompt content (true/false)
DASH0_DEBUG	Print OTel payloads to stderr for local debugging (true/false)
DASH0_DEBUG_FILE	Also write debug output to this file path (e.g. /tmp/dash0-debug.log)

Debug mode

Set DASH0_DEBUG=true to print all OTel payloads to stderr. Works with or without an OTLP endpoint configured — useful for verifying what telemetry the plugin produces.

DASH0_DEBUG=true claude --debug --plugin-dir /path/to/dash0-agent-plugin

To write debug output to a file (useful for tailing in a separate terminal without --debug):

DASH0_DEBUG=true DASH0_DEBUG_FILE=/tmp/dash0-debug.log claude --plugin-dir /path/to/dash0-agent-plugin

# In another terminal:
tail -f /tmp/dash0-debug.log

Output is prefixed with [dash0:trace] or [dash0:log] for filtering:

[dash0:trace] {"resourceSpans":[...]}
[dash0:log]   {"resourceLogs":[...]}

Troubleshooting

If telemetry isn't arriving in Dash0, run Claude Code with --debug to see plugin error messages:

DASH0_OTLP_URL="https://ingress.us1.dash0.com:4318" \
  DASH0_AUTH_TOKEN="your-token" \
  claude --debug --plugin-dir /path/to/dash0-agent-plugin 2>&1 | grep "on-event:"

Plugin errors are prefixed with on-event: in the output.

Releasing

Releases are automated with GoReleaser via GitHub Actions. To create a new release:

git tag v0.1.0
git push --tags

This triggers the release workflow which cross-compiles binaries for darwin/linux × amd64/arm64 and publishes them to GitHub Releases. The on-event.sh script downloads the matching binary on first run.