> For clean Markdown of any page, append .md to the page URL. > For a complete documentation index, see https://www.comet.com/docs/opik/llms.txt. > For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://www.comet.com/docs/opik/_mcp/server. # Observability for Claude Code with Opik > Log Claude Code sessions to Opik with the Opik plugin, or export Claude Code's native OpenTelemetry spans to Opik, and know which one to pick. [Claude Code](https://claude.ai/code) sessions can be logged to Opik in two ways: with the **Opik Claude Code plugin**, which hooks into Claude Code directly and captures every turn, tool call and subagent with full content, or through Claude Code's **native OpenTelemetry export**, which sends spans to Opik's OTLP endpoint. Most teams should start with the plugin. ## Quick start Inside Claude Code: ``` /plugin marketplace add comet-ml/opik-claude-code-plugin /plugin install opik ``` In a terminal, then restart Claude Code: ```bash pip install opik && opik configure ``` Back inside Claude Code: ``` /opik:trace-claude-code start ``` Your next turn appears as a trace in the `claude-code` project in Opik. The rest of this page explains the two options in full, how to route traces to a project or workspace, and how to validate. ## When this guide applies Use this guide if you want to **review Claude Code conversations in Opik**: what developers asked, what the model answered, which tools ran, how subagents nested, and what each turn cost. This guide covers telemetry flowing **from Claude Code to Opik**. For the other direction, letting Claude Code read your traces, score outputs and run evaluations from chat, register the [Opik MCP server](/mcp-server) with it. One command, `uvx opik mcp configure`, installs the server and the Opik skills. The two are independent, and you can use either or both. #### Looking to reduce Claude Code spend rather than review sessions? Opik shows you **what Claude Code did**. If the question is **where the tokens went and how to spend fewer of them**, that is [Cost Intelligence](/cost-intelligence/overview): every Claude Code API call captured on the wire and attributed to system prompt, tool schemas, MCP servers, skills, memory and user input, per user and per repository, with policy controls that typically cut spend by 15% to 30%. Only counts and metadata leave the machine, never content. Claude Code is Cost Intelligence's primary agent, and it runs side by side with the Opik plugin. ## Choose a path | | Opik plugin (recommended) | Native OTel export | | ------------------------------------- | ---------------------------------------------- | ------------------------------------------------------------------------------------- | | **Setup** | Two slash commands in Claude Code | Environment variables before every session | | **Prompt, response and tool content** | Captured by default | Redacted by default; response text needs a beta flag and only in non-interactive runs | | **Subagents** | Nested under the parent Task span | Flat `claude_code.*` spans | | **Project / workspace routing** | `OPIK_CC_PROJECT`, `OPIK_CC_WORKSPACE` | `projectName` and `Comet-Workspace` headers | | **Fleet rollout** | Plugin marketplace, or Claude managed settings | Managed settings can set the env vars | | **Status** | GA | Claude Code tracing is beta | ## Option 1: Opik Claude Code plugin The [opik-claude-code-plugin](https://github.com/comet-ml/opik-claude-code-plugin) turns each conversation turn into an Opik trace. Tool calls, thoughts and responses become spans, and subagent invocations nest under their parent `Task` span. ### Install From inside Claude Code: ``` /plugin marketplace add comet-ml/opik-claude-code-plugin /plugin install opik ``` Restart any running Claude Code session; hooks only load when a session starts. ### Configure the connection ```bash pip install opik opik configure ``` This writes `~/.opik.config` with your Opik URL, API key and workspace. Self-hosted and Enterprise deployments enter their own URL at the prompt. ### Turn tracing on ``` /opik:trace-claude-code start # this project /opik:trace-claude-code start --global # every project on this machine /opik:trace-claude-code status ``` Traces land in the `claude-code` project by default. To route them elsewhere without touching the Opik SDK settings the rest of your code uses: ```bash wordWrap export OPIK_CC_PROJECT="my-project" export OPIK_CC_WORKSPACE="my-workspace" ``` or add `cc_project_name` / `cc_workspace` under `[opik]` in `~/.opik.config`. ### Embed Claude Code in a larger trace If Claude Code runs inside a workflow you already trace with Opik, attach its spans to that trace: ```bash wordWrap export OPIK_CC_PARENT_TRACE_ID="" export OPIK_CC_ROOT_SPAN_ID="" ``` ### What you see in Opik Open the project and pick a trace: the user prompt is the trace input, the assistant's final answer is the output, and each tool call is a span with its input and result. The **Threads** tab groups turns from the same session. Token usage and cost are recorded on each LLM span. ## Option 2: Native OpenTelemetry export Claude Code can emit OTel **metrics**, **events** and, in beta, **trace spans**. Opik ingests the trace spans only. Use this path when you already ship Claude Code telemetry to an OTel collector and want Opik as one more destination, or when you cannot install plugins. Without `CLAUDE_CODE_ENHANCED_TELEMETRY_BETA=1` Claude Code sends only metrics and events, and nothing appears in Opik. Prompt, tool I/O and assistant output are **redacted by default**; the flags in this section un-redact them. Assistant output on spans additionally requires the detailed-tracing beta, which is available for the Claude Agent SDK and non-interactive `claude -p` runs but gated in interactive sessions. If you need full content in interactive sessions, use the plugin. Set these before starting Claude Code (Opik Cloud shown; swap the endpoint for your deployment, see the [Opik OpenTelemetry overview](/integrations/opentelemetry)): ```bash wordWrap # 1. Enable telemetry and trace-span emission export CLAUDE_CODE_ENABLE_TELEMETRY=1 export CLAUDE_CODE_ENHANCED_TELEMETRY_BETA=1 # 2. Export traces to Opik export OTEL_TRACES_EXPORTER=otlp export OTEL_EXPORTER_OTLP_PROTOCOL=http/protobuf export OTEL_EXPORTER_OTLP_ENDPOINT=https://www.comet.com/opik/api/v1/private/otel export OTEL_EXPORTER_OTLP_HEADERS='Authorization=,Comet-Workspace=,projectName=' # 3. Un-redact prompt and tool input/output export OTEL_LOG_USER_PROMPTS=1 export OTEL_LOG_TOOL_DETAILS=1 export OTEL_LOG_TOOL_CONTENT=1 # 4. Assistant output on spans (detailed-tracing beta, non-interactive only) export ENABLE_BETA_TRACING_DETAILED=1 export BETA_TRACING_ENDPOINT=https://www.comet.com/opik/api/v1/private/otel ``` Spans arrive as `claude_code.interaction` (one per prompt) with nested `claude_code.llm_request` and `claude_code.tool` spans. Opik maps their content to trace and span input/output and calculates cost from the model and token attributes. For the full variable reference, endpoint modes and validation steps, see [Claude Agent SDK and Claude Code OpenTelemetry](/integrations/claude-agent-sdk). ## Validation 1. Run a short Claude Code turn that uses a tool, for example "list the files in this directory". 2. Open the target project in Opik (`claude-code` for the plugin, your `projectName` for OTel). 3. Confirm the trace carries content: * **Plugin:** the trace input is your prompt and the trace output is the assistant's answer. * **Native OTel:** the trace is named `claude_code.interaction`, its input is your prompt, and the model's response is on the `claude_code.llm_request` spans (with model, tokens and cost). The trace-level output stays empty on this path. Tool calls appear as `claude_code.tool` spans with their input and result. ## Source references * [opik-claude-code-plugin](https://github.com/comet-ml/opik-claude-code-plugin) * [Claude Code monitoring (official)](https://code.claude.com/docs/en/monitoring-usage) * [Opik OpenTelemetry overview](/integrations/opentelemetry)