Cursor

Cursor generates a lot of signal. Sessions, prompts, tool calls, model switches, compactions, subagents. None of it goes anywhere by default. cursorscope — an open-source collector built by Last9 — fixes that.

cursorscope is a small Node.js service that intercepts Cursor’s hook events and exports them as OpenTelemetry traces, metrics, and logs to Last9. You get full observability into how your team uses Cursor: which models they reach for, how long agent loops run, where tools fail, how token budgets are spent.

It exports three OpenTelemetry signal types:

• Traces — one root span per session, prompt spans as children, tool call spans underneath those, subagent spans branching off when Cursor fans out work
• Metrics — counters and histograms for sessions, prompts, tool executions, lines of code, MCP invocations, and token usage
• Logs — one structured log record per hook event with conversation ID, model, and hook-specific fields

What gets exported

Traces

cursorscope models each Cursor session as a distributed trace. Spans are correlated by cursor.conversation.id and cursor.generation.id so tool calls nest under their parent prompt.

Span events on session spans:

Metrics

Logs

One structured log record per hook event. All records share cursor.conversation.id so you can reconstruct a full session sequence in Last9 Logs.

Key log fields: hook_event_name, cursor.user, cursor.user.email, cursor.repo, gen_ai.request.model, cursor.conversation.id, cursor.generation.id.

Prerequisites

1. Last9 account — Sign up at app.last9.io
2. Cursor IDE — Any version with hook support
3. Node.js 20+ — Required to run the cursorscope ingestor
4. OTLP credentials — Get your endpoint and auth header from Integrations → OpenTelemetry

Setup

1. Get your Last9 OTLP credentials

   Navigate to Integrations → OpenTelemetry in your Last9 dashboard. Copy:

   • OTLP Endpoint (e.g., https://otlp-aps1.last9.io:443)
   • Authorization header (e.g., Basic <base64-token>)

2. Run guided setup

   • Interactive
   • Non-interactive

   npx @last9/cursorscope

   This opens the Last9 OpenTelemetry integration page (or prints the link), then prompts for your endpoint and auth token.

   Setup installs cursorscope to ~/.cursorscope, writes .env with your credentials, registers global Cursor hooks in ~/.cursor/hooks.json, and starts the ingestor.

3. Restart Cursor and send one Agent message

   The ingestor starts in the background automatically on the next Cursor hook event. Logs at ~/.cursor/cursorscope.log.

4. Verify data is arriving

   • Traces — open Traces in Last9, filter by service.name = cursorscope
   • Metrics — open Metrics, search for cursor_prompt_total or gen_ai_client_operation_duration
   • Logs — open Logs, filter by service.name = cursorscope

   Check ingestor health:

   curl http://127.0.0.1:4327/healthz
   # {"ok":true,"service":"cursorscope","version":"..."}

Configuration reference

cursorscope is configured via ~/.cursorscope/.env.

OTLP export

Privacy

Ingestor

Cursor Admin API polling

For Cursor Business accounts — exports team-level daily usage as OTel gauges.

What you can do in Last9

Session traces with nested tool calls

Every agent interaction produces a distributed trace rooted at invoke_agent Cursor. Tool calls appear as child spans with duration and success/failure status. Subagent spans branch off when Cursor fans out work in parallel.

Filter Last9 Traces by service.name = cursorscope and drill into any span to see the full conversation context: model, repo, user, conversation ID.

Token usage and model efficiency (metrics)

gen_ai.client.token.usage is a histogram broken down by token type and model. Compare token counts across models to track efficiency as your team experiments with model selection.

Tool call latency and failure rates (metrics + traces)

cursor_tool_executions_total segmented by tool_name and success shows which tools fail most often. Cross-reference with gen_ai.client.operation.duration to find which tools dominate session time.

MCP server attribution (metrics)

cursor_mcp_invocations_total and cursor_attributed_context_tokens_total reveal which MCP servers are responsible for context token consumption — useful for spotting noisy servers or inefficient tool patterns.

Lines of code output (metrics)

cursor_lines_of_code_total tracks lines added and removed by Cursor agent and Tab edits, broken down by user. Useful for adoption reporting and measuring AI-assisted output.

Session replay via cursor.conversation.id (logs)

Every log record carries cursor.conversation.id. Filter Last9 Logs by a conversation ID to reconstruct the full event sequence for one session:

sessionStart → beforeSubmitPrompt → preToolUse → postToolUse → afterAgentResponse → sessionEnd

Per-user usage breakdowns

All metrics carry cursor_user (the Cursor user email). Group by cursor_user to see per-developer prompt counts, tool usage, and token spend — useful for team leads tracking AI adoption or budget attribution.

Troubleshooting

• No data in Last9 after sending an Agent message

  • Confirm the ingestor is running: curl http://127.0.0.1:4327/healthz
  • Check logs for export errors: tail -50 ~/.cursor/cursorscope.log — look for [otel-export] export failed
  • Probe OTLP connectivity: curl http://127.0.0.1:4327/debug/otlp-probe
  • Verify hooks are registered: ~/.cursor/hooks.json should contain entries calling cursorscope-forward.sh

• Export failing with ENOTFOUND or ETIMEDOUT

  DNS resolution failures happen after VPN toggles or laptop sleep/wake. The ingestor’s DNS resolver doesn’t retry cached failures. Fix: restart the ingestor.

  npx @last9/cursorscope stop
  npx @last9/cursorscope start

• Ingestor restarts on every hook event

  Multiple concurrent hook calls can trigger version-check races in ensure-cursorscope.sh. This is normal during a version upgrade. If it persists, check ~/.cursor/cursorscope.log for restarting (running vX, expected vY) entries and re-run npx @last9/cursorscope setup.

• cursor.user appears as unknown in spans

  cursorscope reads user identity from the user_email field in Cursor’s hook payload. This field is populated when Cursor is signed in. If you see unknown, confirm you are logged into Cursor.

• Metrics appear but traces are missing

  Traces require at least one full session event cycle (sessionStart → sessionEnd or afterAgentResponse). Verify you sent an Agent message (not just opened Cursor). Check ~/.cursor/cursorscope.log for span-related errors.

• 401 / authentication errors

  • Verify header format: Authorization=Basic <token> (no Bearer prefix, no extra quotes)
  • Regenerate the token from Integrations → OpenTelemetry if it has expired

• Metric names in Last9

  Last9 converts OTel metric names to Prometheus format. Examples:

  cursorscope metric	Last9 metric name
  cursor_prompt_total	cursor_prompt_total
  cursor_tool_executions_total	cursor_tool_executions_total
  gen_ai.client.operation.duration	gen_ai_client_operation_duration_seconds
  gen_ai.client.token.usage	gen_ai_client_token_usage_tokens

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