langfuse Seed Test Data
One-shot deterministic test data for local Langfuse. The CLI handles env loading, preflight checks, ClickHouse/Postgres writes, readback verification, and prints UI deep links plus a machine-readable JSON summary (last stdout line).
If anything fails, run doctor first
pnpm run seed -- doctor
Prints PASS/WARN/FAIL per dependency (Postgres, migrations, project, ClickHouse, v4 dev tables, Redis, MinIO, web app) with the exact fix command for every failure. Do not debug Docker/ClickHouse manually before running this.
Need → command
| I need... | Command |
|---|---|
| A very complex observation tree (v3) | pnpm run seed -- trace-tree --observations 5000 --depth 12 --breadth 500 |
| The same tree readable in the v4 events UI | add --v4 (writes events_full; events_core fills via MV) |
| Async parents whose subtree outlives their own span (subtree wall-clock duration badge) | add --async-parents to trace-tree (root + hub end immediately while children keep running) |
| A realistic agent flow over a timeline (graph view + scrubbable timeline) | pnpm run seed -- agent-timeline --turns 6 --v4 (LangGraph refine loop planner→retriever→generator→critic→loop, staggered in time; add --timing-only for the pure timing fallback) |
| A trace that is large as a GRAPH (many distinct node names + connections, the trace-graph layout stress) | pnpm run seed -- agent-graph --v4 (~1,350 distinct connections from 350 observations; --nodes 120 --steps 100 --parallel 8 crosses the layout ceiling, --nodes 80 --steps 30 --parallel 4 is small-but-dense) |
| A dozen SMALL traces, each a different timeline shape (the everyday case, not a stress test) | pnpm run seed -- timeline-shapes --v4 (12 hand-timed traces of 4-25 observations: rag answer, streamed chat with a TTFT split, 8-way fan-out, retry backoff with widening gaps, a 13-minute wait on a human, one slow tool dwarfing everything, an error cascade with failover, in-flight spans with no end time, zero-duration checkpoints, a ten-level ladder, 24 flat siblings, a three-turn agent loop with think time; --shape <slug> for one) |
| A row carrying every annotation at once, to judge whether the timeline is overloaded | pnpm run seed -- timeline-annotated --v4 (ONE trace, 12 observations: one/two/four scores — the last collapsing into +1 — one and twelve comments, a streaming first-token mark, costs and durations spread so the heat map paints some rows, plain rows beside them for contrast, and all three label placements on screen together) |
| A multi-HOUR agent run (wall clock dominated by waiting, as production ones are) | pnpm run seed -- agent-timeline --turns 120 --turn-gap-ms 60000 --v4 (~2.5h; the gap is jittered up to 2x, so the work lands at a few percent of the trace instead of packing every span into a few seconds) |
| A demo-grade, real-looking agent trace (videos, screenshots, docs) | pnpm run seed -- support-agent --v4 --id-prefix <hex> (one fixed, fully handcrafted support-copilot refund run: guardrails, parallel context fan-out, 3-turn ReAct loop with real payloads/costs; deterministic — reseed with a FRESH prefix for a clean take; the prefix is the trace id, so a hex prefix reads like production) |
| A plain trace with no agentic types (collapsed-by-default graph panel) | add --plain to trace-tree (SPAN/GENERATION/EVENT only) |
A trace with MORE observations than the detail view loads (v4 caps the tree at 10k, startTime ASC — the chronological tail is missing) |
pnpm run seed -- trace-tree --observations 12000 --stride-ms 10 --v4 (--stride-ms starts each observation index × N ms in, so start times are unique and strictly increasing: observation index < 10000 loads, -obs-10000 and up fall past the cap. Without it thousands of rows share one millisecond and the boundary is arbitrary. Re-runs that CHANGE timing flags need a fresh --id-prefix: start_time is an events ORDER BY key, so both versions persist in the same trace) |
| An extremely DEEP single-chain trace (tree depth = observation count; layout stress) | pnpm run seed -- deep-chain --v4 (1401 sequential generations, each the sole child of the previous — the mis-parented-instrumentation shape from LFE-10959 that collapses tree/timeline layouts; --observations N to change depth) |
| A super tough session (v3 legacy session view) | pnpm run seed -- long-session --traces 300 --observations-per-trace 8 |
| Diverse v4 session shapes (chat / coding-agent / mixed / media) for the session-detail view | pnpm run seed -- session-shapes --shape all (the agent shape has I/O on AGENT/TOOL with no GENERATION — pre-LFE-10520 the "first generation" default rendered empty cards for it; the current "All observations with I/O" default renders it correctly; v4 on by default) |
| Many sessions for the sessions TABLE and its filters / search bar (not the detail view) | pnpm run seed -- session-variety --sessions 120 --days 14 (searchable topic ids, 1-3 userIds and 1-3 tags per session, four environments, session metadata tier/region/channel/topic, numeric + categorical + boolean session scores, comments on a quarter; v4 on by default. Widen the time-range picker past the default 1 day.) |
| Session messages carrying Langfuse media references (inline image, several refs in one message, bare refs in a content array, link-only payload) | pnpm run seed -- session-shapes --shape media — uploads the image/audio/pdf fixtures to MinIO and links them to the observation, so the inline chip and the "Media" strip both resolve (LFE-14815, LFE-9577) |
| Many traces for list/filter performance | pnpm run seed -- many-traces --count 100000 --days 14 |
| Long-window v4 traffic with cost/latency/token OUTLIERS (outlier chart strip, LFE-14451) | pnpm run seed -- outlier-traffic --days 90 (diurnal base load + deterministic spikes + hour-long ×8-latency incidents; root AGENT + GENERATION carrying cost + TOOL per trace; v4 on by default) |
| Scores with spaces in the name (filter/grammar testing) | pnpm run seed -- scored-traces --traces 24 --v4 |
| Custom model definitions reachable from a trace (price editor entry points) | pnpm run seed -- custom-models --v4 (a tiered model with a condition-gated second tier and one usage type priced at 0, a single-tier model, and a generation whose model matches no definition so its badge opens the create dialog) |
| Many project-owned evaluators for gallery infinite-scroll testing | NEXTAUTH_URL=https://pr-<N>.preview.langfuse.com pnpm run seed -- evaluator-gallery --count 200 (uses the default synthetic seed API key and reconciles deterministic evaluator names; also works against local seeded environments when NEXTAUTH_URL is omitted) |
| Lots of scores on every node (dense score badges, tree-row overflow testing) | add --scores-per-node 12 to trace-tree (N distinct scores per observation; try --depth 2 --breadth 44 for many tall sibling rows) |
| Extra trace tags, incl. mixed case/accents (tag filter ordering) | add --tags "Zebra,apple,Ärger" to trace-tree (comma-separated, appended to the scenario's own tags) |
| Varied human-annotation queues (annotate UI / keyboard testing) | pnpm run seed -- annotation-queue --core-items 12 (creates a "core types" queue covering every score-field render path + an "edge cases" queue with archived/stale/partial scores and observation/session/deleted/completed items) |
| Huge/malformed/unicode payloads | pnpm run seed -- trace-tree --payload-bytes 1000000 --payload-style malformed (styles: json, text, malformed, unicode, bignum, base64) |
| Big integers beyond 2^53-1 (number-precision testing) | pnpm run seed -- trace-tree --observations 1 --payload-style bignum |
| Huge base64 data-URI in ChatML IO (multimodal crash shape, LFE-10152) | pnpm run seed -- trace-tree --observations 30 --payload-bytes 20000000 --payload-style base64 --v4 (one unbroken multi-MB base64 token in trace + root-observation IO; max 50 MB) |
| See all scenarios and flags | pnpm run seed -- list --json |
| Predict without writing | add --dry-run |
Contract
- Last stdout line is a JSON summary:
traceIds,sessionIds,counts,verified(ClickHouse readback),links(UI deep links). Use--jsonto suppress progress logs. Non-zero exit = data did not land; the error includes afix:line. - Deterministic: same
--seed(default 42) and flags → same ids (ids never contain dates), with timestamps anchored to the current UTC day. Re-running within the same day overwrites in place; a later-day re-run updates the same ids with re-anchored timestamps (the previous day's rows persist under their old dates until then). Independent copies come only from--id-prefix. - Default project is the seeded
7a88fb47-b4e2-43b8-a06c-a5ce950dc53a(logindemo@langfuse.com/password); override with--project. - Open the printed
linksin the browser to verify visually. The v4 events-backed UI is the per-user "Fast (Preview)" sidebar toggle, orLANGFUSE_MIGRATION_V4_WRITE_MODE=events_onlyserver-side.
Extending
Add a scenario in packages/shared/scripts/seeder/scenarios/: a plain
function using the deterministic Rng (never Math.random), register it in
scenarios/index.ts, and update the table in
packages/shared/scripts/seeder/AGENTS.md and this skill. Scenario names,
flags, and JSON keys are additive-only contracts. Design rationale:
packages/shared/scripts/seeder/README.md.