How to collect thumbs-up and thumbs-down feedback on LLM answers

// Your chat endpoint: return the trace id with the answer.
app.post('/api/chat', async (req, res) => {
  let traceId = ''
  const answer = await mcpd.withSpan('chat_turn', async (run) => {
    traceId = run.traceId
    return await answerQuestion(req.body.message)
  })
  res.json({ answer, traceId })
})

# Your chat endpoint: return the trace id with the answer.
@app.post("/api/chat")
def chat(body: ChatRequest):
    with mcpd.trace("chat_turn") as run:
        answer = answer_question(body.message)
        return {"answer": answer, "trace_id": run.trace_id}

<div class="feedback" data-trace-id="TRACE_ID_FROM_THE_ANSWER">
  <button type="button" data-vote="up">Helpful</button>
  <button type="button" data-vote="down">Not helpful</button>
</div>

<script>
  document.addEventListener('click', async (e) => {
    const button = e.target.closest('[data-vote]')
    if (!button) return
    const box = button.closest('.feedback')
    await fetch('/api/feedback', {
      method: 'POST',
      headers: { 'content-type': 'application/json' },
      body: JSON.stringify({ traceId: box.dataset.traceId, vote: button.dataset.vote }),
    })
    box.textContent = 'Thanks for the feedback.'
  })
</script>

app.post('/api/feedback', (req, res) => {
  const { traceId, vote, comment } = req.body
  if (vote !== 'up' && vote !== 'down') return res.status(400).end()
  mcpd.feedback({
    kind: 'thumbs',
    value: vote,
    traceId,
    comment,
    authorKind: 'end_user',
    authorId: req.user.id, // hashed by mcpd at ingest, like a user id
  })
  res.status(204).end()
})

from mcpd import FeedbackKind


@app.post("/api/feedback")
def feedback(body: FeedbackRequest, user: User):
    if body.vote not in ("up", "down"):
        raise HTTPException(400)
    mcpd.feedback(
        FeedbackKind.THUMBS,
        body.vote,
        trace_id=body.trace_id,
        comment=body.comment,
        author_kind="end_user",
        author_id=user.id,  # hashed by mcpd at ingest, like a user id
    )

# Needs a write key when the daemon has keys set.
curl -s -X POST http://localhost:4317/v1/api/feedback \
  -H 'content-type: application/json' \
  -H "authorization: Bearer $MCPD_WRITE_KEY" \
  -d "{
    \"feedback_id\": \"\",
    \"trace_id\": \"$TRACE\",
    \"kind\": \"thumbs\",
    \"value\": \"down\",
    \"comment\": \"Named the wrong depot.\",
    \"author_kind\": \"end_user\",
    \"timestamp\": \"$(date -u +%Y-%m-%dT%H:%M:%SZ)\",
    \"correlation\": { \"project\": \"support\" }
  }"

# The thumbs-down votes of the last week, newest first, with the run each one judged.
curl -s --get http://localhost:4317/v1/api/feedback \
  --data-urlencode 'project=support' \
  --data-urlencode 'kind=thumbs' \
  --data-urlencode 'from=-7d' \
  | jq -r '.feedback[] | select(.value == "down") | [.timestamp, .trace_id, .comment] | @tsv'

# Or every run that has any feedback at all.
curl -s "http://localhost:4317/v1/api/traces?project=support&has_feedback=true" \
  | jq -r '.traces[] | [.trace_id, .name, .status] | @tsv'