Setting the file. One moment.
Chapter 33 · Exploring LLM Costs
Subchapter 33.5
references/materializing.mdMarkdown2 KBView on GitHub
After ad-hoc queries answer the question, persist them as insights, bundle into a dashboard, or wire up alerts.
posthog:insight-create
{
"name": "Daily LLM cost",
"query": {
"kind": "TrendsQuery",
"dateRange": {"date_from": "-30d"},
"series": [
{
"kind": "EventsNode",
"event": "$ai_generation",
"math": "sum",
"math_property": "$ai_total_cost_usd"
},
{
"kind": "EventsNode",
"event": "$ai_embedding",
"math": "sum",
"math_property": "$ai_total_cost_usd"
}
],
"trendsFilter": {
"formula": "A + B",
"aggregationAxisPrefix": "$",
"decimalPlaces": 2
}
}
}Both series are required — omitting $ai_embedding silently drops embedding
spend. If the project demonstrably does not use embeddings (count() of
$ai_embedding is zero over the relevant window), you can drop series B and
the formula for a simpler insight.
For “cost per user”, add a third series with math: "dau" and change the
formula to (A + B) / C. For breakdowns, add breakdownFilter with
breakdown: "$ai_model" or any other dimension.
After saving the insights, use posthog:dashboard-create (or -update) to
bundle them. The default /ai-observability/dashboard already includes Cost,
Cost per user, and Cost by model tiles — mirror that structure when building
a custom one.
posthog:alert-create
{
"insight": <insight_id>,
"name": "Daily LLM cost over $100",
"subscribed_users": [<user_id>],
"threshold": {
"configuration": {
"bounds": {"upper": 100},
"type": "absolute"
}
},
"condition": {"type": "absolute_value"},
"config": {"series_index": 0},
"enabled": true
}The insight must be a single-value trends query (e.g. bold-number daily cost).
subscribed_users is required and must contain at least one user id from the
same team. threshold.configuration.type is "absolute" or "percentage";
condition.type is "absolute_value", "relative_increase", or
"relative_decrease". If the MCP tool rejects the payload, run
posthog:docs-search for “alerts” to pull the current schema — the
accepted enum values can change with the alerting API.