Cost Observability

The worker instruments per-client cost telemetry using Cloudflare Analytics Engine. All events are written to the fourai_cost_metrics dataset.

Billing independence: Cost tracking is separate from client billing. Billing uses credits consumed (messages, automations) only. Cost observability tracks all platform events (AI queries, container activity, R2 ops, cron triggers, WebSocket sessions, action completions, action steps) for internal cost analysis and infrastructure optimization. Billing events are a subset of cost tracking events. See VISION.md.

Setup

The ANALYTICS binding must exist in your Cloudflare account before deploying. It is declared in wrangler.jsonc and maps to the fourai_cost_metrics dataset.

Customer identity is read from the AGENT_TENANT env var (e.g. arua). If unset it defaults to default.

Event Schema

ai-query

Emitted for each AI response received over the WebSocket proxy.

Field	Type	Description
blob1	string	Event type: "ai-query"
blob2	string	Model name (e.g. claude-3-5-sonnet)
blob3	string	Provider (e.g. anthropic)
blob4	string	Customer identifier
blob5	string	Action type
blob6	string	Request ID
blob7	string	Session ID (empty if not set)
double1	number	Input tokens
double2	number	Output tokens
double3	number	Estimated cost in USD
double4	number	1 if cached, 0 otherwise

container-active

Emitted on every ensureGateway() call (≈ every request) with a 10-second index bucket to allow deduplication.

Field	Type	Description
blob1	string	Event type: "container-active"
blob2	string	Customer identifier
blob3	string	Instance type (e.g. standard-1)
blob4	string	Action: start | heartbeat | stop
blob5	string	Gateway process ID
double1	number	Always 1 (count)

r2-operation

Emitted for R2 backup/restore operations.

Field	Type	Description
blob1	string	Event type: "r2-operation"
blob2	string	Customer identifier
blob3	string	Operation type: backup | restore | sync | head | delete
blob4	string	R2 pricing class: ClassA | ClassB
double1	number	Bytes transferred
double2	number	Duration in milliseconds

cron-trigger

Emitted on every scheduled cron invocation.

Field	Type	Description
blob1	string	Event type: "cron-trigger"
blob2	string	Customer identifier
blob3	string	Trigger reason
double1	number	Always 1 (count)
double2	number	1 if container was woken, 0 otherwise

ws-session

Emitted when a WebSocket session closes.

Field	Type	Description
blob1	string	Event type: "ws-session"
blob2	string	Customer identifier
blob3	string	Session ID
double1	number	Session duration in seconds
double2	number	Total messages exchanged

action-completed

Emitted when an agent action completes (message or automation).

Field	Type	Description
blob1	string	Event type: "action-completed"
blob2	string	Customer identifier
blob3	string	Instance ID (empty if not set)
blob4	string	Action type: message | automation
blob5	string	Channel type (e.g. slack, api)
blob6	string	Agent identifier
blob7	string	Status: success | failure
blob8	string	Failure reason (empty on success)
double1	number	Input tokens
double2	number	Output tokens
double3	number	Cost in USD
double4	number	Duration in milliseconds

action-step (v0.3.0)

Emitted for each individual step within an action (AI query, tool call, exec call, etc.).

Field	Type	Description
blob1	string	Event type: "action-step"
blob2	string	Customer identifier
blob3	string	Action ID
blob4	string	Step type: ai_query | tool_call | etc.
blob5	string	Tool name (empty if not a tool step)
blob6	string	Outcome: completed | error | blocked
double1	number	Duration in milliseconds
double2	number	AI cost in USD (0 for non-AI steps)
double3	number	Infrastructure cost in USD
double4	number	Credits consumed (1 if completed step)

SQL Queries

Analytics Engine uses a SQL-like syntax. Replace fourai_cost_metrics with your actual dataset name if it differs.

Per-customer AI spend (last 24 hours)

SELECT
  blob4  AS customer,
  blob2  AS model,
  SUM(double1) AS tokens_in,
  SUM(double2) AS tokens_out,
  SUM(double3) AS cost_usd
FROM fourai_cost_metrics
WHERE blob1 = 'ai-query'
  AND timestamp > NOW() - INTERVAL 1 DAY
GROUP BY customer, model
ORDER BY cost_usd DESC

Container active time per customer

Each heartbeat covers a 10-second bucket. Multiply count by 10 for seconds.

SELECT
  blob2 AS customer,
  blob3 AS instance_type,
  COUNT(*) * 10 AS estimated_active_seconds
FROM fourai_cost_metrics
WHERE blob1 = 'container-active'
  AND blob4 = 'heartbeat'
  AND timestamp > NOW() - INTERVAL 1 DAY
GROUP BY customer, instance_type

Container start events

SELECT
  blob2 AS customer,
  COUNT(*) AS cold_starts
FROM fourai_cost_metrics
WHERE blob1 = 'container-active'
  AND blob4 = 'start'
  AND timestamp > NOW() - INTERVAL 7 DAY
GROUP BY customer
ORDER BY cold_starts DESC

R2 bandwidth per customer

SELECT
  blob2 AS customer,
  blob3 AS op_type,
  SUM(double1) AS bytes_transferred,
  AVG(double2) AS avg_duration_ms,
  COUNT(*) AS op_count
FROM fourai_cost_metrics
WHERE blob1 = 'r2-operation'
  AND timestamp > NOW() - INTERVAL 7 DAY
GROUP BY customer, op_type

Cron wake rate (container sleep efficiency)

A high woke_rate means the container is frequently sleeping between crons — consider lowering SANDBOX_SLEEP_AFTER.

SELECT
  blob2 AS customer,
  COUNT(*) AS total_crons,
  SUM(double2) AS woke_count,
  SUM(double2) / COUNT(*) AS woke_rate
FROM fourai_cost_metrics
WHERE blob1 = 'cron-trigger'
  AND timestamp > NOW() - INTERVAL 7 DAY
GROUP BY customer

WebSocket session duration distribution

SELECT
  blob2 AS customer,
  COUNT(*) AS sessions,
  AVG(double1) AS avg_duration_s,
  MAX(double1) AS max_duration_s,
  AVG(double2) AS avg_messages
FROM fourai_cost_metrics
WHERE blob1 = 'ws-session'
  AND timestamp > NOW() - INTERVAL 7 DAY
GROUP BY customer

Cost Estimation

The GET /api/admin/costs endpoint returns the pricing constants used by estimateContainerCost() and an example GraphQL query for the AI Gateway dashboard.

Container pricing (Cloudflare, as of Jul 2026)

Resource	Rate	Billing model
CPU	$0.00002 / vCPU-second	Active usage × 0.2 utilisation
Memory	$0.0000025 / GiB-second	Provisioned (always billed)
Disk	$0.00000007 / GB-second	Provisioned (always billed)

Instance types

Type	vCPU	Memory	Disk
lite	1/16	0.25 GiB	2 GB
basic	1/4	1 GiB	4 GB
standard-1	1/2	4 GiB	8 GB
standard-2	1	6 GiB	12 GB
standard-3	2	8 GiB	16 GB
standard-4	4	12 GiB	20 GB

The default instance is standard-1. Memory and disk are billed continuously regardless of CPU activity, so the sleep setting (SANDBOX_SLEEP_AFTER) does not reduce memory/disk costs.