How do I track and cap LLM token spend per AI agent?

Register each AI agent as its own App in Tyk AI Studio. AI Studio records the prompt tokens, completion tokens, and cost of every LLM call against the App. Set a monthly budget on the App. When the agent reaches the budget, AI Studio refuses its LLM requests with HTTP 403. AI Studio also alerts the App owner at 80% and 100%.

Item	Detail
Applies to	LLM traffic through Tyk AI Studio and its Edge Gateways
Edition	Budget enforcement, Team budgets, and analytics dashboards: Enterprise Edition. In Community Edition, AI Studio records spend but does not block requests.
Version	Tyk AI Studio 2.2 or later. Agent and user fields in proxy logs: 2.2.1 or later.

Why Track Spend for Each Agent

An agent calls the LLM in a loop until it finishes its task. A bad prompt, a tool error, or a retry loop can make it run for hours. If all agents share one key, the invoice shows one total, and you cannot find the agent that caused it. For FinOps, each cost record needs the agent, the model, and the team. AI Studio calculates cost from the token counts in each LLM response and the model prices that you set. It does not estimate cost from your invoice.

How Do I Attribute LLM Token Costs to an Agent, Team, or App?

Create one App for each agent. The App is the identity that AI Studio uses for cost, budgets, and access.

Create an App for the agent, and give it a name that identifies the agent, for example invoice-reconciler. See Creating an App.
Grant the App access only to the LLMs and tools that the agent needs.
Select the App’s Team. The Team is the cost center for Team budgets.
Activate the App’s credentials. See App lifecycle.
Give the App’s credentials to that agent only.

For every LLM call, AI Studio then records:

Field	Description
App ID	The agent
LLM ID and model	The LLM configuration and the model, for example `gpt-4o`
Prompt tokens and completion tokens	Input and output tokens. Cache read and cache write tokens are separate.
Cost	Calculated from the token counts and the model price
Timestamp and latency	When the call happened and how long it took
Response code	The HTTP status of the call

AI Studio adds the costs of each App to its Team. The Team Costs table on the dashboard shows the cost, share, tokens, and requests of each Team. If agents get tokens from your identity provider instead of App keys, use the OAuth2 Client Credentials plugin (Enterprise, 2.2.1 or later). It maps each OAuth client to an App. It can also create an App for each new client from a template.

How Do I Set a Hard Budget Cap on LLM Spend per Agent or Team?

Set a monthly budget on the agent’s App. In the App form, set the budget to Fixed amount and enter the limit. You can also set budgets on an LLM configuration and on a Team. AI Studio checks every budget that applies to a request, and refuses the request if one of them is spent. When the App’s budget is spent, the gateway returns this error on the OpenAI-compatible endpoints:

HTTP status	`code`	Meaning
`403`	`budget_exceeded`	A budget that applies to the request is spent.
`503`	`budget_check_unavailable`	The gateway cannot read the budget. Retry later.

The budget period is one month. For all budget settings, see Budget control. AI Studio does not have a per-App limit for requests per minute (RPM) or tokens per minute (TPM). The monthly budget is the cap on spend.

The Agent Found It Can Call an Expensive API in a Loop: Where Does the Kill Switch Go?

Put it where the loop spends money.

The loop calls	Kill switch	Effect
An LLM through AI Studio	The App’s monthly budget	AI Studio refuses LLM requests when the budget is spent.
An LLM through AI Studio, now	Set the App budget to `$0`, or set the App’s credentials to Inactive	AI Studio refuses all requests from the App.
An MCP tool or a REST API through Tyk Gateway	A rate limit and a quota in the agent’s policy	Tyk Gateway returns `429` when the agent reaches a limit.
An MCP tool or a REST API through Tyk Gateway, now	Revoke the agent’s key in the Tyk Dashboard	Tyk Gateway refuses the next request with that key.

A budget stops a loop only after the loop has spent the budget. A rate limit stops it within seconds. Use both for agents that can call paid APIs. For per-tool rate limits, see MCP Gateway policies. For quotas, see Request quotas.

How Do I Track LLM Costs and Latency in Production?

AI Studio gives you three views of the same data:

View	Use it to
Analytics dashboard in AI Studio	Filter cost, tokens, requests, and latency by App, user, LLM, and time range
Analytics API, for example `GET /api/v1/analytics/team-costs`	Export cost data to your own reports or FinOps tool
Prometheus `/metrics` endpoint	Alert on `aistudio_llm_cost_total`, `aistudio_llm_tokens_total`, and `aistudio_llm_request_duration_seconds`

For the dashboard and the metrics, see Analytics. For OpenTelemetry traces, see Observability. You must turn on analytics in the configuration of each Edge Gateway. If the dashboard shows no data for a gateway, see Edge Gateway analytics configuration.

I Need a Log of Every Call an Agent Made, and Which User It Was Acting As

AI Studio stores a proxy log row for every LLM call. The App and LLM pages show these rows. The user_id of a row is the App owner, not the end user. To record the end user, use one of these methods:

Authenticate the agent with the OAuth2 Client Credentials plugin (2.2.1 or later). For a delegated token, the proxy log stores the user in on_behalf_of and the agent in acting_agent. The App pages show these values as For and Agent.
Create a separate App for each end user or tenant. Each App then has its own budget and its own log.

The on_behalf_of and acting_agent fields are for audit only. AI Studio does not use them for budgets or authorization. Billing stays with the App. Tool calls through Tyk Gateway go to the MCP access logs. Each record shows the JSON-RPC method, the tool name, and a hash of the consumer’s key.

Verify the Setup

Set a small budget on a test App, for example $1.
Send LLM requests with the App’s credentials until the App’s cost passes $1.
Make sure that the next request fails with 403 and the code budget_exceeded.
Make sure that the App owner received the 80% and 100% alerts. See Notifications.
Open the App page. The proxy log shows the tokens and the cost of each call.

​Why Track Spend for Each Agent

​How Do I Attribute LLM Token Costs to an Agent, Team, or App?

​How Do I Set a Hard Budget Cap on LLM Spend per Agent or Team?

​The Agent Found It Can Call an Expensive API in a Loop: Where Does the Kill Switch Go?

​How Do I Track LLM Costs and Latency in Production?

​I Need a Log of Every Call an Agent Made, and Which User It Was Acting As

​Verify the Setup