> ## Documentation Index
> Fetch the complete documentation index at: https://docs.costgraph.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Allocation coverage

> Measure how much of your spend has an owner, and find the largest unallocated spend

Allocation coverage tells you what share of your spend carries a value for a
tag, such as `team` or `cost-center`, and which spend doesn't. Spend without a
value can't be shown back to a team, so coverage is the first number to raise
before you rely on showback.

Both provider tags and [virtual tags](/costgraph/virtual-tags/overview) count.
A virtual tag rule that fills in missing values raises coverage straight away.

## Read coverage

Use `GET /api/v1/tenant/cost/allocation-coverage` in the
[CostGraph API](/api-reference/costgraph/introduction). It works with an API
key that has the `focus:read` scope.

```shell theme={null}
curl "https://api.costgraph.ai/api/v1/tenant/cost/allocation-coverage?tag_key=team&group_by=service&period=last_30d" \
  -H "X-API-Key: $COSTGRAPH_API_KEY" \
  -H "X-CostGraph-Tenant-ID: $TENANT_ID"
```

The following table describes the parameters:

| Parameter | Default | Meaning |
| - | - | - |
| `tag_key` | Any tag | The tag that counts as allocation. Without it, spend with any tag counts |
| `layer` | `billed` | `billed` for your bills, or `allocation` for Kubernetes allocation |
| `group_by` | None | One dimension, such as `service` or `sub_account`, to list where unallocated spend sits |
| `group_limit` | `100` | How many groups to return, up to 100 |
| `period`, `filter` | Month to date | The same period and filters as cost queries |

## Read the response

`byCurrency` has one entry per billed currency, with `total`, `allocated`,
`unallocated`, and `allocatedPct`. Coverage is measured on gross spend, before
credits.

With `group_by`, `groups` lists each group's amounts, largest unallocated spend
first. Start tagging there.

Graph AI and the [MCP server](/costgraph/mcp/usage) read coverage too. Ask
"How much of our spend has no team tag?"


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