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

# Treaty coverage

> The two treaty corpus tokens: US_TAX_TREATY for IRS income tax treaties, US_TREATY for the Senate treaty record

Treaty material sits behind two `corpusType` tokens.
`US_TAX_TREATY` holds the IRS income tax treaties.
`US_TREATY` holds the Senate treaty record.
They were split on 2026-11-06, so a search for one never returns the other.

## What the two tokens hold

| Token | Documents | Retrieval passages |
| - | -: | -: |
| `US_TAX_TREATY` | 173 | 13,081 |
| `US_TREATY` | 1,492 | 6,918 |

Counts measured 2026-11-06.
A document is one citable item.
A retrieval passage is one searchable chunk of it.

> [!NOTE]
>
> `GET /us/statutes/coverage` reports `sectionCount` 1,665 for `US_TAX_TREATY` and 1,492 for `US_TREATY`.
> The endpoint counts sections, not documents.
> The 173 documents of `US_TAX_TREATY` are counted there as 1,665 sections.
> Both numbers are correct.

### Sources

Narrow either token to one body of material with `source`.

| Token | `source` | Documents | What it is |
| - | - | -: | - |
| `US_TAX_TREATY` | `us_tax_treaty` | 102 | Bilateral income tax conventions, protocols, exchanges of notes, the memorandum of understanding and the negotiation statement |
| `US_TAX_TREATY` | `us_tax_treaty_technical_explanation` | 71 | Treasury Technical Explanations |
| `US_TREATY` | `senate_treaty` | 782 | One record for each treaty the Senate has considered since 1949, tax and non-tax: title, parties, subject index and dated procedural history |
| `US_TREATY` | `senate_treaty_resolution` | 407 | The resolution of advice and consent, where the reservations, understandings and declarations live |
| `US_TREATY` | `senate_treaty_document` | 303 | The President's transmittal text, for treaties sent to the Senate from 1995 (the 104th Congress) on |

The 102 documents of `us_tax_treaty` are 71 bilateral income tax conventions for 68 countries, 23 protocols, 6 exchanges of notes, 1 memorandum of understanding and 1 negotiation statement.
A protocol is served as its own document rather than folded into the convention it amends.
That keeps each protocol searchable on its own terms, such as a change to a withholding rate, a limitation-on-benefits article or an entry-into-force date.
The 303 documents of `senate_treaty_document` are 285 numbered Treaty Documents and 18 Serial Set packages.

### Where the text comes from

| Source | Origin |
| - | - |
| `us_tax_treaty`, `us_tax_treaty_technical_explanation` | The IRS tax treaty pages |
| `senate_treaty`, `senate_treaty_resolution` | The Senate treaty record |
| `senate_treaty_document` | GPO, the Government Publishing Office |

## Searching and filtering

Both tokens use the same search route, `POST /us/statutes/search`, and the same `corpusType` and `source` filters described in [Corpus types](https://vaquill.ai/docs/api-guide/concepts/corpus-types.md).

Find a withholding rule in an IRS income tax treaty:

```json theme={"theme":"github-light"}
{ "query": "dividends withholding rate limitation on benefits", "corpusType": "US_TAX_TREATY" }
```

Read the Treasury's explanation of a treaty instead of the treaty itself:

```json theme={"theme":"github-light"}
{ "query": "Technical Explanation permanent establishment", "corpusType": "US_TAX_TREATY", "source": "us_tax_treaty_technical_explanation" }
```

Find the reservations and understandings the Senate attached to its consent:

```json theme={"theme":"github-light"}
{ "query": "understanding declaration extradition", "corpusType": "US_TREATY", "source": "senate_treaty_resolution" }
```

`corpusType` also accepts a list, so one call can search both tokens:

```json theme={"theme":"github-light"}
{ "query": "double taxation relief", "corpusType": ["US_TAX_TREATY", "US_TREATY"] }
```

## Citations

A treaty citation is always recognized as a treaty.
It is never read as a U.S. Code section or a Public Law.
The full list of accepted forms is in [Treaty citations](https://vaquill.ai/docs/api-guide/concepts/citation-formats.md#treaty-citations).

| Citation | Result |
| - | - |
| Senate Treaty Document, such as `S. Treaty Doc. No. 98-9` | Resolves to the Senate record for that treaty: the Treaty Document text when the treaty went to the Senate from 1995 on, otherwise the ratification record |
| U.S.T., T.I.A.S., T.S., E.A.S., Bevans, U.N.T.S., L.N.T.S., such as `20 U.S.T. 361` or `T.I.A.S. No. 6638` | `resolved: false`, `missReason: "not_held"`, with a `missReasonHint` |
| Senate Executive Report, such as `S. Exec. Rep. No. 102-23` | `resolved: false`, `missReason: "not_held"`, with a `missReasonHint` |
| Statutes at Large pages in volumes 1 to 64 | Resolves to the session law printed there when we hold one. A miss says the page may be a treaty |

The `missReasonHint` states that the form was recognized and lists the treaty material we do hold: the Senate ratification record, Treaty Document text from 1995 on, and the IRS income tax treaties.

## Limits

* About 60% of the Senate record is metadata with no instrument text. `source` tells you which records those are.
* `goodLawStatus` is `unknown` on every treaty record. No source we hold states termination.
* Treaty text printed in the Statutes at Large, U.S.T., T.I.A.S. and Bevans is not held.
* Senate Executive Reports are not held.
* The categories `us_treaty` and `senate_executive_report` exist on the `US_TREATY` token and hold no documents.
* `US_TAX_TREATY` covers income tax only. There are no estate or gift tax treaties.

For the other federal tokens, see [Federal coverage](https://vaquill.ai/docs/api-guide/coverage/federal.md).


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