> ## 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.
# Section Intelligence
> Four routes that answer questions about a section you already have: what cites it, what its terms mean, how other states word it, and what has changed
A section lookup tells you what one provision says.
These four routes answer the questions you ask next, each starting from an
`actId` you already hold.
| Route | Answers | Credits |
| ------------------------------ | -------------------------------------------------- | :-----: |
| `/section/{actId}/changes` | Has this moved since we last looked at it? | 1 |
| `/section/{actId}/cited-by` | What else breaks if this changes? | 2 |
| `/section/{actId}/definitions` | What do this section's terms of art actually mean? | 4 |
| `/section/{actId}/cross-state` | How do other states word the same rule? | 6 |
All four are `GET`, all sit under `https://api.vaquill.ai/api/v1/us/statutes`,
and all refund a call that cannot answer.
Each carries a `note` explaining an empty answer that is not a real zero, so an
empty result with `note: null` is a genuine "nothing here".
## Changes: what has moved
`GET /us/statutes/section/{actId}/changes` returns every change our refreshes
have observed to one section: when it was added, each time its text was
replaced, and whether it has since been removed. **1 credit.**
| Parameter | Default | Notes |
| ------------ | ------- | --------------------------------------------------------------------- |
| `limit` | 50 | Max 200. |
| `order` | `desc` | `desc` is newest first. `asc` replays a section's life forward. |
| `changeKind` | all | `added`, `amended`, `removed`. Repeat the parameter for several. |
| `sinceId` | - | Poll forward: return changes with an `id` above this. Carry `cursor`. |
| `beforeId` | - | Walk back: return changes with an `id` below this. |
```bash theme={"theme":"github-dark"}
curl "https://api.vaquill.ai/api/v1/us/statutes/section/USC_T42_C21_S1983/changes?limit=10" \
-H "Authorization: Bearer vq_key_..."
```
Each event carries `changeKind`, `detectedAt`, `displayCitation`, `hasDiff` and
the `corpusType` board it was captured on.
These are OBSERVED changes. `detectedAt` is when our refresh saw the
difference, an upper bound on when it took effect, never the effective date
itself. For the publisher's own dates read `amendmentHistory` on
`GET /us/statutes/section/{actId}`.
Coverage is bounded by capture, not by the age of the law. Change capture
began long after the corpus did, runs per source, and events are swept at 24
months. An empty `changes` list means **no captured change**, not **never
amended**. The `coverage` field on the response says so in prose. Surface it
rather than rendering an empty list as "unchanged".
A `removed` as the newest change means the section is gone from the corpus, so
`section` comes back null.
That is a successful, charged response rather than a 404: learning that a
provision was repealed is the point.
## Cited-by: the reverse index
`GET /us/statutes/section/{actId}/cited-by` returns the sections whose text
cross-references the one you asked about. **2 credits.**
| Parameter | Default | Notes |
| --------- | ------- | --------------------------------------------- |
| `limit` | 25 | Max 100. `truncated` is true when more exist. |
A section lookup already tells you what a section cites.
This is the other direction, and it is the one you cannot get by reading the
section: which provisions elsewhere depend on this one.
That is the question behind "if this changes, what else is affected".
```bash theme={"theme":"github-dark"}
curl "https://api.vaquill.ai/api/v1/us/statutes/section/USC_T42_C21_S1983/cited-by?limit=50" \
-H "Authorization: Bearer vq_key_..."
```
Results are one row per citing section, in statutory order, never one row per
matching chunk.
`total` is the size of `citers` on this page, not a corpus-wide count.
**Scope: USC and CFR.**
State codes and Federal Register rules carry no section-level cross-reference
index, so a section from either returns an empty list with a `note` and is
refunded.
This reads references as the publisher wrote them. A citation the source never
recorded in machine-readable form cannot appear here, so treat a result as
evidence of a citation rather than proof there are no others.
## Definitions: the terms that govern a section
`GET /us/statutes/section/{actId}/definitions` returns the defined terms that
apply to a section, parsed from its chapter's definitions section.
**4 credits.** No parameters.
Statutes do not use ordinary English.
"Person" routinely includes corporations, "employee" routinely excludes
independent contractors, and the section you are reading almost never says so:
the definition lives in a separate section elsewhere in the chapter.
Reading a provision without it is how a clause gets misread.
```bash theme={"theme":"github-dark"}
curl https://api.vaquill.ai/api/v1/us/statutes/section/USC_T15_C1_S1/definitions \
-H "Authorization: Bearer vq_key_..."
```
Each entry in `terms` carries the `term` as the statute writes it, the
`definition` verbatim, and the `marker` it sits under where the source numbers
its definitions.
`definitionsSection` names where the terms came from, so a definition can be
quoted and cited to the provision that actually carries it.
**Scope**: strongest on the U.S. Code, where a chapter's definitions section is
conventionally structured and parses reliably.
CFR and state codes are best-effort, because publishers format definitions
inconsistently.
A definitions section we can locate but not parse returns empty with a `note`
and is refunded, with `definitionsSection` still populated so you can fetch its
text from `/section/{actId}/body` and read it yourself.
## Cross-state: the same rule elsewhere
`GET /us/statutes/section/{actId}/cross-state` returns provisions in other
states that address the same subject as a state statute section.
**6 credits.**
| Parameter | Default | Notes |
| --------- | ------- | ------------------------------------------ |
| `limit` | 5 | Max 25. Counts STATES, one provision each. |
Answering "how does this rule differ across the states we operate in" normally
means running the same search 50 times and reconciling by hand, because every
state words and numbers its provisions differently.
This starts from one section you already have.
```bash theme={"theme":"github-dark"}
curl "https://api.vaquill.ai/api/v1/us/statutes/section/STATE_TX_Cpr_C93_S93.005/cross-state?limit=10" \
-H "Authorization: Bearer vq_key_..."
```
At most one provision per state, most similar first, so the response reads as a
jurisdiction comparison rather than a relevance list.
`statesCovered` says how many distinct states are represented.
Fewer than you asked for means no provision in the remaining states cleared the
similarity floor, not that those states are missing from the corpus.
**Scope**: state statute sections.
USC, CFR, regulations and court rules return empty with a `note`, refunded,
since a federal section has no state analogue by definition.
`similarity` is a retrieval score between 0 and 1 describing how closely two
provisions read. It is not a legal opinion.
A high score means the provisions cover the same ground, never that they
impose the same obligation, and the differences are usually the point. Treat
this as the shortlist to read, not the answer.
## Related
Where an `actId` comes from, and what to do when one misses.
Whether the section you are analysing is still good law.
Point-in-time text with `asOf`, and which fields each corpus populates.
Be told about future changes instead of polling a section's history.