line_context

Use line_context for diagnostics, logs, search hits, stack traces, or user-provided file:line references when you need the containing source items and parent hierarchy.

Use when

You know exact files and 1-based lines but not the containing symbol.
You need context around up to 32 related locations.

Do not use when

You already know an exact range; use smart_read.
You need to resolve a visible identifier; use jump.

Request

{"locations":[{"file":"/workspace/project/src/lib.rs","line":42},{"file":"/workspace/project/src/api.rs","line":118}]}

Batch related locations: an entire failing test run's frames fit in one call.

Parameters

Field	Required	Default / bounds
`locations`	yes	1–32 entries; each `line` is a 1-based integer ≥ 1.
`locations[].file`	yes	Non-empty path (`file_path` is not the nested field name).
`include_docs`	no	`false`.
`output_mode`	no	`type_annotated`; union: `type_annotated`, `plain_text`, `both`.
`workspace_root`	no	Only needed when multiple workspaces are active.

Complete meaningful source items or document sections containing each location, including parent hierarchy. Type-annotated output falls back to plain text with a per-range note when inlay hints are unavailable.

Example

Real output — given only runtime.rs:98, the complete containing function comes back:

saved vs reading full file: 7.3 KB -> 1011 B (87% fewer bytes)

## "context-engine-server/src/connector/runtime.rs" (line 98)

context: impl ConnectorRuntime { ... }
 90|    pub(crate) fn new(
 91|        registration: RegisteredConnector,
 92|        http_client: reqwest::Client,
 93|        use_legacy_schema: bool,
 94|    ) -> Self {
 95|        let (_, request_capability/*: String*/, http_addr/*: SocketAddr*/, lease/*: ConnectorLease*/) = registration.into_parts();
 96|        let endpoint/*: Arc<str>*/ = endpoint(/*address: */http_addr);
 98|        let upstream/*: UpstreamClient*/ = UpstreamClient::new(

The function boundary is the parser's decision, not a guess — and line 95 shows types the raw source cannot: the element types of a destructured tuple, resolved by the language server.

Common mistakes

Sending zero-based lines or quoting the line number.
Sending more than 32 locations in one request.
Enabling include_docs when documentation is not needed.

smart_read reads exact ranges when the boundary is already known.
jump resolves identifiers found in the returned context.
hover inspects one identifier without reading its container.
outline maps the whole file instead of one location.