diff --git a/docs/rules.md b/docs/rules.md
index 9e6f9b63..88df45e2 100644
--- a/docs/rules.md
+++ b/docs/rules.md
@@ -157,7 +157,7 @@ If you have problems getting your `ts_project` to work correctly, read the dedic
 | <a id="ts_project-assets"></a>assets |  Files which are needed by a downstream build step such as a bundler.<br><br>These files are **not** included as inputs to any actions spawned by `ts_project`. They are not transpiled, and are not visible to the type-checker. Instead, these files appear among the *outputs* of this target.<br><br>A typical use is when your TypeScript code has an import that TS itself doesn't understand such as<br><br>`import './my.scss'`<br><br>and the type-checker allows this because you have an "ambient" global type declaration like<br><br>`declare module '*.scss' { ... }`<br><br>A bundler like webpack will expect to be able to resolve the `./my.scss` import to a file and doesn't care about the typing declaration. A bundler runs as a build step, so it does not see files included in the `data` attribute.<br><br>Note that `data` is used for files that are resolved by some binary, including a test target. Behind the scenes, `data` populates Bazel's Runfiles object in `DefaultInfo`, while this attribute populates the `transitive_sources` of the `JsInfo`.   |  `[]` |
 | <a id="ts_project-extends"></a>extends |  Label of the tsconfig file referenced in the `extends` section of tsconfig To support "chaining" of more than one extended config, this label could be a target that provdes `TsConfigInfo` such as `ts_config`.   |  `None` |
 | <a id="ts_project-allow_js"></a>allow_js |  Whether TypeScript will read .js and .jsx files. When used with `declaration`, TypeScript will generate `.d.ts` files from `.js` files.   |  `False` |
-| <a id="ts_project-isolated_declarations"></a>isolated_declarations |  TODO   |  `False` |
+| <a id="ts_project-isolated_declarations"></a>isolated_declarations |  Whether to enforce that declaration output (.d.ts file) can be produced for a single source file at a time. Requires some additional explicit types on exported symbols. See https://www.typescriptlang.org/docs/handbook/release-notes/typescript-5-5.html#isolated-declarations   |  `False` |
 | <a id="ts_project-declaration"></a>declaration |  Whether the `declaration` bit is set in the tsconfig. Instructs Bazel to expect a `.d.ts` output for each `.ts` source.   |  `False` |
 | <a id="ts_project-source_map"></a>source_map |  Whether the `sourceMap` bit is set in the tsconfig. Instructs Bazel to expect a `.js.map` output for each `.ts` source.   |  `False` |
 | <a id="ts_project-declaration_map"></a>declaration_map |  Whether the `declarationMap` bit is set in the tsconfig. Instructs Bazel to expect a `.d.ts.map` output for each `.ts` source.   |  `False` |
diff --git a/ts/defs.bzl b/ts/defs.bzl
index cd8b186c..7844c264 100644
--- a/ts/defs.bzl
+++ b/ts/defs.bzl
@@ -153,7 +153,9 @@ def ts_project(
             See https://www.typescriptlang.org/docs/handbook/compiler-options.html#compiler-options
             Typically useful arguments for debugging are `--listFiles` and `--listEmittedFiles`.
 
-        isolated_declarations: TODO
+        isolated_declarations: Whether to enforce that declaration output (.d.ts file) can be produced for a
+            single source file at a time. Requires some additional explicit types on exported symbols.
+            See https://www.typescriptlang.org/docs/handbook/release-notes/typescript-5-5.html#isolated-declarations
 
         transpiler: A custom transpiler tool to run that produces the JavaScript outputs instead of `tsc`.