diff --git a/.changeset/calm-methods-webdav.md b/.changeset/calm-methods-webdav.md
new file mode 100644
index 00000000000..06dd2272bf4
--- /dev/null
+++ b/.changeset/calm-methods-webdav.md
@@ -0,0 +1,6 @@
+---
+"@effect/platform": patch
+"@effect/ai": patch
+---
+
+Support WebDAV and other uncommon HTTP methods.
diff --git a/packages/ai/ai/src/AiError.ts b/packages/ai/ai/src/AiError.ts
index f87687ea291..7416980617c 100644
--- a/packages/ai/ai/src/AiError.ts
+++ b/packages/ai/ai/src/AiError.ts
@@ -70,6 +70,7 @@
  * @since 1.0.0
  */
 import type * as HttpClientError from "@effect/platform/HttpClientError"
+import * as HttpMethod from "@effect/platform/HttpMethod"
 import * as Effect from "effect/Effect"
 import * as Inspectable from "effect/Inspectable"
 import type { ParseError } from "effect/ParseResult"
@@ -145,7 +146,7 @@ export const isAiError = (u: unknown): u is AiError => Predicate.hasProperty(u,
  * @category Schemas
  */
 export const HttpRequestDetails = Schema.Struct({
-  method: Schema.Literal("GET", "POST", "PATCH", "PUT", "DELETE", "HEAD", "OPTIONS"),
+  method: Schema.Literal(...HttpMethod.all),
   url: Schema.String,
   urlParams: Schema.Array(Schema.Tuple(Schema.String, Schema.String)),
   hash: Schema.Option(Schema.String),
diff --git a/packages/ai/ai/test/AiError.test.ts b/packages/ai/ai/test/AiError.test.ts
new file mode 100644
index 00000000000..9221de03b23
--- /dev/null
+++ b/packages/ai/ai/test/AiError.test.ts
@@ -0,0 +1,18 @@
+import * as AiError from "@effect/ai/AiError"
+import { describe, it } from "@effect/vitest"
+import { strictEqual } from "@effect/vitest/utils"
+import { Schema } from "effect"
+
+describe("AiError", () => {
+  it("accepts uncommon HTTP methods in request details", () => {
+    const details = Schema.decodeUnknownSync(AiError.HttpRequestDetails)({
+      method: "PROPFIND",
+      url: "https://example.com",
+      urlParams: [],
+      hash: { _tag: "None" },
+      headers: {}
+    })
+
+    strictEqual(details.method, "PROPFIND")
+  })
+})
diff --git a/packages/platform/src/HttpLayerRouter.ts b/packages/platform/src/HttpLayerRouter.ts
index dd467adc0ac..079c4ac49cd 100644
--- a/packages/platform/src/HttpLayerRouter.ts
+++ b/packages/platform/src/HttpLayerRouter.ts
@@ -58,7 +58,7 @@ export interface HttpRouter {
   readonly prefixed: (prefix: string) => HttpRouter
 
   readonly add: <E, R>(
-    method: "*" | "GET" | "POST" | "PUT" | "PATCH" | "DELETE" | "OPTIONS",
+    method: HttpMethod.HttpMethod | "*",
     path: PathInput,
     handler:
       | Effect.Effect<HttpServerResponse.HttpServerResponse, E, R>
@@ -299,7 +299,7 @@ export const use = <A, E, R>(
  * @category HttpRouter
  */
 export const add = <E, R>(
-  method: "*" | "GET" | "POST" | "PUT" | "PATCH" | "DELETE" | "OPTIONS",
+  method: HttpMethod.HttpMethod | "*",
   path: PathInput,
   handler:
     | Effect.Effect<HttpServerResponse.HttpServerResponse, E, R>
@@ -442,7 +442,7 @@ const makeRoute = <E, R>(options: {
  * @category Route
  */
 export const route = <E, R>(
-  method: "*" | "GET" | "POST" | "PUT" | "PATCH" | "DELETE" | "OPTIONS",
+  method: HttpMethod.HttpMethod | "*",
   path: PathInput,
   handler:
     | Effect.Effect<HttpServerResponse.HttpServerResponse, E, R>
diff --git a/packages/platform/src/HttpMethod.ts b/packages/platform/src/HttpMethod.ts
index e071ece924d..0e6faf3a92d 100644
--- a/packages/platform/src/HttpMethod.ts
+++ b/packages/platform/src/HttpMethod.ts
@@ -10,6 +10,17 @@ export type HttpMethod =
   | "PATCH"
   | "HEAD"
   | "OPTIONS"
+  | "PROPFIND"
+  | "PROPPATCH"
+  | "MKCOL"
+  | "COPY"
+  | "MOVE"
+  | "LOCK"
+  | "UNLOCK"
+  | "TRACE"
+  | "SEARCH"
+  | "REPORT"
+  | "MKCALENDAR"
 
 /**
  * @since 1.0.0
@@ -20,7 +31,7 @@ export declare namespace HttpMethod {
    * @since 1.0.0
    * @category models
    */
-  export type NoBody = "GET" | "HEAD" | "OPTIONS"
+  export type NoBody = "GET" | "HEAD" | "OPTIONS" | "TRACE"
 
   /**
    * @since 1.0.0
@@ -32,12 +43,32 @@ export declare namespace HttpMethod {
 /**
  * @since 1.0.0
  */
-export const hasBody = (method: HttpMethod): boolean => method !== "GET" && method !== "HEAD" && method !== "OPTIONS"
+export const hasBody = (method: HttpMethod): boolean =>
+  method !== "GET" && method !== "HEAD" && method !== "OPTIONS" && method !== "TRACE"
 
 /**
  * @since 1.0.0
  */
-export const all: ReadonlySet<HttpMethod> = new Set(["GET", "POST", "PUT", "DELETE", "PATCH", "HEAD", "OPTIONS"])
+export const all: ReadonlySet<HttpMethod> = new Set([
+  "GET",
+  "POST",
+  "PUT",
+  "DELETE",
+  "PATCH",
+  "HEAD",
+  "OPTIONS",
+  "PROPFIND",
+  "PROPPATCH",
+  "MKCOL",
+  "COPY",
+  "MOVE",
+  "LOCK",
+  "UNLOCK",
+  "TRACE",
+  "SEARCH",
+  "REPORT",
+  "MKCALENDAR"
+])
 
 /**
  * Tests if a value is a `HttpMethod`.
diff --git a/packages/platform/test/HttpMethod.test.ts b/packages/platform/test/HttpMethod.test.ts
new file mode 100644
index 00000000000..ab3d0eb42bf
--- /dev/null
+++ b/packages/platform/test/HttpMethod.test.ts
@@ -0,0 +1,39 @@
+import * as HttpLayerRouter from "@effect/platform/HttpLayerRouter"
+import * as HttpMethod from "@effect/platform/HttpMethod"
+import * as HttpServerResponse from "@effect/platform/HttpServerResponse"
+import { describe, it } from "@effect/vitest"
+import { assertFalse, assertTrue, strictEqual } from "@effect/vitest/utils"
+
+const uncommonMethods = [
+  "PROPFIND",
+  "PROPPATCH",
+  "MKCOL",
+  "COPY",
+  "MOVE",
+  "LOCK",
+  "UNLOCK",
+  "TRACE",
+  "SEARCH",
+  "REPORT",
+  "MKCALENDAR"
+] as const satisfies ReadonlyArray<HttpMethod.HttpMethod>
+
+describe("HttpMethod", () => {
+  it("recognizes uncommon HTTP methods", () => {
+    for (const method of uncommonMethods) {
+      assertTrue(HttpMethod.isHttpMethod(method))
+      assertTrue(HttpMethod.all.has(method))
+    }
+  })
+
+  it("treats TRACE as a no-body method", () => {
+    assertFalse(HttpMethod.hasBody("TRACE"))
+  })
+
+  it("supports uncommon methods in HttpLayerRouter", () => {
+    for (const method of uncommonMethods) {
+      const route = HttpLayerRouter.route(method, "/", HttpServerResponse.empty())
+      strictEqual(route.method, method)
+    }
+  })
+})