diff --git a/README.md b/README.md
index a232068..2ba0475 100644
--- a/README.md
+++ b/README.md
@@ -63,9 +63,10 @@ request-body shapes fail generation.
 
 Generated clients leave OpenTelemetry dependencies and SDK setup to the
 application. Pass an instrumented transport to a Go client or an instrumented
-`fetch` implementation to a TypeScript client. These examples assume the
-application has initialized an OpenTelemetry SDK; `@opentelemetry/api` alone
-uses no-op tracing and propagation implementations.
+`fetch` implementation to a TypeScript client. Rust clients accept a
+middleware-enabled HTTP client at construction.
+These examples assume the application has initialized an OpenTelemetry SDK;
+`@opentelemetry/api` alone uses no-op tracing and propagation implementations.
 
 ### Go
 
@@ -141,6 +142,36 @@ Context propagator must be registered for `propagation.inject` to add
 origins, the API's CORS policy must also allow the propagation headers configured
 by the application, commonly `traceparent`, `tracestate`, and `baggage`.
 
+### Rust
+
+The insertion point is the **HTTP client passed to `api::Client::new`**. Configure
+[`reqwest-tracing`](https://docs.rs/reqwest-tracing/0.5.8/reqwest_tracing/)
+middleware once; every generated operation's `.send()` then propagates the active
+trace automatically:
+
+```rust
+let http = reqwest_middleware::ClientBuilder::new(reqwest::Client::builder().build()?)
+    .with(reqwest_tracing::TracingMiddleware::default())
+    .build();
+
+let api = api::Client::new(http, "https://api.example.com".into(), None);
+
+// Inside the application's existing tracing span:
+let response = api.create_thing(params).send().await?;
+let result = api::CreateThingResponse::decode(response).await?;
+```
+
+For the generated Reqwest 0.12 client, use `reqwest-middleware` 0.4.2 with its
+`json` feature and `reqwest-tracing` 0.5.8 with its `opentelemetry_0_30` feature.
+The application must already have OpenTelemetry 0.30, a `tracing-opentelemetry`
+0.31 subscriber layer, and a registered W3C `TraceContextPropagator`.
+
+The middleware reads the current `tracing` span when the request is sent, creates
+a child HTTP span, and injects its `traceparent` and `tracestate` headers.
+One shared client can therefore serve calls from different traces. Normal async
+context propagation still applies: instrument spawned tasks with
+[`.in_current_span()`](https://docs.rs/tracing/latest/tracing/trait.Instrument.html#method.in_current_span).
+
 ## Develop
 
 [Go](https://go.dev) builds the generator and runs its tests.
@@ -173,15 +204,19 @@ reports are attached to the workflow, including on failure.
 ## Rust clients
 
 Use `--mode client --lang rust --out src/api`, then `mod api;`. Add `serde` 1
-(with `derive`), `serde_json` 1, and `reqwest` 0.12 (with `json`) to Cargo dependencies.
+(with `derive`), `serde_json` 1, `reqwest` 0.12, and `reqwest-middleware` 0.4.2
+(with `json`) to Cargo dependencies.
 Choose the Reqwest TLS features appropriate to your application.
 
 Construct `api::Client::new(http, base_url, bearer_token)` with your configured
-Reqwest client. Operation methods return request builders, so callers own timeouts,
+`reqwest_middleware::ClientWithMiddleware`. For a client without middleware,
+construct it with `reqwest_middleware::ClientBuilder::new(http).build()`.
+Operation methods return `reqwest_middleware::RequestBuilder`, so callers own timeouts,
 cancellation, tracing, and bounded body reads. Models and operation-specific
 `Response::decode` enums preserve declared HTTP statuses; undeclared statuses
 retain their original response. SSE responses remain streaming Reqwest responses,
 leaving event framing and cancellation to the caller.
+See [Rust trace propagation](#rust) to configure automatic propagation once.
 
 Rust supports JSON and raw request bodies, optional bodies, scalar and repeated
 query parameters, headers, escaped path parameters, enums, nullable values and
diff --git a/internal/rustemit/rustemit.go b/internal/rustemit/rustemit.go
index 5e3e351..7cef8a7 100644
--- a/internal/rustemit/rustemit.go
+++ b/internal/rustemit/rustemit.go
@@ -215,7 +215,7 @@ func (e *emitter) operation(op clientgen.Operation) string {
 	if hasParams {
 		fmt.Fprintf(&body, ", params: %sParams", name)
 	}
-	body.WriteString(") -> reqwest::RequestBuilder {\n")
+	body.WriteString(") -> reqwest_middleware::RequestBuilder {\n")
 	fmt.Fprintf(&body, "        let path = %s.to_owned();\n", strconv.Quote(op.Route.Path))
 	for _, param := range op.Route.Operation.Parameters {
 		typ := e.rustType(param.Schema, name+typeName(param.Name))
@@ -324,7 +324,7 @@ func (e *emitter) response(op clientgen.Operation, name string) {
 const clientPrelude = `
 #[derive(Clone, Debug)]
 pub struct Client {
-    http: reqwest::Client,
+    http: reqwest_middleware::ClientWithMiddleware,
     base_url: String,
     bearer_token: Option<String>,
 }
@@ -336,7 +336,8 @@ fn encode_path(value: &str) -> String {
     }).collect()
 }
 impl Client {
-    pub fn new(http: reqwest::Client, base_url: String, bearer_token: Option<String>) -> Self {
+    /// Every operation uses this client's middleware when its request is sent.
+    pub fn new(http: reqwest_middleware::ClientWithMiddleware, base_url: String, bearer_token: Option<String>) -> Self {
         Self { http, base_url: base_url.trim_end_matches('/').to_owned(), bearer_token }
     }
 `
diff --git a/testdata/rust-client/Cargo.lock b/testdata/rust-client/Cargo.lock
index ed2f137..193fe0a 100644
--- a/testdata/rust-client/Cargo.lock
+++ b/testdata/rust-client/Cargo.lock
@@ -2,6 +2,42 @@
 # It is not intended for manual editing.
 version = 4
 
+[[package]]
+name = "aho-corasick"
+version = "1.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c982642fa9e8606056828ee9a8505737230110bb1099153c79efe865c59d12ba"
+dependencies = [
+ "memchr",
+]
+
+[[package]]
+name = "anyhow"
+version = "1.0.104"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "330a5ed07fa54e4702c9d6c4174f74427fc0ef6e214bbd677ae50a5099946470"
+
+[[package]]
+name = "assert-json-diff"
+version = "2.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "47e4f2b81832e72834d7518d8487a0396a28cc408186a2e8854c0f98011faf12"
+dependencies = [
+ "serde",
+ "serde_json",
+]
+
+[[package]]
+name = "async-trait"
+version = "0.1.92"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "82f6aeea286b8eb4dd3431a1be1b59d290ace00f5bfd8e2a159bc2a05e2c1667"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 3.0.6",
+]
+
 [[package]]
 name = "atomic-waker"
 version = "1.1.2"
@@ -38,6 +74,24 @@ version = "1.0.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4e7648175b45a9a48536d676f68d918270699102aa8dab5496df06904c914600"
 
+[[package]]
+name = "deadpool"
+version = "0.12.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0be2b1d1d6ec8d846f05e137292d0b89133caf95ef33695424c09568bdd39b1b"
+dependencies = [
+ "deadpool-runtime",
+ "lazy_static",
+ "num_cpus",
+ "tokio",
+]
+
+[[package]]
+name = "deadpool-runtime"
+version = "0.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "092966b41edc516079bdf31ec78a2e0588d1d0c08f78b91d8307215928642b2b"
+
 [[package]]
 name = "displaydoc"
 version = "0.2.7"
@@ -46,9 +100,21 @@ checksum = "c6232dd377dcc64799954cbd3a9bb882e9cdc1308ccd87b1c098f1fb2eaf82a8"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 3.0.6",
 ]
 
+[[package]]
+name = "equivalent"
+version = "1.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "877a4ace8713b0bcf2a4e7eec82529c029f1d0619886d18145fea96c3ffe5c0f"
+
+[[package]]
+name = "fnv"
+version = "1.0.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3f9eec918d3f24069decb9af1554cad7c880e2da24a9afd88aca000531ab82c1"
+
 [[package]]
 name = "form_urlencoded"
 version = "1.2.2"
@@ -58,6 +124,21 @@ dependencies = [
  "percent-encoding",
 ]
 
+[[package]]
+name = "futures"
+version = "0.3.34"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9a31d2a3fbaaeb2af2368bbdd904aa8e812d3c04a1ee10d3171f52d556e5d0a3"
+dependencies = [
+ "futures-channel",
+ "futures-core",
+ "futures-executor",
+ "futures-io",
+ "futures-sink",
+ "futures-task",
+ "futures-util",
+]
+
 [[package]]
 name = "futures-channel"
 version = "0.3.34"
@@ -65,6 +146,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b1f9e3d69d39e4862ffed03ed071a76f9a13ba1d9109d355b0f0aa6b15e393c4"
 dependencies = [
  "futures-core",
+ "futures-sink",
 ]
 
 [[package]]
@@ -73,6 +155,40 @@ version = "0.3.34"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "92d699e522242e69e3003b94ecc1f960f3a5e015aa7c5d7486e65ad01dd94f5e"
 
+[[package]]
+name = "futures-executor"
+version = "0.3.34"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "031b47cf1a3c6cc8bc2fc76cd437f521619387907d469316e7c0bc278f1f5432"
+dependencies = [
+ "futures-core",
+ "futures-task",
+ "futures-util",
+]
+
+[[package]]
+name = "futures-io"
+version = "0.3.34"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "53c0fa8157de1303bfffdaa1cc2a673bfffb60102f76b0ef4441659124373fed"
+
+[[package]]
+name = "futures-macro"
+version = "0.3.34"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9fb9654ba8355388abeb8dcb4fc62f511300867002afc858860463bdd9fe0c44"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 3.0.6",
+]
+
+[[package]]
+name = "futures-sink"
+version = "0.3.34"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1944426bf7d03f1d14f708785e4b33efd750b36d48a157b836b3efc15ede8e1d"
+
 [[package]]
 name = "futures-task"
 version = "0.3.34"
@@ -85,12 +201,73 @@ version = "0.3.34"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0d50a92467f8ba5dd6e3ee5d4bd04d73ab2e4e1c44474a0674821dfce14b79bc"
 dependencies = [
+ "futures-channel",
  "futures-core",
+ "futures-io",
+ "futures-macro",
+ "futures-sink",
  "futures-task",
+ "memchr",
  "pin-project-lite",
  "slab",
 ]
 
+[[package]]
+name = "getrandom"
+version = "0.2.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ff2abc00be7fca6ebc474524697ae276ad847ad0a6b3faa4bcb027e9a4614ad0"
+dependencies = [
+ "cfg-if",
+ "js-sys",
+ "libc",
+ "wasi",
+ "wasm-bindgen",
+]
+
+[[package]]
+name = "getrandom"
+version = "0.3.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "899def5c37c4fd7b2664648c28120ecec138e4d395b459e5ca34f9cce2dd77fd"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "r-efi",
+ "wasip2",
+]
+
+[[package]]
+name = "h2"
+version = "0.4.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ef8e5e5a340588f4452631496976cf8636d4a7ecf600239fdc27615d2530bc16"
+dependencies = [
+ "atomic-waker",
+ "bytes",
+ "fnv",
+ "futures-core",
+ "futures-sink",
+ "http",
+ "indexmap",
+ "slab",
+ "tokio",
+ "tokio-util",
+ "tracing",
+]
+
+[[package]]
+name = "hashbrown"
+version = "0.17.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ed5909b6e89a2db4456e54cd5f673791d7eca6732202bbf2a9cc504fe2f9b84a"
+
+[[package]]
+name = "hermit-abi"
+version = "0.5.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e17592d60ebacc7d5e169f4663c5f84f9161cc90328abcfe8456f41e4dfcb284"
+
 [[package]]
 name = "http"
 version = "1.5.0"
@@ -130,6 +307,12 @@ version = "1.10.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6dbf3de79e51f3d586ab4cb9d5c3e2c14aa28ed23d180cf89b4df0454a69cc87"
 
+[[package]]
+name = "httpdate"
+version = "1.0.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "df3b46402a9d5adb4c86a0cf463f42e19994e3ee891101b1841f30a545cb49a9"
+
 [[package]]
 name = "hyper"
 version = "1.11.1"
@@ -140,9 +323,11 @@ dependencies = [
  "bytes",
  "futures-channel",
  "futures-core",
+ "h2",
  "http",
  "http-body",
  "httparse",
+ "httpdate",
  "itoa",
  "pin-project-lite",
  "smallvec",
@@ -277,6 +462,16 @@ dependencies = [
  "icu_properties",
 ]
 
+[[package]]
+name = "indexmap"
+version = "2.14.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cc4e190f5d26ca7051642629da2c52fc03bde85a03197c99408dcd291734c855"
+dependencies = [
+ "equivalent",
+ "hashbrown",
+]
+
 [[package]]
 name = "ipnet"
 version = "2.12.2"
@@ -300,6 +495,12 @@ dependencies = [
  "wasm-bindgen",
 ]
 
+[[package]]
+name = "lazy_static"
+version = "1.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bbd2bcb4c963f2ddae06a2efc7e9f3591312473c50c6685e1f298068316e66fe"
+
 [[package]]
 name = "libc"
 version = "0.2.189"
@@ -318,6 +519,12 @@ version = "0.4.34"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f9f8bd3e56ce4dfc153cf470fffbfa98c7620958b312ca5c3a4b8d5181fd13c6"
 
+[[package]]
+name = "matchit"
+version = "0.8.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2f926ade0c4e170215ae43342bf13b9310a437609c81f29f86c5df6657582ef9"
+
 [[package]]
 name = "memchr"
 version = "2.8.3"
@@ -335,15 +542,43 @@ dependencies = [
  "windows-sys",
 ]
 
+[[package]]
+name = "nu-ansi-term"
+version = "0.50.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7957b9740744892f114936ab4a57b3f487491bbeafaf8083688b16841a4240e5"
+dependencies = [
+ "windows-sys",
+]
+
+[[package]]
+name = "num_cpus"
+version = "1.17.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "91df4bbde75afed763b708b7eee1e8e7651e02d97f6d5dd763e89367e957b23b"
+dependencies = [
+ "hermit-abi",
+ "libc",
+]
+
 [[package]]
 name = "oasmith-rust-contract-tests"
 version = "0.0.0"
 dependencies = [
  "http",
+ "opentelemetry",
+ "opentelemetry-http",
+ "opentelemetry_sdk",
  "reqwest",
+ "reqwest-middleware",
+ "reqwest-tracing",
  "serde",
  "serde_json",
  "tokio",
+ "tracing",
+ "tracing-opentelemetry",
+ "tracing-subscriber",
+ "wiremock",
 ]
 
 [[package]]
@@ -352,6 +587,50 @@ version = "1.21.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9f7c3e4beb33f85d45ae3e3a1792185706c8e16d043238c593331cc7cd313b50"
 
+[[package]]
+name = "opentelemetry"
+version = "0.30.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "aaf416e4cb72756655126f7dd7bb0af49c674f4c1b9903e80c009e0c37e552e6"
+dependencies = [
+ "futures-core",
+ "futures-sink",
+ "js-sys",
+ "pin-project-lite",
+ "thiserror 2.0.21",
+ "tracing",
+]
+
+[[package]]
+name = "opentelemetry-http"
+version = "0.30.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "50f6639e842a97dbea8886e3439710ae463120091e2e064518ba8e716e6ac36d"
+dependencies = [
+ "async-trait",
+ "bytes",
+ "http",
+ "opentelemetry",
+]
+
+[[package]]
+name = "opentelemetry_sdk"
+version = "0.30.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "11f644aa9e5e31d11896e024305d7e3c98a88884d9f8919dbf37a9991bc47a4b"
+dependencies = [
+ "futures-channel",
+ "futures-executor",
+ "futures-util",
+ "opentelemetry",
+ "percent-encoding",
+ "rand",
+ "serde_json",
+ "thiserror 2.0.21",
+ "tokio",
+ "tokio-stream",
+]
+
 [[package]]
 name = "percent-encoding"
 version = "2.3.2"
@@ -373,6 +652,15 @@ dependencies = [
  "zerovec",
 ]
 
+[[package]]
+name = "ppv-lite86"
+version = "0.2.21"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "85eae3c4ed2f50dcfe72643da4befc30deadb458a9b590d720cde2f2b1e97da9"
+dependencies = [
+ "zerocopy",
+]
+
 [[package]]
 name = "proc-macro2"
 version = "1.0.107"
@@ -391,6 +679,70 @@ dependencies = [
  "proc-macro2",
 ]
 
+[[package]]
+name = "r-efi"
+version = "5.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "69cdb34c158ceb288df11e18b4bd39de994f6657d83847bdffdbd7f346754b0f"
+
+[[package]]
+name = "rand"
+version = "0.9.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b9ef1d0d795eb7d84685bca4f72f3649f064e6641543d3a8c415898726a57b41"
+dependencies = [
+ "rand_chacha",
+ "rand_core",
+]
+
+[[package]]
+name = "rand_chacha"
+version = "0.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d3022b5f1df60f26e1ffddd6c66e8aa15de382ae63b3a0c1bfc0e4d3e3f325cb"
+dependencies = [
+ "ppv-lite86",
+ "rand_core",
+]
+
+[[package]]
+name = "rand_core"
+version = "0.9.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "76afc826de14238e6e8c374ddcc1fa19e374fd8dd986b0d2af0d02377261d83c"
+dependencies = [
+ "getrandom 0.3.4",
+]
+
+[[package]]
+name = "regex"
+version = "1.13.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f020237b6c8eed93db2e2cb53c00c60a8e1bc73da7d073199a1180401450218d"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-automata",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-automata"
+version = "0.4.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ad8553b9b26413251cbf30e620595c7a41b3887f03da04579c0e6b0d6a06b4b2"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-syntax"
+version = "0.8.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d6f6ff9a378485b298a5286656da665ba74413d36db0979633275d2e708145d4"
+
 [[package]]
 name = "reqwest"
 version = "0.12.28"
@@ -423,6 +775,39 @@ dependencies = [
  "web-sys",
 ]
 
+[[package]]
+name = "reqwest-middleware"
+version = "0.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "57f17d28a6e6acfe1733fe24bcd30774d13bffa4b8a22535b4c8c98423088d4e"
+dependencies = [
+ "anyhow",
+ "async-trait",
+ "http",
+ "reqwest",
+ "serde",
+ "thiserror 1.0.69",
+ "tower-service",
+]
+
+[[package]]
+name = "reqwest-tracing"
+version = "0.5.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d70ea85f131b2ee9874f0b160ac5976f8af75f3c9badfe0d955880257d10bd83"
+dependencies = [
+ "anyhow",
+ "async-trait",
+ "getrandom 0.2.17",
+ "http",
+ "matchit",
+ "opentelemetry",
+ "reqwest",
+ "reqwest-middleware",
+ "tracing",
+ "tracing-opentelemetry",
+]
+
 [[package]]
 name = "rustversion"
 version = "1.0.23"
@@ -462,7 +847,7 @@ checksum = "e7a5d71263a5a7d47b41f6b3f06ba276f10cc18b0931f1799f710578e2309348"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 3.0.6",
 ]
 
 [[package]]
@@ -490,6 +875,15 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "sharded-slab"
+version = "0.1.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f40ca3c46823713e0d4209592e8d6e826aa57e928f09752619fc696c499637f6"
+dependencies = [
+ "lazy_static",
+]
+
 [[package]]
 name = "slab"
 version = "0.4.12"
@@ -518,6 +912,17 @@ version = "1.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6ce2be8dc25455e1f91df71bfa12ad37d7af1092ae736f3a6cd0e37bc7810596"
 
+[[package]]
+name = "syn"
+version = "2.0.119"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "872831b642d1a07999a962a351ed35b955ea2cfc8f3862091e2a240a84f17297"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-ident",
+]
+
 [[package]]
 name = "syn"
 version = "3.0.6"
@@ -546,7 +951,56 @@ checksum = "901704edd0dfe137f1987838ee4f259e4e063c31371bdb423f7ae38ec6f77f02"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 3.0.6",
+]
+
+[[package]]
+name = "thiserror"
+version = "1.0.69"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b6aaf5339b578ea85b50e080feb250a3e8ae8cfcdff9a461c9ec2904bc923f52"
+dependencies = [
+ "thiserror-impl 1.0.69",
+]
+
+[[package]]
+name = "thiserror"
+version = "2.0.21"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "09e52cb86a36cede5cb101bf8908837b3e4c6e5e59fe7fd85c23fb56200d189e"
+dependencies = [
+ "thiserror-impl 2.0.21",
+]
+
+[[package]]
+name = "thiserror-impl"
+version = "1.0.69"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4fee6c4efc90059e10f81e6d42c60a18f76588c3d74cb83a0b242a2b6c7504c1"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.119",
+]
+
+[[package]]
+name = "thiserror-impl"
+version = "2.0.21"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fe5197923287db20a58125f0bc85c062f7f2c892de97b18c356f9efb14b28524"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 3.0.6",
+]
+
+[[package]]
+name = "thread_local"
+version = "1.1.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1ad99c4c6d32803332c548b1af0540b357b3f5fc0be8f6c6bfe8b2e6ae784070"
+dependencies = [
+ "cfg-if",
 ]
 
 [[package]]
@@ -565,6 +1019,7 @@ version = "1.53.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "202caea871b69668250d242070849eb495be178ed697a3e98aebce5bc81a0bed"
 dependencies = [
+ "bytes",
  "libc",
  "mio",
  "pin-project-lite",
@@ -581,7 +1036,32 @@ checksum = "78773a2a397f451582ce068015985c33193cf6dea8b74d2a639fe457b2f07b0e"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 3.0.6",
+]
+
+[[package]]
+name = "tokio-stream"
+version = "0.1.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a3d06f0b082ba57c26b79407372e57cf2a1e28124f78e9479fe80322cf53420b"
+dependencies = [
+ "futures-core",
+ "pin-project-lite",
+ "tokio",
+]
+
+[[package]]
+name = "tokio-util"
+version = "0.7.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "494815d09bf52b5548659851081238f0ca39ff638363907596da739561c62c52"
+dependencies = [
+ "bytes",
+ "futures-core",
+ "futures-sink",
+ "libc",
+ "pin-project-lite",
+ "tokio",
 ]
 
 [[package]]
@@ -636,9 +1116,21 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "63e71662fa4b2a2c3a26f570f037eb95bb1f85397f3cd8076caed2f026a6d100"
 dependencies = [
  "pin-project-lite",
+ "tracing-attributes",
  "tracing-core",
 ]
 
+[[package]]
+name = "tracing-attributes"
+version = "0.1.31"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7490cfa5ec963746568740651ac6781f701c9c5ea257c58e057f3ba8cf69e8da"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.119",
+]
+
 [[package]]
 name = "tracing-core"
 version = "0.1.36"
@@ -646,6 +1138,50 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "db97caf9d906fbde555dd62fa95ddba9eecfd14cb388e4f491a66d74cd5fb79a"
 dependencies = [
  "once_cell",
+ "valuable",
+]
+
+[[package]]
+name = "tracing-log"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ee855f1f400bd0e5c02d150ae5de3840039a3f54b025156404e34c23c03f47c3"
+dependencies = [
+ "log",
+ "once_cell",
+ "tracing-core",
+]
+
+[[package]]
+name = "tracing-opentelemetry"
+version = "0.31.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ddcf5959f39507d0d04d6413119c04f33b623f4f951ebcbdddddfad2d0623a9c"
+dependencies = [
+ "js-sys",
+ "once_cell",
+ "opentelemetry",
+ "opentelemetry_sdk",
+ "smallvec",
+ "tracing",
+ "tracing-core",
+ "tracing-log",
+ "tracing-subscriber",
+ "web-time",
+]
+
+[[package]]
+name = "tracing-subscriber"
+version = "0.3.23"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cb7f578e5945fb242538965c2d0b04418d38ec25c79d160cd279bf0731c8d319"
+dependencies = [
+ "nu-ansi-term",
+ "sharded-slab",
+ "smallvec",
+ "thread_local",
+ "tracing-core",
+ "tracing-log",
 ]
 
 [[package]]
@@ -678,6 +1214,12 @@ version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b6c140620e7ffbb22c2dee59cafe6084a59b5ffc27a8859a5f0d494b5d52b6be"
 
+[[package]]
+name = "valuable"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ba73ea9cf16a25df0c8caa16c51acb937d5712a8429db78a3ee29d5dcacd3a65"
+
 [[package]]
 name = "want"
 version = "0.3.1"
@@ -693,6 +1235,15 @@ version = "0.11.1+wasi-snapshot-preview1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ccf3ec651a847eb01de73ccad15eb7d99f80485de043efb2f370cd654f4ea44b"
 
+[[package]]
+name = "wasip2"
+version = "1.0.4+wasi-0.2.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b67efb37e106e55ce722a510d6b5f9c17f083e5fc79afc2badeb12cc313d9487"
+dependencies = [
+ "wit-bindgen",
+]
+
 [[package]]
 name = "wasm-bindgen"
 version = "0.2.128"
@@ -735,7 +1286,7 @@ dependencies = [
  "bumpalo",
  "proc-macro2",
  "quote",
- "syn",
+ "syn 3.0.6",
  "wasm-bindgen-shared",
 ]
 
@@ -758,6 +1309,16 @@ dependencies = [
  "wasm-bindgen",
 ]
 
+[[package]]
+name = "web-time"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5a6580f308b1fad9207618087a65c04e7a10bc77e02c8e84e9b00dd4b12fa0bb"
+dependencies = [
+ "js-sys",
+ "wasm-bindgen",
+]
+
 [[package]]
 name = "windows-link"
 version = "0.2.1"
@@ -773,6 +1334,35 @@ dependencies = [
  "windows-link",
 ]
 
+[[package]]
+name = "wiremock"
+version = "0.6.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "08db1edfb05d9b3c1542e521aea074442088292f00b5f28e435c714a98f85031"
+dependencies = [
+ "assert-json-diff",
+ "base64",
+ "deadpool",
+ "futures",
+ "http",
+ "http-body-util",
+ "hyper",
+ "hyper-util",
+ "log",
+ "once_cell",
+ "regex",
+ "serde",
+ "serde_json",
+ "tokio",
+ "url",
+]
+
+[[package]]
+name = "wit-bindgen"
+version = "0.57.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1ebf944e87a7c253233ad6766e082e3cd714b5d03812acc24c318f549614536e"
+
 [[package]]
 name = "writeable"
 version = "0.6.4"
@@ -798,10 +1388,30 @@ checksum = "33811428bee40dbceb6d545e95754741d17a6aef9a4849f0fd62e2ba4f412a78"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 3.0.6",
  "synstructure",
 ]
 
+[[package]]
+name = "zerocopy"
+version = "0.8.59"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6df92bf3d9227be3d53173901ddbffac2babc27ae50f397776ffd6dc33f800cb"
+dependencies = [
+ "zerocopy-derive",
+]
+
+[[package]]
+name = "zerocopy-derive"
+version = "0.8.59"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ac4f328cf2f05d084e496c3e9c3f33ed0a183656a16e1fcec4d464d8373aec82"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.119",
+]
+
 [[package]]
 name = "zerofrom"
 version = "0.1.8"
@@ -819,7 +1429,7 @@ checksum = "f75b4683f6c7f45248d4d64056a24298c6281e0993356d7d1b4a1a962ef10d4a"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 3.0.6",
  "synstructure",
 ]
 
@@ -853,7 +1463,7 @@ checksum = "34df6fc39dbd26ddc9c10e6a2984476e13acce22e64e4487636ef494369225da"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 3.0.6",
 ]
 
 [[package]]
diff --git a/testdata/rust-client/Cargo.toml b/testdata/rust-client/Cargo.toml
index 9e4da3a..106a482 100644
--- a/testdata/rust-client/Cargo.toml
+++ b/testdata/rust-client/Cargo.toml
@@ -7,5 +7,16 @@ publish = false
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
 reqwest = { version = "0.12", default-features = false, features = ["json"] }
-tokio = { version = "1", features = ["macros", "rt"] }
+reqwest-middleware = { version = "0.4.2", features = ["json"] }
+tokio = { version = "1", features = ["macros", "rt", "time"] }
 http = "1"
+
+[dev-dependencies]
+opentelemetry = "0.30"
+opentelemetry_sdk = { version = "0.30", features = ["testing"] }
+opentelemetry-http = "0.30"
+reqwest-tracing = { version = "0.5.8", features = ["opentelemetry_0_30"] }
+tracing = "0.1"
+tracing-opentelemetry = "0.31"
+tracing-subscriber = "0.3"
+wiremock = "0.6"
diff --git a/testdata/rust-client/src/lib.rs b/testdata/rust-client/src/lib.rs
index 4494e20..d19d68c 100644
--- a/testdata/rust-client/src/lib.rs
+++ b/testdata/rust-client/src/lib.rs
@@ -5,7 +5,8 @@ mod models;
 mod tests {
     use super::{public::*, models};
     fn client() -> Client {
-        Client::new(reqwest::Client::new(), "http://localhost:1234/".into(), Some("test-key".into()))
+        let http = reqwest_middleware::ClientBuilder::new(reqwest::Client::new()).build();
+        Client::new(http, "http://localhost:1234/".into(), Some("test-key".into()))
     }
     #[test]
     fn encodes_path_repeated_query_headers_and_json() {
@@ -68,4 +69,81 @@ mod tests {
         assert!(serde_json::from_value::<TerminalResult>(serde_json::json!({"status":"completed","thing":{"id":"a","name":"b"}})).is_ok());
         assert!(serde_json::from_value::<TerminalResult>(serde_json::json!({"status":"unknown","message":"no"})).is_err());
     }
+
+    #[tokio::test]
+    async fn configured_client_propagates_the_context_active_at_send() {
+        use opentelemetry::{global, Context};
+        use opentelemetry::trace::{SpanContext, SpanId, TraceContextExt, TraceFlags, TraceId, TraceState, TracerProvider};
+        use opentelemetry_sdk::{propagation::TraceContextPropagator, trace::{InMemorySpanExporter, SdkTracerProvider}};
+        use tracing::{Instrument, instrument::WithSubscriber};
+        use tracing_opentelemetry::OpenTelemetrySpanExt;
+        use tracing_subscriber::prelude::*;
+        use wiremock::{Mock, MockServer, ResponseTemplate, matchers::{method, path, header, body_json}};
+
+        // This is the only test using the process-wide propagator. The provider,
+        // subscriber, HTTP server, and requests all belong to this test.
+        global::set_text_map_propagator(TraceContextPropagator::new());
+        let exporter = InMemorySpanExporter::default();
+        let provider = SdkTracerProvider::builder().with_simple_exporter(exporter.clone()).build();
+        let subscriber = tracing_subscriber::registry()
+            .with(tracing_opentelemetry::layer().with_tracer(provider.tracer("contract-test")));
+
+        let work = async {
+            let server = MockServer::start().await;
+            Mock::given(method("POST")).and(path("/things/a%2Fb"))
+                .and(header("authorization", "Bearer test-key"))
+                .and(header("x-request-id", "request-one"))
+                .and(body_json(serde_json::json!({"name":"Podcast"})))
+                .respond_with(ResponseTemplate::new(400).set_body_json(serde_json::json!({"message":"invalid"})))
+                .expect(1).mount(&server).await;
+            let event = "event: progress\ndata: {}\n\n";
+            Mock::given(method("GET")).and(path("/events"))
+                .and(header("accept", "text/event-stream"))
+                .and(header("authorization", "Bearer test-key"))
+                .respond_with(ResponseTemplate::new(200).set_body_string(event))
+                .expect(1).mount(&server).await;
+
+            let http = reqwest_middleware::ClientBuilder::new(reqwest::Client::builder().no_proxy().build().unwrap())
+                .with(reqwest_tracing::TracingMiddleware::default()).build();
+            let api = Client::new(http, server.uri(), Some("test-key".into()));
+            // Build before entering either span: injection must happen at send,
+            // including through a clone of the shared generated client.
+            let post = api.create_thing(CreateThingParams {
+                thing_id: "a/b".into(), tag: None, notify: false, label: None,
+                x_request_id: "request-one".into(), body: CreateThing { name: "Podcast".into() },
+            });
+            let events = api.clone().watch_events();
+            let first = tracing::info_span!("first operation");
+            let second = tracing::info_span!("second operation");
+            for (span, trace_id, span_id) in [(&first, 1u128, 2u64), (&second, 3u128, 4u64)] {
+                span.set_parent(Context::new().with_remote_span_context(SpanContext::new(
+                    TraceId::from(trace_id), SpanId::from(span_id), TraceFlags::SAMPLED, true,
+                    TraceState::from_key_value([("acme", "state")]).unwrap(),
+                )));
+            }
+            let parents = [first.context().span().span_context().clone(), second.context().span().span_context().clone()];
+            let (post, events) = tokio::join!(post.send().instrument(first), events.send().instrument(second));
+            assert!(matches!(CreateThingResponse::decode(post.unwrap()).await.unwrap(), CreateThingResponse::Status400(_)));
+            let WatchEventsResponse::Status200(stream) = WatchEventsResponse::decode(events.unwrap()).await.unwrap() else { panic!("wrong event variant") };
+            assert_eq!(stream.text().await.unwrap(), event);
+            server.verify().await;
+
+            let requests = server.received_requests().await.unwrap();
+            let spans = exporter.get_finished_spans().unwrap();
+            for (route, parent) in [("/things/a%2Fb", &parents[0]), ("/events", &parents[1])] {
+                let request = requests.iter().find(|r| r.url.path() == route).unwrap();
+                let cx = global::get_text_map_propagator(|p| p.extract(&opentelemetry_http::HeaderExtractor(&request.headers)));
+                let propagated = cx.span().span_context().clone();
+                assert!(propagated.is_valid());
+                assert_eq!(propagated.trace_id(), parent.trace_id());
+                assert_ne!(propagated.span_id(), parent.span_id());
+                assert_eq!(request.headers["tracestate"], "acme=state");
+                let http_span = spans.iter().find(|s| s.span_context.span_id() == propagated.span_id()).unwrap();
+                assert_eq!(http_span.span_kind, opentelemetry::trace::SpanKind::Client);
+                assert_eq!(http_span.parent_span_id, parent.span_id());
+            }
+        }.with_subscriber(subscriber);
+        tokio::time::timeout(std::time::Duration::from_secs(5), work).await.expect("trace propagation did not complete");
+        provider.shutdown().unwrap();
+    }
 }