diff --git a/lib/components/fabro-llm/src/codec/openai_compatible/request.rs b/lib/components/fabro-llm/src/codec/openai_compatible/request.rs
index 12be9e84b..1ec6dc8fb 100644
--- a/lib/components/fabro-llm/src/codec/openai_compatible/request.rs
+++ b/lib/components/fabro-llm/src/codec/openai_compatible/request.rs
@@ -1,7 +1,7 @@
 //! Request encoding: canonical `Request` → Chat Completions body.
 
 use super::translate;
-use super::wire::{ApiRequest, ChatMessage};
+use super::wire::{ApiRequest, ChatMessage, StreamOptions};
 use crate::codec::{CodecCtx, EncodedRequest, cache, merge_named_provider_options};
 use crate::error::Error;
 
@@ -10,8 +10,10 @@ use crate::error::Error;
 const KNOWN_OPTION_KEYS: &[&str] = &["auto_cache"];
 
 /// Build the Chat Completions request for `ctx.request`. `stream` toggles the
-/// `stream` body field. The body is assembled as a `serde_json::Value` so
-/// `provider_options.<provider_name>` fields can be merged in before sending.
+/// `stream` body field and the `stream_options.include_usage` opt-in that makes
+/// providers emit the trailing usage chunk. The body is assembled as a
+/// `serde_json::Value` so `provider_options.<provider_name>` fields can be
+/// merged in before sending.
 ///
 /// Returns an error when the request contains a custom tool definition, which
 /// the Chat Completions tool envelope cannot represent.
@@ -55,6 +57,9 @@ pub(super) fn encode(ctx: &CodecCtx<'_>, stream: bool) -> Result<EncodedRequest,
         tool_choice,
         response_format,
         stream: stream.then_some(true),
+        stream_options: stream.then_some(StreamOptions {
+            include_usage: true,
+        }),
     };
 
     let mut body = serde_json::to_value(&api_request).unwrap_or_default();
@@ -172,9 +177,13 @@ mod tests {
             tool_choice:      None,
             response_format:  None,
             stream:           Some(true),
+            stream_options:   Some(StreamOptions {
+                include_usage: true,
+            }),
         };
         let json = serde_json::to_value(&req).unwrap();
         assert_eq!(json["stream"], true);
+        assert_eq!(json["stream_options"]["include_usage"], true);
 
         let req_no_stream = ApiRequest {
             model:            "test".into(),
@@ -188,9 +197,48 @@ mod tests {
             tool_choice:      None,
             response_format:  None,
             stream:           None,
+            stream_options:   None,
         };
         let json_no_stream = serde_json::to_value(&req_no_stream).unwrap();
         assert!(json_no_stream.get("stream").is_none());
+        assert!(json_no_stream.get("stream_options").is_none());
+    }
+
+    /// Chat Completions only emits the trailing usage chunk when the request
+    /// opts in; without it streamed responses report zero tokens and cost
+    /// estimation silently produces $0.
+    #[test]
+    fn encode_opts_into_streaming_usage_when_streaming() {
+        let request = minimal_request();
+
+        let body = encode_body(&request, "kimi", true);
+
+        assert_eq!(body["stream"], true);
+        assert_eq!(body["stream_options"]["include_usage"], true);
+    }
+
+    #[test]
+    fn encode_omits_stream_options_when_not_streaming() {
+        let request = minimal_request();
+
+        let body = encode_body(&request, "kimi", false);
+
+        assert!(body.get("stream_options").is_none());
+    }
+
+    /// The `provider_options.<name>` merge runs after the body is built, so a
+    /// caller pointed at a gateway that rejects the field can still turn it
+    /// off.
+    #[test]
+    fn provider_options_can_override_stream_options() {
+        let mut request = minimal_request();
+        request.provider_options = Some(serde_json::json!({
+            "kimi": { "stream_options": serde_json::Value::Null }
+        }));
+
+        let body = encode_body(&request, "kimi", true);
+
+        assert_eq!(body["stream_options"], serde_json::Value::Null);
     }
 
     #[test]
diff --git a/lib/components/fabro-llm/src/codec/openai_compatible/wire.rs b/lib/components/fabro-llm/src/codec/openai_compatible/wire.rs
index 5bc0a3b93..31019a230 100644
--- a/lib/components/fabro-llm/src/codec/openai_compatible/wire.rs
+++ b/lib/components/fabro-llm/src/codec/openai_compatible/wire.rs
@@ -26,6 +26,16 @@ pub(super) struct ApiRequest {
     pub response_format:  Option<serde_json::Value>,
     #[serde(skip_serializing_if = "Option::is_none")]
     pub stream:           Option<bool>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub stream_options:   Option<StreamOptions>,
+}
+
+/// Streaming options. Chat Completions only emits the trailing usage chunk
+/// when the request opts in, so without this a streamed response reports zero
+/// tokens and costs are estimated at $0.
+#[derive(serde::Serialize)]
+pub(super) struct StreamOptions {
+    pub include_usage: bool,
 }
 
 #[derive(serde::Serialize)]
diff --git a/lib/components/fabro-llm/tests/it/wire/snapshots/it__wire__openai_compatible__stream_text_happy_path_request.snap b/lib/components/fabro-llm/tests/it/wire/snapshots/it__wire__openai_compatible__stream_text_happy_path_request.snap
index fa711fab9..297b156fa 100644
--- a/lib/components/fabro-llm/tests/it/wire/snapshots/it__wire__openai_compatible__stream_text_happy_path_request.snap
+++ b/lib/components/fabro-llm/tests/it/wire/snapshots/it__wire__openai_compatible__stream_text_happy_path_request.snap
@@ -11,5 +11,8 @@ expression: rendered
     }
   ],
   "max_tokens": 128,
-  "stream": true
+  "stream": true,
+  "stream_options": {
+    "include_usage": true
+  }
 }