fix(openai): strict OpenAI wire compatibility — Open WebUI can chat again

/v1/chat/completions answered ordinary client payloads with a bare HTTP 422
(a plain-text body no OpenAI client can parse), so Open WebUI showed neither
an answer nor an error — it just hung. Parse the body leniently instead:
content as string/null/content-part array, tools: null, stream: null, a
string reasoning_effort, max_completion_tokens, messages[].name and
tool_call_id, and a missing Content-Type. Unreadable bodies now come back as
an OpenAI error envelope with 400.

Responses are strict OpenAI JSON: no "tool_calls": null, finish_reason mapped
to the spec's closed set (cortiq serve's max_tokens -> length), never an empty
id, and `model` echoes the id the client requested — the model that actually
answered stays in cortiq.selected_model and X-Cortiq-Selected-Model.

Streaming is re-normalised rather than forwarded verbatim: a leading role
delta, message-shaped chunks converted to delta, one terminal finish_reason,
always a trailing data: [DONE], and an SSE error event when the upstream dies
mid-flight. Adds X-Accel-Buffering: no so a fronting proxy cannot buffer the
stream into a hang.

GET /v1/models now lists managed [[cmf.servers]] models with their live
running/healthy state, so clients can pin a local .cmf directly.

Also strips client bookkeeping keys (chat_id, session_id, metadata, features,
...) from the upstream call and drops the leftover [to_wire] debug prints.

src/admin/mod.rs

@@ -870,6 +870,7 @@ async fn probe_model(State(state): State<SharedState>, Path(id): Path<String>) -
             role: "user".into(),
             content: "ping".into(),
             tool_calls: vec![],
+            ..Default::default()
         }],
         tools: vec![],
         params: GenParams {

src/model.rs

@@ -15,13 +15,53 @@ pub enum RoutingDirective {
     Pinned { model_id: String },
 }
 
-#[derive(Clone, Debug, Serialize, Deserialize)]
+#[derive(Clone, Debug, Default, Serialize, Deserialize)]
 pub struct Message {
     pub role: String, // system | user | assistant | tool
-    #[serde(default)]
+    /// Always a plain string internally. On the wire OpenAI clients legitimately
+    /// send `null` (assistant turns that only carry tool calls) or an array of
+    /// content parts (Open WebUI and every other multimodal UI), so
+    /// [`de_content`] flattens both shapes instead of rejecting the request.
+    #[serde(default, deserialize_with = "de_content")]
     pub content: String,
     #[serde(default, skip_serializing_if = "Vec::is_empty")]
     pub tool_calls: Vec<serde_json::Value>,
+    /// Speaker name (`messages[].name`) — proxied through when the client sends it.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub name: Option<String>,
+    /// Set on `role = "tool"` replies; dropping it breaks multi-turn tool calling.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub tool_call_id: Option<String>,
+}
+
+/// Deserialize `messages[].content` from any shape an OpenAI-compatible client
+/// may send: a string, `null`, or an array of content parts. Text parts are
+/// concatenated; non-text parts (images, audio, files) are skipped — this
+/// gateway routes text, and a picture must not turn into a 422.
+fn de_content<'de, D>(d: D) -> std::result::Result<String, D::Error>
+where
+    D: serde::Deserializer<'de>,
+{
+    use serde::Deserialize as _;
+    Ok(match serde_json::Value::deserialize(d)? {
+        serde_json::Value::Null => String::new(),
+        serde_json::Value::String(s) => s,
+        serde_json::Value::Array(parts) => {
+            let mut out = String::new();
+            for part in parts {
+                // {"type":"text","text":"..."} / {"type":"input_text","text":"..."}
+                let text = part
+                    .get("text")
+                    .and_then(|t| t.as_str())
+                    .or_else(|| part.as_str());
+                if let Some(t) = text {
+                    out.push_str(t);
+                }
+            }
+            out
+        }
+        other => other.to_string(),
+    })
 }
 
 #[derive(Clone, Debug, Default)]

src/pipeline.rs

@@ -430,6 +430,7 @@ impl Pipeline {
                                 role: "system".into(),
                                 content: sys.clone(),
                                 tool_calls: Vec::new(),
+                                ..Default::default()
                             },
                         );
                     }
@@ -457,6 +458,7 @@ impl Pipeline {
                                 role: "system".into(),
                                 content: sys.clone(),
                                 tool_calls: Vec::new(),
+                                ..Default::default()
                             },
                         );
                     }
@@ -564,6 +566,7 @@ impl Pipeline {
                                 role: "system".into(),
                                 content: sys.clone(),
                                 tool_calls: Vec::new(),
+                                ..Default::default()
                             },
                         );
                     }
@@ -591,6 +594,7 @@ impl Pipeline {
                                 role: "system".into(),
                                 content: sys.clone(),
                                 tool_calls: Vec::new(),
+                                ..Default::default()
                             },
                         );
                     }
@@ -734,6 +738,7 @@ fn cached_response(hit: &crate::cache::CacheHit) -> ChatResponse {
                 role: "assistant".into(),
                 content: hit.content.clone(),
                 tool_calls: vec![],
+                ..Default::default()
             },
             finish_reason: "stop".into(),
         }],
@@ -956,6 +961,7 @@ fn shadow_req(model_id: &str, content: String, max_tokens: u32) -> ChatRequest {
             role: "user".to_string(),
             content,
             tool_calls: Vec::new(),
+            ..Default::default()
         }],
         tools: Vec::new(),
         params: GenParams {

src/protocols/anthropic_messages.rs

@@ -5,7 +5,7 @@
 
 use crate::error::{GatewayError, Result};
 use crate::model::{ChatRequest, GenParams, Message, RequestMeta, RoutingDirective};
-use crate::protocols::openai_chat::cortiq_headers;
+use crate::protocols::openai_chat::{cortiq_headers, sse_headers};
 use crate::state::SharedState;
 use axum::response::{IntoResponse, Response};
 use axum::{extract::State, routing::post, Json, Router};
@@ -84,6 +84,7 @@ async fn handler(
             role: "system".into(),
             content: sys,
             tool_calls: vec![],
+            ..Default::default()
         });
     }
     for m in &req.messages {
@@ -91,9 +92,12 @@ async fn handler(
             role: m["role"].as_str().unwrap_or("user").to_string(),
             content: content_to_string(&m["content"]),
             tool_calls: vec![],
+            ..Default::default()
         });
     }
 
+    // Echoed back as-is: clients match the reply against the id they asked for.
+    let requested_model = req.model.clone();
     let canonical = ChatRequest {
         routing: parse_routing(&req.model),
         messages,
@@ -116,13 +120,12 @@ async fn handler(
 
     if req.stream {
         let (info, stream) = state.pipeline.run_stream(canonical, &state).await?;
-        let mut headers = cortiq_headers(&info);
-        headers.insert(
-            axum::http::header::CONTENT_TYPE,
-            axum::http::HeaderValue::from_static("text/event-stream"),
-        );
-        let translated = openai_to_anthropic_sse(stream);
-        return Ok((headers, axum::body::Body::from_stream(translated)).into_response());
+        let translated = openai_to_anthropic_sse(stream, requested_model);
+        return Ok((
+            sse_headers(&info),
+            axum::body::Body::from_stream(translated),
+        )
+            .into_response());
     }
 
     let resp = state.pipeline.run(canonical, &state).await?;
@@ -136,7 +139,7 @@ async fn handler(
         "id": resp.id,
         "type": "message",
         "role": "assistant",
-        "model": resp.model_used,
+        "model": requested_model,
         "content": [{ "type": "text", "text": answer }],
         "stop_reason": "end_turn",
         "stop_sequence": serde_json::Value::Null,
@@ -152,6 +155,7 @@ async fn handler(
 /// events, so Anthropic-native clients can stream regardless of the upstream provider.
 fn openai_to_anthropic_sse(
     stream: crate::providers::ChatStream,
+    model: String,
 ) -> impl futures::Stream<Item = Result<bytes::Bytes>> + Send + 'static {
     use futures::StreamExt;
     async_stream::stream! {
@@ -162,7 +166,7 @@ fn openai_to_anthropic_sse(
         yield Ok(evt("message_start", serde_json::json!({
             "type": "message_start",
             "message": {"id": "msg_gw", "type": "message", "role": "assistant",
-                        "content": [], "model": "cortiq-auto", "stop_reason": null,
+                        "content": [], "model": model, "stop_reason": null,
                         "usage": {"input_tokens": 0, "output_tokens": 0}}
         })));
         yield Ok(evt("content_block_start", serde_json::json!({

src/protocols/mcp.rs

@@ -94,6 +94,7 @@ async fn handle_tool_call(
                     role: "user".into(),
                     content: prompt.to_string(),
                     tool_calls: vec![],
+                    ..Default::default()
                 }],
                 tools: vec![],
                 params: GenParams::default(),

src/protocols/openai_chat.rs

@@ -1,6 +1,17 @@
 //! Incoming adapter for OpenAI Chat Completions: `POST /v1/chat/completions`.
 //! Translates the OpenAI request body into a canonical [`ChatRequest`], passes it
 //! to the pipeline, then converts the canonical [`ChatResponse`] back to OpenAI format.
+//!
+//! Wire-compatibility rules this adapter enforces (see docs/PROTOCOLS.md §2):
+//!   * the request body is parsed leniently — every shape a real OpenAI client
+//!     sends (`content: null`, content-part arrays, `tools: null`, a string
+//!     `reasoning_effort`, UI-private extras) is accepted, and a body we truly
+//!     cannot read comes back as an OpenAI error envelope, never a bare 422;
+//!   * the response is strict OpenAI JSON — no optional `null` fields, a
+//!     spec-legal `finish_reason`, and the *requested* model id echoed back;
+//!   * the SSE stream is re-normalised chunk by chunk and always terminates
+//!     with `data: [DONE]`, so a client can never sit waiting on a half-formed
+//!     stream from an upstream that improvises.
 
 use crate::error::{GatewayError, Result};
 use crate::model::{ChatRequest, GenParams, Message, RequestMeta, RouteInfo, RoutingDirective};
@@ -34,32 +45,113 @@ pub(crate) fn cortiq_headers(c: &RouteInfo) -> axum::http::HeaderMap {
     h
 }
 
+/// Headers every SSE response carries. `X-Accel-Buffering: no` matters when the
+/// gateway sits behind nginx/Traefik — without it the proxy buffers the whole
+/// stream and the client's chat window just spins.
+pub(crate) fn sse_headers(info: &RouteInfo) -> axum::http::HeaderMap {
+    use axum::http::HeaderValue;
+    let mut headers = cortiq_headers(info);
+    headers.insert(
+        axum::http::header::CONTENT_TYPE,
+        HeaderValue::from_static("text/event-stream; charset=utf-8"),
+    );
+    headers.insert(
+        axum::http::header::CACHE_CONTROL,
+        HeaderValue::from_static("no-cache"),
+    );
+    headers.insert("X-Accel-Buffering", HeaderValue::from_static("no"));
+    headers
+}
+
 pub fn routes() -> Router<SharedState> {
     Router::new().route("/v1/chat/completions", post(handler))
 }
 
+/// `reasoning_effort` is a string in the OpenAI spec (`low` | `medium` | `high`)
+/// but a token budget in several local runtimes. Accept both.
+#[derive(Deserialize)]
+#[serde(untagged)]
+enum Effort {
+    Budget(u32),
+    Level(String),
+}
+
+impl Effort {
+    fn to_budget(&self) -> Option<u32> {
+        match self {
+            Self::Budget(n) => Some(*n),
+            Self::Level(s) => match s.trim().to_ascii_lowercase().as_str() {
+                "none" | "off" | "minimal" => Some(0),
+                "low" => Some(512),
+                "medium" | "default" | "auto" => Some(2048),
+                "high" | "max" => Some(8192),
+                _ => None,
+            },
+        }
+    }
+}
+
 #[derive(Deserialize)]
 struct OpenAiChatRequest {
-    model: String,
+    model: Option<String>,
     messages: Vec<Message>,
     #[serde(default)]
     temperature: Option<f32>,
     #[serde(default)]
     max_tokens: Option<u32>,
+    /// The modern spelling of `max_tokens`; clients send one or the other.
+    #[serde(default)]
+    max_completion_tokens: Option<u32>,
     #[serde(default)]
     top_p: Option<f32>,
     #[serde(default)]
     think_budget: Option<u32>,
     #[serde(default)]
-    reasoning_effort: Option<u32>,
+    reasoning_effort: Option<Effort>,
+    /// `null` is a legal value here for several clients, hence `Option`.
     #[serde(default)]
-    stream: bool,
+    stream: Option<bool>,
     #[serde(default)]
-    tools: Vec<serde_json::Value>,
+    tools: Option<Vec<serde_json::Value>>,
     #[serde(flatten)]
     rest: serde_json::Map<String, serde_json::Value>,
 }
 
+/// Keys chat UIs attach to the payload for their own bookkeeping. They are not
+/// part of the OpenAI request schema, and forwarding them to a strict upstream
+/// (llama.cpp, vLLM, `cortiq serve`) is a needless way to earn a 400.
+const CLIENT_PRIVATE_KEYS: &[&str] = &[
+    "chat_id",
+    "session_id",
+    "id",
+    "metadata",
+    "background_tasks",
+    "features",
+    "variables",
+    "model_item",
+    "tool_ids",
+    "filter_ids",
+    "files",
+    "citations",
+    "params",
+    "direct",
+];
+
+/// Strip client-private bookkeeping from the passthrough map, and drop a
+/// non-string `user` (Open WebUI sends an object there for pipelines, which the
+/// OpenAI schema does not allow).
+fn sanitize_passthrough(
+    mut rest: serde_json::Map<String, serde_json::Value>,
+) -> serde_json::Map<String, serde_json::Value> {
+    for k in CLIENT_PRIVATE_KEYS {
+        rest.remove(*k);
+    }
+    if rest.get("user").map(|u| !u.is_string()).unwrap_or(false) {
+        rest.remove("user");
+    }
+    rest
+}
+
 /// Parse the `model` field value into a routing directive.
 /// `cortiq-auto[:profile]` → Auto; otherwise → Pinned(real id).
 fn parse_routing(model: &str) -> RoutingDirective {
@@ -73,10 +165,43 @@ fn parse_routing(model: &str) -> RoutingDirective {
     }
 }
 
+fn now_secs() -> u64 {
+    std::time::SystemTime::now()
+        .duration_since(std::time::UNIX_EPOCH)
+        .unwrap_or_default()
+        .as_secs()
+}
+
+/// Map whatever an upstream calls its stop reason onto the closed set the
+/// OpenAI schema defines. Clients that validate the field (LiteLLM, the
+/// official SDKs, several agent frameworks) reject anything else.
+pub(crate) fn normalize_finish_reason(raw: &str) -> &'static str {
+    match raw.trim().to_ascii_lowercase().as_str() {
+        "length" | "max_tokens" | "max_new_tokens" | "token_limit" => "length",
+        "tool_calls" | "tool_use" | "function_call" => "tool_calls",
+        "content_filter" | "safety" => "content_filter",
+        _ => "stop",
+    }
+}
+
+/// A response id every client can key on. Upstreams that omit `id` (or send an
+/// empty one) would otherwise leave the field blank, which some clients treat
+/// as a malformed completion.
+fn response_id(upstream: &str) -> String {
+    let trimmed = upstream.trim();
+    if !trimmed.is_empty() {
+        return trimmed.to_string();
+    }
+    format!("chatcmpl-{}", crate::admin::random_token(12))
+}
+
 async fn handler(
     State(state): State<SharedState>,
     acct: Option<axum::Extension<super::AccountTag>>,
-    Json(req): Json<OpenAiChatRequest>,
+    // Taken as raw bytes rather than `Json<T>`: axum's extractor rejection is a
+    // plain-text 422 that OpenAI clients cannot parse, and a client that cannot
+    // parse the failure has no answer to show — it just hangs.
+    body: axum::body::Bytes,
 ) -> Result<Response> {
     // hot protocol toggle: if the adapter is disabled in config — return 404
     if !state.live().cfg.protocols.openai_chat {
@@ -84,25 +209,43 @@ async fn handler(
             "openai_chat protocol is disabled".into(),
         ));
     }
+    let req: OpenAiChatRequest = serde_json::from_slice(&body)
+        .map_err(|e| GatewayError::InvalidRequest(format!("invalid request body: {e}")))?;
+
     if req.messages.is_empty() {
         return Err(GatewayError::InvalidRequest(
             "messages must not be empty".into(),
         ));
     }
 
+    // Echoed back verbatim: OpenAI returns the model the caller asked for, and
+    // clients (Open WebUI among them) match the reply against their own id. The
+    // model that actually answered travels in `cortiq.selected_model` and the
+    // `X-Cortiq-Selected-Model` header.
+    let requested_model = req
+        .model
+        .as_deref()
+        .map(str::trim)
+        .filter(|m| !m.is_empty())
+        .unwrap_or("cortiq-auto")
+        .to_string();
+    let stream = req.stream.unwrap_or(false);
+
     let canonical = ChatRequest {
-        routing: parse_routing(&req.model),
+        routing: parse_routing(&requested_model),
         messages: req.messages,
-        tools: req.tools,
+        tools: req.tools.unwrap_or_default(),
         params: GenParams {
             temperature: req.temperature,
-            max_tokens: req.max_tokens,
+            max_tokens: req.max_tokens.or(req.max_completion_tokens),
             top_p: req.top_p,
-            think_budget: req.think_budget.or(req.reasoning_effort),
+            think_budget: req
+                .think_budget
+                .or_else(|| req.reasoning_effort.as_ref().and_then(Effort::to_budget)),
             stop: Vec::new(),
-            passthrough: req.rest,
+            passthrough: sanitize_passthrough(req.rest),
         },
-        stream: req.stream,
+        stream,
         meta: RequestMeta {
             protocol: "openai_chat".into(),
             account: acct.map(|e| e.0 .0.clone()).unwrap_or_default(),
@@ -110,43 +253,51 @@ async fn handler(
         },
     };
 
-    // streaming: forward provider SSE chunks verbatim with X-Cortiq-* headers
-    if req.stream {
-        let (info, stream) = state.pipeline.run_stream(canonical, &state).await?;
-        let mut headers = cortiq_headers(&info);
-        headers.insert(
-            axum::http::header::CONTENT_TYPE,
-            axum::http::HeaderValue::from_static("text/event-stream"),
-        );
-        headers.insert(
-            axum::http::header::CACHE_CONTROL,
-            axum::http::HeaderValue::from_static("no-cache"),
-        );
-        return Ok((headers, axum::body::Body::from_stream(stream)).into_response());
+    // streaming: provider SSE is re-normalised into strict OpenAI chunks
+    if stream {
+        let (info, raw) = state.pipeline.run_stream(canonical, &state).await?;
+        let headers = sse_headers(&info);
+        let normalized = normalize_sse(raw, requested_model);
+        return Ok((headers, axum::body::Body::from_stream(normalized)).into_response());
     }
 
     let resp = state.pipeline.run(canonical, &state).await?;
     let headers = cortiq_headers(&resp.cortiq);
 
-    let mut body = serde_json::json!({
-        "id": resp.id,
-        "object": "chat.completion",
-        "created": std::time::SystemTime::now()
-            .duration_since(std::time::UNIX_EPOCH)
-            .unwrap_or_default()
-            .as_secs(),
-        "model": resp.model_used,
-        "choices": resp.choices.iter().map(|c| {
+    let choices: Vec<serde_json::Value> = resp
+        .choices
+        .iter()
+        .map(|c| {
+            let mut message = serde_json::Map::new();
+            message.insert("role".into(), serde_json::json!(c.message.role));
+            message.insert("content".into(), serde_json::json!(c.message.content));
+            // Absent tool calls are omitted entirely — `"tool_calls": null` is
+            // not in the schema and trips strict clients.
+            if !c.message.tool_calls.is_empty() {
+                message.insert(
+                    "tool_calls".into(),
+                    serde_json::Value::Array(c.message.tool_calls.clone()),
+                );
+            }
+            let finish = if c.message.tool_calls.is_empty() {
+                normalize_finish_reason(&c.finish_reason)
+            } else {
+                "tool_calls"
+            };
             serde_json::json!({
                 "index": c.index,
-                "message": {
-                    "role": c.message.role,
-                    "content": c.message.content,
-                    "tool_calls": if c.message.tool_calls.is_empty() { serde_json::Value::Null } else { serde_json::Value::Array(c.message.tool_calls.clone()) },
-                },
-                "finish_reason": c.finish_reason,
+                "message": serde_json::Value::Object(message),
+                "finish_reason": finish,
             })
-        }).collect::<Vec<_>>(),
+        })
+        .collect();
+
+    let mut body = serde_json::json!({
+        "id": response_id(&resp.id),
+        "object": "chat.completion",
+        "created": now_secs(),
+        "model": requested_model,
+        "choices": choices,
         "usage": {
             "prompt_tokens": resp.usage.prompt_tokens,
             "completion_tokens": resp.usage.completion_tokens,
@@ -155,7 +306,7 @@ async fn handler(
     });
 
     if state.live().cfg.cortiq.echo {
-        body["cortiq"] = serde_json::json!({
+        let mut echo = serde_json::json!({
             "task_label": resp.cortiq.task_label,
             "complexity": {
                 "score": resp.cortiq.complexity_score,
@@ -163,10 +314,230 @@ async fn handler(
             },
             "selected_model": resp.cortiq.selected_model,
             "route_source": resp.cortiq.route_source,
-            "router_request_id": resp.cortiq.router_request_id,
             "cost_usd": resp.cortiq.cost_usd,
         });
+        if let Some(rid) = &resp.cortiq.router_request_id {
+            echo["router_request_id"] = serde_json::json!(rid);
+        }
+        body["cortiq"] = echo;
     }
 
     Ok((headers, Json(body)).into_response())
 }
+
+/// Rewrite an upstream SSE stream into strict OpenAI `chat.completion.chunk`
+/// events.
+///
+/// Every chunk is reissued with an id, `created`, and the *requested* model id;
+/// `message`-shaped chunks are converted to `delta`; stop reasons are mapped to
+/// the spec's closed set; empty deltas are dropped. The stream is guaranteed to
+/// open with a `role` delta, to carry exactly one terminal `finish_reason`, and
+/// to end with `data: [DONE]` — even when the upstream dies mid-flight, in
+/// which case the failure is delivered as an SSE `error` event so the client
+/// shows a message instead of waiting forever.
+fn normalize_sse(
+    stream: crate::providers::ChatStream,
+    model: String,
+) -> impl futures::Stream<Item = Result<bytes::Bytes>> + Send + 'static {
+    use futures::StreamExt;
+    async_stream::stream! {
+        let fallback_id = response_id("");
+        let created = now_secs();
+        let mut buf = String::new();
+        let mut id: Option<String> = None;
+        // Which choice indices already carried a `role` delta (n > 1 gets one each).
+        let mut roled: std::collections::HashSet<u64> = std::collections::HashSet::new();
+        let mut sent_finish = false;
+        let mut failure: Option<String> = None;
+
+        // Emit one normalised event; `None` means "nothing worth sending".
+        macro_rules! chunk {
+            ($choices:expr, $extra:expr) => {{
+                let mut evt = serde_json::json!({
+                    "id": id.clone().unwrap_or_else(|| fallback_id.clone()),
+                    "object": "chat.completion.chunk",
+                    "created": created,
+                    "model": model,
+                    "choices": $choices,
+                });
+                for (k, v) in $extra {
+                    evt[k] = v;
+                }
+                bytes::Bytes::from(format!("data: {evt}\n\n"))
+            }};
+        }
+
+        futures::pin_mut!(stream);
+        'outer: while let Some(item) = stream.next().await {
+            let bytes = match item {
+                Ok(b) => b,
+                Err(e) => {
+                    failure = Some(e.to_string());
+                    break 'outer;
+                }
+            };
+            buf.push_str(&String::from_utf8_lossy(&bytes));
+
+            while let Some(idx) = buf.find("\n\n") {
+                let event: String = buf.drain(..idx + 2).collect();
+                for line in event.lines() {
+                    let Some(data) = line.trim_start().strip_prefix("data:") else { continue };
+                    let data = data.trim();
+                    if data.is_empty() || data == "[DONE]" {
+                        continue;
+                    }
+                    let Ok(v) = serde_json::from_str::<serde_json::Value>(data) else { continue };
+
+                    // An upstream error delivered inside the stream: pass it on
+                    // and stop — the client needs to see it, not time out.
+                    if let Some(err) = v.get("error").filter(|e| !e.is_null()) {
+                        failure = Some(err.to_string());
+                        break 'outer;
+                    }
+
+                    if id.is_none() {
+                        id = v["id"].as_str().filter(|s| !s.is_empty()).map(str::to_string);
+                    }
+
+                    let mut choices = Vec::new();
+                    if let Some(arr) = v["choices"].as_array() {
+                        for (i, c) in arr.iter().enumerate() {
+                            // Some upstreams send a full `message` per chunk
+                            // instead of a `delta`; both mean the same thing here.
+                            let src = if c["delta"].is_object() { &c["delta"] } else { &c["message"] };
+                            let index = c["index"].as_u64().unwrap_or(i as u64);
+                            let mut delta = serde_json::Map::new();
+                            if roled.insert(index) {
+                                delta.insert("role".into(), serde_json::json!("assistant"));
+                            }
+                            if let Some(text) = src["content"].as_str() {
+                                if !text.is_empty() {
+                                    delta.insert("content".into(), serde_json::json!(text));
+                                }
+                            }
+                            // Reasoning traces and citations are not in the base
+                            // schema but every client that understands them
+                            // ignores them safely, so they are worth keeping.
+                            for key in ["reasoning_content", "reasoning", "thinking", "refusal", "annotations"] {
+                                if let Some(val) = src.get(key).filter(|v| !v.is_null()) {
+                                    delta.insert(key.into(), val.clone());
+                                }
+                            }
+                            if let Some(tc) = src["tool_calls"].as_array().filter(|a| !a.is_empty()) {
+                                delta.insert("tool_calls".into(), serde_json::Value::Array(tc.clone()));
+                            }
+
+                            let finish = c["finish_reason"].as_str().map(normalize_finish_reason);
+                            if finish.is_none() && delta.is_empty() {
+                                continue;
+                            }
+                            let mut choice = serde_json::json!({
+                                "index": index,
+                                "delta": serde_json::Value::Object(delta),
+                            });
+                            if let Some(f) = finish {
+                                choice["finish_reason"] = serde_json::json!(f);
+                                sent_finish = true;
+                            }
+                            choices.push(choice);
+                        }
+                    }
+
+                    // Terminal metadata rides on a choice-less chunk, exactly
+                    // as OpenAI ships `usage` when `stream_options` asks for it.
+                    let mut extra: Vec<(&str, serde_json::Value)> = Vec::new();
+                    if let Some(u) = v.get("usage").filter(|u| !u.is_null()) {
+                        extra.push(("usage", u.clone()));
+                    }
+                    for key in ["cortiq_cost_usd", "cortiq_estimated"] {
+                        if let Some(val) = v.get(key).filter(|v| !v.is_null()) {
+                            extra.push((key, val.clone()));
+                        }
+                    }
+
+                    if !choices.is_empty() || !extra.is_empty() {
+                        yield Ok(chunk!(choices, extra));
+                    }
+                }
+            }
+        }
+
+        if let Some(message) = failure {
+            let evt = serde_json::json!({
+                "error": { "message": message, "type": "upstream_unavailable", "code": "stream_failed" }
+            });
+            yield Ok(bytes::Bytes::from(format!("data: {evt}\n\n")));
+        }
+
+        // Close the stream properly whatever the upstream did: a client that
+        // never sees a stop reason and a [DONE] keeps its spinner turning.
+        if !sent_finish {
+            let mut delta = serde_json::Map::new();
+            if roled.insert(0) {
+                delta.insert("role".into(), serde_json::json!("assistant"));
+            }
+            let choices = vec![serde_json::json!({
+                "index": 0,
+                "delta": serde_json::Value::Object(delta),
+                "finish_reason": "stop",
+            })];
+            let extra: Vec<(&str, serde_json::Value)> = Vec::new();
+            yield Ok(chunk!(choices, extra));
+        }
+        yield Ok(bytes::Bytes::from("data: [DONE]\n\n"));
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn content_parts_and_null_are_accepted() {
+        let body = serde_json::json!({
+            "model": "cortiq-auto",
+            "messages": [
+                {"role": "user", "content": [{"type": "text", "text": "hello "}, {"type": "image_url", "image_url": {"url": "x"}}, {"type": "text", "text": "world"}]},
+                {"role": "assistant", "content": null},
+                {"role": "tool", "content": "42", "tool_call_id": "call_1"}
+            ],
+            "tools": null,
+            "reasoning_effort": "high",
+            "chat_id": "owui-123"
+        });
+        let req: OpenAiChatRequest = serde_json::from_value(body).expect("must parse");
+        assert_eq!(req.messages[0].content, "hello world");
+        assert_eq!(req.messages[1].content, "");
+        assert_eq!(req.messages[2].tool_call_id.as_deref(), Some("call_1"));
+        assert!(req.tools.unwrap_or_default().is_empty());
+        assert_eq!(
+            req.reasoning_effort.as_ref().and_then(Effort::to_budget),
+            Some(8192)
+        );
+        assert!(!sanitize_passthrough(req.rest).contains_key("chat_id"));
+    }
+
+    #[test]
+    fn finish_reasons_map_to_the_openai_set() {
+        assert_eq!(normalize_finish_reason("max_tokens"), "length");
+        assert_eq!(normalize_finish_reason("eos"), "stop");
+        assert_eq!(normalize_finish_reason("tool_use"), "tool_calls");
+    }
+
+    #[tokio::test]
+    async fn stream_is_closed_even_when_the_upstream_stops_early() {
+        use futures::StreamExt;
+        let upstream = futures::stream::iter(vec![Ok(bytes::Bytes::from(
+            "data: {\"choices\":[{\"index\":0,\"delta\":{\"content\":\"hi\"}}]}\n\n",
+        ))]);
+        let out: Vec<String> = normalize_sse(Box::pin(upstream), "cortiq-auto".into())
+            .map(|b| String::from_utf8_lossy(&b.unwrap()).to_string())
+            .collect()
+            .await;
+        let joined = out.join("");
+        assert!(joined.contains("\"role\":\"assistant\""));
+        assert!(joined.contains("\"model\":\"cortiq-auto\""));
+        assert!(joined.contains("\"finish_reason\":\"stop\""));
+        assert!(joined.trim_end().ends_with("data: [DONE]"));
+    }
+}

src/protocols/openai_completions.rs

@@ -4,7 +4,7 @@
 
 use crate::error::{GatewayError, Result};
 use crate::model::{ChatRequest, GenParams, Message, RequestMeta, RoutingDirective};
-use crate::protocols::openai_chat::cortiq_headers;
+use crate::protocols::openai_chat::{cortiq_headers, normalize_finish_reason, sse_headers};
 use crate::state::SharedState;
 use axum::response::{IntoResponse, Response};
 use axum::{extract::State, routing::post, Json, Router};
@@ -71,12 +71,15 @@ async fn handler(
         ));
     }
 
+    // Echoed back as-is: clients match the reply against the id they asked for.
+    let requested_model = req.model.clone();
     let canonical = ChatRequest {
         routing: parse_routing(&req.model),
         messages: vec![Message {
             role: "user".into(),
             content: prompt,
             tool_calls: vec![],
+            ..Default::default()
         }],
         tools: vec![],
         params: GenParams {
@@ -97,13 +100,8 @@ async fn handler(
 
     if req.stream {
         let (info, stream) = state.pipeline.run_stream(canonical, &state).await?;
-        let mut headers = cortiq_headers(&info);
-        headers.insert(
-            axum::http::header::CONTENT_TYPE,
-            axum::http::HeaderValue::from_static("text/event-stream"),
-        );
         return Ok((
-            headers,
+            sse_headers(&info),
             axum::body::Body::from_stream(chat_to_completions_sse(stream)),
         )
             .into_response());
@@ -115,11 +113,12 @@ async fn handler(
         .first()
         .map(|c| c.message.content.clone())
         .unwrap_or_default();
-    let finish = resp
-        .choices
-        .first()
-        .map(|c| c.finish_reason.clone())
-        .unwrap_or_else(|| "stop".into());
+    let finish = normalize_finish_reason(
+        resp.choices
+            .first()
+            .map(|c| c.finish_reason.as_str())
+            .unwrap_or("stop"),
+    );
     let headers = cortiq_headers(&resp.cortiq);
     let body = serde_json::json!({
         "id": resp.id,
@@ -128,7 +127,7 @@ async fn handler(
             .duration_since(std::time::UNIX_EPOCH)
             .unwrap_or_default()
             .as_secs(),
-        "model": resp.model_used,
+        "model": requested_model,
         "choices": [{ "text": answer, "index": 0, "logprobs": serde_json::Value::Null, "finish_reason": finish }],
         "usage": {
             "prompt_tokens": resp.usage.prompt_tokens,

src/protocols/openai_models.rs

@@ -1,5 +1,10 @@
 //! Inbound OpenAI Models adapter: `GET /v1/models`.
-//! Lists the configured pool (plus the virtual `cortiq-auto`) for client discovery.
+//! Lists everything a client can address: the virtual `cortiq-auto`, the
+//! configured `[[models]]` pool, and the managed local `[[cmf.servers]]`.
+//!
+//! The managed CMF servers belong here because they are routable model ids like
+//! any other — omitting them left OpenAI clients (Open WebUI among them) unable
+//! to pin a local model even though the gateway would happily serve it.
 
 use crate::error::{GatewayError, Result};
 use crate::state::SharedState;
@@ -9,6 +14,13 @@ pub fn routes() -> Router<SharedState> {
     Router::new().route("/v1/models", get(handler))
 }
 
+fn now_secs() -> u64 {
+    std::time::SystemTime::now()
+        .duration_since(std::time::UNIX_EPOCH)
+        .unwrap_or_default()
+        .as_secs()
+}
+
 async fn handler(State(state): State<SharedState>) -> Result<impl IntoResponse> {
     let live = state.live();
     if !live.cfg.protocols.openai_models {
@@ -16,17 +28,51 @@ async fn handler(State(state): State<SharedState>) -> Result<impl IntoResponse>
             "openai_models protocol is disabled".into(),
         ));
     }
+    let created = now_secs();
     let mut data = vec![serde_json::json!({
         "id": "cortiq-auto",
         "object": "model",
+        "created": created,
         "owned_by": "cortiq",
     })];
+    let mut seen: std::collections::HashSet<String> =
+        std::collections::HashSet::from(["cortiq-auto".to_string()]);
+
     for m in &live.cfg.models {
+        if !seen.insert(m.id.clone()) {
+            continue;
+        }
         data.push(serde_json::json!({
             "id": m.id,
             "object": "model",
+            "created": created,
             "owned_by": m.provider,
         }));
     }
+
+    // Managed local CMF servers. Health is reported alongside (a non-standard
+    // field clients ignore) rather than used as a filter: a large `.cmf` takes
+    // minutes to load, and a model that vanishes from the list while it warms up
+    // is worse than one marked "not ready yet".
+    let cmf = state.cmf.status();
+    for s in live.cfg.cmf.effective_servers() {
+        if !seen.insert(s.id.clone()) {
+            continue; // a static [[models]] entry with the same id wins
+        }
+        let status = cmf.servers.iter().find(|st| st.id == s.id);
+        data.push(serde_json::json!({
+            "id": s.id,
+            "object": "model",
+            "created": created,
+            "owned_by": "cortiq-cmf",
+            "cortiq": {
+                "kind": "cmf",
+                "local": true,
+                "running": status.map(|st| st.running).unwrap_or(false),
+                "healthy": status.map(|st| st.healthy).unwrap_or(false),
+            },
+        }));
+    }
+
     Ok(Json(serde_json::json!({ "object": "list", "data": data })))
 }

src/providers/anthropic.rs

@@ -146,6 +146,7 @@ impl Provider for AnthropicProvider {
                     role: "assistant".into(),
                     content,
                     tool_calls: vec![],
+                    ..Default::default()
                 },
                 finish_reason: v["stop_reason"].as_str().unwrap_or("stop").to_string(),
             }],

src/providers/openai.rs

@@ -54,13 +54,11 @@ impl OpenAiProvider {
         if let Some(m) = req.params.max_tokens {
             body["max_tokens"] = m.into();
         }
-        eprintln!("[to_wire] think_budget={:?}", req.params.think_budget);
         if let Some(tb) = req.params.think_budget {
             body["think_budget"] = tb.into();
             body["reasoning_effort"] = tb.into();
             // cortiq serve uses enable_thinking (bool): 0 = off, >0 = on
             body["enable_thinking"] = (tb > 0).into();
-            eprintln!("[to_wire] SET enable_thinking={}", tb > 0);
         }
         if !req.tools.is_empty() {
             body["tools"] = serde_json::Value::Array(req.tools.clone());
@@ -69,10 +67,6 @@ impl OpenAiProvider {
         for (k, v) in &req.params.passthrough {
             body[k] = v.clone();
         }
-        eprintln!(
-            "[to_wire] enable_thinking={:?}",
-            body.get("enable_thinking")
-        );
         body
     }
 }
@@ -141,6 +135,7 @@ impl Provider for OpenAiProvider {
                     role,
                     content,
                     tool_calls,
+                    ..Default::default()
                 },
                 finish_reason: c["finish_reason"].as_str().unwrap_or("stop").to_string(),
             });