OpenAI-compatible HTTP API: stdlib-only gateway over SERVE with KV prefix reuse across stateless requests (#21)

* Add OpenAI-compatible HTTP API

* Support browser API clients

* Handle missing KV cache during rewind

README.md

@@ -93,6 +93,45 @@ COLI_MODEL=/nvme/glm52_i4 ./coli chat
 
 The engine at runtime is pure C — python is only used by the one-time converter.
 
+### OpenAI-compatible API
+
+`coli serve` keeps one model process loaded and exposes a text-only OpenAI-compatible
+HTTP API. The gateway uses only the Python standard library; inference still runs in
+the same dependency-free C engine.
+
+```bash
+cd c
+COLI_MODEL=/nvme/glm52_i4 COLI_API_KEY=local-secret ./coli serve \
+  --host 127.0.0.1 --port 8000 --model-id glm-5.2-colibri
+
+curl http://127.0.0.1:8000/v1/chat/completions \
+  -H 'Authorization: Bearer local-secret' \
+  -H 'Content-Type: application/json' \
+  -d '{
+    "model": "glm-5.2-colibri",
+    "messages": [{"role": "user", "content": "Hello"}],
+    "stream": true
+  }'
+```
+
+Implemented endpoints are `GET /v1/models`, `GET /v1/models/{model}`,
+`POST /v1/chat/completions`, and legacy `POST /v1/completions`. Chat and
+completion requests support JSON responses, SSE streaming, usage counts,
+`max_tokens`/`max_completion_tokens`, `temperature`, and `top_p`. The extension
+`enable_thinking: true` enables GLM-5.2's reasoning block; the standard
+`reasoning_effort` field also enables it unless set to `none`.
+
+The first version is deliberately text-only and serves one generation at a time:
+the 744B model stays in one persistent process, so concurrent HTTP requests queue
+instead of loading duplicate model copies. Tools, image/audio input, custom stop
+sequences, log probabilities, and token penalties return an explicit error rather
+than being silently ignored. The default bind address is localhost; set
+`COLI_API_KEY` before exposing the server beyond the machine.
+
+Browser access from the Vite development server and Tauri local origins is enabled
+by default. Repeat `--cors-origin https://your-ui.example` to allow another exact
+origin, or use `--cors-origin '*'` only on a trusted local network.
+
 ### Experimental resident CUDA backend
 
 colibrì includes an opt-in CUDA backend for model-resident tensors. Streaming
@@ -266,6 +305,7 @@ c/
 ├── backend_cuda.*        optional CUDA tier
 ├── Makefile              build and local checks
 ├── coli                  user-facing CLI
+├── openai_server.py      OpenAI-compatible HTTP gateway
 ├── setup.sh              one-command local setup
 ├── tools/                offline conversion, fixtures and benchmarks
 ├── scripts/              long-running conversion helpers

c/coli

@@ -4,6 +4,7 @@ colibrì — piccolo motore, modello immenso.
 CLI per far girare GLM-5.2 (744B) in locale, su CPU, in ~15-26 GB di RAM.
 
   coli chat                 chat interattiva (carica il modello UNA volta)
+  coli serve                API HTTP compatibile OpenAI (motore persistente)
   coli run "prompt"         generazione singola
   coli info                 stato: modello, RAM, disco, config
   coli bench [task...]      benchmark di qualità (MMLU/HellaSwag/...)
@@ -375,6 +376,12 @@ def cmd_chat(a):
         except Exception: pass
     print(f"  {C.teal}ciao{C.r} {C.dim}— il colibrì torna al nido{C.r} 🐦\n")
 
+def cmd_serve(a):
+    need_model(a.model)
+    from openai_server import serve
+    serve(a.model, a.host, a.port, a.model_id, a.api_key,
+          a.cap, a.ngen, GLM, env_for(a), a.cors_origin)
+
 def cmd_bench(a):
     need_model(a.model)
     banner("bench")
@@ -427,13 +434,18 @@ def main():
     sub.add_parser("build", parents=[common]); sub.add_parser("info", parents=[common])
     pr=sub.add_parser("run", parents=[common]);  pr.add_argument("prompt", nargs="*")
     sub.add_parser("chat", parents=[common])
+    ps=sub.add_parser("serve", parents=[common])
+    ps.add_argument("--host",default="127.0.0.1"); ps.add_argument("--port",type=int,default=8000)
+    ps.add_argument("--model-id",default=os.environ.get("COLI_MODEL_ID","glm-5.2-colibri"))
+    ps.add_argument("--api-key",default=os.environ.get("COLI_API_KEY"))
+    ps.add_argument("--cors-origin",action="append",default=None)
     pb=sub.add_parser("bench", parents=[common]); pb.add_argument("tasks", nargs="*")
     pb.add_argument("--limit",type=int,default=40); pb.add_argument("--data",default=os.path.join(HERE,"bench"))
     pc=sub.add_parser("convert", parents=[common]); pc.add_argument("--repo",default="zai-org/GLM-5.2-FP8")
     pc.add_argument("--ebits",type=int,default=4); pc.add_argument("--io-bits",type=int,default=8); pc.add_argument("--xbits",type=int,default=0)
     pc.add_argument("--no-mtp",action="store_true",help="salta la testa MTP (niente draft speculativi)")
     a=ap.parse_args()
-    {"build":cmd_build,"info":cmd_info,"run":cmd_run,"chat":cmd_chat,"bench":cmd_bench,
+    {"build":cmd_build,"info":cmd_info,"run":cmd_run,"chat":cmd_chat,"serve":cmd_serve,"bench":cmd_bench,
      "convert":cmd_convert}.get(a.cmd, lambda _:(banner(),print(__doc__)))(a)
 
 if __name__=="__main__":

c/glm.c

@@ -1828,12 +1828,14 @@ static void kv_hdr(Model *m, int32_t *h, int nrec){
     h[0]=c->n_layers; h[1]=c->kv_lora; h[2]=c->qk_rope;
     h[3]=m->has_dsa?c->index_hd:0; h[4]=nic; h[5]=c->vocab; h[6]=nrec; h[7]=0;
 }
-static void kv_disk_reset(void){
+static void kv_disk_truncate(int nrec){
     if(!g_kvsave) return;
-    FILE *f=fopen(g_kv_path,"r+b"); if(!f) return;
+    FILE *f=fopen(g_kv_path,"r+b");
-    int32_t nz=0; fseek(f,8+6*4,SEEK_SET); fwrite(&nz,4,1,f); fclose(f);
+    if(!f){ g_kv_nrec=0; return; }
-    g_kv_nrec=0;
+    g_kv_nrec=nrec;
+    int32_t nr=nrec; fseek(f,8+6*4,SEEK_SET); fwrite(&nr,4,1,f); fclose(f);
 }
+static void kv_disk_reset(void){ kv_disk_truncate(0); }
 static void kv_disk_append(Model *m, const int *hist, int len){
     if(!g_kvsave || len<=g_kv_nrec) return;
     Cfg *c=&m->c;
@@ -1930,33 +1932,79 @@ static void run_serve(Model *m, const char *snap){
             printf("STAT %d %.2f %.1f %.2f\n", prod, prod/tdt, (dh+dm)>0?100.0*dh/(dh+dm):0.0, rss_gb());
             fflush(stdout); kv_disk_append(m,hist,len); repin_pass(m); continue; }   /* RFC: re-pin a caldo tra i turni / live re-pin between turns */
         if(nr<1){ printf("\x01\x01" "END" "\x01\x01\n"); printf("STAT 0 0.00 0.0 %.2f\n", rss_gb()); fflush(stdout); continue; }
-        int bl=0;                                /* costruisce il testo del turno (con template) */
+        /* API mode: an exact, length-prefixed prompt. Unlike the interactive
+         * line protocol this accepts newlines. The tokenized prompt is matched
+         * against hist so the common KV prefix survives stateless HTTP turns.
+         * Per-request generation controls follow the byte count:
+         *   \x02PROMPT <bytes> <max_tokens> <temperature> <top_p>\n<prompt>\n */
+        char *raw=NULL, *input=line;
+        int input_n=(int)nr, raw_mode=0, req_ngen=ngen, prompt_tokens=0;
+        float base_temp=g_temp, base_nuc=g_nuc;
+        if(!strncmp(line,"\x02PROMPT ",8)){
+            unsigned long long nb=0; double rt=0, rp=0;
+            if(sscanf(line+8,"%llu %d %lf %lf",&nb,&req_ngen,&rt,&rp)!=4 ||
+               nb>(16u<<20) || req_ngen<1 || rt<0 || rt>2 || rp<=0 || rp>1){
+                printf("\x01\x01" "END" "\x01\x01\n"); printf("STAT 0 0.00 0.0 %.2f 0 0\n",rss_gb()); fflush(stdout); continue;
+            }
+            raw=malloc((size_t)nb+1); if(!raw){fprintf(stderr,"OOM raw prompt\n");exit(1);}
+            if(fread(raw,1,(size_t)nb,stdin)!=(size_t)nb){free(raw);break;}
+            int delim=fgetc(stdin); if(delim!='\n' && delim!=EOF) ungetc(delim,stdin);
+            if(memchr(raw,0,(size_t)nb)){free(raw); printf("\x01\x01" "END" "\x01\x01\n");
+                printf("STAT 0 0.00 0.0 %.2f 0 0\n",rss_gb()); fflush(stdout); continue;}
+            raw[nb]=0; input=raw; input_n=(int)nb; raw_mode=1;
+            if(req_ngen>ngen) req_ngen=ngen;
+            g_temp=(float)rt; g_nuc=(float)rp;
+        }
+        int bl=0, k=0;                           /* costruisce/tokenizza il turno */
         /* template UFFICIALE GLM-5.2 (chat_template.jinja): niente \n dopo i ruoli, e dopo
          * <|assistant|> serve SEMPRE il blocco think — <think></think> lo DISATTIVA (nothink):
          * col template sbagliato il modello farfuglia e non emette mai lo stop. THINK=1 lo abilita. */
         const char *tk = getenv("THINK")&&atoi(getenv("THINK"))? "<think>" : "<think></think>";
+        if(raw_mode){
+            int *tmp=malloc(maxctx*sizeof(int)); if(!tmp){fprintf(stderr,"OOM raw tokens\n");exit(1);}
+            prompt_tokens=tok_encode(&T,input,input_n,tmp,maxctx-8-g_draft);
+            int old_len=len, prefix=0;
+            while(prefix<old_len && prefix<prompt_tokens && hist[prefix]==tmp[prefix]) prefix++;
+            if(prefix<old_len){
+                len=prefix;
+                if(m->has_mtp) m->kv_start[m->c.n_layers]=-1;
+                kv_disk_truncate(len);             /* il prossimo append sovrascrive solo la coda */
+            }
+            k=prompt_tokens-len;
+            if(k>0) memcpy(hist+len,tmp+len,k*sizeof(int));
+            fprintf(stderr,"[API] KV prefix %d/%d token, prefill %d\n",len,prompt_tokens,k);
+            free(tmp);
+        } else {
             if(templ){ if(first) bl+=snprintf(buf+bl,(1<<16)-bl,"[gMASK]<sop>");
-                   bl+=snprintf(buf+bl,(1<<16)-bl,"<|user|>%s<|assistant|>%s",line,tk); }
+                       bl+=snprintf(buf+bl,(1<<16)-bl,"<|user|>%s<|assistant|>%s",input,tk); }
-        else bl+=snprintf(buf+bl,(1<<16)-bl,"%s",line);
+            else bl+=snprintf(buf+bl,(1<<16)-bl,"%s",input);
-        int k=tok_encode(&T,buf,bl,hist+len,maxctx-len);
+            k=tok_encode(&T,buf,bl,hist+len,maxctx-len); prompt_tokens=k;
-        if(k<1){ printf("\x01\x01" "END" "\x01\x01\n"); printf("STAT 0 0.00 0.0 %.2f\n", rss_gb()); fflush(stdout); continue; }
+            if(len+k+8+g_draft>=maxctx){ len=0; first=1; kv_disk_reset();
-        if(len+k+8+g_draft>=maxctx){ len=0; first=1; kv_disk_reset();   /* contesto pieno: azzera e ricomincia */
+                bl=0; if(templ){ bl+=snprintf(buf+bl,(1<<16)-bl,"[gMASK]<sop><|user|>%s<|assistant|>%s",input,tk); }
-            bl=0; if(templ){ bl+=snprintf(buf+bl,(1<<16)-bl,"[gMASK]<sop><|user|>%s<|assistant|>%s",line,tk); }
+                else bl+=snprintf(buf+bl,(1<<16)-bl,"%s",input);
-            else bl+=snprintf(buf+bl,(1<<16)-bl,"%s",line);
+                k=tok_encode(&T,buf,bl,hist,maxctx); if(k>maxctx-8-g_draft) k=maxctx-8-g_draft;
-            k=tok_encode(&T,buf,bl,hist,maxctx); if(k>maxctx-8-g_draft) k=maxctx-8-g_draft; }
+                prompt_tokens=k;
+            }
+        }
+        if(prompt_tokens<1){ free(raw); g_temp=base_temp; g_nuc=base_nuc;
+            printf("\x01\x01" "END" "\x01\x01\n"); printf("STAT 0 0.00 0.0 %.2f 0 0\n", rss_gb()); fflush(stdout); continue; }
         first=0;
-        int cur=ngen; if(len+k+cur+g_draft+2>=maxctx) cur=maxctx-len-k-g_draft-2;
+        int cur=req_ngen; if(len+k+cur+g_draft+2>=maxctx) cur=maxctx-len-k-g_draft-2;
         uint64_t h0=m->hits, ms0=m->miss; double tt0=now_s();
-        float *logit=step(m,hist+len,k,len); len+=k;
+        float *logit;
+        if(k>0){ logit=step(m,hist+len,k,len); len+=k; }
+        else logit=step(m,hist+len-1,1,len-1);   /* prompt identico/prefisso: rigenera i logits */
         EmitStream es={&T,m,now_s(),0,1};
         int prod=0;
         if(cur>0) prod=spec_decode(m,hist,len,cur,eos,logit,emit_stream,&es,&len);
         else free(logit);
         double tdt=now_s()-tt0; if(tdt<1e-6) tdt=1e-6;
         double dh=(double)(m->hits-h0), dm=(double)(m->miss-ms0);
-        printf("\n\x01\x01" "END" "\x01\x01\n");
+        printf("%s\x01\x01" "END" "\x01\x01\n",raw_mode?"":"\n");
-        printf("STAT %d %.2f %.1f %.2f\n", prod, prod/tdt, (dh+dm)>0?100.0*dh/(dh+dm):0.0, rss_gb());
+        printf("STAT %d %.2f %.1f %.2f %d %d\n", prod, prod/tdt,
+            (dh+dm)>0?100.0*dh/(dh+dm):0.0, rss_gb(), prompt_tokens, prod>=cur);
         fflush(stdout);
+        free(raw); g_temp=base_temp; g_nuc=base_nuc;
         usage_save(m);                   /* la cache che impara: storia aggiornata a ogni turno */
         kv_disk_append(m,hist,len);      /* KV su disco: il prossimo avvio riparte da qui */
     }

c/openai_server.py

@@ -0,0 +1,466 @@
+#!/usr/bin/env python3
+"""Dependency-free OpenAI-compatible HTTP gateway for the colibri engine."""
+
+import argparse
+import codecs
+import json
+import os
+import signal
+import subprocess
+import sys
+import threading
+import time
+import uuid
+from http.server import BaseHTTPRequestHandler, ThreadingHTTPServer
+from pathlib import Path
+from urllib.parse import unquote, urlsplit
+
+
+HERE = Path(__file__).resolve().parent
+END = b"\x01\x01END\x01\x01\n"
+READY = b"\x01\x01READY\x01\x01\n"
+MAX_BODY = 4 << 20
+DEFAULT_CORS_ORIGINS = (
+    "http://127.0.0.1:5173",
+    "http://localhost:5173",
+    "http://tauri.localhost",
+    "tauri://localhost",
+)
+
+
+class APIError(Exception):
+    def __init__(self, status, message, param=None, code=None, error_type="invalid_request_error"):
+        super().__init__(message)
+        self.status = status
+        self.message = message
+        self.param = param
+        self.code = code
+        self.error_type = error_type
+
+
+def error_object(error):
+    return {"error": {"message": error.message, "type": error.error_type,
+                      "param": error.param, "code": error.code}}
+
+
+def content_text(content, param):
+    if isinstance(content, str):
+        return content
+    if not isinstance(content, list):
+        raise APIError(400, "Message content must be a string or an array of text parts.", param)
+    parts = []
+    for index, part in enumerate(content):
+        if not isinstance(part, dict) or part.get("type") not in ("text", "input_text"):
+            raise APIError(400, "Colibri currently supports text message content only.",
+                           f"{param}.{index}", "unsupported_content_type")
+        if not isinstance(part.get("text"), str):
+            raise APIError(400, "Text content parts require a string `text` field.",
+                           f"{param}.{index}.text")
+        parts.append(part["text"])
+    return "".join(parts)
+
+
+def render_chat(messages, enable_thinking=False, reasoning_effort=None):
+    """Render the text-only subset of the official GLM-5.2 chat template."""
+    if not isinstance(messages, list) or not messages:
+        raise APIError(400, "`messages` must be a non-empty array.", "messages")
+    prompt = ["[gMASK]<sop>"]
+    if enable_thinking:
+        effort = "High" if reasoning_effort == "high" else "Max"
+        prompt.append(f"<|system|>Reasoning Effort: {effort}")
+    for index, message in enumerate(messages):
+        if not isinstance(message, dict):
+            raise APIError(400, "Each message must be an object.", f"messages.{index}")
+        role = message.get("role")
+        text = content_text(message.get("content"), f"messages.{index}.content")
+        if role in ("system", "developer"):
+            prompt.append(f"<|system|>{text}")
+        elif role == "user":
+            prompt.append(f"<|user|>{text}")
+        elif role == "assistant":
+            prompt.append(f"<|assistant|><think></think>{text.strip()}")
+        else:
+            raise APIError(400, f"Unsupported message role: {role!r}.",
+                           f"messages.{index}.role", "unsupported_role")
+    prompt.append("<|assistant|><think>" if enable_thinking else
+                  "<|assistant|><think></think>")
+    return "".join(prompt)
+
+
+def generation_options(body, limit):
+    if body.get("n", 1) != 1:
+        raise APIError(400, "Colibri currently supports `n=1` only.", "n", "unsupported_value")
+    for name in ("tools", "functions"):
+        if body.get(name):
+            raise APIError(400, f"`{name}` is not supported yet.", name, "unsupported_parameter")
+    if body.get("stop") is not None:
+        raise APIError(400, "Custom stop sequences are not supported yet.", "stop", "unsupported_parameter")
+    if body.get("logprobs"):
+        raise APIError(400, "Log probabilities are not supported yet.", "logprobs", "unsupported_parameter")
+    if body.get("frequency_penalty", 0) or body.get("presence_penalty", 0):
+        raise APIError(400, "Token penalties are not supported yet.", None, "unsupported_parameter")
+    if body.get("seed") is not None:
+        raise APIError(400, "Per-request seeds are not supported yet.", "seed", "unsupported_parameter")
+    response_format = body.get("response_format")
+    if response_format not in (None, {"type": "text"}):
+        raise APIError(400, "Only the default text response format is supported.",
+                       "response_format", "unsupported_parameter")
+
+    maximum = body.get("max_completion_tokens")
+    maximum_param = "max_completion_tokens"
+    if maximum is None:
+        maximum = body.get("max_tokens")
+        maximum_param = "max_tokens"
+    if maximum is None:
+        maximum = min(256, limit)
+    temperature = body.get("temperature")
+    top_p = body.get("top_p")
+    temperature = 0.7 if temperature is None else temperature
+    top_p = 0.9 if top_p is None else top_p
+    if isinstance(maximum, bool) or not isinstance(maximum, int) or not 1 <= maximum <= limit:
+        raise APIError(400, f"`{maximum_param}` must be an integer between 1 and {limit}.", maximum_param)
+    if isinstance(temperature, bool) or not isinstance(temperature, (int, float)) or not 0 <= temperature <= 2:
+        raise APIError(400, "`temperature` must be between 0 and 2.", "temperature")
+    if isinstance(top_p, bool) or not isinstance(top_p, (int, float)) or not 0 < top_p <= 1:
+        raise APIError(400, "`top_p` must be greater than 0 and at most 1.", "top_p")
+    return maximum, float(temperature), float(top_p)
+
+
+def read_engine_turn(stream, sentinel, on_bytes):
+    pending = b""
+    while True:
+        byte = stream.read(1)
+        if byte == b"":
+            raise RuntimeError("colibri engine exited unexpectedly")
+        pending += byte
+        if pending.endswith(sentinel):
+            data = pending[:-len(sentinel)]
+            if data:
+                on_bytes(data)
+            break
+        if len(pending) > len(sentinel):
+            on_bytes(pending[:-len(sentinel)])
+            pending = pending[-len(sentinel):]
+
+    fields = stream.readline().decode("utf-8", "replace").strip().split()
+    if len(fields) < 5 or fields[0] != "STAT":
+        raise RuntimeError(f"invalid engine status: {' '.join(fields)}")
+    return {
+        "completion_tokens": int(fields[1]),
+        "tokens_per_second": float(fields[2]),
+        "cache_hit_percent": float(fields[3]),
+        "rss_gb": float(fields[4]),
+        "prompt_tokens": int(fields[5]) if len(fields) > 5 else 0,
+        "length_limited": bool(int(fields[6])) if len(fields) > 6 else False,
+    }
+
+
+class Engine:
+    def __init__(self, executable, model, cap=8, max_tokens=1024, env=None):
+        child_env = dict(env or os.environ, SNAP=str(model), SERVE="1", NGEN=str(max_tokens))
+        self.process = subprocess.Popen(
+            [str(executable), str(cap)], env=child_env, stdin=subprocess.PIPE,
+            stdout=subprocess.PIPE, bufsize=0,
+        )
+        self.lock = threading.Lock()
+        read_engine_turn(self.process.stdout, READY, lambda _: None)
+
+    def generate(self, prompt, max_tokens, temperature, top_p, on_text):
+        payload = prompt.encode("utf-8")
+        if b"\0" in payload:
+            raise APIError(400, "NUL bytes are not supported in prompts.", "messages")
+        decoder = codecs.getincrementaldecoder("utf-8")("replace")
+
+        def decode(data):
+            text = decoder.decode(data)
+            if text:
+                on_text(text)
+
+        with self.lock:
+            if self.process.poll() is not None:
+                raise RuntimeError("colibri engine is not running")
+            header = f"\x02PROMPT {len(payload)} {max_tokens} {temperature:.8g} {top_p:.8g}\n".encode()
+            self.process.stdin.write(header + payload + b"\n")
+            self.process.stdin.flush()
+            stats = read_engine_turn(self.process.stdout, END, decode)
+            tail = decoder.decode(b"", final=True)
+            if tail:
+                on_text(tail)
+            return stats
+
+    def close(self):
+        if self.process.poll() is None:
+            self.process.terminate()
+            try:
+                self.process.wait(timeout=5)
+            except subprocess.TimeoutExpired:
+                self.process.kill()
+
+
+def model_object(model_id, created):
+    return {"id": model_id, "object": "model", "created": created, "owned_by": "colibri"}
+
+
+class APIServer(ThreadingHTTPServer):
+    daemon_threads = True
+
+    def __init__(self, address, engine, model_id, api_key=None, max_tokens=1024,
+                 cors_origins=DEFAULT_CORS_ORIGINS):
+        super().__init__(address, APIHandler)
+        self.engine = engine
+        self.model_id = model_id
+        self.api_key = api_key
+        self.max_tokens = max_tokens
+        self.cors_origins = tuple(cors_origins)
+        self.created = int(time.time())
+
+
+class APIHandler(BaseHTTPRequestHandler):
+    protocol_version = "HTTP/1.1"
+    server_version = "colibri"
+
+    def log_message(self, fmt, *args):
+        sys.stderr.write("[api] %s - %s\n" % (self.address_string(), fmt % args))
+
+    def send_json(self, status, body, request_id=None):
+        data = json.dumps(body, ensure_ascii=False, separators=(",", ":")).encode()
+        self.send_response(status)
+        self.send_header("Content-Type", "application/json")
+        self.send_header("Content-Length", str(len(data)))
+        if request_id:
+            self.send_header("x-request-id", request_id)
+        self.send_cors_headers()
+        self.end_headers()
+        self.wfile.write(data)
+
+    def send_cors_headers(self):
+        origin = self.headers.get("Origin")
+        if not origin or ("*" not in self.server.cors_origins and origin not in self.server.cors_origins):
+            return
+        self.send_header("Access-Control-Allow-Origin", "*" if "*" in self.server.cors_origins else origin)
+        self.send_header("Access-Control-Allow-Methods", "GET, POST, OPTIONS")
+        self.send_header("Access-Control-Allow-Headers", "Authorization, Content-Type")
+        self.send_header("Access-Control-Expose-Headers", "x-request-id")
+        self.send_header("Access-Control-Max-Age", "600")
+        if "*" not in self.server.cors_origins:
+            self.send_header("Vary", "Origin")
+
+    def require_auth(self):
+        if self.server.api_key and self.headers.get("Authorization") != f"Bearer {self.server.api_key}":
+            raise APIError(401, "Invalid or missing API key.", None, "invalid_api_key",
+                           "authentication_error")
+
+    def read_json(self):
+        try:
+            length = int(self.headers.get("Content-Length", "0"))
+        except ValueError:
+            raise APIError(400, "Invalid Content-Length header.")
+        if length < 1 or length > MAX_BODY:
+            raise APIError(400, f"Request body must be between 1 and {MAX_BODY} bytes.")
+        try:
+            body = json.loads(self.rfile.read(length))
+        except (json.JSONDecodeError, UnicodeDecodeError):
+            raise APIError(400, "Request body must be valid JSON.")
+        if not isinstance(body, dict):
+            raise APIError(400, "Request body must be a JSON object.")
+        return body
+
+    def check_model(self, body):
+        model = body.get("model")
+        if model != self.server.model_id:
+            raise APIError(404, f"The model `{model}` does not exist.", "model", "model_not_found")
+
+    def do_GET(self):
+        request_id = "req_" + uuid.uuid4().hex
+        try:
+            path = urlsplit(self.path).path
+            if path == "/health":
+                self.send_json(200, {"status": "ok"}, request_id)
+                return
+            self.require_auth()
+            if path == "/v1/models":
+                self.send_json(200, {"object": "list", "data": [model_object(
+                    self.server.model_id, self.server.created)]}, request_id)
+            elif path.startswith("/v1/models/") and unquote(path[11:]) == self.server.model_id:
+                self.send_json(200, model_object(self.server.model_id, self.server.created), request_id)
+            else:
+                raise APIError(404, "Not found.", None, "not_found")
+        except APIError as error:
+            self.send_json(error.status, error_object(error), request_id)
+
+    def do_OPTIONS(self):
+        self.send_response(204)
+        self.send_header("Content-Length", "0")
+        self.send_cors_headers()
+        self.end_headers()
+
+    def do_POST(self):
+        request_id = "req_" + uuid.uuid4().hex
+        try:
+            self.require_auth()
+            body = self.read_json()
+            self.check_model(body)
+            path = urlsplit(self.path).path
+            if path == "/v1/chat/completions":
+                self.chat_completion(body, request_id)
+            elif path == "/v1/completions":
+                self.completion(body, request_id)
+            else:
+                raise APIError(404, "Not found.", None, "not_found")
+        except APIError as error:
+            self.send_json(error.status, error_object(error), request_id)
+        except (BrokenPipeError, ConnectionResetError):
+            pass
+        except Exception as error:
+            self.log_error("request failed: %s", error)
+            api_error = APIError(500, "The colibri engine failed to process the request.",
+                                 None, "engine_error", "server_error")
+            try:
+                self.send_json(500, error_object(api_error), request_id)
+            except OSError:
+                pass
+
+    def generation(self, body, prompt, request_id, chat):
+        maximum, temperature, top_p = generation_options(body, self.server.max_tokens)
+        stream = body.get("stream", False)
+        if not isinstance(stream, bool):
+            raise APIError(400, "`stream` must be a boolean.", "stream")
+        object_name = "chat.completion" if chat else "text_completion"
+        id_prefix = "chatcmpl-" if chat else "cmpl-"
+        completion_id = id_prefix + uuid.uuid4().hex
+        created = int(time.time())
+
+        if not stream:
+            output = []
+            stats = self.server.engine.generate(prompt, maximum, temperature, top_p, output.append)
+            text = "".join(output)
+            finish = "length" if stats["length_limited"] else "stop"
+            choice = ({"index": 0, "message": {"role": "assistant", "content": text,
+                       "refusal": None}, "logprobs": None, "finish_reason": finish} if chat else
+                      {"index": 0, "text": text, "logprobs": None, "finish_reason": finish})
+            self.send_json(200, {"id": completion_id, "object": object_name, "created": created,
+                "model": self.server.model_id, "choices": [choice], "usage": self.usage(stats)}, request_id)
+            return
+
+        stream_options = body.get("stream_options")
+        if stream_options is not None and not isinstance(stream_options, dict):
+            raise APIError(400, "`stream_options` must be an object.", "stream_options")
+        include_usage = bool((stream_options or {}).get("include_usage"))
+        stream_object = "chat.completion.chunk" if chat else object_name
+        self.send_response(200)
+        self.send_header("Content-Type", "text/event-stream")
+        self.send_header("Cache-Control", "no-cache")
+        self.send_header("X-Accel-Buffering", "no")
+        self.send_header("x-request-id", request_id)
+        self.send_cors_headers()
+        self.end_headers()
+        connected = True
+
+        def event(choices, usage_marker=False):
+            nonlocal connected
+            if not connected:
+                return
+            event_body = {"id": completion_id, "object": stream_object, "created": created,
+                          "model": self.server.model_id, "choices": choices}
+            if include_usage:
+                event_body["usage"] = None if not usage_marker else usage_marker
+            try:
+                data = json.dumps(event_body, ensure_ascii=False, separators=(",", ":"))
+                self.wfile.write(f"data: {data}\n\n".encode())
+                self.wfile.flush()
+            except OSError:
+                connected = False
+
+        if chat:
+            event([{"index": 0, "delta": {"role": "assistant", "content": ""},
+                    "logprobs": None, "finish_reason": None}])
+
+        def emit(text):
+            choice = ({"index": 0, "delta": {"content": text}, "logprobs": None,
+                       "finish_reason": None} if chat else
+                      {"index": 0, "text": text, "logprobs": None, "finish_reason": None})
+            event([choice])
+
+        stats = self.server.engine.generate(prompt, maximum, temperature, top_p, emit)
+        finish = "length" if stats["length_limited"] else "stop"
+        final_choice = ({"index": 0, "delta": {}, "logprobs": None, "finish_reason": finish}
+                        if chat else {"index": 0, "text": "", "logprobs": None,
+                                      "finish_reason": finish})
+        event([final_choice])
+        if include_usage:
+            event([], self.usage(stats))
+        if connected:
+            try:
+                self.wfile.write(b"data: [DONE]\n\n")
+                self.wfile.flush()
+            except OSError:
+                pass
+        self.close_connection = True
+
+    @staticmethod
+    def usage(stats):
+        prompt = stats["prompt_tokens"]
+        completion = stats["completion_tokens"]
+        return {"prompt_tokens": prompt, "completion_tokens": completion,
+                "total_tokens": prompt + completion}
+
+    def chat_completion(self, body, request_id):
+        reasoning_effort = body.get("reasoning_effort")
+        efforts = (None, "none", "minimal", "low", "medium", "high", "xhigh")
+        if reasoning_effort not in efforts:
+            raise APIError(400, "`reasoning_effort` must be none, minimal, low, medium, high, or xhigh.",
+                           "reasoning_effort")
+        enable_thinking = body.get("enable_thinking", reasoning_effort not in (None, "none"))
+        if not isinstance(enable_thinking, bool):
+            raise APIError(400, "`enable_thinking` must be a boolean.", "enable_thinking")
+        prompt = render_chat(body.get("messages"), enable_thinking, reasoning_effort)
+        self.generation(body, prompt, request_id, True)
+
+    def completion(self, body, request_id):
+        prompt = body.get("prompt")
+        if not isinstance(prompt, str):
+            raise APIError(400, "Colibri currently requires `prompt` to be a string.", "prompt")
+        self.generation(body, prompt, request_id, False)
+
+
+def serve(model, host="127.0.0.1", port=8000, model_id="glm-5.2-colibri", api_key=None,
+          cap=8, max_tokens=1024, engine=HERE / "glm", env=None, cors_origins=None):
+    if not 1 <= max_tokens:
+        raise ValueError("max_tokens must be positive")
+    if not 1 <= port <= 65535:
+        raise ValueError("port must be between 1 and 65535")
+    if host not in ("127.0.0.1", "localhost", "::1") and not api_key:
+        print("WARNING: API is listening beyond localhost without COLI_API_KEY", file=sys.stderr)
+    runtime = Engine(engine, model, cap, max_tokens, env)
+    origins = DEFAULT_CORS_ORIGINS if cors_origins is None else tuple(cors_origins)
+    server = APIServer((host, port), runtime, model_id, api_key, max_tokens, origins)
+    print(f"OpenAI-compatible API listening on http://{host}:{port}/v1", file=sys.stderr)
+    previous_sigterm = signal.getsignal(signal.SIGTERM)
+    signal.signal(signal.SIGTERM, lambda *_: threading.Thread(target=server.shutdown, daemon=True).start())
+    try:
+        server.serve_forever()
+    finally:
+        signal.signal(signal.SIGTERM, previous_sigterm)
+        server.server_close()
+        runtime.close()
+
+
+def main():
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument("--model", default=os.environ.get("COLI_MODEL"), required=not os.environ.get("COLI_MODEL"))
+    parser.add_argument("--engine", default=str(HERE / "glm"))
+    parser.add_argument("--host", default="127.0.0.1")
+    parser.add_argument("--port", type=int, default=8000)
+    parser.add_argument("--model-id", default=os.environ.get("COLI_MODEL_ID", "glm-5.2-colibri"))
+    parser.add_argument("--api-key", default=os.environ.get("COLI_API_KEY"))
+    parser.add_argument("--cors-origin", action="append", default=None,
+                        help="allowed browser origin; repeat as needed (use '*' for any origin)")
+    parser.add_argument("--cap", type=int, default=8)
+    parser.add_argument("--max-tokens", type=int, default=1024)
+    args = parser.parse_args()
+    serve(args.model, args.host, args.port, args.model_id, args.api_key,
+          args.cap, args.max_tokens, args.engine, cors_origins=args.cors_origin)
+
+
+if __name__ == "__main__":
+    main()

c/tests/test_openai_server.py

@@ -0,0 +1,152 @@
+import io
+import json
+import threading
+import unittest
+from urllib.error import HTTPError
+from urllib.request import Request, urlopen
+
+from openai_server import APIError, APIServer, END, generation_options, read_engine_turn, render_chat
+
+
+class FakeEngine:
+    def __init__(self):
+        self.calls = []
+
+    def generate(self, prompt, maximum, temperature, top_p, on_text):
+        self.calls.append((prompt, maximum, temperature, top_p))
+        on_text("Hé")
+        on_text("llo")
+        return {"prompt_tokens": 7, "completion_tokens": 2, "length_limited": False}
+
+
+class TemplateTest(unittest.TestCase):
+    def test_renders_text_subset_of_official_template(self):
+        prompt = render_chat([
+            {"role": "system", "content": "System"},
+            {"role": "developer", "content": "Developer"},
+            {"role": "user", "content": [{"type": "text", "text": "Hi"}]},
+            {"role": "assistant", "content": " Hello "},
+            {"role": "user", "content": "Again"},
+        ])
+        self.assertEqual(
+            prompt,
+            "[gMASK]<sop><|system|>System<|system|>Developer<|user|>Hi"
+            "<|assistant|><think></think>Hello<|user|>Again"
+            "<|assistant|><think></think>",
+        )
+
+    def test_rejects_non_text_content(self):
+        with self.assertRaisesRegex(APIError, "text message content only"):
+            render_chat([{"role": "user", "content": [
+                {"type": "image_url", "image_url": {"url": "x"}}
+            ]}])
+
+    def test_renders_thinking_prefix(self):
+        self.assertEqual(
+            render_chat([{"role": "user", "content": "Hi"}], True, "high"),
+            "[gMASK]<sop><|system|>Reasoning Effort: High<|user|>Hi<|assistant|><think>",
+        )
+
+    def test_validates_generation_limits(self):
+        self.assertEqual(generation_options({"max_tokens": 4, "temperature": 0, "top_p": 1}, 8),
+                         (4, 0.0, 1.0))
+        with self.assertRaises(APIError):
+            generation_options({"max_tokens": 9}, 8)
+        self.assertEqual(generation_options({"temperature": None, "top_p": None}, 8),
+                         (8, 0.7, 0.9))
+
+
+class ProtocolTest(unittest.TestCase):
+    def test_reads_payload_and_extended_status(self):
+        stream = io.BytesIO(b"hello" + END + b"STAT 2 3.5 44 1.2 7 1\n")
+        chunks = []
+        stats = read_engine_turn(stream, END, chunks.append)
+        self.assertEqual(b"".join(chunks), b"hello")
+        self.assertEqual(stats["prompt_tokens"], 7)
+        self.assertTrue(stats["length_limited"])
+
+
+class HTTPTest(unittest.TestCase):
+    @classmethod
+    def setUpClass(cls):
+        cls.engine = FakeEngine()
+        cls.server = APIServer(("127.0.0.1", 0), cls.engine, "test-model", "secret", 16)
+        cls.thread = threading.Thread(target=cls.server.serve_forever, daemon=True)
+        cls.thread.start()
+        cls.base = f"http://127.0.0.1:{cls.server.server_port}"
+
+    @classmethod
+    def tearDownClass(cls):
+        cls.server.shutdown()
+        cls.server.server_close()
+        cls.thread.join(timeout=2)
+
+    def request(self, path, body=None, key="secret"):
+        headers = {"Authorization": f"Bearer {key}"}
+        data = None
+        if body is not None:
+            data = json.dumps(body).encode()
+            headers["Content-Type"] = "application/json"
+        return urlopen(Request(self.base + path, data=data, headers=headers), timeout=2)
+
+    def test_lists_models_and_checks_auth(self):
+        with self.request("/v1/models") as response:
+            self.assertEqual(json.load(response)["data"][0]["id"], "test-model")
+        with self.assertRaises(HTTPError) as caught:
+            self.request("/v1/models", key="wrong")
+        self.assertEqual(caught.exception.code, 401)
+
+    def test_browser_preflight(self):
+        request = Request(self.base + "/v1/chat/completions", method="OPTIONS", headers={
+            "Origin": "http://localhost:5173",
+            "Access-Control-Request-Method": "POST",
+            "Access-Control-Request-Headers": "authorization,content-type",
+        })
+        with urlopen(request, timeout=2) as response:
+            self.assertEqual(response.status, 204)
+            self.assertEqual(response.headers["Access-Control-Allow-Origin"], "http://localhost:5173")
+            self.assertIn("Authorization", response.headers["Access-Control-Allow-Headers"])
+
+    def test_chat_completion(self):
+        with self.request("/v1/chat/completions", {
+            "model": "test-model", "messages": [{"role": "user", "content": "Hi"}],
+            "max_tokens": 4,
+        }) as response:
+            body = json.load(response)
+        self.assertEqual(body["object"], "chat.completion")
+        self.assertEqual(body["choices"][0]["message"]["content"], "Héllo")
+        self.assertEqual(body["usage"], {"prompt_tokens": 7, "completion_tokens": 2, "total_tokens": 9})
+        self.assertIn("<|user|>Hi<|assistant|><think></think>", self.engine.calls[-1][0])
+
+    def test_streaming_chat_completion(self):
+        with self.request("/v1/chat/completions", {
+            "model": "test-model", "messages": [{"role": "user", "content": "Hi"}],
+            "stream": True, "stream_options": {"include_usage": True},
+        }) as response:
+            stream = response.read().decode()
+        self.assertIn('\"delta\":{\"role\":\"assistant\",\"content\":\"\"}', stream)
+        self.assertIn('\"object\":\"chat.completion.chunk\"', stream)
+        self.assertIn('\"content\":\"Hé\"', stream)
+        self.assertIn('\"usage\":{\"prompt_tokens\":7,\"completion_tokens\":2,\"total_tokens\":9}', stream)
+        self.assertTrue(stream.endswith("data: [DONE]\n\n"))
+
+    def test_legacy_completion(self):
+        with self.request("/v1/completions", {
+            "model": "test-model", "prompt": "Complete me", "temperature": 0,
+        }) as response:
+            body = json.load(response)
+        self.assertEqual(body["object"], "text_completion")
+        self.assertEqual(body["choices"][0]["text"], "Héllo")
+        self.assertEqual(self.engine.calls[-1][0], "Complete me")
+
+    def test_rejects_invalid_stream_options(self):
+        with self.assertRaises(HTTPError) as caught:
+            self.request("/v1/chat/completions", {
+                "model": "test-model", "messages": [{"role": "user", "content": "Hi"}],
+                "stream": True, "stream_options": "usage",
+            })
+        self.assertEqual(caught.exception.code, 400)
+
+
+if __name__ == "__main__":
+    unittest.main()