Commit fc343a84b for llama.cpp

commit fc343a84bbd925b37dde3219de35ea0bed50d630
Author: Xuan-Son Nguyen <son@huggingface.co>
Date:   Thu Sep 24 16:25:07 2026 +0200

    llama: add llama_batch_ext (#24669)

    * (wip) add llama_batch_ext

    * wip

    * updated design

    * updated impl

    * change signature

    * unused var

    * demo common_prompt_batch_decode

    * fix pos

    * tmp disable test-batch-alloc

    * fix compat

    * nits: add const

    * no more pos_max

    * add comment about llama_batch_ext_set_embd_state

    * handle n_embd_out properly

    * rename api --> embd_token

    * llama_embd

    * stub llama_batch_ext_set_embd_state

    * support both token + embd + state in batch

    * llama_batch_ext_add_embd

    * upstream some changes

    * nits

    * fix test-batch-alloc

    * add test for compat

diff --git a/common/common.cpp b/common/common.cpp
index d8319cd9a..a316b2ae1 100644
--- a/common/common.cpp
+++ b/common/common.cpp
@@ -2198,9 +2198,28 @@ bool common_replay_last_token(struct llama_context * ctx, llama_token last_token
     return true;
 }

+llama_batch_ext_ptr common_batch_ext_get_one(llama_context * ctx, const llama_tokens & tokens) {
+    llama_batch_ext_ptr batch(llama_batch_ext_init(ctx));
+
+    auto mem = llama_get_memory(ctx);
+    llama_pos pos = mem ? llama_memory_seq_pos_max(mem, 0) + 1 : 0;
+
+    for (size_t i = 0; i < tokens.size(); ++i) {
+        const int32_t idx = llama_batch_ext_add_token(batch.get(), 0, tokens[i]);
+        llama_batch_ext_set_pos(batch.get(), idx, &pos);
+        pos++;
+    }
+
+    if (!tokens.empty()) {
+        llama_batch_ext_set_output_logits(batch.get(), (int32_t) tokens.size() - 1, true);
+    }
+
+    return batch;
+}
+
 bool common_prompt_batch_decode(
               struct llama_context * ctx,
-    const std::vector<llama_token> & all_tokens,
+                const llama_tokens & all_tokens,
                                int   n_new,
                                int & n_past,
                                int   n_batch,
@@ -2221,7 +2240,9 @@ bool common_prompt_batch_decode(
         // Memory implementations in recurrent/hybrid models don't support removing tokens from their
         // memory, so we can't just remove the last token from the memory and replay the last token which
         // is the reason for this logic.
-        if (llama_decode(ctx, llama_batch_get_one(const_cast<llama_token*>(all_tokens.data() + offset), n_tokens_before_last))) {
+        llama_tokens prefix_tokens(all_tokens.begin() + offset, all_tokens.begin() + offset + n_tokens_before_last);
+        llama_batch_ext_ptr batch_prefix = common_batch_ext_get_one(ctx, prefix_tokens);
+        if (llama_process(ctx, LLAMA_PROCESS_TYPE_DECODE, batch_prefix.get())) {
             COM_ERR("%s", "failed to eval\n");
             return false;
         }
@@ -2231,17 +2252,19 @@ bool common_prompt_batch_decode(
         COM_INF("saved session before last token to %s, n_new = %zu\n", state_path.data(), all_tokens.size());

         llama_token last_token = all_tokens.back();
-        llama_batch batch = llama_batch_get_one(&last_token, 1);
-        int32_t pos = n_past;
-        batch.pos = &pos;
+        llama_batch_ext_ptr batch_last = common_batch_ext_get_one(ctx, { last_token });
+        llama_pos pos = n_past;
+        llama_batch_ext_set_pos(batch_last.get(), 0, &pos);

-        if (llama_decode(ctx, batch)) {
+        if (llama_process(ctx, LLAMA_PROCESS_TYPE_DECODE, batch_last.get())) {
             COM_ERR("%s", "failed to eval last token\n");
             return false;
         }
         n_past++;
     } else {
-        if (llama_decode(ctx, llama_batch_get_one(const_cast<llama_token*>(all_tokens.data() + offset), n_new))) {
+        llama_tokens new_tokens(all_tokens.begin() + offset, all_tokens.begin() + offset + n_new);
+        llama_batch_ext_ptr batch = common_batch_ext_get_one(ctx, new_tokens);
+        if (llama_process(ctx, LLAMA_PROCESS_TYPE_DECODE, batch.get())) {
             COM_ERR("%s", "failed to eval\n");
             return false;
         }
diff --git a/common/common.h b/common/common.h
index 7afc266ac..39f855c4f 100644
--- a/common/common.h
+++ b/common/common.h
@@ -1021,6 +1021,10 @@ void common_batch_add(
     const std::vector<llama_seq_id> & seq_ids,
                                bool   logits);

+// create a single-sequence batch from a list of tokens
+// last token always have output_logits set to true
+llama_batch_ext_ptr common_batch_ext_get_one(struct llama_context * ctx, const llama_tokens & tokens);
+
 // decodes a single batch of tokens for a prompt and manages session tokens
 //
 // Note: We save state before the last token so that we can replay it to ensure
@@ -1028,7 +1032,7 @@ void common_batch_add(
 // tokens from memory, so this approach works across all model architectures.
 bool common_prompt_batch_decode(
               struct llama_context * ctx,
-    const std::vector<llama_token> & all_tokens,
+                const llama_tokens & all_tokens,
                                int   n_new,
                                int & n_past,
                                int   n_batch,
diff --git a/include/llama-cpp.h b/include/llama-cpp.h
index 8f6368177..880a6a5fa 100644
--- a/include/llama-cpp.h
+++ b/include/llama-cpp.h
@@ -24,7 +24,12 @@ struct llama_adapter_lora_deleter {
     void operator()(llama_adapter_lora * adapter) { llama_adapter_lora_free(adapter); }
 };

+struct llama_batch_ext_deleter {
+    void operator()(llama_batch_ext * batch) { llama_batch_ext_free(batch); }
+};
+
 typedef std::unique_ptr<llama_model, llama_model_deleter> llama_model_ptr;
 typedef std::unique_ptr<llama_context, llama_context_deleter> llama_context_ptr;
 typedef std::unique_ptr<llama_sampler, llama_sampler_deleter> llama_sampler_ptr;
 typedef std::unique_ptr<llama_adapter_lora, llama_adapter_lora_deleter> llama_adapter_lora_ptr;
+typedef std::unique_ptr<llama_batch_ext, llama_batch_ext_deleter> llama_batch_ext_ptr;
diff --git a/include/llama.h b/include/llama.h
index 31bbf8b0d..1805ed055 100644
--- a/include/llama.h
+++ b/include/llama.h
@@ -293,6 +293,11 @@ extern "C" {
         LLAMA_MODEL_META_KEY_SAMPLING_MIROSTAT_ETA,
     };

+    enum llama_process_type {
+        LLAMA_PROCESS_TYPE_ENCODE,
+        LLAMA_PROCESS_TYPE_DECODE,
+    };
+
     struct llama_model_kv_override {
         enum llama_model_kv_override_type tag;

@@ -999,6 +1004,91 @@ extern "C" {
             struct llama_context * ctx,
               struct llama_batch   batch);

+    //
+    // Extended batch API
+    //
+
+    struct llama_batch_ext;
+
+    struct llama_embd {
+        const float * data;
+        size_t n_rows; // number of embedding rows in data
+        size_t n_embd; // size of one row
+    };
+
+    LLAMA_API struct llama_batch_ext * llama_batch_ext_init (struct llama_context * ctx);
+    LLAMA_API void                     llama_batch_ext_free (struct llama_batch_ext * batch);
+    LLAMA_API void                     llama_batch_ext_clear(struct llama_batch_ext * batch);
+
+    // Add an input token to the batch, with default values:
+    //     id = LLAMA_TOKEN_NULL
+    //     embd = nullptr
+    //     pos = not set, the caller must set it with llama_batch_ext_set_pos()
+    // Returns the batch index (>= 0)
+    // On error:
+    //     -1: batch is full
+    //     -2: token is invalid (id == LLAMA_TOKEN_NULL or invalid embd)
+    //     -3: invalid sequence id
+    LLAMA_API int32_t llama_batch_ext_add      (struct llama_batch_ext * batch, llama_seq_id seq_id);
+
+    // Add an input token to the batch, with a specified token ID or token embedding
+    LLAMA_API int32_t llama_batch_ext_add_token(struct llama_batch_ext * batch, llama_seq_id seq_id, llama_token id);
+    LLAMA_API int32_t llama_batch_ext_add_embd (struct llama_batch_ext * batch, llama_seq_id seq_id, struct llama_embd embd);
+
+    // Add the token at index idx in the batch to another sequence id. The position will stays the same.
+    // Note: this should be called before other _set() functions
+    LLAMA_API bool llama_batch_ext_add_seq(
+                                struct llama_batch_ext * batch,
+                                               int32_t   idx,
+                                          llama_seq_id   seq_id);
+
+    // Set the token embedding for the token at index idx in the batch
+    // use it after llama_batch_ext_add_token() to have an entry with both a token id and an embedding
+    LLAMA_API bool llama_batch_ext_set_embd_token(
+                                struct llama_batch_ext * batch,
+                                               int32_t   idx,
+                                     struct llama_embd   embd);
+
+    // Set the "state" embedding for the token at index idx in the batch
+    // "state" here means extra hidden state carried over from a previous stage, e.g.:
+    //   - MTP: state from N layers of the target model
+    //   - Qwen3 VL (deepstack): state from N layers of the vision encoder
+    LLAMA_API bool llama_batch_ext_set_embd_state(
+                                struct llama_batch_ext * batch,
+                                               int32_t   idx,
+                                     struct llama_embd   embd);
+
+    // Set if output embeddings should be available for the token at index idx in the batch
+    // Note: for now, this is equivalent to setting the output logits
+    LLAMA_API bool llama_batch_ext_set_output_embd(
+                                struct llama_batch_ext * batch,
+                                               int32_t  idx,
+                                                  bool  value);
+
+    // Set output logits for the token at index idx in the batch
+    // Note: for now, this is equivalent to setting the output embd
+    LLAMA_API bool llama_batch_ext_set_output_logits(
+                                struct llama_batch_ext * batch,
+                                               int32_t  idx,
+                                                  bool  value);
+
+    // Set custom position for the token at index idx in the batch
+    // For M-RoPE models:
+    //     - Embedding tokens must have multiple positions per token
+    //     - Text token only requires one single position per token
+    LLAMA_API bool llama_batch_ext_set_pos(
+                                struct llama_batch_ext * batch,
+                                               int32_t   idx,
+                                       const llama_pos * pos);
+
+    // TODO: implement get_embeddings() and get_logits() for llama_batch_ext
+
+    // Return values are the same as llama_decode()
+    LLAMA_API int32_t llama_process(
+                                struct llama_context * ctx,
+                             enum llama_process_type   type,
+                              struct llama_batch_ext * batch);
+
     // Set the number of threads used for decoding
     // n_threads is the number of threads used for generation (single token)
     // n_threads_batch is the number of threads used for prompt and batch processing (multiple tokens)
diff --git a/src/llama-batch.cpp b/src/llama-batch.cpp
index 2b98a552f..89a1f3f37 100644
--- a/src/llama-batch.cpp
+++ b/src/llama-batch.cpp
@@ -3,6 +3,9 @@
 #include "llama-impl.h"
 #include "llama-vocab.h"
 #include "llama-memory.h"
+#include "llama-hparams.h"
+#include "llama-model.h"
+#include "llama-context.h"

 #include <cassert>
 #include <cstring>
@@ -23,135 +26,164 @@ llama_batch_allocr::llama_batch_allocr(uint32_t n_pos_per_embd) : n_pos_per_embd
 }

 bool llama_batch_allocr::init(
-        const llama_batch & batch_inp,
+        const llama_batch_ext & batch_inp,
         const llama_vocab & vocab,
-        const llama_memory_i * memory,
-        uint32_t n_embd,
-        uint32_t n_seq_max,
         bool output_all) {
     clear();

-    batch = batch_inp;
+    this->vocab     = &vocab;
+    this->n_embd    = batch_inp.n_embd > 0 ? batch_inp.n_embd : batch_inp.n_embd_inp;
+    this->n_seq_max = batch_inp.n_seq_max;

-    this->vocab = &vocab;
+    const int32_t n_tok = (int32_t) batch_inp.tokens.size();

-    GGML_ASSERT(batch.n_tokens > 0);
+    GGML_ASSERT(n_tok > 0);
+
+    if ((uint32_t) n_seq_max > LLAMA_MAX_SEQ) {
+        LLAMA_LOG_ERROR("%s: n_seq_max = %d > %d\n", __func__, n_seq_max, LLAMA_MAX_SEQ);
+        return false;
+    }
+
+    const llama_memory_i * mem = batch_inp.mem;

     //
-    // validate input batch
+    // determine the content types of the batch
+    // an entry can carry a token id, a token embedding, or both (e.g. MTP hook batches)
+    // all entries must carry the same combination
     //

-    if (n_seq_max > LLAMA_MAX_SEQ) {
-        LLAMA_LOG_ERROR("%s: n_seq_max = %d > %d\n", __func__, n_seq_max, LLAMA_MAX_SEQ);
+    const bool has_token = batch_inp.tokens[0].id != LLAMA_TOKEN_NULL;
+    const bool has_embd  = batch_inp.tokens[0].has_embd;
+
+    for (int32_t i = 1; i < n_tok; ++i) {
+        if ((batch_inp.tokens[i].id != LLAMA_TOKEN_NULL) != has_token ||
+             batch_inp.tokens[i].has_embd                != has_embd) {
+            LLAMA_LOG_ERROR("%s: all entries in the batch must have the same content types\n", __func__);
+            return false;
+        }
+    }
+
+    if (!has_token && !has_embd) {
+        LLAMA_LOG_ERROR("%s: batch has neither token ids nor embeddings\n", __func__);
         return false;
     }

-    if (batch.token) {
-        for (int32_t i = 0; i < batch.n_tokens; ++i) {
-            if (batch.token[i] < 0 || (uint32_t) batch.token[i] >= vocab.n_tokens()) {
-                LLAMA_LOG_ERROR("%s: invalid token[%d] = %d\n", __func__, i, batch.token[i]);
+    //
+    // build flat token/embd array
+    //
+
+    if (has_token) {
+        token_vec.resize(n_tok);
+        for (int32_t i = 0; i < n_tok; ++i) {
+            const llama_token id = batch_inp.tokens[i].id;
+            if (id < 0 || id >= batch_inp.n_vocab) {
+                LLAMA_LOG_ERROR("%s: invalid token[%d] = %d\n", __func__, i, id);
                 return false;
             }
+            token_vec[i] = id;
         }
     }

-    if (batch.seq_id) {
-        for (int32_t i = 0; i < batch.n_tokens; ++i) {
-            for (int32_t s = 0; s < batch.n_seq_id[i]; ++s) {
-                if (batch.seq_id && (batch.seq_id[i][s] < 0 || batch.seq_id[i][s] >= (llama_seq_id) n_seq_max)) {
-                    LLAMA_LOG_ERROR("%s: invalid seq_id[%d][%d] = %d >= %d\n", __func__, i, s, batch.seq_id[i][s], (llama_seq_id) n_seq_max);
-                    return false;
+    if (has_embd) {
+        embd_vec = batch_inp.embd;
+    }
+
+    //
+    // build flat pos array
+    // token batch:     pos[i]            = tokens[i].pos[0]
+    // embedding batch: pos[j*n_tok + i]  = tokens[i].pos[j]  (section-major)
+    //
+
+    {
+        const int32_t n_pos_total = has_token ? n_tok : n_tok * (int32_t) n_pos_per_embd;
+        pos.resize(n_pos_total);
+        if (has_token) {
+            for (int32_t i = 0; i < n_tok; ++i) {
+                pos[i] = batch_inp.tokens[i].pos[0];
+            }
+        } else {
+            for (int32_t i = 0; i < n_tok; ++i) {
+                for (uint32_t j = 0; j < n_pos_per_embd; ++j) {
+                    pos[(int32_t) j * n_tok + i] = batch_inp.tokens[i].pos[j];
                 }
             }
         }
     }

     //
-    // auto-generate missing fields
+    // build n_seq_id / seq_id arrays
     //

-    if (!batch.n_seq_id) {
-        n_seq_id.resize(batch.n_tokens);
-        for (int32_t i = 0; i < batch.n_tokens; i++) {
-            n_seq_id[i] = seq_id_0.size();
-        }
-        batch.n_seq_id = n_seq_id.data();
-    }
+    n_seq_id.resize(n_tok);
+    seq_id.resize(n_tok + 1);
+    seq_id[n_tok] = nullptr;

-    if (!batch.seq_id) {
-        seq_id.resize(batch.n_tokens + 1);
-        seq_id[batch.n_tokens] = NULL;
-        for (int32_t i = 0; i < batch.n_tokens; i++) {
-            seq_id[i] = seq_id_0.data();
+    {
+        size_t total = 0;
+        for (int32_t i = 0; i < n_tok; ++i) {
+            total += batch_inp.tokens[i].seq_ids.size();
         }
-        batch.seq_id = seq_id.data();
-    }
+        seq_id_data.reserve(total);

-    if (!batch.pos) {
-        pos.resize(batch.n_tokens);
-
-        // initialize the starting position for each sequence based on the positions in the memory
-        llama_pos p0[LLAMA_MAX_SEQ];
-        for (uint32_t s = 0; s < n_seq_max; ++s) {
-            if (!memory) {
-                // if no memory -> start from 0
-                p0[s] = 0;
-            } else {
-                p0[s] = memory->seq_pos_max(s) + 1;
+        for (int32_t i = 0; i < n_tok; ++i) {
+            for (auto sid : batch_inp.tokens[i].seq_ids) {
+                seq_id_data.push_back(sid);
             }
         }

-        for (int32_t i = 0; i < batch.n_tokens; i++) {
-            const llama_seq_id seq_id = batch.seq_id[i][0];
+        size_t off = 0;
+        for (int32_t i = 0; i < n_tok; ++i) {
+            n_seq_id[i] = (int32_t) batch_inp.tokens[i].seq_ids.size();
+            seq_id[i]   = seq_id_data.data() + off;
+            off += n_seq_id[i];

-            pos[i] = p0[seq_id];
-
-            // update the starting position for all sequences that are assigned to the this token
-            for (int32_t s = 0; s < batch.n_seq_id[i]; ++s) {
-                const llama_seq_id seq_id = batch.seq_id[i][s];
-
-                p0[seq_id] = pos[i] + 1;
+            for (int32_t s = 0; s < n_seq_id[i]; ++s) {
+                if (seq_id[i][s] < 0 || seq_id[i][s] >= (llama_seq_id) n_seq_max) {
+                    LLAMA_LOG_ERROR("%s: invalid seq_id[%d][%d] = %d >= %d\n", __func__, i, s, seq_id[i][s], (llama_seq_id) n_seq_max);
+                    return false;
+                }
             }
         }
-
-        batch.pos = pos.data();
     }

-    if (!batch.logits) {
-        if (output_all) {
-            // return the output for all tokens
-            output.resize(batch.n_tokens, true);
-        } else {
-            // return the output only for the last token
-            output.resize(batch.n_tokens, false);
-            output[output.size() - 1] = true;
-        }
+    //
+    // build output/logits array
+    //

-        batch.logits = output.data();
-    } else if (output_all) {
-        bool warn = false;
+    {
+        output.resize(n_tok, 0);
+        for (int32_t i = 0; i < n_tok; ++i) {
+            output[i] = batch_inp.tokens[i].output ? 1 : 0;
+        }

-        for (int32_t i = 0; i < batch.n_tokens; ++i) {
-            if (batch.logits[i] == 0) {
-                warn = true;
+        if (output_all) {
+            bool warn = false;
+            for (int32_t i = 0; i < n_tok; ++i) {
+                if (!output[i]) { warn = true; break; }
+            }
+            if (warn) {
+                LLAMA_LOG_WARN("%s: embeddings required but some input tokens were not marked as outputs -> overriding\n", __func__);
+                std::fill(output.begin(), output.end(), 1);
             }
         }
+    }

-        if (warn) {
-            LLAMA_LOG_WARN("%s: embeddings required but some input tokens were not marked as outputs -> overriding\n", __func__);
+    //
+    // set up the internal llama_batch to point to our owned arrays
+    //

-            output.resize(batch.n_tokens, true);
-            batch.logits = output.data();
-        }
-    }
+    batch.n_tokens = n_tok;
+    batch.token    = has_token ? token_vec.data() : nullptr;
+    batch.embd     = has_embd  ? embd_vec.data()  : nullptr;
+    batch.pos      = pos.data();
+    batch.n_seq_id = n_seq_id.data();
+    batch.seq_id   = seq_id.data();
+    batch.logits   = output.data();

     //
     // compute stats
     //

-    this->n_embd    = n_embd;
-    this->n_seq_max = n_seq_max;
-
     // count the outputs in this batch
     for (int32_t i = 0; i < batch.n_tokens; ++i) {
         n_outputs += batch.logits[i] != 0;
@@ -259,7 +291,7 @@ bool llama_batch_allocr::init(
                 continue;
             }

-            const llama_pos p0 = memory ? memory->seq_pos_max(s) : -1;
+            const llama_pos p0 = mem ? mem->seq_pos_max(s) : -1;

             if (batch.token) {
                 if (p0 >= 0 && p0 >= seq_pos_min(s)) {
@@ -292,7 +324,7 @@ bool llama_batch_allocr::init(
                 continue;
             }

-            const llama_pos p0 = memory ? memory->seq_pos_max(s) : -1;
+            const llama_pos p0 = mem ? mem->seq_pos_max(s) : -1;

             if (p0 >= 0) {
                 bool ok = true;
@@ -320,12 +352,12 @@ bool llama_batch_allocr::init(
         }
     }

-    if (memory) {
+    if (mem) {
         for (uint32_t s0 = 0; s0 < n_seq_max; ++s0) {
             for (uint32_t s1 = 0; s1 < n_seq_max; ++s1) {
                 if (seq_cpl[s0][s1]) {
-                    if (memory->seq_pos_min(s0) != memory->seq_pos_min(s1) ||
-                        memory->seq_pos_max(s0) != memory->seq_pos_max(s1)) {
+                    if (mem->seq_pos_min(s0) != mem->seq_pos_min(s1) ||
+                        mem->seq_pos_max(s0) != mem->seq_pos_max(s1)) {
                         LLAMA_LOG_ERROR("%s: sequence %d is coupled to %d in the input batch, but have divereged\n", __func__, s0, s1);
                         return false;
                     }
@@ -725,11 +757,14 @@ void llama_batch_allocr::clear() {

     batch = {};

-    pos       .clear();
-    n_seq_id  .clear();
-    seq_id    .clear();
-    seq_id_unq.clear();
-    output    .clear();
+    token_vec   .clear();
+    embd_vec    .clear();
+    seq_id_data .clear();
+    pos         .clear();
+    n_seq_id    .clear();
+    seq_id      .clear();
+    seq_id_unq  .clear();
+    output      .clear();

     for (auto & cur : seq_pos) {
         cur.clear();
@@ -985,3 +1020,305 @@ void llama_batch_free(struct llama_batch batch) {
     }
     if (batch.logits)   free(batch.logits);
 }
+
+
+// llama_batch_ext
+
+size_t llama_batch_ext_select_n_embd_inp(llama_context_type ctx_type, llm_arch arch, const llama_hparams & hparams) {
+    if (ctx_type == LLAMA_CONTEXT_TYPE_MTP) {
+        return hparams.n_embd_out();
+    }
+    if (arch == LLM_ARCH_DFLASH) {
+        return hparams.n_embd_inp_enc();
+    }
+    return hparams.n_embd_inp();
+}
+
+llama_batch_ext::llama_batch_ext(llama_context * ctx) :
+        n_tokens_max(llama_n_batch(ctx)),
+        n_embd_inp(llama_batch_ext_select_n_embd_inp(ctx->get_cparams().ctx_type, llama_get_model(ctx)->arch, llama_get_model(ctx)->hparams)),
+        n_embd_inp_enc(llama_get_model(ctx)->hparams.n_embd_inp_enc()),
+        n_seq_max(llama_n_seq_max(ctx)),
+        mem(llama_get_memory(ctx)),
+        n_vocab(llama_vocab_n_tokens(llama_model_get_vocab(llama_get_model(ctx)))),
+        n_pos_per_embd(llama_get_model(ctx)->hparams.n_pos_per_embd()) {
+    clear();
+}
+
+llama_batch_ext::llama_batch_ext(
+        size_t n_tokens_max,
+        size_t n_embd_inp,
+        size_t n_embd_inp_enc,
+        llama_seq_id n_seq_max,
+        llama_memory_i * mem,
+        llama_token n_vocab,
+        size_t n_pos_per_embd) :
+        n_tokens_max(n_tokens_max),
+        n_embd_inp(n_embd_inp),
+        n_embd_inp_enc(n_embd_inp_enc),
+        n_seq_max(n_seq_max),
+        mem(mem),
+        n_vocab(n_vocab),
+        n_pos_per_embd(n_pos_per_embd) {
+    clear();
+}
+
+void llama_batch_ext::clear() {
+    tokens.clear();
+    embd  .clear();
+    n_embd = 0;
+}
+
+int32_t llama_batch_ext::add_token(llama_seq_id seq_id) {
+    if (tokens.size() >= n_tokens_max) {
+        return -1; // size limit reached
+    }
+    if (seq_id < 0 || seq_id >= n_seq_max) {
+        return -3; // invalid sequence id
+    }
+
+    // position is left undefined; call set_token_pos() before decoding
+    token t;
+    t.seq_ids.insert(seq_id);
+
+    tokens.push_back(t);
+
+    return (int32_t)(tokens.size() - 1);
+}
+
+bool llama_batch_ext::add_seq(int32_t idx, llama_seq_id seq_id) {
+    if (idx < 0 || idx >= (int32_t) tokens.size()) {
+        return false;
+    }
+    if (seq_id < 0 || seq_id >= n_seq_max) {
+        return false;
+    }
+
+    token & t = tokens[idx];
+
+    t.seq_ids.insert(seq_id);
+
+    return true;
+}
+
+bool llama_batch_ext::set_token_id(int32_t idx, llama_token id) {
+    if (idx < 0 || idx >= (int32_t) tokens.size()) {
+        return false;
+    }
+    if (id < 0 || id >= n_vocab) {
+        return false;
+    }
+    tokens[idx].id = id;
+    return true;
+}
+
+bool llama_batch_ext::set_token_embd(int32_t idx, llama_embd embd_in) {
+    if (idx < 0 || idx >= (int32_t) tokens.size()) {
+        return false;
+    }
+    if (!embd_in.data) {
+        return false;
+    }
+
+    const size_t n_total = embd_in.n_rows * embd_in.n_embd;
+    if (n_embd == 0) {
+        if (n_total != n_embd_inp && n_total != n_embd_inp_enc) {
+            LLAMA_LOG_ERROR("%s: embedding size mismatch, got %zu rows x %zu = %zu, expected %zu or %zu\n",
+                    __func__, embd_in.n_rows, embd_in.n_embd, n_total, n_embd_inp, n_embd_inp_enc);
+            return false;
+        }
+        n_embd = n_total;
+    } else if (n_total != n_embd) {
+        LLAMA_LOG_ERROR("%s: embedding size mismatch, got %zu rows x %zu = %zu, expected %zu\n",
+                __func__, embd_in.n_rows, embd_in.n_embd, n_total, n_embd);
+        return false;
+    }
+
+    token & t = tokens[idx];
+
+    if (t.has_embd) {
+        LLAMA_LOG_ERROR("%s: embedding for token %d is already set\n", __func__, idx);
+        return false;
+    }
+
+    t.has_embd = true;
+    t.embd_off = embd.size();
+    embd.insert(embd.end(), embd_in.data, embd_in.data + n_total);
+
+    return true;
+}
+
+bool llama_batch_ext::set_token_pos(int32_t idx, const llama_pos * pos_in) {
+    if (idx < 0 || idx >= (int32_t) tokens.size()) {
+        return false;
+    }
+    if (!pos_in) {
+        return false;
+    }
+
+    token & t = tokens[idx];
+
+    size_t n_pos = t.id != LLAMA_TOKEN_NULL ? 1 : n_pos_per_embd;
+    for (size_t i = 0; i < n_pos; ++i) {
+        t.pos[i] = pos_in[i];
+    }
+
+    return true;
+}
+
+bool llama_batch_ext::set_output(int32_t idx, bool output_last) {
+    if (idx < 0 || idx >= (int32_t) tokens.size()) {
+        return false;
+    }
+    tokens[idx].output = output_last;
+    return true;
+}
+
+// llama_batch_ext C API
+
+llama_batch_ext * llama_batch_ext_init(llama_context * ctx) {
+    return new llama_batch_ext(ctx);
+}
+
+void llama_batch_ext_free(llama_batch_ext * batch) {
+    delete batch;
+}
+
+void llama_batch_ext_clear(llama_batch_ext * batch) {
+    batch->clear();
+}
+
+int32_t llama_batch_ext_add(llama_batch_ext * batch, llama_seq_id seq_id) {
+    return batch->add_token(seq_id);
+}
+
+int32_t llama_batch_ext_add_token(llama_batch_ext * batch, llama_seq_id seq_id, llama_token id) {
+    int32_t idx = batch->add_token(seq_id);
+    if (idx < 0) {
+        return idx;
+    }
+    if (!batch->set_token_id(idx, id)) {
+        return -2;
+    }
+    return idx;
+}
+
+int32_t llama_batch_ext_add_embd(llama_batch_ext * batch, llama_seq_id seq_id, llama_embd embd) {
+    int32_t idx = batch->add_token(seq_id);
+    if (idx < 0) {
+        return idx;
+    }
+    if (!batch->set_token_embd(idx, embd)) {
+        return -2;
+    }
+    return idx;
+}
+
+bool llama_batch_ext_add_seq(llama_batch_ext * batch, int32_t idx, llama_seq_id seq_id) {
+    return batch->add_seq(idx, seq_id);
+}
+
+bool llama_batch_ext_set_pos(llama_batch_ext * batch, int32_t idx, const llama_pos * pos) {
+    return batch->set_token_pos(idx, pos);
+}
+
+bool llama_batch_ext_set_embd_token(llama_batch_ext * batch, int32_t idx, llama_embd embd) {
+    return batch->set_token_embd(idx, embd);
+}
+
+bool llama_batch_ext_set_embd_state(llama_batch_ext * batch, int32_t idx, llama_embd embd) {
+    // TODO
+    GGML_UNUSED(batch);
+    GGML_UNUSED(idx);
+    GGML_UNUSED(embd);
+    return false;
+}
+
+bool llama_batch_ext_set_output_embd(llama_batch_ext * batch, int32_t idx, bool value) {
+    return batch->set_output(idx, value);
+}
+
+bool llama_batch_ext_set_output_logits(llama_batch_ext * batch, int32_t idx, bool value) {
+    return batch->set_output(idx, value);
+}
+
+// llama_batch_compat
+
+void llama_batch_compat::init(llama_batch_ext & dst, const llama_batch & batch_inp, size_t n_embd_row) {
+    llama_batch_ext * batch_ext = &dst;
+
+    if (n_embd_row == 0) {
+        n_embd_row = batch_ext->n_embd_inp;
+    }
+
+    // a batch can carry both, for example the MTP hook batches
+    const bool has_token = batch_inp.token != nullptr;
+    const bool has_embd  = batch_inp.embd  != nullptr;
+
+    static const llama_seq_id default_seq_id    = 0;
+    static const int32_t      default_n_seq_id  = 1;
+
+    // auto-generates positions locally when batch_inp.pos is null, continuing from memory
+    std::vector<llama_pos> pos_next(batch_ext->n_seq_max);
+    for (llama_seq_id s = 0; s < (llama_seq_id) batch_ext->n_seq_max; ++s) {
+        pos_next[s] = llama_memory_seq_pos_max(batch_ext->mem, s) + 1; // assume next pos
+    }
+
+    for (int32_t i = 0; i < batch_inp.n_tokens; ++i) {
+        const int32_t      n_sid = batch_inp.n_seq_id ? batch_inp.n_seq_id[i]    : default_n_seq_id;
+        const llama_seq_id * sids = batch_inp.seq_id  ? batch_inp.seq_id[i]      : &default_seq_id;
+
+        llama_batch_ext::token t;
+
+        // seq_ids
+        for (int32_t s = 0; s < n_sid; ++s) {
+            t.seq_ids.insert(sids[s]);
+        }
+
+        // position(s)
+        if (batch_inp.pos) {
+            if (has_token) {
+                // token batch: one position per token
+                t.pos[0] = batch_inp.pos[i];
+            } else {
+                // embedding batch (M-RoPE): section-major layout pos[j*n_tokens + i]
+                for (uint32_t j = 0; j < batch_ext->n_pos_per_embd; ++j) {
+                    t.pos[j] = batch_inp.pos[(int32_t) j * batch_inp.n_tokens + i];
+                }
+            }
+        } else {
+            // auto-generate position from the first seq_id
+            t.pos[0] = pos_next[sids[0]]++;
+        }
+
+        // token id and/or embeddings
+        if (has_token) {
+            t.id = batch_inp.token[i];
+        }
+
+        if (has_embd) {
+            t.has_embd = true;
+            t.embd_off = batch_ext->embd.size();
+            const float * src = batch_inp.embd + (size_t) i * n_embd_row;
+            batch_ext->embd.insert(batch_ext->embd.end(), src, src + n_embd_row);
+            batch_ext->n_embd = n_embd_row;
+        }
+
+        // output flag
+        // if no logits array is given, default to only the last token being an output
+        t.output = batch_inp.logits
+            ? (batch_inp.logits[i] != 0)
+            : (i == batch_inp.n_tokens - 1);
+
+        batch_ext->tokens.push_back(t);
+    }
+}
+
+llama_batch_compat::llama_batch_compat(llama_context * ctx, const llama_batch & batch_inp, size_t n_embd_row) {
+    batch_ext = new llama_batch_ext(ctx);
+    init(*batch_ext, batch_inp, n_embd_row);
+}
+
+llama_batch_compat::~llama_batch_compat() {
+    delete batch_ext;
+}
diff --git a/src/llama-batch.h b/src/llama-batch.h
index a3d1889d4..201d48cce 100644
--- a/src/llama-batch.h
+++ b/src/llama-batch.h
@@ -2,6 +2,7 @@

 #include "llama.h"

+#include "llama-arch.h"
 #include "llama-cparams.h"

 #include <array>
@@ -10,6 +11,7 @@
 #include <bitset>
 #include <memory>
 #include <unordered_map>
+#include <unordered_set>

 // keep this struct lightweight
 struct llama_ubatch {
@@ -68,19 +70,71 @@ struct llama_ubatch {
     std::shared_ptr<data_t> data;
 };

+struct llama_hparams;
+
+// MTP hook batches carry the target model's hidden state (n_embd_out size).
+// DFlash batches carry the fused target features at the encoder input width (n_embd_inp_enc size).
+// Normal batches carry token embeddings (n_embd_inp size).
+size_t llama_batch_ext_select_n_embd_inp(llama_context_type ctx_type, llm_arch arch, const llama_hparams & hparams);
+
+struct llama_batch_ext {
+    const size_t n_tokens_max;     // max number of tokens that can be stored in the batch
+    const size_t n_embd_inp;       // decoder embd row width
+    const size_t n_embd_inp_enc;   // encoder embd row width (e.g. eagle3/dflash extracted features)
+    const llama_seq_id n_seq_max;  // max number of sequences
+    llama_memory_i * mem;          // memory for position inference
+    const llama_token n_vocab;     // max token ID that we accept
+    const size_t n_pos_per_embd;
+
+    // actual embd row width of this batch, set by the first set_token_embd()
+    // must be either n_embd_inp or n_embd_inp_enc; encode/decode verify it against the graph input
+    size_t n_embd = 0;
+
+    struct token {
+        llama_token  id = LLAMA_TOKEN_NULL;
+        bool         has_embd = false; // whether embd_off is set
+        size_t       embd_off = 0; // index offset in the embd array
+        bool         output = false; // TODO: have dedicated output flags
+        std::unordered_set<llama_seq_id> seq_ids;
+        std::array<llama_pos, GGML_MROPE_SECTIONS> pos = {0, 0, 0, 0};
+    };
+    std::vector<token> tokens;
+    std::vector<float> embd;
+
+    llama_batch_ext(llama_context * ctx);
+
+    // build without a llama_context, used by tests
+    llama_batch_ext(
+            size_t n_tokens_max,
+            size_t n_embd_inp,
+            size_t n_embd_inp_enc,
+            llama_seq_id n_seq_max,
+            llama_memory_i * mem,
+            llama_token n_vocab,
+            size_t n_pos_per_embd);
+
+    void clear();
+
+    // add an entry with an undefined position
+    // the caller must set it explicitly via set_token_pos()
+    int32_t add_token(llama_seq_id seq_id);
+
+    bool add_seq(int32_t idx, llama_seq_id seq_id);
+    bool set_token_id(int32_t idx, llama_token id);
+    bool set_token_embd(int32_t idx, llama_embd embd_in);
+    bool set_token_pos(int32_t idx, const llama_pos * pos_in);
+    bool set_output(int32_t idx, bool output_last);
+};
+
 // a helper for sanitizing, fulfilling and splitting a batch
 class llama_batch_allocr {
 public:
     llama_batch_allocr(uint32_t n_pos_per_embd);

-    // sanitize and auto-gen missing data in the input batch
-    // memory is optional. if provided will be used to check for sequence continuity and to determine the positions
+    // convert a llama_batch_ext to internal llama_batch and sanitize it
     bool init(
-            const llama_batch & batch_inp,
+            const llama_batch_ext & batch_inp,
             const llama_vocab & vocab,
-            const llama_memory_i * memory,
-            uint32_t n_embd,
-            uint32_t n_seq_max,
             bool output_all);

     const llama_batch & get_batch() const;
@@ -137,7 +191,9 @@ private:
     uint32_t n_seq_max;
     uint32_t n_outputs;

-    std::array<llama_seq_id, 1> seq_id_0 = {{ 0 }}; // default sequence id
+    std::vector<llama_token>    token_vec;    // owned token IDs built from llama_batch_ext
+    std::vector<float>          embd_vec;     // owned embeddings built from llama_batch_ext
+    std::vector<llama_seq_id>   seq_id_data;  // flat storage for seq_id pointers below

     std::vector<llama_pos>      pos;
     std::vector<int32_t>        n_seq_id;
@@ -172,3 +228,16 @@ private:

     int debug;
 };
+
+// RAII translation layer: converts a llama_batch (old API) into a llama_batch_ext
+struct llama_batch_compat {
+    llama_batch_ext * batch_ext;
+
+    // n_embd_row is the embd row width of batch_inp, 0 = use the decoder width
+    llama_batch_compat(llama_context * ctx, const llama_batch & batch_inp, size_t n_embd_row = 0);
+    ~llama_batch_compat();
+
+    // fill an existing llama_batch_ext from a llama_batch (old API)
+    // note: this is called directly by the tests, skipping llama_context creation
+    static void init(llama_batch_ext & batch_ext, const llama_batch & batch_inp, size_t n_embd_row = 0);
+};
diff --git a/src/llama-context.cpp b/src/llama-context.cpp
index fcd4dfb13..da9c558d2 100644
--- a/src/llama-context.cpp
+++ b/src/llama-context.cpp
@@ -1463,24 +1463,25 @@ llm_graph_result * llama_context::process_ubatch(const llama_ubatch & ubatch, ll
     return res;
 }

-int llama_context::encode(const llama_batch & batch_inp) {
-    // MTP hook batches carry both token (next-token id) and embd (h_nextn row),
-    // so accept either present rather than requiring exactly one.
-    GGML_ASSERT(batch_inp.token || batch_inp.embd);
-
-    if (batch_inp.n_tokens == 0) {
+int llama_context::encode(const llama_batch_ext & batch_inp) {
+    if (batch_inp.tokens.empty()) {
         LLAMA_LOG_ERROR("%s: n_tokens == 0\n", __func__);
         return -1;
     }

     const auto & hparams = model.hparams;

+    if (batch_inp.n_embd > 0 && batch_inp.n_embd != hparams.n_embd_inp_enc()) {
+        LLAMA_LOG_ERROR("%s: embd row width %zu does not match the encoder input %u\n",
+                __func__, batch_inp.n_embd, hparams.n_embd_inp_enc());
+        return -1;
+    }
+
     // eagle3/DFlash: features as encoder input, and non-draft paths fall back to model's input dim
-    const int64_t n_embd = hparams.n_embd_inp_enc();
     const int64_t n_vocab = model.vocab.n_tokens();

-    // note: during encode, we always pass the full sequence starting from pos = 0
-    if (!balloc->init(batch_inp, model.vocab, nullptr, n_embd, cparams.kv_unified ? LLAMA_MAX_SEQ : cparams.n_seq_max, true)) {
+    // note: during encode, we always output all tokens and skip position continuity checks (output_all=true)
+    if (!balloc->init(batch_inp, model.vocab, true)) {
         LLAMA_LOG_ERROR("%s: failed to initialize batch\n", __func__);
         return -1;
     }
@@ -1701,29 +1702,27 @@ static bool needs_raw_logits(const llama_ubatch & ubatch, const std::map<llama_s
     return false; // all sequences use backend sampling
 }

-int llama_context::decode(const llama_batch & batch_inp) {
-    // MTP hook batches carry both token (next-token id) and embd (h_nextn row),
-    // so accept either present rather than requiring exactly one.
-    GGML_ASSERT(batch_inp.token || batch_inp.embd);
-
+int llama_context::decode(const llama_batch_ext & batch_inp) {
     if (!memory) {
         LLAMA_LOG_DEBUG("%s: cannot decode batches with this context (calling encode() instead)\n", __func__);
         return encode(batch_inp);
     }

-    if (batch_inp.n_tokens == 0) {
+    if (batch_inp.tokens.empty()) {
         LLAMA_LOG_ERROR("%s: n_tokens == 0\n", __func__);
         return -1;
     }

+    if (batch_inp.n_embd > 0 && batch_inp.n_embd != batch_inp.n_embd_inp) {
+        LLAMA_LOG_ERROR("%s: embd row width %zu does not match the decoder input %zu\n",
+                __func__, batch_inp.n_embd, batch_inp.n_embd_inp);
+        return -1;
+    }
+
     const auto & vocab   = model.vocab;
     const auto & hparams = model.hparams;

     const int64_t n_vocab = vocab.n_tokens();
-    const bool    mtp_embd = cparams.ctx_type == LLAMA_CONTEXT_TYPE_MTP && batch_inp.embd;
-    // DFlash embd batches carry the fused target features at the encoder input width
-    const bool    dflash_embd = model.arch == LLM_ARCH_DFLASH && batch_inp.embd;
-    const int64_t n_embd  = mtp_embd ? hparams.n_embd_out() : dflash_embd ? hparams.n_embd_inp_enc() : hparams.n_embd_inp();

     // when computing embeddings, all tokens are output
     const bool output_all   = cparams.embeddings;
@@ -1731,20 +1730,17 @@ int llama_context::decode(const llama_batch & batch_inp) {

     const uint32_t n_seq_max = cparams.kv_unified ? LLAMA_MAX_SEQ : cparams.n_seq_max;

-    // embedding contexts output every token even when batch.logits is not set
-    if (has_samplers && (output_all || batch_inp.logits)) {
+    // TODO: avoid this workaround in the future
+    // embedding contexts output every token even when no token is explicitly marked as output
+    if (has_samplers) {
         std::vector<int32_t> seq_output_count(n_seq_max, 0);

-        for (int32_t i = 0; i < batch_inp.n_tokens; ++i) {
-            if (!output_all && batch_inp.logits[i] == 0) {
+        for (const auto & tok : batch_inp.tokens) {
+            if (!output_all && !tok.output) {
                 continue;
             }

-            const int ns = batch_inp.n_seq_id ? batch_inp.n_seq_id[i] : 1;
-
-            for (int32_t s = 0; s < ns; ++s) {
-                const llama_seq_id seq_id = batch_inp.seq_id ? batch_inp.seq_id[i][s] : 0;
-
+            for (auto seq_id : tok.seq_ids) {
                 if (seq_id < 0 || (uint32_t) seq_id >= n_seq_max) {
                     continue;
                 }
@@ -1762,7 +1758,7 @@ int llama_context::decode(const llama_batch & batch_inp) {
         }
     }

-    if (!balloc->init(batch_inp, vocab, memory.get(), n_embd, n_seq_max, output_all)) {
+    if (!balloc->init(batch_inp, vocab, output_all)) {
         LLAMA_LOG_ERROR("%s: failed to initialize batch\n", __func__);
         return -1;
     }
@@ -3557,9 +3553,13 @@ void llama_context::opt_epoch_iter(
             batch.logits  [pos_batch]    = true;
         }

-        if (!balloc->init(batch, model.vocab, nullptr, model.hparams.n_embd_inp(), cparams.kv_unified ? LLAMA_MAX_SEQ : cparams.n_seq_max, true)) {
-            LLAMA_LOG_ERROR("%s: failed to initialize batch\n", __func__);
-            return;
+        // TODO: use llama_batch_ext here
+        {
+            llama_batch_compat compat(this, batch);
+            if (!balloc->init(*compat.batch_ext, model.vocab, true)) {
+                LLAMA_LOG_ERROR("%s: failed to initialize batch\n", __func__);
+                return;
+            }
         }

         const uint32_t n_tokens_all = balloc->get_n_tokens();
@@ -4310,6 +4310,18 @@ size_t llama_state_seq_load_file(llama_context * ctx, const char * filepath, lla
     }
 }

+// compat: llama_batch -> llama_batch_ext -> encode/decode
+
+int llama_context::encode(const llama_batch & batch_inp) {
+    llama_batch_compat compat(this, batch_inp, model.hparams.n_embd_inp_enc());
+    return encode(*compat.batch_ext);
+}
+
+int llama_context::decode(const llama_batch & batch_inp) {
+    llama_batch_compat compat(this, batch_inp);
+    return decode(*compat.batch_ext);
+}
+
 ///

 int32_t llama_encode(
@@ -4399,6 +4411,14 @@ void llama_opt_epoch(
         callback_eval);
 }

+int32_t llama_process(llama_context * ctx, llama_process_type type, llama_batch_ext * batch) {
+    switch (type) {
+        case LLAMA_PROCESS_TYPE_ENCODE: return ctx->encode(*batch);
+        case LLAMA_PROCESS_TYPE_DECODE: return ctx->decode(*batch);
+    }
+    return -1;
+}
+
 //
 // ext
 //
diff --git a/src/llama-context.h b/src/llama-context.h
index 77ef92fc6..b403b099b 100644
--- a/src/llama-context.h
+++ b/src/llama-context.h
@@ -141,6 +141,10 @@ struct llama_context {
             llama_memory_context_i * mctx,
                        ggml_status & ret);

+    int encode(const llama_batch_ext & batch_inp);
+    int decode(const llama_batch_ext & batch_inp);
+
+    // compat version
     int encode(const llama_batch & batch_inp);
     int decode(const llama_batch & batch_inp);

diff --git a/src/llama-hparams.cpp b/src/llama-hparams.cpp
index 34b3c6880..b83f45ba9 100644
--- a/src/llama-hparams.cpp
+++ b/src/llama-hparams.cpp
@@ -283,7 +283,8 @@ bool llama_hparams::is_ple(uint32_t il) const {
 }

 uint32_t llama_hparams::n_pos_per_embd() const {
-    return rope_type == LLAMA_ROPE_TYPE_MROPE || rope_type == LLAMA_ROPE_TYPE_IMROPE ? 4 : 1;
+    return (rope_type == LLAMA_ROPE_TYPE_MROPE || rope_type == LLAMA_ROPE_TYPE_IMROPE)
+            ? GGML_MROPE_SECTIONS : 1;
 }

 bool llama_hparams::is_swa(uint32_t il) const {
diff --git a/tests/test-batch-alloc.cpp b/tests/test-batch-alloc.cpp
index 66d29d6f5..ad186c693 100644
--- a/tests/test-batch-alloc.cpp
+++ b/tests/test-batch-alloc.cpp
@@ -3,6 +3,8 @@
 #include "llama.h"

 #include "../src/llama-batch.h"
+#include "../src/llama-arch.h"
+#include "../src/llama-hparams.h"
 #include "../src/llama-memory.h"
 #include "../src/llama-vocab.h"

@@ -47,49 +49,55 @@ struct mock_memory : public llama_memory_i {
     void state_read (llama_io_read_i &,  llama_seq_id, llama_state_seq_flags) override { GGML_ASSERT(false && "not implemented"); }
 };

-// builds embedding batches - an empty llama_vocab rejects all token ids, so
-// the tests use embeddings everywhere except the token validation tests
+// builds a llama_batch_ext without a llama_context
+// n_vocab = 0 by default, so every token id is invalid and the tests use embeddings unless stated otherwise
 struct batch_builder {
-    uint32_t n_embd;
-
-    std::vector<float>     embd;
-    std::vector<llama_pos> pos;
-    std::vector<int32_t>   n_seq_id;
-    std::vector<int8_t>    logits;
-
-    std::vector<std::vector<llama_seq_id>> seq;
-    std::vector<llama_seq_id *>            seq_ptr;
-
-    batch_builder(uint32_t n_embd = 2) : n_embd(n_embd) {}
-
-    // embd values are 100*i + k so that ubatch contents can be traced back to batch indices
-    void add(llama_pos p, std::initializer_list<llama_seq_id> seq_ids, bool output) {
-        const int32_t i = (int32_t) seq.size();
-        for (uint32_t k = 0; k < n_embd; ++k) {
-            embd.push_back(100.0f*i + k);
+    const uint32_t n_embd;
+
+    llama_batch_ext b;
+
+    batch_builder(
+            uint32_t n_embd = 2,
+            llama_memory_i * mem = nullptr,
+            llama_seq_id n_seq_max = 4,
+            uint32_t n_pos_per_embd = 1,
+            llama_token n_vocab = 0,
+            uint32_t n_embd_inp_enc = 0)
+        : n_embd(n_embd),
+          b(/*n_tokens_max*/ 64, n_embd, n_embd_inp_enc > 0 ? n_embd_inp_enc : n_embd, n_seq_max, mem, n_vocab, n_pos_per_embd) {}
+
+    // one embedding row for batch index i, values 100*i + k so ubatch contents can be traced back
+    std::vector<float> row(int32_t i, uint32_t width) const {
+        std::vector<float> r(width);
+        for (uint32_t k = 0; k < width; ++k) {
+            r[k] = 100.0f*i + k;
         }
-        pos.push_back(p);
-        n_seq_id.push_back((int32_t) seq_ids.size());
-        seq.emplace_back(seq_ids);
-        logits.push_back(output ? 1 : 0);
+        return r;
     }

-    llama_batch make(bool with_pos = true, bool with_seq = true, bool with_logits = true) {
-        seq_ptr.clear();
-        for (auto & s : seq) {
-            seq_ptr.push_back(s.data());
+    // embedding entry with full M-RoPE positions
+    int32_t add_embd(const llama_pos * pos, std::initializer_list<llama_seq_id> seq_ids, bool output, uint32_t width = 0) {
+        width = width > 0 ? width : n_embd;
+
+        auto it = seq_ids.begin();
+        const int32_t idx = b.add_token(*it);
+        GGML_ASSERT(idx >= 0);
+        for (++it; it != seq_ids.end(); ++it) {
+            GGML_ASSERT(b.add_seq(idx, *it));
         }
-        seq_ptr.push_back(nullptr);

-        llama_batch res = {};
-        res.n_tokens = (int32_t) seq.size();
-        res.embd     = embd.data();
-        res.pos      = with_pos    ? pos.data()      : nullptr;
-        res.n_seq_id = with_seq    ? n_seq_id.data() : nullptr;
-        res.seq_id   = with_seq    ? seq_ptr.data()  : nullptr;
-        res.logits   = with_logits ? logits.data()   : nullptr;
+        const auto r = row(idx, width);
+        GGML_ASSERT(b.set_token_embd(idx, { r.data(), 1, width }));
+        GGML_ASSERT(b.set_token_pos(idx, pos));
+        GGML_ASSERT(b.set_output(idx, output));

-        return res;
+        return idx;
+    }
+
+    // embedding entry with a single sequential position
+    int32_t add(llama_pos p, std::initializer_list<llama_seq_id> seq_ids, bool output) {
+        const llama_pos pos[GGML_MROPE_SECTIONS] = { p, 0, 0, 0 };
+        return add_embd(pos, seq_ids, output);
     }
 };

@@ -97,22 +105,31 @@ static void test_init(testing & t) {
     llama_vocab vocab;

     t.test("rejects_n_seq_max_too_large", [&](testing & t) {
-        batch_builder bb;
+        batch_builder bb(2, nullptr, LLAMA_MAX_SEQ + 1);
         bb.add(0, {0}, true);

         llama_batch_allocr ba(1);
-        t.assert_true(!ba.init(bb.make(), vocab, nullptr, bb.n_embd, LLAMA_MAX_SEQ + 1, false));
+        t.assert_true(!ba.init(bb.b, vocab, false));
     });

     t.test("rejects_invalid_token", [&](testing & t) {
-        llama_token tok = 0; // empty vocab -> every token id is out of range
-        llama_batch batch = llama_batch_get_one(&tok, 1);
+        // n_vocab = 0 -> every token id is out of range
+        // set_token_id() refuses such ids, so the token is poked directly to reach the init() check
+        batch_builder bb;
+        const int32_t idx = bb.b.add_token(0);
+        const llama_pos pos = 0;
+        bb.b.set_token_pos(idx, &pos);
+        bb.b.set_output(idx, true);

         llama_batch_allocr ba(1);
-        t.assert_true("token id >= n_tokens", !ba.init(batch, vocab, nullptr, 0, 1, false));

-        tok = -1;
-        t.assert_true("negative token id", !ba.init(batch, vocab, nullptr, 0, 1, false));
+        t.assert_true("set_token_id refuses out of range id", !bb.b.set_token_id(idx, 0));
+
+        bb.b.tokens[idx].id = 0;
+        t.assert_true("token id >= n_vocab", !ba.init(bb.b, vocab, false));
+
+        bb.b.tokens[idx].id = -1;
+        t.assert_true("negative token id", !ba.init(bb.b, vocab, false));
     });

     t.test("rejects_invalid_seq_id", [&](testing & t) {
@@ -120,33 +137,44 @@ static void test_init(testing & t) {

         {
             batch_builder bb;
-            bb.add(0, {4}, true);
-            t.assert_true("seq_id >= n_seq_max", !ba.init(bb.make(), vocab, nullptr, bb.n_embd, 4, false));
+            t.assert_true("add_token refuses seq_id >= n_seq_max", bb.b.add_token(4) == -3);
+            t.assert_true("add_token refuses negative seq_id",   bb.b.add_token(-1) == -3);
         }
         {
+            // poke the seq_ids directly to reach the init() check
             batch_builder bb;
-            bb.add(0, {-1}, true);
-            t.assert_true("negative seq_id", !ba.init(bb.make(), vocab, nullptr, bb.n_embd, 4, false));
+            const int32_t idx = bb.add(0, {0}, true);
+            bb.b.tokens[idx].seq_ids = { 4 };
+            t.assert_true("seq_id >= n_seq_max", !ba.init(bb.b, vocab, false));
+        }
+        {
+            batch_builder bb;
+            const int32_t idx = bb.add(0, {0}, true);
+            bb.b.tokens[idx].seq_ids = { -1 };
+            t.assert_true("negative seq_id", !ba.init(bb.b, vocab, false));
         }
     });

-    t.test("autofill_defaults", [&](testing & t) {
+    t.test("copies_pos_seq_output", [&](testing & t) {
         batch_builder bb;
         for (int i = 0; i < 4; ++i) {
-            bb.add(0, {0}, false);
+            bb.add(i, {0}, i == 3);
         }

         llama_batch_allocr ba(1);
-        t.assert_true(ba.init(bb.make(false, false, false), vocab, nullptr, bb.n_embd, 4, false));
+        t.assert_true(ba.init(bb.b, vocab, false));

         const llama_batch & batch = ba.get_batch();

         t.assert_equal(4u, ba.get_n_tokens());
+        t.assert_true("embedding batch", batch.embd  != nullptr);
+        t.assert_true("no token ids",    batch.token == nullptr);

         for (int i = 0; i < 4; ++i) {
-            t.assert_equal("pos defaults to 0..n-1", i, batch.pos[i]);
-            t.assert_equal("n_seq_id defaults to 1", 1, batch.n_seq_id[i]);
-            t.assert_equal("seq_id defaults to 0",   0, batch.seq_id[i][0]);
+            t.assert_equal(i, batch.pos[i]);
+            t.assert_equal(1, batch.n_seq_id[i]);
+            t.assert_equal(0, batch.seq_id[i][0]);
+            t.assert_equal(100.0f*i, batch.embd[i*bb.n_embd]);
         }

         t.assert_equal("only the last token is an output", 1u, ba.get_n_outputs());
@@ -165,7 +193,7 @@ static void test_init(testing & t) {
         }

         llama_batch_allocr ba(1);
-        t.assert_true(ba.init(bb.make(true, true, false), vocab, nullptr, bb.n_embd, 4, true));
+        t.assert_true(ba.init(bb.b, vocab, true));
         t.assert_equal(4u, ba.get_n_outputs());
     });

@@ -176,7 +204,7 @@ static void test_init(testing & t) {
         bb.add(2, {0}, true);

         llama_batch_allocr ba(1);
-        t.assert_true(ba.init(bb.make(), vocab, nullptr, bb.n_embd, 4, false));
+        t.assert_true(ba.init(bb.b, vocab, false));
         t.assert_equal(2u, ba.get_n_outputs());

         llama_ubatch ub = ba.split_simple(10);
@@ -191,17 +219,17 @@ static void test_init(testing & t) {
         t.assert_equal(2, out_ids[1]);
     });

-    t.test("pos_from_memory", [&](testing & t) {
+    t.test("pos_after_memory", [&](testing & t) {
         mock_memory mem;
         mem.ranges[0] = {0, 9};

-        batch_builder bb;
+        batch_builder bb(2, &mem);
         for (int i = 0; i < 3; ++i) {
-            bb.add(0, {0}, false);
+            bb.add(10 + i, {0}, false);
         }

         llama_batch_allocr ba(1);
-        t.assert_true(ba.init(bb.make(false, true, false), vocab, &mem, bb.n_embd, 4, false));
+        t.assert_true(ba.init(bb.b, vocab, false));

         t.assert_equal("pos continues after memory", 10, ba.seq_pos_min(0));
         t.assert_equal(12, ba.seq_pos_max(0));
@@ -214,22 +242,22 @@ static void test_init(testing & t) {
         llama_batch_allocr ba(1);

         {
-            batch_builder bb;
+            batch_builder bb(2, &mem);
             bb.add(10, {0}, false);
             bb.add(11, {0}, true);
-            t.assert_true("pos_max + 1 is accepted", ba.init(bb.make(), vocab, &mem, bb.n_embd, 4, false));
+            t.assert_true("pos_max + 1 is accepted", ba.init(bb.b, vocab, false));
         }
         {
-            batch_builder bb;
+            batch_builder bb(2, &mem);
             bb.add(11, {0}, false);
             bb.add(12, {0}, true);
-            t.assert_true("gap after memory is rejected", !ba.init(bb.make(), vocab, &mem, bb.n_embd, 4, false));
+            t.assert_true("gap after memory is rejected", !ba.init(bb.b, vocab, false));
         }
         {
-            batch_builder bb;
+            batch_builder bb(2, &mem);
             bb.add(9, {0}, false);
             bb.add(10, {0}, true);
-            t.assert_true("overlap with memory is rejected", !ba.init(bb.make(), vocab, &mem, bb.n_embd, 4, false));
+            t.assert_true("overlap with memory is rejected", !ba.init(bb.b, vocab, false));
         }
     });

@@ -240,7 +268,7 @@ static void test_init(testing & t) {
         bb.add(3, {0}, true);

         llama_batch_allocr ba(1);
-        t.assert_true(!ba.init(bb.make(), vocab, nullptr, bb.n_embd, 4, false));
+        t.assert_true(!ba.init(bb.b, vocab, false));
     });

     t.test("rejects_decreasing_positions", [&](testing & t) {
@@ -253,7 +281,7 @@ static void test_init(testing & t) {
         // seq 0 sees positions 4,5,6,3 in batch order -> the trailing 3 decreases

         llama_batch_allocr ba(1);
-        t.assert_true(!ba.init(bb.make(true, true, false), vocab, nullptr, bb.n_embd, 4, false));
+        t.assert_true(!ba.init(bb.b, vocab, false));
     });

     t.test("allows_equal_positions_in_seq", [&](testing & t) {
@@ -263,23 +291,143 @@ static void test_init(testing & t) {
         bb.add(1, {0}, true);

         llama_batch_allocr ba(1);
-        t.assert_true(ba.init(bb.make(true, true, false), vocab, nullptr, bb.n_embd, 4, false));
+        t.assert_true(ba.init(bb.b, vocab, false));
     });

-
     t.test("rejects_coupled_diverged_seqs", [&](testing & t) {
-        batch_builder bb;
-        bb.add(6, {0, 1}, true);
-
         llama_batch_allocr ba(1);

         mock_memory mem;
         mem.ranges[0] = {0, 5};
         mem.ranges[1] = {2, 5}; // same pos_max, different pos_min -> diverged
-        t.assert_true(!ba.init(bb.make(), vocab, &mem, bb.n_embd, 4, false));
+        {
+            batch_builder bb(2, &mem);
+            bb.add(6, {0, 1}, true);
+            t.assert_true(!ba.init(bb.b, vocab, false));
+        }

         mem.ranges[1] = {0, 5};
-        t.assert_true(ba.init(bb.make(), vocab, &mem, bb.n_embd, 4, false));
+        {
+            batch_builder bb(2, &mem);
+            bb.add(6, {0, 1}, true);
+            t.assert_true(ba.init(bb.b, vocab, false));
+        }
+    });
+}
+
+static void test_content_types(testing & t) {
+    llama_vocab vocab;
+
+    t.test("token_and_embd_together", [&](testing & t) {
+        // e.g. MTP hook batches: a token id and its embedding on the same entry
+        batch_builder bb(2, nullptr, 4, 1, /*n_vocab*/ 10);
+
+        const int32_t idx = bb.b.add_token(0);
+        t.assert_true(bb.b.set_token_id(idx, 3));
+        const auto r = bb.row(idx, bb.n_embd);
+        t.assert_true(bb.b.set_token_embd(idx, { r.data(), 1, bb.n_embd }));
+        const llama_pos pos = 0;
+        bb.b.set_token_pos(idx, &pos);
+        bb.b.set_output(idx, true);
+
+        llama_batch_allocr ba(1);
+        t.assert_true(ba.init(bb.b, vocab, false));
+
+        const llama_batch & batch = ba.get_batch();
+        t.assert_true("token ids are kept",   batch.token != nullptr);
+        t.assert_true("embeddings are kept",  batch.embd  != nullptr);
+        t.assert_equal(3, batch.token[0]);
+        t.assert_equal(0.0f, batch.embd[0]);
+        t.assert_equal(1.0f, batch.embd[1]);
+
+        llama_ubatch ub = ba.split_simple(1);
+        t.assert_true(ub.token != nullptr && ub.embd != nullptr);
+        t.assert_equal(3, ub.token[0]);
+    });
+
+    t.test("rejects_mixed_content_types", [&](testing & t) {
+        batch_builder bb(2, nullptr, 4, 1, /*n_vocab*/ 10);
+
+        // entry 0: token only, entry 1: token + embd
+        const llama_pos p0 = 0;
+        const llama_pos p1 = 1;
+
+        int32_t i0 = bb.b.add_token(0);
+        bb.b.set_token_id(i0, 1);
+        bb.b.set_token_pos(i0, &p0);
+
+        int32_t i1 = bb.b.add_token(0);
+        bb.b.set_token_id(i1, 2);
+        const auto r = bb.row(i1, bb.n_embd);
+        bb.b.set_token_embd(i1, { r.data(), 1, bb.n_embd });
+        bb.b.set_token_pos(i1, &p1);
+        bb.b.set_output(i1, true);
+
+        llama_batch_allocr ba(1);
+        t.assert_true(!ba.init(bb.b, vocab, false));
+    });
+
+    t.test("rejects_neither_token_nor_embd", [&](testing & t) {
+        batch_builder bb;
+        const int32_t idx = bb.b.add_token(0);
+        const llama_pos pos = 0;
+        bb.b.set_token_pos(idx, &pos);
+        bb.b.set_output(idx, true);
+
+        llama_batch_allocr ba(1);
+        t.assert_true(!ba.init(bb.b, vocab, false));
+    });
+
+    t.test("rejects_embd_size_mismatch", [&](testing & t) {
+        batch_builder bb; // n_embd = 2, n_embd_inp_enc = 2
+        const int32_t idx = bb.b.add_token(0);
+        const auto r = bb.row(idx, 8);
+
+        t.assert_true("too small", !bb.b.set_token_embd(idx, { r.data(), 1, 1 }));
+        t.assert_true("too large", !bb.b.set_token_embd(idx, { r.data(), 1, 3 }));
+        t.assert_true("zero rows", !bb.b.set_token_embd(idx, { r.data(), 0, 2 }));
+        t.assert_true("null data", !bb.b.set_token_embd(idx, { nullptr,  1, 2 }));
+        t.assert_true("same total via a different split is accepted", bb.b.set_token_embd(idx, { r.data(), 2, 1 }));
+    });
+
+    t.test("rejects_double_embd", [&](testing & t) {
+        batch_builder bb;
+        const int32_t idx = bb.add(0, {0}, true);
+        const auto r = bb.row(idx, bb.n_embd);
+        t.assert_true(!bb.b.set_token_embd(idx, { r.data(), 1, bb.n_embd }));
+    });
+
+    t.test("encoder_width", [&](testing & t) {
+        // e.g. eagle3/dflash: extracted features are wider than the decoder input
+        const uint32_t n_embd_enc = 6;
+        batch_builder bb(2, nullptr, 4, 1, 0, n_embd_enc);
+
+        const llama_pos p0 = 0;
+        const llama_pos p1 = 1;
+        bb.add_embd(&p0, {0}, false, n_embd_enc);
+        bb.add_embd(&p1, {0}, true,  n_embd_enc);
+
+        t.assert_equal("batch width follows the first embedding", (size_t) n_embd_enc, bb.b.n_embd);
+
+        llama_batch_allocr ba(1);
+        t.assert_true(ba.init(bb.b, vocab, false));
+
+        // the ubatch uses the encoder stride: token 1 starts at offset n_embd_enc
+        llama_ubatch ub = ba.split_simple(2);
+        t.assert_equal(2u, ub.n_tokens);
+        t.assert_equal(100.0f, ub.embd[n_embd_enc]);
+        t.assert_equal(105.0f, ub.embd[n_embd_enc + 5]);
+    });
+
+    t.test("rejects_mixing_widths", [&](testing & t) {
+        batch_builder bb(2, nullptr, 4, 1, 0, /*n_embd_inp_enc*/ 6);
+
+        const llama_pos p0 = 0;
+        bb.add_embd(&p0, {0}, false, 2); // first entry fixes the batch width to 2
+
+        const int32_t idx = bb.b.add_token(0);
+        const auto r = bb.row(idx, 6);
+        t.assert_true(!bb.b.set_token_embd(idx, { r.data(), 1, 6 }));
     });
 }

@@ -293,7 +441,7 @@ static void test_split(testing & t) {
         }

         llama_batch_allocr ba(1);
-        t.assert_true(ba.init(bb.make(), vocab, nullptr, bb.n_embd, 4, false));
+        t.assert_true(ba.init(bb.b, vocab, false));

         llama_ubatch ub = ba.split_simple(2);
         t.assert_equal(2u, ub.n_tokens);
@@ -336,7 +484,7 @@ static void test_split(testing & t) {
         }

         llama_batch_allocr ba(1);
-        t.assert_true(ba.init(bb.make(), vocab, nullptr, bb.n_embd, 4, false));
+        t.assert_true(ba.init(bb.b, vocab, false));

         while (ba.split_simple(1).n_tokens > 0) {
         }
@@ -359,7 +507,7 @@ static void test_split(testing & t) {
         }

         llama_batch_allocr ba(1);
-        t.assert_true(ba.init(bb.make(), vocab, nullptr, bb.n_embd, 4, false));
+        t.assert_true(ba.init(bb.b, vocab, false));

         llama_ubatch ub = ba.split_equal(8, false, 0);
         t.assert_true(ub.equal_seqs());
@@ -395,7 +543,7 @@ static void test_split(testing & t) {
         bb.add(1, {0, 1}, true);

         llama_batch_allocr ba(1);
-        t.assert_true(ba.init(bb.make(), vocab, nullptr, bb.n_embd, 4, false));
+        t.assert_true(ba.init(bb.b, vocab, false));

         llama_ubatch ub = ba.split_equal(4, true, 0);
         t.assert_equal("sequential split rejects coupled seqs", 0u, ub.n_tokens);
@@ -417,7 +565,7 @@ static void test_split(testing & t) {
         }

         llama_batch_allocr ba(1);
-        t.assert_true(ba.init(bb.make(), vocab, nullptr, bb.n_embd, 4, false));
+        t.assert_true(ba.init(bb.b, vocab, false));

         for (llama_seq_id s = 0; s < 3; ++s) {
             llama_ubatch ub = ba.split_seq(8);
@@ -459,14 +607,14 @@ static void test_keep_tail(testing & t) {
             }
             ++s;
         }
-        return bb.make();
     };

     t.test("noop_when_seqs_complete", [&](testing & t) {
         batch_builder bb;
+        make_batch(bb, {2, 2});

         llama_batch_allocr ba(1);
-        t.assert_true(ba.init(make_batch(bb, {2, 2}), vocab, nullptr, bb.n_embd, 4, false));
+        t.assert_true(ba.init(bb.b, vocab, false));

         llama_ubatch ub = ba.split_equal(4, false, 2);
         t.assert_equal("both seqs fit whole", 4u, ub.n_tokens);
@@ -478,9 +626,10 @@ static void test_keep_tail(testing & t) {

     t.test("defers_seq_with_short_remainder", [&](testing & t) {
         batch_builder bb;
+        make_batch(bb, {2, 3});

         llama_batch_allocr ba(1);
-        t.assert_true(ba.init(make_batch(bb, {2, 3}), vocab, nullptr, bb.n_embd, 4, false));
+        t.assert_true(ba.init(bb.b, vocab, false));

         // expansion stops at 2 tokens per seq: seq 0 completes, seq 1 would be left
         // with 1 < n_keep_tail remaining, so it is deferred entirely
@@ -504,9 +653,10 @@ static void test_keep_tail(testing & t) {

     t.test("completes_first_seq_when_all_violate", [&](testing & t) {
         batch_builder bb;
+        make_batch(bb, {3, 3});

         llama_batch_allocr ba(1);
-        t.assert_true(ba.init(make_batch(bb, {3, 3}), vocab, nullptr, bb.n_embd, 4, false));
+        t.assert_true(ba.init(bb.b, vocab, false));

         // expansion stops at 2 tokens per seq, leaving both with 1 < n_keep_tail remaining;
         // seq 0 still fits in n_ubatch, so it is extended to completion and emitted alone
@@ -528,9 +678,10 @@ static void test_keep_tail(testing & t) {

     t.test("truncates_to_preserve_tail", [&](testing & t) {
         batch_builder bb;
+        make_batch(bb, {5});

         llama_batch_allocr ba(1);
-        t.assert_true(ba.init(make_batch(bb, {5}), vocab, nullptr, bb.n_embd, 4, false));
+        t.assert_true(ba.init(bb.b, vocab, false));

         // 4 tokens would leave a remainder of 1, and the seq does not fit in n_ubatch,
         // so the ubatch is truncated until n_keep_tail tokens remain
@@ -551,9 +702,10 @@ static void test_keep_tail(testing & t) {

     t.test("keeps_full_ubatch_with_sufficient_remainder", [&](testing & t) {
         batch_builder bb;
+        make_batch(bb, {6});

         llama_batch_allocr ba(1);
-        t.assert_true(ba.init(make_batch(bb, {6}), vocab, nullptr, bb.n_embd, 4, false));
+        t.assert_true(ba.init(bb.b, vocab, false));

         llama_ubatch ub = ba.split_equal(4, false, 2);
         t.assert_equal("remainder >= n_keep_tail, no truncation", 4u, ub.n_tokens);
@@ -567,10 +719,11 @@ static void test_keep_tail(testing & t) {
     });

     t.test("multi_seq_prefix_kept", [&](testing & t) {
-        batch_builder bb;
+        batch_builder bb(2, nullptr, 6);
+        make_batch(bb, {3, 4});

         llama_batch_allocr ba(1);
-        t.assert_true(ba.init(make_batch(bb, {3, 4}), vocab, nullptr, bb.n_embd, 6, false));
+        t.assert_true(ba.init(bb.b, vocab, false));

         // expansion stops at 3 tokens per seq: seq 0 completes, seq 1 has 1 < n_keep_tail
         // remaining and is deferred even though its tokens were already gathered
@@ -591,32 +744,26 @@ static void test_mrope(testing & t) {
     llama_vocab vocab;

     t.test("pos_layout_and_split", [&](testing & t) {
-        const uint32_t n_pos = 4;
+        const uint32_t n_pos  = 4;
         const uint32_t n_embd = 2;

-        batch_builder bb(n_embd);
-        bb.add(10, {0}, false);
-        bb.add(11, {0}, true);
-
-        // M-RoPE positions for embeddings are laid out [n_pos][n_tokens]
-        std::vector<llama_pos> pos = {
-            10, 11, // temporal
-             5,  6, // y
-             7,  8, // x
-             0,  0,
-        };
+        batch_builder bb(n_embd, nullptr, 4, n_pos);

-        llama_batch batch = bb.make(false, true, true);
-        batch.pos = pos.data();
+        // M-RoPE positions per embedding: [temporal, y, x, other]
+        const llama_pos pos0[n_pos] = { 10, 5, 7, 0 };
+        const llama_pos pos1[n_pos] = { 11, 6, 8, 0 };
+        bb.add_embd(pos0, {0}, false);
+        bb.add_embd(pos1, {0}, true);

         llama_batch_allocr ba(n_pos);
-        t.assert_true(ba.init(batch, vocab, nullptr, n_embd, 4, false));
+        t.assert_true(ba.init(bb.b, vocab, false));

         llama_ubatch ub = ba.split_simple(2);
         t.assert_equal(2u, ub.n_tokens);
         t.assert_equal(n_pos, ub.n_pos);
         t.assert_true(ub.is_pos_2d());

+        // the ubatch stores positions section-major: [n_pos][n_tokens]
         const llama_pos expected[8] = {10, 11, 5, 6, 7, 8, 0, 0};
         for (int i = 0; i < 8; ++i) {
             t.assert_equal(expected[i], ub.pos[i]);
@@ -624,7 +771,7 @@ static void test_mrope(testing & t) {
     });

     t.test("pos_jump_allowed", [&](testing & t) {
-        const uint32_t n_pos = 4;
+        const uint32_t n_pos  = 4;
         const uint32_t n_embd = 2;

         mock_memory mem;
@@ -633,15 +780,12 @@ static void test_mrope(testing & t) {
         llama_batch_allocr ba(n_pos);

         auto try_pos = [&](llama_pos p0) {
-            batch_builder bb(n_embd);
-            bb.add(p0, {0}, true);
-
-            std::vector<llama_pos> pos = {p0, 1, 1, 0};
+            batch_builder bb(n_embd, &mem, 4, n_pos);

-            llama_batch batch = bb.make(false, true, true);
-            batch.pos = pos.data();
+            const llama_pos pos[n_pos] = { p0, 1, 1, 0 };
+            bb.add_embd(pos, {0}, true);

-            return ba.init(batch, vocab, &mem, n_embd, 4, false);
+            return ba.init(bb.b, vocab, false);
         };

         t.assert_true("gap after memory is allowed",     try_pos(15));
@@ -650,6 +794,254 @@ static void test_mrope(testing & t) {
     });
 }

+// conversion from the old llama_batch API (llama_batch_compat::init)
+static void test_compat(testing & t) {
+    llama_vocab vocab;
+
+    t.test("token_batch_explicit_fields", [&](testing & t) {
+        llama_token  token[3]    = { 5, 6, 7 };
+        llama_pos    pos[3]      = { 3, 4, 5 };
+        int32_t      n_seq_id[3] = { 1, 1, 2 };
+        llama_seq_id s0[1]       = { 1 };
+        llama_seq_id s1[1]       = { 1 };
+        llama_seq_id s2[2]       = { 1, 2 };
+        llama_seq_id * seq_id[4] = { s0, s1, s2, nullptr };
+        int8_t       logits[3]   = { 0, 1, 0 };
+
+        llama_batch lb = {};
+        lb.n_tokens = 3;
+        lb.token    = token;
+        lb.pos      = pos;
+        lb.n_seq_id = n_seq_id;
+        lb.seq_id   = seq_id;
+        lb.logits   = logits;
+
+        batch_builder bb(2, nullptr, 4, 1, /*n_vocab*/ 100);
+        llama_batch_compat::init(bb.b, lb);
+
+        t.assert_equal((size_t) 3, bb.b.tokens.size());
+        t.assert_true("no embeddings", bb.b.embd.empty() && bb.b.n_embd == 0);
+        for (int i = 0; i < 3; ++i) {
+            t.assert_equal(token[i], bb.b.tokens[i].id);
+            t.assert_equal(pos[i],   bb.b.tokens[i].pos[0]);
+            t.assert_true(!bb.b.tokens[i].has_embd);
+            t.assert_equal(logits[i] != 0, bb.b.tokens[i].output);
+        }
+        t.assert_equal((size_t) 1, bb.b.tokens[0].seq_ids.size());
+        t.assert_true(bb.b.tokens[0].seq_ids.count(1) == 1);
+        t.assert_equal((size_t) 2, bb.b.tokens[2].seq_ids.size());
+        t.assert_true(bb.b.tokens[2].seq_ids.count(1) == 1 && bb.b.tokens[2].seq_ids.count(2) == 1);
+
+        // round trip through the allocator
+        llama_batch_allocr ba(1);
+        t.assert_true(ba.init(bb.b, vocab, false));
+        const llama_batch & batch = ba.get_batch();
+        t.assert_true(batch.token != nullptr && batch.embd == nullptr);
+        for (int i = 0; i < 3; ++i) {
+            t.assert_equal(token[i], batch.token[i]);
+            t.assert_equal(pos[i],   batch.pos[i]);
+        }
+        t.assert_equal(1u, ba.get_n_outputs());
+    });
+
+    t.test("defaults_for_null_fields", [&](testing & t) {
+        // llama_batch_get_one: only token and n_tokens are set
+        mock_memory mem;
+        mem.ranges[0] = {0, 9};
+
+        llama_token token[3] = { 5, 6, 7 };
+        llama_batch lb = llama_batch_get_one(token, 3);
+
+        batch_builder bb(2, &mem, 4, 1, /*n_vocab*/ 100);
+        llama_batch_compat::init(bb.b, lb);
+
+        t.assert_equal((size_t) 3, bb.b.tokens.size());
+        for (int i = 0; i < 3; ++i) {
+            t.assert_equal("pos continues after memory",  10 + i, bb.b.tokens[i].pos[0]);
+            t.assert_equal("seq_id defaults to 0",        (size_t) 1, bb.b.tokens[i].seq_ids.size());
+            t.assert_true(bb.b.tokens[i].seq_ids.count(0) == 1);
+        }
+        t.assert_true("only the last token is an output", !bb.b.tokens[0].output && !bb.b.tokens[1].output && bb.b.tokens[2].output);
+
+        llama_batch_allocr ba(1);
+        t.assert_true(ba.init(bb.b, vocab, false));
+        t.assert_equal(10, ba.seq_pos_min(0));
+        t.assert_equal(12, ba.seq_pos_max(0));
+    });
+
+    t.test("auto_pos_starts_at_zero_without_memory", [&](testing & t) {
+        llama_token token[2] = { 5, 6 };
+        llama_batch lb = llama_batch_get_one(token, 2);
+
+        batch_builder bb(2, nullptr, 4, 1, /*n_vocab*/ 100);
+        llama_batch_compat::init(bb.b, lb);
+
+        t.assert_equal(0, bb.b.tokens[0].pos[0]);
+        t.assert_equal(1, bb.b.tokens[1].pos[0]);
+    });
+
+    t.test("auto_pos_is_tracked_per_seq", [&](testing & t) {
+        mock_memory mem;
+        mem.ranges[0] = {0, 9}; // seq 1 is empty
+
+        llama_token  token[4]    = { 5, 6, 7, 8 };
+        int32_t      n_seq_id[4] = { 1, 1, 1, 1 };
+        llama_seq_id s0[1] = { 0 };
+        llama_seq_id s1[1] = { 1 };
+        llama_seq_id * seq_id[5] = { s0, s1, s0, s1, nullptr };
+
+        llama_batch lb = {};
+        lb.n_tokens = 4;
+        lb.token    = token;
+        lb.n_seq_id = n_seq_id;
+        lb.seq_id   = seq_id;
+
+        batch_builder bb(2, &mem, 4, 1, /*n_vocab*/ 100);
+        llama_batch_compat::init(bb.b, lb);
+
+        t.assert_equal("seq 0 continues after memory", 10, bb.b.tokens[0].pos[0]);
+        t.assert_equal("seq 1 starts from 0",           0, bb.b.tokens[1].pos[0]);
+        t.assert_equal(11, bb.b.tokens[2].pos[0]);
+        t.assert_equal( 1, bb.b.tokens[3].pos[0]);
+    });
+
+    t.test("embd_batch_with_mrope_positions", [&](testing & t) {
+        const uint32_t n_pos  = 4;
+        const uint32_t n_embd = 2;
+
+        float embd[2*n_embd] = { 0, 1, 100, 101 };
+        // section-major layout: pos[j*n_tokens + i]
+        llama_pos pos[n_pos*2] = {
+            10, 11, // temporal
+             5,  6, // y
+             7,  8, // x
+             0,  0,
+        };
+
+        llama_batch lb = {};
+        lb.n_tokens = 2;
+        lb.embd     = embd;
+        lb.pos      = pos;
+
+        batch_builder bb(n_embd, nullptr, 4, n_pos);
+        llama_batch_compat::init(bb.b, lb);
+
+        t.assert_equal((size_t) 2, bb.b.tokens.size());
+        t.assert_equal("batch width", (size_t) n_embd, bb.b.n_embd);
+        for (int i = 0; i < 2; ++i) {
+            t.assert_true(bb.b.tokens[i].has_embd);
+            t.assert_equal(LLAMA_TOKEN_NULL, bb.b.tokens[i].id);
+            t.assert_equal((size_t) i*n_embd, bb.b.tokens[i].embd_off);
+            for (uint32_t j = 0; j < n_pos; ++j) {
+                t.assert_equal(pos[j*2 + i], bb.b.tokens[i].pos[j]);
+            }
+        }
+        t.assert_equal(100.0f, bb.b.embd[2]);
+        t.assert_equal(101.0f, bb.b.embd[3]);
+
+        llama_batch_allocr ba(n_pos);
+        t.assert_true(ba.init(bb.b, vocab, false));
+        llama_ubatch ub = ba.split_simple(2);
+        const llama_pos expected[8] = {10, 11, 5, 6, 7, 8, 0, 0};
+        for (int i = 0; i < 8; ++i) {
+            t.assert_equal(expected[i], ub.pos[i]);
+        }
+    });
+
+    t.test("token_and_embd_both_set", [&](testing & t) {
+        // e.g. MTP hook batches
+        llama_token token[2] = { 5, 6 };
+        float       embd[4]  = { 0, 1, 100, 101 };
+        llama_pos   pos[2]   = { 3, 4 };
+
+        llama_batch lb = {};
+        lb.n_tokens = 2;
+        lb.token    = token;
+        lb.embd     = embd;
+        lb.pos      = pos;
+
+        batch_builder bb(2, nullptr, 4, 1, /*n_vocab*/ 100);
+        llama_batch_compat::init(bb.b, lb);
+
+        for (int i = 0; i < 2; ++i) {
+            t.assert_equal(token[i], bb.b.tokens[i].id);
+            t.assert_true(bb.b.tokens[i].has_embd);
+            t.assert_equal("one position per token", pos[i], bb.b.tokens[i].pos[0]);
+        }
+        t.assert_equal(100.0f, bb.b.embd[2]);
+
+        llama_batch_allocr ba(1);
+        t.assert_true(ba.init(bb.b, vocab, false));
+        const llama_batch & batch = ba.get_batch();
+        t.assert_true("both kept", batch.token != nullptr && batch.embd != nullptr);
+    });
+
+    t.test("embd_row_width_override", [&](testing & t) {
+        // encoder input (e.g. eagle3/dflash) is wider than the decoder input
+        const uint32_t n_embd_enc = 6;
+        float embd[2*n_embd_enc];
+        for (int i = 0; i < 2*6; ++i) {
+            embd[i] = (float) i;
+        }
+
+        llama_batch lb = {};
+        lb.n_tokens = 2;
+        lb.embd     = embd;
+
+        batch_builder bb(2, nullptr, 4, 1, 0, n_embd_enc);
+        llama_batch_compat::init(bb.b, lb, n_embd_enc);
+
+        t.assert_equal((size_t) n_embd_enc, bb.b.n_embd);
+        t.assert_equal((size_t) 2*n_embd_enc, bb.b.embd.size());
+        t.assert_equal((size_t) n_embd_enc, bb.b.tokens[1].embd_off);
+        t.assert_equal(6.0f, bb.b.embd[n_embd_enc]);
+
+        llama_batch_allocr ba(1);
+        t.assert_true(ba.init(bb.b, vocab, false));
+        llama_ubatch ub = ba.split_simple(2);
+        t.assert_equal("ubatch uses the encoder stride", 6.0f, ub.embd[n_embd_enc]);
+    });
+}
+
+static void test_mtp_embd_width(testing & t) {
+    t.test("mtp_uses_n_embd_out", [&](testing & t) {
+        llama_hparams hparams = {};
+        hparams.n_embd             = 64;
+        hparams.n_deepstack_layers = 2;   // makes n_embd_inp() = 64 + 64*2 = 192
+        hparams.n_embd_out_impl    = 96;  // makes n_embd_out() = 96
+
+        t.assert_equal("default context uses n_embd_inp (deepstack-aware)",
+                (size_t) 192, llama_batch_ext_select_n_embd_inp(LLAMA_CONTEXT_TYPE_DEFAULT, LLM_ARCH_LLAMA, hparams));
+
+        t.assert_equal("MTP context uses n_embd_out instead (target-model hidden state width)",
+                (size_t) 96, llama_batch_ext_select_n_embd_inp(LLAMA_CONTEXT_TYPE_MTP, LLM_ARCH_LLAMA, hparams));
+    });
+
+    t.test("mtp_falls_back_to_n_embd_when_no_override", [&](testing & t) {
+        llama_hparams hparams = {};
+        hparams.n_embd = 64; // no deepstack, no n_embd_out_impl override
+
+        t.assert_equal((size_t) 64, llama_batch_ext_select_n_embd_inp(LLAMA_CONTEXT_TYPE_DEFAULT, LLM_ARCH_LLAMA, hparams));
+        t.assert_equal((size_t) 64, llama_batch_ext_select_n_embd_inp(LLAMA_CONTEXT_TYPE_MTP, LLM_ARCH_LLAMA, hparams));
+    });
+
+    t.test("dflash_uses_n_embd_inp_enc", [&](testing & t) {
+        llama_hparams hparams = {};
+        hparams.n_embd              = 64;
+        hparams.n_embd_inp_enc_impl = 128; // makes n_embd_inp_enc() = 128
+        hparams.n_embd_out_impl     = 96;  // makes n_embd_out() = 96
+
+        t.assert_equal("DFlash uses the encoder input width",
+                (size_t) 128, llama_batch_ext_select_n_embd_inp(LLAMA_CONTEXT_TYPE_DEFAULT, LLM_ARCH_DFLASH, hparams));
+
+        t.assert_equal("other archs ignore n_embd_inp_enc",
+                (size_t) 64, llama_batch_ext_select_n_embd_inp(LLAMA_CONTEXT_TYPE_DEFAULT, LLM_ARCH_LLAMA, hparams));
+
+        t.assert_equal("MTP takes precedence over DFlash",
+                (size_t) 96, llama_batch_ext_select_n_embd_inp(LLAMA_CONTEXT_TYPE_MTP, LLM_ARCH_DFLASH, hparams));
+    });
+}
+
 int main(int argc, char ** argv) {
     testing t;

@@ -665,10 +1057,13 @@ int main(int argc, char ** argv) {
         t.set_filter(argv[1]);
     }

-    t.test("init",      test_init);
-    t.test("split",     test_split);
-    t.test("keep_tail", test_keep_tail);
-    t.test("mrope",     test_mrope);
+    t.test("init",           test_init);
+    t.test("content_types",  test_content_types);
+    t.test("compat",         test_compat);
+    t.test("split",          test_split);
+    t.test("keep_tail",      test_keep_tail);
+    t.test("mrope",          test_mrope);
+    t.test("mtp_embd_width", test_mtp_embd_width);

     return t.summary();
 }