archdb

LLM architectures and pretraining recipes, with sources.

Command A+ (command-a-plus-05-2026)

Cohere · reasoning checkpoint

No base checkpoint is public; facts describe the released post-trained checkpoint.

Open in the comparison table Hugging Face ↗ Blog ↗

KV calculations use one sequence at 131,072 tokens and 16-bit cache elements. They include bounded sliding-window caches. This is retained cache payload, not peak prefill memory. The comparison table also offers sourced mixed-precision layouts, including quantization scales.

Release

Released

2026-05-20

Source: blog · post header
May 20, 2026 4 minute read Introducing Command A+

Post: 'Today, we’re releasing Command A+ open-source.'

Date the weights (or, if earlier, the technical report) were first made public, YYYY-MM-DD, as dated by the publisher. A Hugging Face repository creation date is used only when no dated publisher page exists, with a note.

License

apache-2.0

Source: model-card · README.md; YAML front matter
license: apache-2.0

License of the released weights as declared by the publisher (model card metadata or license file), e.g. apache-2.0, mit, or the name of a custom license.

Input modalities

text + image

Source: model-card · README.md; Model Details
**Input**: Text and images.

Input modalities of the released checkpoint as the publisher states them, from: text, image, video, audio, joined with ' + ' in that order ("text", "text + image + video").

Parameters

Total params

218B parameters

Source: model-card · README.md; Model Summary
Model Size: 25B active parameters, 218B total parameters

Total parameter count as reported by the publisher. See params.note for whether embeddings, MTP heads or vision towers are included.

Active params

25B parameters

Source: model-card · README.md; Model Summary
Model Size: 25B active parameters, 218B total parameters

Parameters used per token in the forward pass, as reported by the publisher.

Active non-embedding (stated)

Not disclosed

Active parameters excluding the input embedding and the output head (unembedding). Stated by the publisher, or computed from params.active by subtracting vocab × d_model for each of the embedding and output head that params.active is stated to include (basis inferred, note with the arithmetic). Not disclosed when the scope of params.active is not stated.

Counted total params

218.3B parameters

Calculated: embedding + output head + all experts + other weights, CohereLabs/command-a-plus-05-2026-bf16@5fb6fde safetensors headers; reproduces stated total (backbone) and active (with embedding)

Parameters of the text backbone counted from the released checkpoint's safetensors headers (embedding, output head, all experts and other weights; excluding MTP modules, vision/audio towers and n-gram lookup tables). Shown only when the counts reproduce the publisher's stated total and active parameters within 5% under some scope.

Counted embedding + head

1.074B parameters

Calculated: input embedding + output head, CohereLabs/command-a-plus-05-2026-bf16@5fb6fde safetensors headers

Input embedding plus output head (once if tied), counted from the checkpoint.

Non-emb. params (counted)

217.2B parameters

Calculated: dense + routed backbone weights; excludes input embedding, output head, lookup tables, MTP and other modalities, CohereLabs/command-a-plus-05-2026-bf16@5fb6fde safetensors headers; reproduces stated total (backbone) and active (with embedding)

Language backbone weights excluding input embeddings, output head, lookup/Engram tables, MTP modules and vision/audio towers. Equals params.counted_total minus params.counted_embedding. Same validation as params.counted_total.

Largest layer (counted)

6.787B parameters

Calculated: max(sum of dense and routed weights sharing a full layers.<index> tensor path), all experts included, CohereLabs/command-a-plus-05-2026-bf16@5fb6fde safetensors headers

Largest group of language-backbone weights sharing a full layers.<index> tensor path, including every routed expert. Excludes lookup/Engram tables, embeddings, output head, MTP and other modalities. Hybrid checkpoints may store mixers and FFNs as separate layers. All-gather volume also depends on wrapping, sharding and dtype.

Active non-emb. (counted)

23.91B parameters

Calculated: non-expert weights + routed experts × 8/128, excluding embedding and output head, CohereLabs/command-a-plus-05-2026-bf16@5fb6fde safetensors headers; reproduces stated total (backbone) and active (with embedding)

Active parameters per token excluding the input embedding and output head, counted from the checkpoint as all non-expert weights plus routed-expert weights × top_k / experts. Same validation as params.counted_total.

Counting scope

Card does not state scope; the checkpoint index lists 218,750,277,872 parameters including the SigLIP vision tower and projector.

Source: config · model.safetensors.index.json; metadata.total_parameters
"total_parameters": 218750277872

What the publisher's counts include or exclude (MTP modules, embeddings, vision encoder, n-gram tables).

Shape

Layers

32

Source: config · /text_config/num_hidden_layers

Number of transformer blocks in the main backbone (attention or token mixer plus FFN), excluding MTP modules.

d_model

4,096

Source: config · /text_config/hidden_size

Residual stream width.

Vocab

262,144

Source: config · /text_config/vocab_size

Embedding table rows (vocab_size in config, may include padding).

Tied embeddings

Yes

Source: config · /text_config/tie_word_embeddings

Input embedding and output head share weights.

Tokenizer

New Cohere tokenizer, first used in Command A+

Source: blog · Efficiency section
Command A+ is the first model to use our latest tokenizer

Tokenizer type and lineage as described by the publisher (e.g. byte-level BPE shared with an earlier model).

d_model / layers

128

Calculated: d_model / layers

Width-to-depth ratio, d_model divided by the number of blocks.

Attention

Token mixers

GQA, SWA

Source: model-card · README.md; Model Architecture
The attention layers interleave sliding-window attention layers with Rotational Positional Embeddings and global attention layers without positional embeddings in a 3:1 ratio

Token-mixing layer types in the backbone, e.g. GQA, MLA, SWA, Gated DeltaNet, Mamba-2, DSA (DeepSeek sparse attention).

Layer layout

3 SWA : 1 global

Inferred from the source; see the explanation below.

Source: config · config.json; /text_config/layer_types
"layer_types": [ "sliding_attention", "sliding_attention", "sliding_attention", "full_attention", "sliding_attention", "sliding_attention", "sliding_attention", "full_attention", "sliding_attention", "sliding_attention", "sliding_attention", "full_attention", "sliding_attention", "sliding_attention", "sliding_attention", "full_attention", "sliding_attention", "sliding_attention", "sliding_attention", "full_attention", "sliding_attention", "sliding_attention", "sliding_attention", "full_attention", "sliding_attention", "sliding_attention", "sliding_attention", "full_attention", "sliding_attention", "sliding_attention", "sliding_attention", "full_attention" ]

Ordered 32-layer backbone from /text_config/layer_types; auxiliary modules are excluded.

Token-mixer order, summarized as a pattern or layer positions. The fact's optional sequence lists each mixer in order; a ratio alone does not establish the order. Auxiliary prediction modules and standalone FFNs are excluded.

Global-attention layers

8

Source: config · /text_config/layer_types | count full_attention

Layers whose KV cache grows with full context (dense or sparse global attention, MLA). Excludes sliding-window and linear/recurrent layers.

SWA : global

3

Calculated: attn.local_layers / attn.global_layers

attn.local_layers divided by attn.global_layers, the sliding-window to global interleave ratio (5 for '5 SWA : 1 global').

Sliding-window layers

24

Source: config · /text_config/layer_types | count sliding_attention

Layers with a fixed attention window.

Query heads

128

Source: config · /text_config/num_attention_heads

Query heads in the global-attention layers.

KV heads

8

Source: config · /text_config/num_key_value_heads

Key/value heads in the global-attention layers. Not applicable to MLA, whose cache is a shared latent.

Heads × head dim

16,384

Calculated: heads × head_dim

attn.heads × attn.head_dim, the query projection width of global layers.

Q heads / KV head

16

Calculated: heads / kv_heads

attn.heads divided by attn.kv_heads in global layers.

QK head dim

128

Source: config · /text_config/head_dim

Query/key dimension per head in global-attention layers (for MLA, nope + rope dims).

Window

4.096K tokens

Source: config · /text_config/sliding_window

Sliding-window size of the local layers.

SWA KV heads

8

Source: config · /text_config/num_key_value_heads

KV heads in sliding-window layers (stated even when equal to attn.kv_heads).

SWA query heads

128

Source: config · /text_config/num_attention_heads

Cohere2MoeAttention uses the same num_attention_heads, num_key_value_heads and head_dim for both layer types; only sliding_window and RoPE differ.

Query heads in sliding-window layers (stated even when equal to attn.heads).

SWA QK head dim

128

Source: config · /text_config/head_dim

Query/key head dimension in sliding-window layers. Value head dimensions may differ; see attn.local_v_head_dim.

Positional encoding

RoPE (SWA), NoPE (global)

Source: model-card · README.md; Model Architecture
The attention layers interleave sliding-window attention layers with Rotational Positional Embeddings and global attention layers without positional embeddings

config rope_theta 50000 applies only to the sliding-window layers; rotation is GPT-J-style interleaved pairs.

Positional scheme in global layers: RoPE, partial RoPE, NoPE, or mixed per layer type.

SWA RoPE base

50,000

Source: config · /text_config/rope_parameters/rope_theta

Cohere2MoeRotaryEmbedding reads rope_parameters rope_theta; one rotary table, applied only on sliding-window layers.

RoPE base frequency of the sliding-window layers (stated even when equal to attn.rope_theta).

QK norm

No

Source: code · modeling_cohere2_moe.py; Cohere2MoeAttention.forward
query_states = self.q_proj(hidden_states).view(hidden_shape).transpose(1, 2) key_states = self.k_proj(hidden_states).view(hidden_shape).transpose(1, 2)

Queries and keys are normalized per head before the dot product.

QKV bias

No

Source: config · /text_config/attention_bias

Query/key/value projections have bias terms.

Feed-forward

Activation

SwiGLU

Source: code · modeling_cohere2_moe.py; Cohere2MoeExperts.forward
current_hidden_states = self.act_fn(gate) * up

act_fn from config hidden_act silu; the shared expert (Cohere2MoeMLP) uses the same gate × up form.

FFN activation (SwiGLU, GeGLU, ...).

FFN bias

No

Source: code · modeling_cohere2_moe.py; Cohere2MoeMLP.__init__
self.gate_proj = nn.Linear(self.hidden_size, self.intermediate_size, bias=False)

FFN projections have bias terms.

Mixture of experts

Routed experts

128

Source: config · /text_config/num_experts

Routed experts per MoE layer.

Experts per token

8

Source: config · /text_config/num_experts_per_tok

Routed experts selected per token.

Shared experts

1

Source: model-card · README.md; Model Architecture
and a single shared expert is applied to all tokens

Always-on experts per MoE layer.

Expert dim

4,096

Source: config · /text_config/intermediate_size

Intermediate width of one routed expert.

Shared expert dim

16,384

Inferred from the source; see the explanation below.

Source: code · modeling_cohere2_moe.py; Cohere2MoeSparseMoeBlock.__init__
intermediate_size=config.intermediate_size * config.num_shared_experts,

intermediate_size 4096 × num_shared_experts 4 (config.json), built as one MLP; checkpoint shared_experts.gate_proj is [16384, 4096]. Combined as (routed + shared) / 2 (shared_expert_combination_strategy average).

Total intermediate width of the shared expert(s).

Leading dense layers

0

Source: config · /text_config/first_k_dense_replace

Number of initial blocks that use a dense FFN instead of MoE.

Router score

normalized sigmoid (over the top-k logits)

Source: model-card · README.md; Model Architecture
swap out the softmax router activation function with a normalized sigmoid over the topk expert logits per token

Config expert_selection_fn sigmoid with norm_topk_prob; Cohere2MoeTopKRouter takes top-k of raw logits, then sigmoid and renormalizes.

Gating function over expert logits (softmax, sigmoid).

Load balancing

additive expert bias

Source: model-card · README.md; Model Architecture
We use additive-bias-based load balancing to encourage balanced token load across all experts

Dropless, token-choice routing.

Load-balancing method, with coefficients where disclosed.

Renormalize top-k

Yes

Source: config · /text_config/norm_topk_prob

Selected expert weights are renormalized to sum to 1.

Expert dim / d_model

1

Calculated: moe.expert_dim / d_model

moe.expert_dim divided by shape.d_model.

Sparsity (experts / top-k)

16

Calculated: experts / top_k

Routed experts divided by experts selected per token.

Active / total

0.114679

Calculated: params.active / params.total

params.active divided by params.total.

Multi-token prediction

MTP depth

Not disclosed

Additional future tokens predicted during pretraining (0 when the model was trained without MTP).

Normalization and stability

Norm

LayerNorm (no bias)

Source: code · modeling_cohere2_moe.py; Cohere2MoeDecoderLayer.__init__
else Cohere2MoeLayerNorm(hidden_size=config.hidden_size, eps=config.layer_norm_eps)

rms_norm_eps is null in config.json, so LayerNorm (mean-subtracted, weight only) is used.

Normalization layer type in the blocks.

Norm placement

parallel

Source: code · modeling_cohere2_moe.py; Cohere2MoeDecoderLayer.forward
hidden_states = residual + hidden_states_attention + hidden_states_mlp

One pre-norm (input_layernorm) feeds both attention and MoE.

Pre-norm, post-norm, or sandwich (pre and post).

Norm epsilon

1e-05

Source: config · /text_config/layer_norm_eps

Epsilon of the block normalization layers.

Context length

Pretraining context

Not disclosed

Sequence length of the main pretraining stage.

Trained context

Not disclosed

Longest sequence length trained on after context extension.

Advertised context

131.1K tokens

Source: model-card · README.md; Context Length
Command A+ supports a context length of 128K & 64K output length.

Card: 128K input plus 64K output; config max_position_embeddings is 200,000.

Longest context the publisher says the model supports, possibly beyond trained length via RoPE scaling.

Pretraining recipe

Pretraining tokens

Not disclosed

Tokens seen in pretraining including annealing and context extension, as reported.

Optimizer

Not disclosed

Optimizer used for the bulk of parameters.

Peak LR

Not disclosed

Peak learning rate of the main pretraining stage.

Final LR

Not disclosed

Learning rate at the end of the decay.

LR schedule

Not disclosed

Learning-rate schedule shape with phase boundaries.

Warmup

Not disclosed

Warmup length in steps or tokens.

Batch size

Not disclosed

Global batch size, including any batch-size ramp: sequences × sequence length (token total), or the token total alone when only that is stated.

Weight decay

Not disclosed

Decoupled weight decay coefficient.

Adam betas

Not disclosed

(beta1, beta2) of the Adam-family optimizer or its AdamW fallback.

Grad clip

Not disclosed

Global gradient-norm clipping threshold.

Training precision

Not disclosed

Matmul precision of pretraining (BF16, FP8 recipe, NVFP4 recipe) with the scaling granularity where disclosed. Never inferred from the released checkpoint dtype.

Data mix

48 languages

Source: model-card · README.md; Languages covered
The model has been trained on 48 languages

Pretraining data composition as disclosed (domain shares, synthetic fraction, repetition).

KV cache

KV bytes / token

35,840 bytes

Calculated: kv.bytes_at_context / 131072 tokens; uniform BF16, payload only; quantization overhead excluded. Global KV: 8 × (2048 × 16/8) B/entry; SWA KV: 24 × (2048 × 16/8) B/entry

Retained KV cache divided by context length, including bounded SWA caches and indexer keys. Exports use uniform BF16 at 131,072 tokens. The website can select uniform payload precision (no quantization overhead) or sourced component formats (including scales and documented padding). This is cache payload, not peak prefill memory or persistent prefix storage.

Global KV bytes / token

32,768 bytes

Calculated: 32768 B / 1 tokens (Global KV); uniform BF16, payload only; quantization overhead excluded. Global KV: 8 × (2048 × 16/8) B/entry; SWA KV: 24 × (2048 × 16/8) B/entry

Long-context global KV bytes per token, including indexer keys; excludes bounded SWA caches. Compression rates and cross-layer cache reuse are included. Exports use uniform BF16; the website's storage selector also applies here. This is the field to compare with global-KV figures in reports, using the matching storage recipe.

KV bytes / token / B active

1,434 bytes

Calculated: kv.bytes_per_token (131072 tokens) / (params.active / 1e9); uniform BF16, payload only; quantization overhead excluded. Global KV: 8 × (2048 × 16/8) B/entry; SWA KV: 24 × (2048 × 16/8) B/entry

kv.bytes_per_token divided by active parameters in billions (131,072 tokens in exports).

KV at context / B active

187,904,819 bytes

Calculated: kv.bytes_at_context (131072 tokens) / (params.active / 1e9); uniform BF16, payload only; quantization overhead excluded. Global KV: 8 × (2048 × 16/8) B/entry; SWA KV: 24 × (2048 × 16/8) B/entry

kv.bytes_at_context divided by active parameters in billions (131,072 tokens in exports).

KV at context

4,697,620,480 bytes

Calculated: 32768 B × 131072 (Global KV) + 98304 B × min(131072, 4096) (SWA KV); uniform BF16, payload only; quantization overhead excluded. Global KV: 8 × (2048 × 16/8) B/entry; SWA KV: 24 × (2048 × 16/8) B/entry

Retained KV cache for one sequence at the selected context, including SWA windows and indexer keys. Exports use uniform BF16 at 131,072 tokens. Excludes recurrent state, compressor tail state, draft/MTP caches, temporary prefill tensors, allocator metadata and persistent prefix snapshots. Does not estimate peak prefill or total serving memory.

Evaluations

AA Intelligence Index

13

Source: leaderboard · Artificial Analysis model page /models/command-a-plus, Wayback snapshot 2026-10-19
Command A+ scores 13 on the Artificial Analysis Intelligence Index

Variant: Command A+. Index v4.3.2.

Artificial Analysis Intelligence Index v4.3.2 of the post-trained model, from a dated Wayback snapshot of its Artificial Analysis page. The note names the variant (reasoning setting).

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