Spec Keys

A Spec Key names a set of nodes in the compute graph of one model at one spec version:

<org>/<model>@<version>:<layer-path>

Part	Meaning	Example
`org/model`	The model, named like its Hugging Face repository	`Qwen/Qwen3.8-27B`
`@version`	Spec version: `major.minor`. The lock pins the exact patch version and content hash.	`@1.0`
`:layer-path`	One or more nodes of the compute graph	`layers[*].attn.core`

Layer selectors

Per-layer nodes take a layer selector. Top-level nodes (embed, final_norm, lm_head) take none.

Selector	Selects	Example
`[*]`	Every layer that has the node	`layers[*].attn.core`: the 16 attention layers of Qwen3.8-27B, not the 48 Gated DeltaNet layers
`[a..b]`	Layers `a` to `b`, inclusive	`layers[3..15].mlp.act`
`[n]`	One layer	`layers[7].attn.core`
`[i]`, `[i+1]`	Relative layers, for fusion across a layer boundary	`{layers[i].mlp_residual, layers[i+1].input_norm}`
(none)	A top-level node	`lm_head`

When a selector covers layers whose node has different constants (for example, sliding-window and global attention layers in Gemma 4), the kernel is verified against each variant separately.

Common forms

# one node in every layer
"Qwen/Qwen3.8-27B@1.0:layers[*].input_norm"

# a node that exists only in some layers (Gated Attention: layers 3, 7, …, 63)
"Qwen/Qwen3.8-27B@1.0:layers[*].attn.core"

# one kernel fusing adjacent nodes of a layer
"Qwen/Qwen3.8-27B@1.0:layers[*].{attn_residual, post_attn_norm}"

# a kernel fusing across a layer boundary
"Qwen/Qwen3.8-27B@1.0:{layers[i].mlp_residual, layers[i+1].input_norm}"

# a top-level node
"Qwen/Qwen3.8-27B@1.0:lm_head"

A kernel used in several places lists several keys. Each one is verified separately:

@tfe.implements(["Qwen/Qwen3.8-27B@1.0:layers[*].input_norm",
                 "Qwen/Qwen3.8-27B@1.0:layers[*].post_attn_norm"], grid=("T",))

Versions

You may omit @version. The locked version is used.
If you give a version, it must match the lock: @1.0 with a lock at 1.0.4 is fine; @1.1 is reported as UNKNOWN with “annotation asks for … but the lock pins …”.
Spec versions follow semantic versioning. Patch releases change only docs and metadata, never definitions. Minor releases add nodes or optional domains. Major releases change semantics.

Reserved forms

Form	Status
`layers[]` (a whole layer) and `` (the whole model)	Parsed, reserved for MegaKernel verification; resolving them reports that it is on the roadmap.
`ops/<name>@<version>` (a generic Op Spec, not bound to a model)	Parsed; bind the kernel to a model node instead for now.

Finding node names

The nodes of each model are listed on its Spec Hub page, or from the CLI:

theformalera spec show 'Qwen/Qwen3.8-27B@1.0:layers[*].mlp.act'

A typo in a node name is reported with the list of nodes that do exist:

Qwen/Qwen3.8-27B@1.0.0 has no node `mlp.actt` (nodes: embed, input_norm, gdn.in_proj, …)

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Layer selectors

Common forms

Versions

Reserved forms

Finding node names

​Layer selectors

​Common forms

​Versions

​Reserved forms

​Finding node names

Layer selectors

Common forms

Versions

Reserved forms

Finding node names