lambda
Since v1.10.0 · Top-level declaration
Grammar
lambda <Name> {
ontology: "<string>" # optional — ontological class
certainty: <0.0..1.0> # optional — confidence (default 1.0)
temporal_frame: "<start>" ["<end>"] # optional — validity window
provenance: "<string>" # optional — source provenance
derivation: <raw|inferred|derived|aggregated|transformed> # optional — derivation kind
}
# Inside a flow body — application form:
step <Name> {
...
lambda <Name> on <target> -> <OutputType>
...
}
lambda declares typed lambda-data — a value with explicit
provenance, certainty, temporal frame, and derivation status.
Where type declares structural shape and axonstore
declares persistent rows, lambda declares epistemic
metadata for a derived value: what it claims, how confident,
when valid, where it came from, how it was derived.
The companion flow-step form lambda <Name> on <target> -> <Out> (the "lambda apply" pattern, v1.10.0) applies the
declared metadata to a step's output — producing a typed,
audit-traceable derived value.
Surface
lambda is a top-level declaration. The flow-step
application is a separate parser path (parse_lambda_data_apply)
that lives inside a flow body.
Top-level declaration
lambda DiagnosisCandidate {
ontology: "ClinicalInference"
certainty: 0.85
temporal_frame: "2025-01-01" "2026-12-31"
provenance: "EHR cohort 2024 + clinical guideline ICD-11"
derivation: inferred
}
Flow-step application
flow DiagnoseSymptoms(symptoms: SymptomList) -> Diagnosis {
step Cluster {
given: symptoms
ask: "Cluster the symptoms."
output: ClusteredSymptoms
}
step Decide {
given: Cluster.output
lambda DiagnosisCandidate on Cluster.output -> Diagnosis
ask: "Emit the diagnosis."
output: Diagnosis
}
}
Fields
ontology: (optional)
A string literal declaring the ontological class the
value claims membership in. Examples: "ClinicalInference",
"FinancialPrediction", "LegalOpinion". The runtime carries
this verbatim into the audit row; downstream consumers can
filter / route by ontology.
certainty: (optional, defaults to 1.0)
A numeric literal in [0.0, 1.0]. The declared confidence
of the value. Pairs with the persona's
confidence_threshold: and the anchor's confidence_floor::
runtime checks the chain.
temporal_frame: (optional)
One or two string literals declaring the validity window.
| Form | Meaning |
|---|---|
"<start>" | Open-ended frame starting at the named date/time. |
"<start>" "<end>" | Closed frame between start and end. |
The runtime treats values used outside their declared frame
as Uncertainty per the epistemic lattice (v1.4.0).
provenance: (optional)
A string literal documenting the source provenance — where the data came from, who curated it, what version. Free-form; appears verbatim in audit rows for human review.
derivation: (optional)
A single identifier from the closed derivation catalogue
(axon-frontend::type_checker::VALID_DERIVATIONS):
| Value | Meaning |
|---|---|
raw | Direct measurement / unprocessed input. |
inferred | Output of a cognitive inference (LLM, classifier). |
derived | Computed from other values via deterministic rules. |
aggregated | Summed / averaged over multiple inputs. |
transformed | Re-shaped from another representation (encoding shift). |
The lambda apply flow-step form
The v1.10.0 application pattern attaches a top-level lambda
declaration to a specific step's output. The grammar is:
lambda <LambdaName> on <TargetStep>.output -> <OutputType>
The runtime stamps the lambda's metadata (ontology, certainty,
temporal_frame, provenance, derivation) onto the target's
output as it flows downstream. Audit row:
lambda:<name>:applied_to:<target>:<output_type>.
What this primitive is NOT
- Not a function in the Church / λ-calculus sense. The
name is borrowed for the "derived-value metadata" surface;
there is no first-class function abstraction at this layer.
For function-like composition, use
flow+apply. - Not a
type.typedeclares structural shape;lambdadeclares epistemic metadata about an instance. - Not a
compute. Compute pins the backend that produces the value; lambda annotates the produced value with provenance. - Not optional for high-stakes derivations. Production
flows in regulated domains (clinical, financial, legal)
declare
lambdaon every inferred output so the audit trail records(ontology, certainty, temporal_frame, provenance, derivation).
See also
axon://primitives/type— structural-shape counterpart.axon://primitives/anchor—confidence_floor:pairs with lambda'scertainty:.axon://primitives/compute— pins WHICH model produced the value the lambda annotates.axon://compliance/gxp— examples of GxP section 21 CFR Part 11 audit-trail propagation through lambda metadata.