Crate warble

Expand description

Warble front-end compiler (warble): parses a Warble project (profile + components + context binding), merges component defaults with profile overrides, runs the loud-fail compile checks, and emits the language-neutral IR JSON that any back-end dispatcher consumes.

§Architecture

profile + components + context  ──►  warble compile  ──►  IR JSON  ──►  warble dispatch  ──►  native agent
   (declarative YAML + prompts)       (front-end, Rust)   (the seam)    (per-target back-end)

This crate is the first arrow: it owns the authoring types (ProfileFile, ComponentFile, and friends), ContextLoader (the host’s semantic-layer probe), and compile, which resolves a parsed project into IR. Everything downstream of the IR — the claude-code-cli and vercel back-ends (both fold into the warble binary), plus the separate TS claude-agent-sdk back-end — depends only on the IR schema, never on this crate’s Rust types. See authoring.md for the authoring-side contract and ir-schema.md for the emitted shape.

§Sans-IO

This crate performs no filesystem or network access. compile takes already-parsed authoring values, the raw step markdown, and a ContextLoader the caller has already built from the bound semantic layer — it never reads a path itself. The example below is exactly this: it deserializes YAML strings in-memory and calls compile directly, no disk involved. Keeping the core pure is what lets the same crate target native, WASM, and language bindings unchanged; the native host adapter lives in the warble-cli crate.

§Example

A minimal project — one component, one step — compiled against an empty in-memory ContextLoader. Both the profile and the component are parsed from YAML exactly as a host would read them off disk; only the reading itself is out of scope for this sans-IO crate.

use warble::{compile, BindingFile, ComponentFile, ProfileFile, SlotContents};

let profile: ProfileFile = serde_yaml::from_str(concat!(
    "profile: demo\n",
    "context:\n",
    "  project: ./context/binding.yml\n",
    "components:\n",
    "  - use: hello\n",
))?;
let binding: BindingFile = serde_yaml::from_str("kind: external\nproject: ./warehouse\n")?;
let component: ComponentFile = serde_yaml::from_str(concat!(
    "id: hello\n",
    "verb: greet\n",
    "type: analytical\n",
    "realization_kind: skill\n",
    "binding_mode: runtime_selected\n",
    "llm_steps:\n",
    "  - name: say_hello\n",
    "    tier: cheap\n",
    "    prompt_ref: steps/say_hello.md\n",
    "trigger:\n",
    "  kind: one_shot\n",
    "guardrails:\n",
    "  - name: read_only_execution\n",
    "    locked: true\n",
    "effect:\n",
    "  render_blocks: []\n",
    "  outcome:\n",
    "    kind: none\n",
))?;

let mut components = HashMap::new();
components.insert(component.id.clone(), component);
let mut steps = HashMap::new();
steps.insert("say_hello".to_string(), "Say hello to {{project_name}}.".to_string());
let mut step_contents = HashMap::new();
step_contents.insert("hello".to_string(), steps);

let ir = compile(
    &profile,
    &components,
    &binding.project,
    &EmptyContext(LineageGraph::default()),
    &step_contents,
    &SlotContents::default(),
)?;
assert_eq!(ir["warble_ir_version"], "0.9");

§Invariants

These hold across the whole workspace, not just this crate — they matter to you as an API consumer too, not only to contributors:

If you write your own back-end that consumes the IR compile returns, drive it off the three enum fields — realization_kind, outcome.kind, trigger.kind — never off a component’s id or verb string. Any enum value your back-end can’t handle must be a hard error, not a best-effort guess or a silent no-op.
Depending on warble alone pulls in no I/O and no wren dependency. compile never touches a filesystem or network — you build the ContextLoader yourself and hand it in — and this crate has no dependency on any semantic-format library. That’s what lets you embed it in a native binary, WASM, or another language’s bindings without inheriting a dependency graph you didn’t ask for. Nothing in this workspace links such a library any more: a host reads its own format and hands the projection over as a prepared-context document.
No DSL in the composition layer — there’s no boolean algebra, expression language, or imperative logic in the profile/IR schema. The one form of conditionality that does exist is a closed vocabulary: a step can set conditional: true with a when guard whose guard is one of on_failure / on_flag / on_missing and whose target names what it’s checking — never an arbitrary predicate. If you’re writing a dispatcher, that means you must either realize when or loud-fail on it, not silently treat it as a no-op. IR growth is additive (a new optional field), never a new mechanism.
The IR compile emits never names a specific mechanism (no cron, slack, subagent, …). If you’re writing a dispatcher, those names only show up later, at the capability layer via realize-via — so the same IR is valid input to any runtime’s back-end, including ones this crate has never heard of. See capability-model.md.
This crate builds exactly one native capability: blast_radius (semantic lineage — see blast-radius.md). If you’re checking what a target back-end can support natively versus needs to borrow from its runtime, know that everything else — human approval, VCS/rollback, scheduling, subagent dispatch, schema introspection — is expected to come from the runtime (realize-via), not from core.

Structs§

AssetDecl: One assets: entry: a file this component needs present on disk at run time — a themed template, a stylesheet, a whole scaffold tree — that is never read into the IR.
BindingFile: The root of context/binding.yml: which context a profile binds against.
CompileError: A compile failure with a human-facing message. Every compile-time check is loud-fail: on the first violation compile returns one of these rather than emitting a silently-wrong IR (see ir-schema.md §checks).
ComponentFile: The root of a component.yml: identity, anatomy (type / realization_kind / trigger), the LLM steps that realize it, and everything that gates or governs how it runs (guardrails, preconditions, capabilities).
DimensionInfo: A dimension the semantic layer can group/slice by — a cube dimension or a selectable model column. is_temporal marks a DATE/TIMESTAMP-typed dimension (satisfies has_time_dimension).
Effect: What a component’s steps produce for the host to act on: any render blocks plus the outcome classification.
ExternalContext: A binding whose semantic layer is not reachable from here — held by a service that answers the questions itself, or simply not pulled onto this machine.
Guardrail: A guardrail attached to a component: whether it is locked (unpatchable by a mounting profile) or overridable, its scope, and an optional threshold.
GuardrailPatch: A profile-level override to a mounted component’s guardrail. Only locked is patchable today; patching a guardrail whose component default is locked: true is always a compile error, regardless of what the patch requests.
HostAnalysis: The host’s own analysis of the layer it resolved, carried on the wire so Warble can use results it does not derive. Absent entirely when the host analysed nothing — which is not the same as an analysis that found nothing.
HostConsumers: The counts the IR’s lineage.consumers block reports. Which node kinds count as consumers is the host’s call, so the host supplies the totals rather than Warble deriving them.
HostImpact: One seed’s impact, as the host computed it.
LineageEdge: A directed dependency edge, oriented upstream → downstream: from is the thing depended on, to is the dependent that would break if from changed. A producer’s closure follows them forward.
LineageGraph: The semantic lineage DAG, as the layer’s owner built it (from structural refs: relationships, cube base objects, column expressions, view statements). Warble does not traverse it — the downstream closure arrives already computed, in HostAnalysis — and reads it only to check that every edge endpoint is a declared node (Self::is_resolvable).
LineageNode: A node in the lineage DAG. id is a stable, adapter-assigned identifier (e.g. model:orders, column:orders.amount, metric:revenue.total_revenue); it is what an impact analysis is keyed by.
LlmStep: One llm_steps entry: a single LLM call — its tier, its prompt reference, and the artifact-flow (consumes/produces) linking it to other steps.
MetricInfo: A queryable metric — either a declared cube measure (whose additivity is determinable) or an implicit numeric column projected as a metric so that has_metric holds on cube-less projects. declared is the line between the two; additivity is Some only when declared.
ModelInfo: A model in the semantic layer, narrowed to what the precondition vocabulary needs.
NoContext: No context was authored. It answers no semantic probe and never claims parse success.
Outcome: The component’s outcome classification (kind: none / assertion / mutation / dispatch) and the outcome-kind-specific fields that go with it.
Param: A component parameter, either bound at dispatch time (bind, with an optional default) or sourced from context (source). Exactly one of bind/source is expected to be present per the schema, but both are optional here since this is a Deserialize-only view.
PreparedContext: A ContextLoader built from a host-supplied snapshot rather than from a semantic layer this process knows how to read.
ProfileComponentMount: One components: entry: which component to mount, plus the config/binding/tier-override/ guardrail patches layered on top of that component’s own defaults.
ProfileConfig: The profile’s global config block — settings that apply to the profile as a whole.
ProfileContext: Where the bound context lives, relative to the profile.
ProfileFile: The root of profile.yml: which components are mounted, the context this profile binds against, and profile-level config defaults.
RankedSeverity: A severity as the host ranked it. Warble orders by rank and never interprets name: deciding that a silently shifted metric outranks a broken model is a statement about what those objects mean, which belongs to whoever owns the semantic format.
RawSourceContext: A ContextLoader backed by a raw (pre-MDL) source. Carries no metrics/dimensions/models/lineage — that is what a CONSTITUTIVE component’s output produces — but answers the two raw-shape probes that make source_introspectable / raw_docs_readable evaluable instead of unanswerable.
RawSources: The raw file contents of a raw source, read by the host. from_sources operates purely over these bytes (WASM-friendly); the native read_raw_dir convenience fills them from disk.
RenderBlock: A render block entry, authored either as a bare type name (shorthand, no fields) or as a mapping with an explicit fields schema. Always normalized to {type, fields} in the IR.
SlotContents: Slot-variant file contents, read by the host and handed to crate::compile — the slot counterpart of the step_contents map, and for the same reason: core is sans-IO, so every authored file is read by the caller and passed in.
SlotDecl: One slots: entry: a named position in prompt text, a set of alternative wordings for it, and optionally a condition that removes it entirely.
Trigger: How this component starts (kind: one_shot / scheduled / event).

Enums§

Additivity: Whether a metric’s aggregation is additive across the dimensions a decomposition would drill along. Inferred by an adapter from the metric’s underlying aggregation; it is not a field any current MDL carries.
LineageKind: The kind of a node in the semantic lineage DAG. Ordered coarse→fine along the dependency flow raw → models → relationships → metrics/dimensions → views → consumers (capability-model §7.1). Query and Dashboard are consumer nodes — artifacts outside the semantic layer (a confirmed saved query, a dashboard spec) that depend on it; they are always sinks, never upstream of a semantic node.
PreparedContextError: Why a prepared-context document could not be read.

Constants§

PREPARED_CONTEXT_VERSION: The wire-format version of a prepared-context document.

Traits§

ContextLoader: Host-injected semantic-layer access. Pure on the core side (operates over an already-loaded adapter); the host owns all I/O. One accessor per capability the compiler needs to probe the bound Context for, plus lineage and the impact analysis over it.

Functions§

compile: Resolves a Warble project into its IR JSON document.
prepared_document_from: Render any ContextLoader as a prepared-context document.
read_raw_dir: Read a raw-source directory into RawSources (native host only; the pure RawSourceContext::from_sources path is what a WASM host feeds directly). Returns None if the directory has no schema.json — i.e. it is not a raw source — so the caller can fall through to another adapter or an unparseable context.
verify_context_preconditions: Validate resolved runtime predicates against a host-owned context snapshot.

Crate warble

Crate warble Copy item path

§Architecture

§Sans-IO

§Example

§Invariants

Structs§

Enums§

Constants§

Traits§

Functions§

Crate warble