A guided tour
Every artifact on this page was produced during the site build: compiled from real source, executed with scripted answers, and replay-verified before publication. What you inspect here is evidence, not a mockup. Diagrams are interactive — drag to pan, ⌘-scroll to zoom, click a cell for its contract, replay the recorded run.
One executable meaning
A diagram comes from the program. An execution overlay comes from its receipt. The views stay connected to the artifact they explain.
Immutable values, explicit model effects, exhaustive choices, and declared budgets.
.algal sourceA deterministic compiler produces a typed manifest and a source-map sidecar. Diagrams come from that manifest.
.algal.json + diagramReceipts record execution. Replay checks the orchestration against recorded external answers.
receipt + verificationReplay checks execution consistency. It does not establish that a model answer is true or attest that a provider performed an operation.
Follow one execution
Choose a recorded decision. Support and sales each draft a reply with the declared email context. Human review returns a fixed message. Inactive branches stay visible—and skipped.
I can help with that. What happens when you try to sign in?
Tell me about your team and I can suggest a plan that fits.
Needs a human review.
program route(email: text) -> text {
budget { max_agent_calls: 2 }
let intent = decide "What does this email need?" using email
as choice {
help: "Help with a problem",
sales: "Information before buying",
other: "Anything else"
}
return match intent.value {
help => generate "Draft a helpful support reply." using email,
sales => generate "Draft a concise sales reply." using email,
other => "Needs a human review."
}
}Each view comes from an actual runtime receipt generated and replay-checked during the site build. The selector changes which receipt you inspect; it does not run a model in your browser.
A useful program becomes a building block
Import a local helper, call it for one preview, then apply it to a bounded list. The same compiled child handles every email with the tone you pass explicitly.
import draft from "./draft.algal"
program inbox(sample: text, emails: json) -> json {
budget { max_agent_calls: 4 }
let preview = call draft using {
email: sample, tone: "helpful"
}
let replies = each draft over email in emails
using { tone: "helpful" } max_items 3
return { preview: preview, replies: replies }
}program draft(email: text, tone: text) -> text {
budget { max_agent_calls: 1 }
return generate "Draft a reply using the requested tone."
using { email: email, tone: tone }
}4 executor attempts maximum. Replies keep input order; items execute sequentially.
check reports 2 source files · 1 child level required. Structural bounds, not a cost forecast.
Scripted executions; no live model calls
The empty-list run returns [] for replies and uses 1 executor attempt for the separate preview. Empty-list receipt
Scripted executions; no live model calls
Follow a call into its helper. Each view shows only that email’s recorded cell states, with the root receipt and invocation path retained.
I can help you sign in. What happens when you enter your email?
b2-replies-each/i0 · draft.algal
I can help update your delivery address. Has the order shipped?
b2-replies-each/i1 · draft.algal
Your invoice is available under Billing in your account.
b2-replies-each/i2 · draft.algal
A pure batch calculation divides by zero in its second item. The report points to the expression in ratio.algal and its caller. The first item completed; the third never started. No model calls.
Algal failed · digest-bound (not replay verification)
Receipt: sha256:73d89664e04152e4b72a5c16c3d83ea2f82572b0c3c60bf8d5e0149a5b2ef8b3
Manifest: sha256:5ec7e848d41521355bd6a01554ca3976edabff289cd9901471365ab1a2be56e0
Source: sha256:b9064efdd18d4115f9675279636cdf94f1ef3151f1eb3839338128297f2e75de
failure · EXPR_FAILED · result-each/i1/b1-fraction
Recorded message: expr {"code":"EXPR_DIV_ZERO","op":"div"}
At ratio.algal:4:18 (fraction) [expression]
let fraction = sample.numerator / sample.denominator
Called from ratios.algal:6:10 (return) [each index 1]
Source report Original receipt Reproduce from bundle Inputs Helper source
The same core, more ambitious programs
Refine a draft. Suspend for approval. Apply a child program to a collection. Propose a new program. Every effect and boundary has a place in the graph.
An editor rewrites a draft. A critic returns ship or revise. A repeat cell carries the draft into the next round, up to 4 rounds.
The final verdict still matters. Reaching the round limit returns the last outputs; it does not turn revise into success. The graph sends that result to hold.
Each round contains an editor and a critic. The parent's attempt budget also bounds nested execution.
A model reviews evidence and proposes a recommendation. The process can suspend while a child program waits for a host-supplied approval message.
On resume, a pure check requires both an approve decision and a matching release identifier before the publication effect becomes eligible.
This example publishes a report to a local mailbox. The model does not approve or deploy a release.
The each cell applies a pinned child program to each question, up to 8 items. A pure function joins the answers.
The child's interface makes it reusable. Its content digest fixes which program is being called. The parent bounds how much work the collection can create.
Independent work is visible in the graph. This does not promise concurrent execution or a wall-clock speedup.
A designer produces a child manifest as data. A bounded spawn operation admits and runs it, and its digest is appended to a persistent population slot.
That is the starting point for a habitat. Foundry and civilization workflows evaluate candidates on declared cases; host selection decides what to retain or promote.
The graph shown records a proposed child's digest. It does not itself prove improvement or promote a winner.
These are generated views of existing executable manifests. Readable source covers values, decisions, generation, conditional branches, local imports, named calls, and bounded each; repeat, waits, and evolution remain available through the manifest API.
Immutable values and deterministic expressions carry the structure. Models, tools, and durable state have visible boundaries.
Programs declare limits. The host owns admitted functions, providers, tools, and capabilities. A manifest grants no OS isolation.
Content-addressed programs and receipts connect source, structure, and execution. Measure quality on the workload that matters.
