* feat(cli): add --max-steps for step-bounded runs runner.Options.MaxSteps already worked but was unreachable from the command line. A step budget is what makes two generators comparable: one making a model call per step and one drawing from a PRNG are not comparable per second. Claude-Session: https://claude.ai/code/session_01A5KmftdEJ49A9z5mF5ESrX * feat(trace): record arm membership and host in meta.json meta.json recorded the seed but not which picker ran, how it was configured, what budget it was given, or which machine produced it. A directory of runs cannot be attributed to an experiment cell without those, which makes any factorial computed from such a directory unanalysable after the fact. Claude-Session: https://claude.ai/code/session_01A5KmftdEJ49A9z5mF5ESrX * feat(cli): add --arm and populate run meta from it Model and instructions are recorded only when the LLM picker is the one that will actually run, so a spec declaring generator = llm() that is run under the seeded picker does not label its trace with a model it never called. Claude-Session: https://claude.ai/code/session_01A5KmftdEJ49A9z5mF5ESrX * feat(campaign): sweep seeds for one experiment cell campaign.json lists the seeds a sweep intended to run and is written before the first run, so a host that dropped runs shows up as missing seeds rather than as a smaller sample. Seed 0 is rejected: sanderling test reads it as "derive a seed from the clock", which is why conformance/gates.sh controls nothing today. Each run contributes one runs.jsonl line carrying steps to first violation by origin step, the step that armed the failed obligation, so the survival analysis never reopens a trace. Claude-Session: https://claude.ai/code/session_01A5KmftdEJ49A9z5mF5ESrX * fix(runner): no silent generator fallback, and llm on web --generator llm against a spec declaring no generator = llm(...) logged a warning and ran the seeded picker. For a comparison campaign that is silent arm corruption: the run completes, the directory looks correct, and the wrong policy drove it. It is now fatal. pickSources also returned the V8 source for both action and extractor on web before it looked at the generator, so the llm policy was unreachable there. The two axes are now independent: the driver picks the extractor source, the flag picks the action source, and llmSource composes with either because the runner populates the candidate list and screenshot on every platform. Claude-Session: https://claude.ai/code/session_01A5KmftdEJ49A9z5mF5ESrX * fix(chrome): make the hierarchy dump agree with the web runtime Three facts differed between the dump the goja host reads and the DOM the V8 host reads, so the two enumerated different candidates on one page. scrollable was never emitted, and worker.go reads exactly that attribute while targets.ts requires it for scrolls, so the goja host could not offer a single web scroll. clickable tested el.onclick, which React assigns to its root container for event delegation, making the whole viewport a tap target here and in no other enumeration. Both now resolve through the selector sets in pkg/spec/src/web-runtime.ts. The dump also rooted at body while collectTargets walks querySelectorAll("*"), so the goja host never saw html, where page-level scrolling lives. It now roots at documentElement and skips the head subtree, which is all zero-bounds and would otherwise carry script and title text into the trace. Claude-Session: https://claude.ai/code/session_01A5KmftdEJ49A9z5mF5ESrX * fix(conformance): give the gate reproducible seeds SEED defaulted to 0 and sanderling test reads --seed 0 as "derive a seed from the clock", so the tunable controlled nothing and a gate failure could not be re-run. SEEDS now takes one explicit non-zero seed per run, recorded in the results table so a failing row names its stream. The five runs stay on five different streams: a gate that scored one path five times would catch less than one that scores five. Claude-Session: https://claude.ai/code/session_01A5KmftdEJ49A9z5mF5ESrX * fix(chrome): emit editable as a plain boolean editable was emitted as `isEditable || null`, and an absent field sends internal/hierarchy into the native fallback, which reads any class name containing "EditText" as an Android text widget. On web that is just a CSS class, so a page styling a div with it was editable to the goja host and not to the web runtime, and the model policy could be offered typing into a div. Claude-Session: https://claude.ai/code/session_01A5KmftdEJ49A9z5mF5ESrX * fix(spec): leave the head subtree out of the web target walk collectTargets walked querySelectorAll("*") while the hierarchy dump skips head, so the two hosts enumerated different element sets on every page with a <head>. No candidate changes: builtinCandidates pushes only for targets acceptsTarget admits, and head elements have no positive bounds, so the list the draw ranges over is untouched. What changes is that targetIndex now means the same thing on both hosts. Claude-Session: https://claude.ai/code/session_01A5KmftdEJ49A9z5mF5ESrX * test(chrome): compare the facts both hosts derive from one DOM The existing parity harness hand-authors the facts on both sides, so it proves that given identical facts both hosts select identical candidates, and says nothing about the two code paths that derive those facts from a real page. Four divergences lived in that blind spot and it passed throughout. This drives one real page and compares clickable, enabled, editable, scrollable and positiveBounds element by element, plus the element sets themselves, which is what catches a host that omits html or includes head. Reverting any of the four fixes makes it fail naming the element and the fact. Claude-Session: https://claude.ai/code/session_01A5KmftdEJ49A9z5mF5ESrX * chore(make): run the browser packages one at a time Both launch Chrome and launching two at once has failed with "Launch: context canceled". Claude-Session: https://claude.ai/code/session_01A5KmftdEJ49A9z5mF5ESrX * style: remove every em-dash and en-dash Eighteen occurrences across fourteen files. Each sentence was repunctuated to suit what the dash was doing rather than swapped for a hyphen, which produces comma splices. The minus sign in folio-web's ledger is a minus sign and stays. Claude-Session: https://claude.ai/code/session_01A5KmftdEJ49A9z5mF5ESrX * fix(chrome): honor the caller context in Launch Launch and clearState ran against d.tabCtx, so a target that accepts the connection and never answers wedged the process past its own --duration and through SIGTERM, needing SIGKILL. Unattended that is a campaign worker lost for the rest of the sweep with no diagnostic. The browser is still allocated against d.tabCtx first, because chromedp starts Chrome under whichever context calls Run first and allocating under a caller deadline would kill the browser when Launch returns. Everything after allocation goes through runCtx. Claude-Session: https://claude.ai/code/session_01A5KmftdEJ49A9z5mF5ESrX * fix(sidecarassets): publish the extracted jar through a rename Extract wrote a 96 MB jar with a plain WriteFile into a temp path every sanderling process on the host shares. On a cold host several concurrent workers all miss the checksum and all write the same path, and O_TRUNC lets one spawn a JVM against another's half-written archive. A fresh experiment host is exactly a cold host. Claude-Session: https://claude.ai/code/session_01A5KmftdEJ49A9z5mF5ESrX * feat(campaign): kill a run that outlives --run-timeout A wedged run holds its worker for the rest of the sweep, and on an unattended host nothing else will send it a signal. Defaults to three times --duration and must exceed it. A killed run is recorded as timed_out rather than as a generic failure, so the analysis can tell a lost cell from a real crash. Claude-Session: https://claude.ai/code/session_01A5KmftdEJ49A9z5mF5ESrX * style(test): gofmt browser_test.go Claude-Session: https://claude.ai/code/session_01A5KmftdEJ49A9z5mF5ESrX
3.9 KiB
Folio
A minimal Kotlin Multiplatform personal-ledger app: login with demo credentials, create accounts, add credits and debits. Shared UI across Android, iOS, and web (wasmJs via Compose for Web). Doubles as the example sanderling runs its property-based specs against.
Stack
- Kotlin Multiplatform + Compose Multiplatform (shared UI)
- SQLDelight for the data layer (unified across platforms)
- kotlinx.coroutines for state flows
- kotlinx.serialization for
@Serializableroute types
Prerequisites
just- JDK 17
- Android SDK (auto-discovered under
$ANDROID_HOME,~/Library/Android/sdk, or the Homebrew cask) - Xcode 16+ and
xcodegen(brew install xcodegen) for iOS
Android
just install # build + install on a booted emulator / device
just uninstall
just clean
iOS
just ios # default device: iPhone 17 Pro
IOS_DEVICE="iPhone 15" just ios # pick a different simulator
just ios regenerates app/iosApp/iosApp.xcodeproj from app/iosApp/project.yml,
builds the KMP framework (Shared.framework from :app:shared), links it
into the SwiftUI host, installs, and launches.
Web
just web # webpack dev server with COOP/COEP headers
just web-build # produce a webpack distributable bundle
just web runs :app:webApp:wasmJsBrowserDevelopmentRun --continuous, so
edits to shared code reload in the browser.
Demo credentials
email: [email protected]
password: ledger123
Run a sanderling test (Android)
just test
If no device is connected, sanderling boots the single AVD it finds. With multiple AVDs, pick one:
AVD=Pixel_7 just test
Persistent settings can live in .env alongside the justfile:
AVD=Pixel_7
DURATION=5m
Traces land in ./sanderling/runs/<timestamp>/.
Run with the LLM action generator
The same sanderling/spec.ts runs under either generator: --generator seeded
(the default weighted fuzzer) or --generator llm, where a vision model picks
from the SAME weighted candidate set (reading the screenshot plus a numbered,
weight-annotated list of concrete actions) and returns one number. The spec's
generator = llm({ model, instructions }) export configures it.
export OPENROUTER_API_KEY=sk-or-... # or OPENAI_API_KEY=sk-... for OpenAI direct
just test-llm # or: sanderling test --generator llm --spec sanderling/spec.ts --bundle-id app.folio
OpenRouter wins when both keys are set. With a plain OpenAI key, drop the vendor
prefix from the model id in spec.ts (gpt-5.4-nano, not
openai/gpt-5.4-nano). The model must support image input and strict
json_schema structured outputs. Each step is one multimodal call, so keep the
duration / step budget modest. The trace records the model's reasoning, the
chosen number, and source: "llm" on each action, so the replay UI shows why
each pick was made.
Run a sanderling test (iOS)
just test-ios # default simulator: iPhone 17 Pro
IOS_DEVICE="iPhone 15" just test-ios # pick a different simulator
just test-ios boots the simulator if needed, runs just ios to install
and launch the app, then invokes sanderling test --platform ios. Same
DURATION, SEED, and OUTPUT env vars as the Android target.
How it connects to sanderling
- Each screen sets a stable Compose
testTag(HomeScreen,AccountCard,LedgerRow,TxnAmount, ...). The Sanderling SDK resolvestestTagtoresource-idon Android andaccessibilityIdentifieron iOS. - Identity for list items is the visible text content (account name; txn note + amount). No synthetic IDs encoded in semantics.
contentDescriptionis reserved for real accessibility labels, never as a data carrier.sanderling/spec.tsimports@sanderling/spec, reads state vias.ax.*, asserts properties, and weights the actions the fuzzer picks from.just testinvokessanderling testagainst the installed APK.