* feat(cli): classify identity persistence on every telemetry event
Install-grain metrics currently trust every anonymousId equally, but
ephemeral/isolated-HOME workloads mint a fresh id per run — one machine
produced 2,956 rotating render identities since Jul 30 (94.4% seen on a
single render command), inflating acquisition and diluting per-install
penetration while looking like real product usage.
Every event now carries:
- identity_persistence: durable (id loaded from a preexisting config —
proven to survive a process boundary) | unknown (minted+persisted this
run; an ephemeral HOME is indistinguishable from a genuine first run
from inside one process) | process_only (persist failed). Sticky per
process so a fresh install re-reading its own write cannot self-promote.
- config_write_outcome: ok | ok_unmirrored | failed for the identity-
establishing write; absent when the id came from disk.
- invocation_id: random uuid per CLI process, so one invocation's events
group even when the install identity is untrustworthy (unlike run_id,
which needs an orchestrator to set HYPERFRAMES_RUN_ID).
Install metrics can then count only durable identities, and a daily
churn monitor can alert on the unknown share.
* fix(cli): require the anonymousId to come off disk before classifying durable
Review finding: materializeConfig mints a replacement anonymousId when a
hand-edited/image-baked config lacks one. That replacement only reaches
disk when the bucket-seed backfill happens to write; with a seed present
the read path performs no write at all, so the install re-mints a fresh
id every run while the unconditional durable branch stamped each of them
with the one label durable-only counting is allowed to trust.
durable now requires parseNonEmptyString(parsed.anonymousId): a minted
replacement classifies like a fresh mint — by the backfill write outcome
when that path runs (unknown/process_only), and process_only on the
no-write path where the id provably dies with the process. Two tests pin
both shapes.
#2740 added `--` to one of nine independent ffprobe invocations, so the
bug class it closed stayed open everywhere else while CI reported it
fixed — the regression test asserts the argv of that single site.
Reproduced on ffprobe 8.1.1: an asset named `-intro.mp4` probes fine
through extractMediaMetadata but fails with "Missing argument for option
'intro.mp4'" in audio pad/trim (mid-render), `hyperframes init`, whisper
duration probing and webmAlphaCheck. hevcPreviewLint catches and returns
false, so a dash-prefixed HEVC preview silently passes the lint rule.
Terminated at all of them:
producer/services/render/audioPadTrim.ts (x2)
producer/plan-parity-analysis.ts
cli/commands/init.ts
cli/utils/webmAlphaCheck.ts
cli/whisper/transcribe.ts (x2)
core/mediaGradeAnalyzer.ts
lint/hevcPreviewLint.ts
audioPadTrim's runFfprobeJson is a near-verbatim clone of the engine's
runFfprobe and structurally cannot add the terminator itself, because
callers bake the input path into `args`. It now asserts the terminator
is present rather than letting a dash-prefixed path through, takes the
same stdio ["ignore", ...] as the engine helper, and redacts its stderr
— it was throwing raw ffprobe output, which echoes the input path, into
logs and telemetry.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Extends the studio-preview fix to the render path and the asset-discovery
utilities, which share the same resolver and had the same defect.
`rewriteAssetPath` takes an optional `assetExists` probe. A plain relative ref
authored in a sub-composition (`_shared.css`, `clip.mp4`) is re-pointed at the
composition's own directory when that sibling exists on disk; project-root refs
with no sibling (the registry's `assets/logo.png` convention) stay as authored.
Callers that can see the filesystem supply the probe, so the module stays free
of node:fs.
Also fixes a second defect in the inliner: `<head>` <link> hrefs and external
script srcs are hoisted into the root document but never went through the
rewrite at all, so even the documented `../` form escaped the project and 404'd
at render time.
Wired into the preview bundler, the producer compiler, the studio preview
builder, the HEVC preview lint, the project lint's asset scans, publish proxy
baking, and media-treatment source resolution.
citty parses string options greedily, so a bare --frame-check consumed
the following flag as its value (--caption-zone silently dropped,
--json disabled) and failed with an error blaming --caption-zone.
Normalize rawArgs at the check command boundary (bare --frame-check
followed by a flag or at end becomes --frame-check=), attribute
frame-check spec errors to --frame-check, and detect dash-prefixed
values with corrective guidance.
Fixes#2965
* fix(cli): stop dropping queued telemetry when process.exit races the final flush
Two exit-path defects introduced by the 0.7.65 process-lifecycle refactor:
1. The 'exit' handler returned early once finalizeCli had started, which
also skipped the flushSync() fallback. When an agent-pipe EPIPE killed
the process mid-flush (the NORMAL teardown under Claude Code / Codex),
the still-queued render_complete was silently dropped — fleet delivery
fell from ~90% (0.7.55-0.7.64) to ~35%. flushSync() is now
unconditional: empty queue is a no-op, event uuids dedupe re-sends.
2. The EPIPE handlers set commandFailed unconditionally, so every piped
successful render scored success:false in cli_command_result (fleet
success rate collapsed 89% -> 5-25%). EPIPE now only marks failure
when the pipe died before the render artifact was validated, matching
the existing isRenderSucceeded() exemption on the uncaughtException
path.
Regression tests cover both: flushSync-after-finalize, and EPIPE
before/after artifact validation.
* fix(cli): don't score a validated render as failed due to pre-artifact noise
Review follow-up: commandFailed can be set by noise that precedes artifact
validation — a stray unhandledRejection mid-render, or an EPIPE firing
before markRenderSucceeded on a run that still completes. Once the
artifact validates, that earlier noise must not flip the run's
cli_command_result to success:false. Genuine failures keep a non-zero
exit code and are still caught by the exitCode check.
Extracted commandSucceededForTelemetry() and applied it at both tracking
sites (finalizeCli and the exit handler), with a regression test.
* test(cli): pin the production-reachable producer of the stale-failure override
Review note: the pre-artifact-noise test drives the scenario with an
EPIPE, which only reaches 'render validates afterwards' because
process.exit is mocked — that sequence can't occur in production. Add a
test for the reachable producer: an unhandledRejection before validation
(the handler deliberately does not exit), followed by a validated render,
must score success:true at exit code 0. Verified red on the pre-override
cli.ts.
R6/R7 blockers.
An already-open Studio kept emitting server-side render telemetry after
another process disabled CLI telemetry. refreshTelemetryPosture() only ran
while serving a fresh SPA document and on /api/telemetry-identity, which
Studio has no consumer for, so the render POST and its async outcome used
the posture cached when the preview server booted. It now refreshes at the
render boundary and again immediately before the completion/error event,
so an opt-out during a long render is honoured.
The identity tests were passing vacuously: their mocks omitted
readConfigFresh and resetTelemetryPostureCache, and the resulting
missing-export error was swallowed by the refresh's own catch. Mocked
properly, plus the enabled -> external disable -> next response transition
and the suppression path at the layer that drops the event.
A full reset also did not persist its new lineage in a long-lived process:
syncInstallState returned early on a process-lifetime memo even after
~/.hyperframes was deleted, so install-state was never recreated and the
next config-only re-mint rolled a third seed instead of inheriting the
second. The memo is now revalidated against the file.
Also drops a stale reference to assertNoOverdueCanaries and stops the
workflow and docs claiming the sunset job routes anything to the owner —
it names them in the run log and notifies nobody.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
- A long-lived preview cached its telemetry posture in two places
(readConfig and shouldTrack). Running `telemetry disable` in another
terminal left it resolving canaries and injecting the CLI id for hours.
Both caches are now dropped together at a request boundary.
- Studio minted and shipped a telemetry id for every render regardless of
the browser profile's opt-out, and the server emitted the outcome under
CLI policy, which cannot see localStorage or DNT. The browser now sends
an explicit telemetryOptOut, distinct from an old client's omission.
- Any non-empty HYPERFRAMES_PREVIEW_HOST disabled the DNS-rebinding guard,
so even a loopback bind accepted a hostile Host. The guard now holds for
loopback binds and, on a LAN bind, admits only names this machine
answers on.
- sunsetAfter had no reader of the current date. A scheduled workflow runs
scripts/check-canary-sunset.ts weekly, so a failure lands on the
rollout's owner rather than on an unrelated PR author.
- The install-state seed memo outlived `rm -rf ~/.hyperframes`,
resurrecting a cleared cohort. Removed; it only saved a read on a
readConfig cache miss.
Docs updated for the Host rule and the 100% exclusion carve-out.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
R5 blockers
- Negative install-state latch was cached for the process lifetime, but
only `true` is monotonic across processes. A long-lived preview server
held a stale `false` and could re-enrol after another process tripped
the breaker. Only the positive is cached now; `false` re-reads.
- The real breaker writer used writeConfig(), which collapses
{ok:true, mirrored:false} to success, so a run that mirrored nothing
reported done with the latch only on the erasable store. It consumes
writeConfigWithResult and retries until both stores carry it.
Bucketing integrity
- Storage-restricted Studio profiles all bucketed on the literal
"anonymous": computed against the shipped hash, 100% of them were
enrolled in calibration-50 rather than 50%, and they merged into one
PostHog person. Per-session random id instead — persists nothing.
- bucketSeed had read/write authority backwards: install-state is
write-once authoritative, but readConfig took config.json's blindly, so
the stores could hold different seeds until a re-mint flipped every
cohort. Merged on read, like the latch.
- An unwritable ~/.hyperframes with no config.json re-minted per call,
re-rolling the seed on every command, and the "cohorts will not be
stable" warning was unreachable on that path.
- A corrupt PRE-MOVE state file was never deleted, so a machine reset
with `rm -rf ~/.hyperframes` reported predecessorFound/stateFileCorrupt
forever — poisoning the exact metric this work exists to produce.
Opt-out honoring
- CLI canary decisions memoized per process, so `hyperframes telemetry
disable` during a running preview server was ignored for hours while
the server kept serving pre-opt-out decisions. The memo is keyed on the
telemetry posture.
- shouldTrack() memoized, contradicting policy.ts's documented "not
memoized" contract that policy.test.ts asserts.
- The Studio override path resolved the bucket unit eagerly as an
argument, minting and PERSISTING a tracking id for an opted-out profile
— a value evaluateCanary discards unread.
- Storage reads could throw out of telemetry into a post-commit catch
block, reporting an already-committed edit as failed.
- readConfig printed an unsilenceable stderr warning on every invocation
for installs that opted out of telemetry entirely.
Host split
- isLoopbackHost rejected 0.0.0.0, so the documented
HYPERFRAMES_PREVIEW_HOST LAN mode silently lost CLI→Studio identity
stitching and split one user across two PostHog persons. Identity is
now allowed when the operator explicitly opted into LAN binding.
- Corrected the comment claiming the guard refuses spoofed Hosts: a
non-browser client sets Host freely. It is a browser DNS-rebinding
mitigation, not access control, and now says so.
Semantics and test hygiene
- percentage:100 did not mean everyone — exclude and no_unit_id sat above
the fast path, so the registry's "delete the entry at 100" step was an
unstaged flip for CI and seedless installs.
- CLI cohort adoption returned before evaluateCanary, dropping Studio's
own webdriver exclusion.
- overdueCanaries() was asserted against wall-clock time, so the whole
core suite would go red on 2026-09-15 for every unrelated PR; and `>`
against midnight made a canary overdue ON its sunset date.
- Statistical assertions ran on unseeded randomUUID() populations tight
enough to fail ~1 run in 200. Seeded.
Also: broke a config -> policy -> transport -> config import cycle by
moving POSTHOG_API_KEY to a leaf module.
Tests: 2347 CLI (bundle absent), 3153 Studio, 1450 core. Fault injection
covers the latch, seed authority, LAN identity, webdriver exclusion and
the anonymous-bucket fix. Two pre-existing tests asserted behaviour these
findings identify as wrong (shouldTrack memoization, 100%-excludes-CI)
and were rewritten with the reasoning stated.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
P1 — the required Test lane was red, and it was my test. The
hostile-Host SPA case asserted a 200, which only holds when
packages/studio/dist is built: true on a dev box, false in CI, so it
passed locally and failed there. The Host split moved into a pure
buildStudioHeadScriptsForHost() and is asserted directly; the route test
no longer depends on build state. Verified by running the CLI suite with
the bundle moved aside — 2330 pass.
P1 — studio:* still bypassed most privacy controls. It honoured two
localStorage keys but not navigator.doNotTrack,
VITE_HYPERFRAMES_NO_TELEMETRY, Vite dev mode or API-key eligibility, and
canary enrolment honoured a different single control. New
telemetry/policy.ts is the one answer to "may this profile be measured",
consumed by both transports and by enrolment. It imports only ./config,
so no cycle with the modules that import it. Each control is asserted
individually.
P1 — LAN/remote preview lost the authoritative decisions. Withholding
the whole head script for any non-loopback Host also dropped the safe
{enabled, forced} map, sending a supported HYPERFRAMES_PREVIEW_HOST=
0.0.0.0 Studio back to re-deriving. Identity injection is now gated
separately from decision injection: identity is loopback-only, decisions
always publish.
P1 — the breaker latch was neither authoritative nor truthfully
persisted. syncInstallState swallowed its own failures so
writeConfigWithResult always reported ok, and reads took the flag only
from config.json. The latch is now merged into every effective read,
which makes install-state authoritative and closes both the failed-mirror
and stale-concurrent-writer paths; the write additionally reports
mirrored: false rather than swallowing.
P2 — public contracts. canary-rollouts.mdx said a config wipe loses the
breaker (it does not) and documented the superseded {name: boolean} map
with unconditional CLI precedence; both corrected, with the precedence
ladder written out and the override exception stated explicitly. PR body
rewritten — it still named ~/.local/state, claimed state survives
deleting ~/.hyperframes, and carried stale counts.
Tests: 2330 CLI (bundle absent), 3151 Studio, 24 core. Fault injection:
reverting each fix alone fails 5 CLI / 5 Studio.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
P1 — SPA route bypassed the DNS-rebinding guard. Guarding only
/api/telemetry-identity left the catch-all as an open side door: a
rebound origin could fetch `/` and read __HF_CLI_DISTINCT_ID and
__HF_CLI_BUCKET_SEED straight out of the returned HTML. The SPA response
now applies the same isLoopbackHost() check; an untrusted Host still gets
a working Studio, just with no identity, seed or decisions injected.
Route-level regression added.
P1 — a CLI cohort roll could override Studio's own opt-out.
decideStudioCanary() adopted the injected decision before checking
isOptedOut(), so CLI-telemetry-on plus Studio-opted-out still enrolled
Studio. A bare boolean could not express the difference between a
deliberate override and an ordinary cohort roll, so the injected map now
carries provenance ({ enabled, forced }). Forced wins outright — it is
the documented escalation channel and must behave the same on both
surfaces — while a percentage roll now loses to this profile's opt-out.
Full interaction matrix tested.
P1 — the legacy studio:* path sat outside both contracts.
utils/studioTelemetry.ts shipped its own opt-out key and its own send
loop, so the documented hyperframes-studio:telemetryDisabled did not
silence it and its events carried no cohort assignment. It now honours
both keys (the legacy one stays, so nobody already opted out is quietly
re-enabled) and mixes in canaryEventProperties(), making "every
telemetry event carries the assignment" actually true.
P2 — partial salvage could drop a tripped breaker.
salvageInstallState() discarded the whole record when markerAt and
bucketSeed were both unusable, taking deParallelRouterTrialFired with it
and re-enrolling a machine whose router already failed. All three fields
are now independently salvageable.
Docs: canary-rollouts.mdx said "disabling telemetry disables the
reporting, not the enrolment" — exactly backwards since the opt-out gate
landed. Corrected; checked for other copies, none.
Tests: 13 new (4 opt-out precedence, 4 legacy-path opt-out and canary
props, 3 route-level host guard, 2 breaker salvage). Fault injection:
each of the four fixes reverted independently fails its own tests
(2 CLI + 1 Studio + 2 Studio).
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Six findings from review, none behaviour-critical on their own but three
of them quietly corrupt the data the rollout is judged by.
Endpoint no longer serves bucketSeed (studioServer.ts). Studio gets its
canary answers from the injected decisions map now, so nothing needed the
seed over HTTP — and an unauthenticated local endpoint is a strictly
worse place for it than a script scoped to Studio's own document. The
endpoint itself predates this PR and still serves distinctId, so it also
gains a Host guard: a remote page can rebind its hostname to 127.0.0.1
and read the response as same-origin, but the request still carries THAT
hostname, which is what makes it refusable.
predecessorFound no longer reports corruption as a fresh install. It
returned null for both "file absent" and "file unreadable", so a partial
disk write looked like a new machine — understating recoverable churn,
the one thing the field measures. Now distinguishes absent from corrupt
and emits install_state_file_corrupt alongside.
A mangled markerAt no longer discards a salvageable bucketSeed. markerAt
is only a timestamp and can be restamped; the seed cannot be recovered,
and losing it silently re-rolls the install's cohort.
The seed backfill no longer ignores its write result. An unwritable
~/.hyperframes meant a different seed every invocation with no
diagnostic, and made the field's own "backfilled once" docstring false.
Warns once per process with the underlying error.
FNV-1a's ASCII constraint is now explicit rather than incidental. It
hashes UTF-16 code units while reference FNV-1a is byte-oriented, so the
two agree only on ASCII; the registry's kebab-case assertion is what
makes non-ASCII unreachable, and both ends now say so. Not a live bug —
names are kebab-case and units are UUIDs.
de-parallel-router is pinned at 0%. The registry is data, so a ramp is a
one-line edit with no review surface, and its own description says to
ramp only alongside the circuit breaker.
Tests: 8 new (corruption vs absence, seed salvage, backfill write
failure, 17 host-guard cases, registry pin). One existing test asserted
predecessorFound: false on corruption — that was the bug, updated with a
note. Fault injection: restoring the old corrupt handling fails 4.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Closes both cross-surface findings with one mechanism. The CLI publishes
window.__HF_CLI_CANARY_DECISIONS ({ name: boolean }); a CLI-launched
Studio takes it as authoritative over its own seed, URL override and the
registry percentage.
Studio re-deriving could not agree with the CLI in three cases:
- Telemetry off. The CLI resolves telemetry_opt_out, but Studio's
opt-out is a separate localStorage flag it cannot see, so it would
evaluate normally and could enrol on a render the CLI excluded. The
previous commit gated each surface independently; that fixed silent
enrolment per surface but NOT the disagreement between them.
- HF_CANARY_* override. Env vars never cross into the browser — Studio
reads only its URL param / sessionStorage — so a support session
forcing a canary on got the CLI forced and Studio guessing.
- No seed injected. Studio falls back to a different unit id, i.e. a
different bucket.
Shipping the decision instead of the inputs makes divergence structurally
impossible: one evaluation, two surfaces. It also exposes strictly less —
booleans about features, rather than the seed buckets derive from — which
is why it is safe to publish with telemetry off, the case it exists for.
Studio still evaluates locally when standalone, or for a canary the CLI
did not publish, and ignores a non-boolean value rather than trusting it.
Tests: 6 Studio (CLI-off wins over unset local flag, CLI-on with no URL
param, beats contradicting override, beats seed, falls back per-canary,
rejects non-boolean) and 4 CLI (decisions with telemetry off and no
identity, alongside identity when on, script-tag escaping on a hostile
canary name, throwing resolver degrades to identity only). Four existing
identity tests asserted the old "nothing when telemetry off" contract and
were updated; the registry is now mocked there so string assertions don't
move when a canary is added or ramped. Fault injection: dropping the
adoption fails 4.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Both reviewers flagged the same gap: seed injection was gated on
telemetryShouldTrack(), but canary EVALUATION was not. An install with
DO_NOT_TRACK=1 was still bucketed and still had real code paths flipped
(e.g. HF_DE_PARALLEL_ROUTER), silently and unmeasurably.
A canary is a measured rollout — we enrol a slice precisely so it can be
compared against everyone else. An install that sends nothing can't be
compared, so enrolling it buys no signal and only changes that user's
code path, on an experimental feature, without their knowledge. That is
the wrong side of an opt-out.
Resolves to a new `telemetry_opt_out` reason BEFORE bucketing, so no
cohort is assigned at all. Distinct from `excluded` because "why is my
canary off" has a very different answer for CI than for opted-out, and
the reason never reaches telemetry by construction.
Covers every opt-out route: persisted preference, the runtime env vars
and dev/telemetry-disabled builds via policy.ts, and Studio's
hyperframes-studio:telemetryDisabled.
An explicit HF_CANARY_* / ?hf_canary_*= override still wins — a
deliberate local choice, not silent enrolment, and the documented way to
exercise a canary with telemetry off.
The CLI check mirrors shouldTrack() rather than importing it: client.ts
already imports canary.ts for canaryEventProperties, so depending on it
would be a cycle. Both read the same two inputs, so they cannot disagree.
Tests: 9 new across CLI and Studio (preference off, each runtime
override, no bucket assigned, override still honoured, flag properties
all-false). Fault injection: removing the CLI gate fails 6, removing the
Studio gate fails 3.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Adopts the #2904 pattern for bucketSeed. The seed rides in
install-state.json, which now lives beside config.json in ~/.hyperframes
rather than in ~/.local/state/hyperframes/.
Review rejected persisting state outside the config dir to defeat a
user's reset, and that objection is sharpest for the seed: it is the one
field that would turn install-state into a persistent pseudonymous
identifier surviving `rm -rf ~/.hyperframes`.
The carryover still earns its place, just against the churn that
actually happens. config.json is rewritten on every command and every
render, and readConfig recovers from any parse/permission/IO failure by
minting a fresh identity — so a re-mint would reshuffle cohorts
mid-rollout. A no-schema file written once at mint is decoupled from
that without leaving the directory. Config re-mint: cohorts hold.
Directory deleted: cohorts go too, deliberately.
A pre-move seed is adopted by the same migration, so installs already
carrying one do not have a live cohort reshuffled under them.
Tests: seed survives a re-mint, does NOT survive deleting the config
dir, and migrates from the pre-move path. Prose in config.ts, canary.ts
and canary-rollouts.mdx corrected — it still claimed cohorts survive a
wipe. Docs gain a removal-path section.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Cohort membership now survives a config wipe. Canaries bucket on a
dedicated bucketSeed (fresh random UUID, distinct from anonymousId by
design) that is mirrored write-once into the install-state file and
inherited at mint: a wipe re-rolls the telemetry id but never the canary
assignment. This removes cumulative-exposure drift for the recoverable
churn bucket entirely — the residual drift comes only from fresh
machines, containers, and genuinely new users — and keeps before/after
comparisons valid across a reinstall.
The seed is never emitted in telemetry (only the resulting true/false
assignments are), so it does not link the old id to the new one
server-side. The residual linker is the flag vector itself (k bits for k
live canaries), documented as such. An explicit reset still works by
deleting the state file, and the no-identity test now also asserts the
seed differs from the anonymousId.
Cross-surface coherence: the CLI's studio server injects the seed as
window.__HF_CLI_BUCKET_SEED (same telemetry gate and script-escaping as
the distinct id, and on the /api/telemetry-identity fallback), and the
Studio binding buckets on it when present — without this the CLI would
bucket on the seed while Studio bucketed on the distinct id, splitting
one machine across cohorts (calibration check 4 would catch exactly
this). Standalone Studio still buckets on its localStorage id: the
browser has no second storage location, so that id doubles as the seed.
Legacy configs are backfilled once (lineage seed if the state file has
one, else minted) and persisted immediately — an unpersisted seed would
re-roll cohorts every process. Safe to ship in the same release as the
first canaries: no prior release emitted canary properties, so the
bucketing-unit change is unobservable.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Replaces the single `canaries: "a,b"` telemetry property with PostHog's own
flag shape, one property per registered canary:
$feature/canary-de-parallel-router: "true" | "false"
PostHog treats `$feature/<key>` as a first-class flag property, so breakdowns,
funnels split by cohort and the experiment surfaces work on a canary with
nothing configured server-side. The decision still happens locally: the render
path forbids render-time network calls, behaviour must not depend on analytics
being reachable, and neither the CLI nor Studio ships posthog-js (both
hand-roll a batch POST, so there is no SDK to evaluate a real flag with).
Decide locally, analyse natively.
Two decisions worth recording:
- BOTH ARMS ARE EMITTED. A non-enrolled install reports "false" rather than
omitting the property. Absent means "this build predates the canary", which
is a different fact from "this install is control" — collapsing them makes a
ramp unreadable, because you cannot separate a control group from an old
version.
- KEYS ARE NAMESPACED with a `canary-` infix. A real PostHog flag namespace
already exists in this project, owned by the web app (`enable-chat-tab`, set
by posthog-js from `$lib=web` events). Namespacing guarantees a canary key
can never alias a real flag key and have the two fight over one property.
Values are the strings "true"/"false" to match how PostHog records boolean
flag values, so the property is directly comparable to a real flag.
98 core / 1437, 166 cli / 2194, 269 studio / 2982 green; tsc clean across all
three packages.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Adds the Studio (browser) binding so a canary can span the CLI and the editor,
and fixes a bundling mistake the studio test suite caught.
## The binding
Same public API as the CLI — `isCanaryEnabled("name")` — so a call site reads
identically whether it runs in Node or the browser. Three inputs differ:
- UNIT ID: `resolveStudioDistinctId()`, which already adopts
`window.__HF_CLI_DISTINCT_ID` when the CLI launched Studio. A CLI-launched
Studio therefore lands in the SAME cohort as the CLI: a rollout spanning
render and editor is coherent for that user instead of enrolling their
terminal but not their editor. A test pins that the id is passed through
unmodified — prefixing or re-hashing it would silently break that parity.
- OVERRIDE: no `process.env` in a page, so `?hf_canary_<name>=on` mirrored
into sessionStorage. Session scope is deliberate. A URL is the right carrier
(shareable — "support: open this link"), but persisting a URL-borne override
to localStorage would let one click silently pin a browser into a cohort
forever, long after anyone remembers why. Closing the tab is the reset;
`=reset` clears it explicitly.
- EXCLUSION: `navigator.webdriver` stands in for the CLI's `is_ci`. Automated
browsers mint a fresh localStorage id per run, so they would hop cohorts
between runs — noise in the signal, nothing learned about real users. An
override still reaches them, which is how you test a canary under Playwright.
Studio's `trackEvent` now attaches `canaries` to every event, mirroring the CLI.
## The bundling fix
Importing the `@hyperframes/core` barrel into studio browser code broke two
unrelated hook test files with an esbuild TextEncoder invariant violation. The
barrel re-exports the whole core surface (parsers, lint, studio-server), so it
drags a Node-oriented dependency graph into a browser bundle — the test
failure was the symptom, the bundle bloat was the bug.
`@hyperframes/core` now exposes `./canary` and `./canary-registry`, declared in
packages/core/package-subpaths.json (the generated source of truth for exports —
hand-editing package.json is reverted by the sync script) and marked
`environments: [browser, bun, node]`. Both the studio AND cli bindings import
the leaf modules; the CLI gets the same benefit for a different reason, since
this resolves on the startup path — the reason the producer is lazily loaded.
Verified: the two hook files pass again; 269 studio files / 2982 tests, 98
core / 1433, 166 cli / 2194 green, `bun run lint` clean including the subpath
check. Fault-injection confirms both design decisions are pinned — swapping
session for local storage fails the scope test, prefixing the unit id fails the
CLI/Studio cohort-parity test.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Follow-up to the canary primitive.
Telemetry: every event now carries a `canaries` property listing the cohorts
the install is enrolled in, attached in `trackEvent` so it lands on ALL
events rather than renders only — a staged rollout is only as useful as the
ability to split any metric by cohort. Resolved after the shouldTrack guard,
so opted-out installs never pay for it, and omitted entirely (not null or "")
when the install is in no canary, since PostHog treats those as real values.
Test hardening, after validating the shipped code against 60k synthetic and
101 real fleet install ids:
- Pin FNV-1a against canonical vectors, AND assert the shipped canaryBucket
actually uses that hash. Without the second assertion the first is
tautological — it would only prove the test's own copy is correct while
canary.ts drifted to a different hash, silently reshuffling every live
cohort. Fault-injection confirms only this assertion catches a hash change;
the distribution tests stay green because a perturbed hash is still
well-distributed.
- Tighten the share test from a 0.6x-1.4x band to +/-1 percentage point.
Measured error was 0.16pp at n=60k, so the old band would have passed a
badly skewed hash.
- Add chi-square uniformity across all 100 buckets (chi2 89.0 vs 148.2
critical at p=0.001). A lumpy hash yields roughly the right total share
while overloading some buckets, so the share test alone cannot catch it.
- Assert N concurrent canaries enrol binomially rather than in lockstep:
8 canaries at 10% put ~43% of installs in none and zero in all eight,
matching binomial(8, 0.1). Correlated slices would put ~10% in all eight.
Also verified 88,443 of 88,448 fleet install ids are well-formed UUIDs; the
5 that are not fail closed, which is the intended direction.
Docs: docs/contributing/canary-rollouts.mdx, registered in docs.json (an
unregistered page is invisible in the nav).
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Adds a reusable staged-rollout primitive so a change can ship to a stable
slice of installs instead of all-or-nothing.
The gap it fills: the repo carries ~49 HF_*/PRODUCER_* booleans and every one
is binary — a feature is either off (and therefore unexercised on real
traffic) or on for everyone (and therefore a fleet-wide bet). The
parallel-drawElement router sat in that gap for weeks: default-off produced
almost no signal, and flipping it default-on would have exposed 100% of
eligible installs at once.
Shape:
- packages/core/src/canary.ts — pure evaluator. No fs, no network, no
`process`; the caller supplies the unit id and overrides, so it imports
cleanly into the CLI, producer, engine, studio-server, the browser-side
studio bundle and the embeddable player. FNV-1a rather than node:crypto for
the same reason.
- packages/core/src/canaryRegistry.ts — every rollout in one table (name,
percentage, owner, description, sunsetAfter), so "what is rolling out, to
whom, owned by whom" is answerable without grepping 49 env vars.
- packages/cli/src/telemetry/canary.ts — supplies the three things only the
CLI knows: anonymousId, the HF_CANARY_<FEATURE> override, and is_ci.
Day-to-day API is `isCanaryEnabled("name")`.
Three properties the tests pin, because getting them wrong is subtle:
- Slices are INDEPENDENT per feature: the bucket hashes `feature:unitId`, not
the id alone. Bucketing on the id would hand every concurrent experiment to
the same unlucky cohort and make two rollouts unreadable apart.
- Ramping is INCLUSIVE: `bucket < percentage`, so widening 10 -> 25 keeps the
original cohort and before/after comparisons survive the ramp.
- It fails CLOSED: no unit id, unknown name, or CI install means not enrolled.
A canary exists to bound blast radius, so "we don't know who this is" must
never mean "enrol everyone".
Registry entries also carry a sunset date, and a test fails once one is past
due — a canary that outlives its rollout is a permanent fork of the product
with none of the review a permanent fork would get.
Ships with de-parallel-router registered at 0%: inert, and ready to ramp in a
patch release once #2840 lands.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Miguel Ángel