Owner decision 2026-09-22: 'it doesn't make sense to have any default
model configured anywhere; the application is bring your own keys.'
config.ts: MODELS deleted; ModelRole becomes an explicit 9-role union;
DEFAULT_THINKING_ORDER (medium, low, high, minimal, xhigh, max) bakes
the unset-level default — first entry the model supports; explicitly
set levels keep pi's native nearest-clamp.
core/settings-resolution: the factory layer dissolves — the chain is
role override → slot → NOTHING. resolveSettings(record) takes no
factory. Empty chains resolve to null/undefined; a thinkingLevel-only
slot is inert (stored, never run). resolveConversationSpec: chat.model
override over the strong slot, null when both empty. resolveRoleSpec
spans all nine roles for the job/extraction engines.
Refusal envelope (core/settings.ts): modelsNotConfigured(missing) —
{error, code: 'models_not_configured', missing: [slot tiers]} +
ModelsNotConfiguredError with .envelope. Per-need gates, each honest:
- chat-handler: universal turn gate (new + continuing turns) returns
503 before beginTurn — no liveness, no write-ahead persist, no graph
trigger before the gate fires.
- runner.runJob: unresolvable engine lands the job as error with the
envelope wording; no phantom loop, no result steer.
- extraction: refuseIfStagesUnconfigured throws before any stage
(turn-service info-skips so coverage retries next turn; the import
route surfaces per-file code+missing); labeler-less runs skip
cluster naming with a console line and still merge.
Write side: slot entries must carry a model — level-only slot writes
are 400s (absent slot key = clear). piEngineForSpec resolves unset
thinking levels via DEFAULT_THINKING_ORDER; piEngineFor now throws
honestly; thinkingLevelFor/modelIdFor deleted; teacher-agent, pi-run,
visual-maker, pdf-reader all read engine.level.
model-catalog: defaults/slots/rolePins null when the chain is empty
(contracts nullable) — no phantom ids in payloads. Stores drop
MODEL_PINS entirely.
Tests: pin-leaners converted to explicit injection (per-chat model
pins on scripted chats — exactly what the setup flow writes; faux
engines for agent-construction tests). New coverage: the 503 gate
envelope, the runner refusal, the extraction refusal + labeler skip.
Gates: typecheck, lint, 815/815, build.
Live-smoke follow-up the user approved (2026-09-19): the GEB read showed
"78 pages consulted" when the reader genuinely READ ~12 - pdf_search hit
snippets inflated the count. PdfResult now carries both:
- pagesRead: extract/render output entered the loop - the honest count
the badge and brief footer show ("read N pages", "Pages read: ...").
- pagesConsulted: every page whose content entered the loop, search-hit
context lines included - unchanged, still the citation audit set (the
reader's instructions still say "Pages consulted: N, N, ..." and the
footer still lists it when it exceeds the read set).
The unread-finish gate deliberately stays on CONSULTED: search hits are
genuine consultation (anti-fabrication duty), so a search-only brief is
honest and must deliver - pagesRead is a reporting refinement, not a
delivery gate. Pinned by the search-only faux test (read [], consulted
[1], delivered).
UI tolerates pre-split persisted records via ?? fallbacks (old steers
lack pagesRead).
User pivot (2026-09-19): no attachments UI at all. Pasting paths is native
for technical users and alien for everyone else - so the agent gets the
tools to find what the learner merely NAMES. The learner communicates in
messages; the agent locates and reads. Zero cross-stream seams: paths
already live in tool parts, so the sources "list" is the transcript.
- ls/find/grep: pi-verbatim schemas, descriptions, and output formats
(fd's glob semantics, rg's path:line: match format, pi's truncation
notices), ported to pure Node - no binaries, no shell-out, read-only by
construction. Deltas from pi: home-anchored resolution (the harness has
no cwd), .gitignore replaced by hard noise exclusions
(node_modules/.git/Library/.Trash), 10s walk timeout with partial results.
- read: description swapped to pi-verbatim (doctrine moved to the prompt);
relative paths now resolve against the learner's home like the rest.
- prompts/shared/05-learner-files.md: one minimal doctrine fragment
composed into BOTH agents (composeInstructions grew a shared/ dir,
before the agent's own fragments). teacher/30-jobs.md keeps only the
pdf-dispatch addendum.
- ToolCallCard: the generic quiet tool-call card the user specced -
collapsed one-liner (tool name + headline argument), expandable to full
input/output, errors red, image payloads never render. Registered for
read/ls/find/grep.
- ui-message.ts: TeacherUITools entries for the four tools (mechanical).
- tests: fs-tools suite (glob semantics, pi formats, exclusions, limits),
registry/card renders, shared-fragment composition pins, tool-registry
key updates, read re-anchor.
The browser e2e check on the live dispatch session found the tool-pdf
part rendered NO card: the artifact renderer registry had no pdf entry
(the doc comment literally says "add your renderer here"), and the typed
TeacherUITools union + the chat.tsx job-part enumerations (poll cadence,
dispatch nudge, settle-sync) all missed the new tool kind.
- PdfJobCard in job-card.tsx: the research JobCard idiom, kind pdf —
registered in artifacts/index.ts.
- ui-message.ts: pdf entry in TeacherUITools (fire-and-forget ack output).
- chat.tsx: two mechanical "tool-pdf" additions to the research/demo/visual
enumerations — UI-stream file, flagged for review at merge (same
treatment as the activity-dock type-forced entries).
- demos.test.tsx: live/settled dispatch-card renders + registry pin.
Learner source files, on the teacher's own terms (nothing auto-injects):
- read tool (src/agent/tools/read.ts): pi-read port — path/offset/limit,
2000-line/50KB truncation with use-offset continuation notices, image
files (jpg/png/gif/webp/bmp) returned as native image content parts
(new LhToolImageResult escape hatch in lh-tool.ts). Always-on in both
the prober and teacher registries (user-decided 2026-09).
- pdf-reader sub-agent (JobKind 'pdf', toggleable, ack-and-steer): triage
via pdf_info (pdfjs text layer: per-page text/image/math-density),
targeted pdf_extract, regex pdf_search (hits count as consultation),
and pdf_render — pages painted by pdfjs onto a canvas shim in headless
Chrome (the pdfium viewer doesn't paint headless), screenshot fed back
image-in-the-loop (visual-maker idiom, providerSafePng applied). The
unread-finish gate bounces a zero-consultation brief once. Teacher gets
a text brief with page citations only; renders never leave the loop.
- MODELS.pdfReader = qwen/qwen3.8-flash (user override 2026-09-19: the
look-at-renders workload wants the vision-proven model; catalog listed
glm-5.3-flash as image-capable but qwen is the known-good daily driver).
- UI: PdfCompleteBadge + PdfBriefCard (steer-card, job-card), dispatch
card + activity-dock kind entries (type-forced, flagged for UI review).
- Prompts: 'Learner source files' section in teacher/30-jobs.md; read
line in prober/10-probe-doctrine.md. Doctrine rides tool descriptions
per the self-contained-tools principle.
The custom-message scheme (user-decided 2026-09-12): system-authored
user-role messages are NOT human messages — they carry marker data parts
only, the adapter owns their model-facing wording, and the UI renders
them under control. Nothing fake is ever persisted as human speech.
The inventory (all migrated):
- probe→teacher handoff wake: was a text-bearing user message rendering
as a fake user bubble; now data-probe-handoff marker-only — the
adapter flattens it to HANDOFF_TEXT (core/contracts/chat.ts), the UI
renders a quiet 'Preparing your plan…' system line.
- plan accept/decline: was boilerplate text ('The plan is accepted…',
'I'd like the plan revised…') masquerading as learner speech — the
decline wasn't even marked; now data-verdict {accepted, at} on its own
message, adapter flattens to verdictText(), UI renders the quiet
verdict marker ('✓ Plan accepted' / '↻ Plan revision requested').
sendVerdict sends TWO REAL MESSAGES when the learner typed a note
(the note as a genuine user message, then the verdict) in ONE turn
via setMessages + sendMessage() — no 409 dance, no double teacher turn.
- sub-agent steers: the abort steer gains its data-subagent-aborted
marker part; the UI keys steer rendering off PARTS (artifact/aborted),
not metadata — metadata stays as pump mechanics only.
- record-adapter: systemTextOf() flattens marker-only messages; steers
keep their text (payload — briefs are content, not boilerplate).
phases.ts: plan→teach advances on data-verdict{accepted:true} only;
learner text alone can never sanction teaching (pinned). data-plan-
accepted retired, no back-compat (user-decided: wiped-data doctrine).
Pinned: record-adapter.test.ts (verdict/handoff flattening, note+verdict
order, steer payload kept, UI-only parts skipped), phases.test.ts
(verdict marker semantics, out-of-order, text-never-fakes), jobs.test.ts
(abort marker part), demos.test.tsx (badge renders off the part, not
metadata).
Live GLM smoke (disposable driver, deleted): probe→conclude→wake→plan→
decline-with-note (revised, still plan)→accept-with-note (teach) — ALL
CHECKS PASS, including marker-only handoff/verdict on the wire and zero
fake human speech in the transcript.
Gates: tsc, lint, build, 335/335.
The Vercel AI SDK survives only as Band D (useChat client + UIMessage
record types); @openrouter/ai-sdk-provider is uninstalled.
- src/agent/models.ts: PiEngine {model, streamFn} via createModels +
openrouterProvider subpath; thinkingLevelFor maps config effort none->off
- src/agent/lh-tool.ts: neutral LhTool (zod authoring, optional execute,
clientQuestion flag); toPiTool converts via z.toJSONSchema and re-runs
zod inside execute so refinements ride the error-result retry path
- src/server/pi/record-adapter.ts: UIMessage records -> pi Messages
(dangling tool calls get synthesized interrupted results)
- src/server/pi/ui-stream.ts: SSE bridge emitting AI-SDK-shaped chunks so
the useChat client parses unchanged (continuation id rule, question
tools never emit output, tool-input-error for bad authoring)
- teacher-agent.ts: stateless per-turn pi Agents; shouldStopAfterTurn
stops only when every question-tool call resolved cleanly (errors retry)
- chat-handler.ts: buildAgent(outgoing) factory seam (stateless doctrine);
assertValidUiMessages owns the retired SDK validation gate
- sub-agents via shared runSubagent (pi-run.ts); extraction stages stop
after a clean submit; visual-maker keeps its hand-rolled loop over
direct streamSimple calls; aborted model calls bill no usage
- tests: all model seams ported to pi-ai faux provider (scripted
FauxResponseSteps, agent factories); handleChatRequest second param
is now an agent factory
Gates: tsc, lint, build, 305/305. Live GLM smoke (disposable driver,
deleted): prober streaming + persistence, question seam, turn-2
continuation same message id, per-turn real token usage - ALL PASS.
Data wiped at the pivot (chats/graph/jobs, .gitkeeps kept).
Diagnosis (2026-09-11 user testing, minimal-effort GLM): sessions stuck on
'plan' forever. Two causes: (1) the three-phase view read the stored tree's
currentNodeId, which nothing ever writes post author-once (2026-09-03) — a
structural dead seam; (2) the teacher stochastically left quiz.nodeId
untagged, and done-by-quiz-result semantics would have falsely completed
nodes anyway.
The redesign (docs/probe-teach-split.md) abolishes derived occupancy in
favor of explicit events:
- Two agents over one transcript: createProberAgent (quiz without a
nodeId field, ask, probe_done) and createTeacherAgent (full toolset,
plan_init onward). The chat-handler construction branch keys on a
probe_done part in the transcript. MODELS.prober added.
- probe_done: server-side seam tool — carries the learner assessment
(strands + free-form edge read), refuses while a question is open or
the probe is already concluded, and queues a handoff steer through the
generalized wake pipeline (steers now dedupe by id, not jobId; job
finalization only for job steers). The teacher auto-wakes and authors
the plan; the learner sees the assessment via the probe-done card.
- phases: probe ends at a concluded probe_done, plan ends at a
successful plan_init — strictly sequential, no skipping, no legacy
compatibility (data wiped at the pivot per doctrine).
- Plan map = position, not completion: derivePlanStatuses reads only
tagged quiz CALLS (state/outcome feed nothing); current = latest
tagged node with consecutive duplicates collapsed, visited = earlier
distinct stays (a revisit stays in both — current wins at render).
PlanTree is structure-only; currentNodeId/doneNodeIds and the dead
mutation helpers are gone. No fallback current.
- Prompts split per agent (prompts/prober/, prompts/teacher/ over the
trimmed shared base); graph-context injection removed entirely
(shelved, docs/probe-teach-split.md §5); knowledge-graph context no
longer reaches either agent.
- Plan blocks are full-only snapshots at plan_init (neighborhood
machinery retired; the persistent DAG window is the future UI wave);
usage capture unchanged.
Gates: tsc clean, 294/294 tests (phases/plan-tree/plan-blocks/question-
tools rewritten to the new semantics; probe-done + handoff-wake tests
added), lint, build. Live GLM smoke PASS: prober concluded with an honest
assessment, teacher auto-woke, authored a 10-node plan with the block
attached, then tagged checks on slope-instinct → secant derived current/
visited exactly as designed; grading honest both ways (driver off-by-one
proved a wrong answer grades false).
The plan now lives IN the chat (plan blocks, wave-4 item 3) and background
processes live in the activity dock (item 1), so the right sidebar's
tree panel + sub-agent fleet column is retired from the chat view:
- delete components/tree-panel.tsx (three-mode rail/list/graph panel) and
components/sub-agents-panel.tsx; their graph interaction machinery lives
on in plan-block.tsx and fleet observability in activity-dock.tsx.
- app/layout.tsx drops TreePanelModeProvider (the mode no longer exists).
- chat.tsx drops the xl:flex right column; the middle column is the view.
- tests: render-tree-panel.test.tsx deleted; the sub-agents panel suite
removed from demos.test.tsx (dispatch cards' jobs-context stays — the
central poll drives transcript dispatch cards).
Wave 4 (agent-side observability + control), reconciled with the dock
contract (master relay 2026-09):
- abortJob in src/server/jobs.ts, exported through the server barrel for
POST /api/activity/abort (master's thin route): fires the job's
AbortController (real kill — the in-flight model call aborts, not just
the next loop check), drops any queued result steer, flips the record
to error "Aborted by learner" + activity "aborted" synchronously, and
queues a one-line abort steer (buildAbortSteer) through the same wake
pipeline so the teacher's promise doesn't hang in the lesson. Shares
the result steer's deterministic id space, so abort + racing result
can never both deliver (steerDelivered dedupe).
- Abort registry (src/agent/subagents/aborts.ts) on globalThis, mirroring
the wake pipeline's module-state pattern; runner registers/unregisters
per run, so the route's module instance sees the loop's controller.
- Runner usage capture: LoopContext (abortSignal + onUsage) threads into
all three kind loops; per-step usage folds via accumulateJobUsage into
JobRecord.usage (model from config MODELS, absent-never-zero), flushed
in runJob's finally so an aborted job's money record survives the kill.
- Contracts: JobUsage token fields optional + lastStep (most recent
call's accounting, for the dock's per-blob context line vs
CONTEXT_LIMITS); SubagentResultMeta.aborted; AbortSteerMessage;
buildAbortSteer; SteerMessage union generalized.
- demo-builder/visual-maker accept abortSignal + onUsage (visual folds
generateText usage per iteration).
- stillRunning/finishJob/jobContext guards: an aborted job is never
overwritten by the runner (terminal no matter what the wake does);
failJob and the pump's finalizeJob keep the flip.
- UI: abort steer renders a quiet aborted chip (job-aborted-badge).
- Prompt 20-jobs.md: one line about aborted jobs.
Tests: accumulateJobUsage folds (undefined-preservation, lastStep),
runner usage capture, real-kill abort (sync flip, silent unwind,
abort steer wakes), usage-so-far survives the kill, aborting a
delivering job drops the queued result steer, outcome reasons,
abort-chip render. 330/330, typecheck/lint/build green.
The Research-complete one-liner is now a native <details> disclosure:
collapsed it reads exactly as before (Research · complete · N sources);
one click expands the full persisted brief + source links via
ResearchBriefCard. No fetch, no state, no protocol change — the
data-subagent-artifact part in the record is the single source of truth,
which is what made this affordance 'feasible later' back in wave 1.
The brief still never clutters the transcript by default; the teacher's
wake turn remains the primary channel for weaving it into the lesson.
Test updated: the brief + sources now assert PRESENT inside the details
(and collapsed — no open attribute) instead of absent from the DOM.
Gates: typecheck, 279/279 tests, lint, build — all green.
Figures now always fill the card's width (h-auto keeps the aspect
ratio): narrower svgs scale up instead of leaving a white strip on the
right when they carry their own background color; oversized ones still
shrink to fit. bg-white stays as a neutral backing for svgs without
their own background.
Three refinements from live testing:
- Steer messages no longer sit inside the user Message container (the
bubble background + right alignment it gave artifact cards). chat.tsx
renders SubagentSteerCard directly in the transcript column — full
width, centered, same register as the teacher's artifacts.
- Research steers render a quiet "Research complete · N sources" badge
(the dispatch-settled idiom), not the full brief: briefs are long, the
wake turn weaves them into the lesson anyway, and the full text stays
persisted in the artifact part — a "view full research" affordance
can be added later without any protocol change. Failures keep the
failure card (the brief explains what went wrong).
- The sub-agents' verification notes (visual/demo builder notes) are
model-facing glue and no longer render on success; failure notes
remain the error explanation.
SSR-verified against a synthetic record: badge + SVG bare in the
transcript (no is-user wrapper), notes/brief confined to the RSC
payload. 229/229, typecheck, lint, build green.
The pi-style ack protocol (previous commit) left the client describing the
old world: artifact cards read the ack string as a result ("could not be
displayed"), the only job poller rendered on input-available parts that no
longer exist (so wake turns landed invisibly until re-navigation), steers
rendered as learner bubbles with no SVG anywhere, and server-persisted
assistant messages carried empty SDK ids (duplicate React keys).
- persistTurn (turn-service): fill empty message ids at the canonical write
— server-only messages (last turn's, wake turns') now key uniquely;
client-authored ids untouched.
- chat.tsx: ONE central /api/jobs poll (fast while jobs run, slow discovery
cadence, off for job-less sessions) drives every job surface, re-syncs
once when a job settles (the record already holds the steer + wake
response at flip time), and adopts server-side wake turns via the same
turnInFlight machinery as returning mid-turn. Steers branch to the
artifact card — never a bubble. Composer no longer gates on jobs.
- /api/jobs now reports turnInFlight alongside the job list.
- dispatch-card: the tool-call box — live activity by toolCallId while
running, quiet "delivered"/"failed" one-liner after; the ack is visible
observability, the artifact lives in the steer.
- steer-card: renders the delivered artifact by kind (research brief /
sanitized SVG / sandboxed demo iframe) from the data-subagent-artifact
part; result renderers extracted and exported from the artifact cards.
- sub-agents-panel: right-sidebar section above the plan tree listing
running sub-agents (kind, elapsed, live activity) — vanishes when idle.
- tests: dispatch/steer/panel render tests re-target the new protocol;
persistTurn id-hygiene suite. 229/229 green, build green.
Out-of-lane touches for master review: chat.tsx + components/** (cleared
this wave), app/api/jobs/route.ts, src/server/turn-service.ts, contracts
protocol doc §2. Live-verified on :3003 (full loop, SSR DOM checked).
The job tools (research/demo/visual) switch from client-side turn-breaking
calls to pi's model: execute resolves IMMEDIATELY with a fire-and-forget
ack, the teacher's turn continues, and the result arrives later as an
injected user-role steer message that wakes the teacher in a new
server-side turn.
- contracts.ts: THE ASYNC PROTOCOL rewritten (ack now, steer later); steer
types (SubagentSteerMessage, metadata.subagentResult + data-subagent-
artifact part), pure buildSubagentSteer/steerDelivered/isSubagentFailure
- tools/jobs.ts: jobTools(ctx) factory — server-side execute creates the
job (deduped by toolCallId), fires spawn with the dispatch-time input
(the part isn't persisted yet at execute — a transcript scan would race)
- runner.ts: runJob(jobId, input?) builds the steer and hands it to the
injected deliver seam; pipeline owns the done/error flip (a polling
client re-syncs once, at the end); failures still steer
- server/jobs.ts (new pipeline): per-chat serialized queues on globalThis,
idle gates (turn liveness + pending question, 1.5s grace), 409 retry
with backoff, idempotent per jobId, stale-job recovery sweep (re-deliver
or re-spawn); wake turns run through the same handleChatRequest
composition via setTurnRunner injection
- chat-handler.ts: wires runner+deliver+tools ctx; drops spawnTurnJobs
from onFinish; teacher default registry = question tools only
- plan.ts: PlanToolContext split out (plan tools need no job wiring)
- visual-maker: edit_svg added (pi parity — exact-match single
replacement, fuzzy context on a miss); researcher: pi's kept/dropped
source accounting restored
- prompts 20-jobs/40-demos: async discipline rewritten (announce and keep
teaching, no waiting/polling/fabricating, parallel dispatch, teach with
the artifact when it arrives)
- tests: jobs.test.ts rewritten (dispatch ack mid-turn, runner steers,
wake pipeline: deferral/409/idempotency/failure), demos.test.tsx runner
tests ported to runJob + fake deliver; 222 green
FLAGGED surgical touches outside the stream's owned files, for master
review at merge: src/core/contracts.ts (protocol doc + steer types),
src/core/ui-message.ts (job tool + data-part types), src/server/
chat-handler.ts (wiring), src/server/turn-service.ts (spawnTurnJobs
retirement), src/agent/teacher-agent.ts (default tools), src/agent/tools/
plan.ts (context type split).
Verified live on PORT=3003 with real models: teacher dispatched research
mid-turn, researcher ran real searches/fetches, steer injected on quiz
answer, wake turn wove the brief in citing its sources, job flipped done;
a client/wake race correctly 409'd.
The chat turn is now composed, not implemented, by chat-handler.ts:
- src/server/turn-service.ts: one named, error-contained seam per turn
responsibility — buildTeacherContext (W8 read channel), persistTurn
(canonical state write), spawnTurnJobs (async protocol kick-off),
foldTurnIntoGraph (session→graph consolidation; the extraction-pipeline
stage swaps this body behind the same seam). Each takes its deps
explicitly; failures log one [chat <id>] line and never touch the
response.
- chat-handler.ts wires: storage ports (stores), the job runner, the
teacher tools (ctx = chatId + injected ChatStore), and the services.
It no longer contains any logic beyond request validation.
Agent layer now receives dependencies instead of importing them — a new
lint zone enforces it (src/agent never imports src/server or src/store;
verified to fire both ways):
- runner.ts: createJobRunner({ chatStore, jobStore }) factory returning
the spawn hook + the three job runners; the model-override test seam
stays module-level. Bodies otherwise verbatim.
- plan tools: persist through the ctx-injected ChatStore
(TeacherToolContext = { chatId, chatStore }).
- teacher-agent's dependency-free default registry is now the true
client-side set: questionTools + jobTools (jobTools was ctx-parameter-
shaped but never used its ctx — now honestly context-free). Production
always passes createTeacherTools({ chatId, chatStore }); tests that
drive a bare mock model get the client-side set unchanged.
Zero behavior change: tsc clean, 190/190 tests, eslint clean, production
build clean. Tests inject the same fs ports the chat-handler does.
Per-entity semantic ports (src/core/ports.ts), one adapter family
(src/store/*, fs JSON/JSONL), exactly one composition point
(src/server/stores.ts). Dependency direction is now machine-checked:
adapters implement core interfaces; core never imports an adapter.
The inversion:
- core/graph.ts (emitChat/getGraph/graphSnapshot/foldStaleChats) is now
pure — it takes the storage ports as explicit parameters (GraphDeps).
No store imports; newGraphNodeId is local; node id format unchanged.
- core/graph-context.ts buildGraphContext() no longer defaults to the
live ledgers: the chat-handler hands in getGraph(graphStore) per turn.
- store adapters export exactly one object each implementing their port
(chatStore/graphStore/jobStore); bodies otherwise verbatim.
NodeMapping + SessionCheckpoint moved store/graph -> core/contracts
(they ARE contract shapes); CreateJobInit/JobPatch live in ports.
- titleFromPrompt moved store/chats -> core/contracts (pure helper,
planNodeStatus precedent). Store modules now contain persistence only.
- server/stores.ts is the composition root; server/{chats,graph,jobs}.ts
and chat-handler wire from it; agent (plan tools, sub-agent runner)
call the port objects. The shell surface (@/src/server exports) is
unchanged.
Lint law extended: the whole of src/core is now a purity zone (was a
file glob with a graph/graph-context exemption). Verified it fires on
core->store imports; tsc clean, 190/190 tests, eslint clean, prod build
clean (prerender 6/6). Tests pass deps explicitly — graph.test uses the
same fs-adapter pair stores.ts wires in production; graph-context.test
keeps its in-memory ledgers as a GraphStore implementation.