V0.3.0

OntoBricks — Release Notes V0.3.0

Release window: May, 2026
Test status: all changes shipped with the suite green (2045 passing, 80 CloudFetch probe tests conditionally skipped in CI).

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Highlights

• Cohort Discovery — new end-to-end feature for business-friendly entity grouping: rule-based linkage (shared resources via predicates), compatibility constraints, a 6-stage deterministic engine, full Volume + Lakebase persistence, graph-triple + Unity Catalog Delta materialisation, and a natural-language Stage 2 agent that translates free-text prompts into validated CohortRule JSON.
• Live Digital Twin build log — the Build page now shows a real-time per-step log panel with elapsed timers, phase descriptions, a one-click export to .log, and honest background-archive handling. TaskManager gains skip_step / complete_current_step so skipped phases are labelled correctly.
• Real /health readiness probe — 11 checks covering filesystem, Databricks auth, SQL warehouse, registry Volume read/write, registry UC DDL permissions, Lakebase schema/table/sequence grants, and CloudFetch capability. /health/detailed retired. New admin Health tab in Settings surfaces the same payload in-app.
• Mapping diagnostics: source table permissions — new third section runs a non-destructive SELECT … LIMIT 0 against every Unity Catalog table referenced by the mapping and reports ok / PERMISSION_DENIED / TABLE_OR_VIEW_NOT_FOUND per table, surfacing missing grants before a build attempt.
• Knowledge Graph — right-click Expand neighbours — any node can be expanded N hops in place without re-running a full SPARQL query. Non-blocking spinner, depth picker, camera zoom + highlight on new nodes. KG preview/expand also hardened against timeouts and 502 errors on large graphs.
• Deployment: single source of truth — scripts/deploy.config.sh + app.yaml.template replace scattered literals across Makefile, deploy.sh, and bootstrap scripts. app.yaml is now a generated artifact. App name ontobricks-030 unified across all tooling.
• CloudFetch — runtime capability probe — DatabricksAuth detects at runtime whether the Apps sandbox can actually reach the CloudFetch storage host, sets use_cloud_fetch accordingly, and exposes the verdict in /health. A new Settings → Global toggle lets admins override the default.
• Task duration & UTC timestamps — TaskManager emits START task / END task log lines with compact durations, serialises duration_seconds in to_dict(), and uses UTC-aware ISO timestamps throughout to prevent timezone-drift bugs in the browser.

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Cohort Discovery

Stage 1 — deterministic engine, UI, persistence, materialisation

• New CohortRule model with validate(), CRUD endpoints, dry-run + materialise, and a 6-stage pure-Python engine (CohortBuilder) that works against both Delta/Spark SQL and LadybugDB/Cypher backends.
• Materialise to graph (idempotent DELETE then INSERT, per-rule :inCohort<RuleId> predicate) and to Unity Catalog Delta (partitioned by rule_id, chunked INSERT).
• Content-hash cohort URIs (<base>/cohort/<rule_id>/c-sha256(…)[:8]).
• Live preview helpers: class stats, edge count, node count, sample property values, explain_membership (Why? / Why not?).
• 59 new tests across test_cohort_models.py, test_cohort_builder.py, test_dtwin_cohort.py.
• New docs/cohort_discovery.md with mental model, UX walkthrough, 4 worked examples, API summary.

Stage 2 — NL agent for rule generation

• agents/agent_cohort/ — six read-only tools (list_classes, list_properties_of, count_class_members, sample_values_of, propose_rule, dry_run) wired to Stage 1 endpoints.
• One-shot agent loop with 10-iteration cap; never writes — saving still goes through the Builder-protected endpoint.
• UI: Describe tab (NL prompt + agent trace with tool calls, durations, iterations) auto-switches to Build rule tab when a rule is proposed.
• Fix: list_properties_of was returning empty arrays when rdfs:domain was stored as a local name or property URIs were missing — resolved with _domain_matches + _ensure_uri helpers and a fallback to the full object-property list.
• 22 new tests across test_agent_cohort_tools.py (19) and test_agent_cohort_engine.py (3).

Cohort designer — UX refinements

• Three-tab layout (Describe / Build rule / Preview) replaces the full-width drawer; the Preview tab carries a live cohort-count badge.
• Saved rules pane promoted to a persistent right/left rail, always reachable regardless of active tab.
• Dependent dropdowns in the "Link members" section: via property narrows to predicates whose domain is the source class and range is the chosen shared class; falls back to the full list when ontology metadata is incomplete.
• camelCase rule name enforcement: live input sanitisation, paste-to-camelCase, _isValidRuleName validator, _toCamelCase helper applied to agent-generated names. id = label (no more slug fork).
• Rule-scoped predicate and UC table: membership triples use :inCohort<RuleId>; Auto-pick proposes cohorts_<snake_rule_name>. Both the graph-triples hint and the UC-table hint in the Configure-outputs modal now show the actual predicate / table name for the active rule.
• Clickable entity badge in the Preview pane: each cohort member renders as a pill that links to the Sigma graph focused on that node. URI is demoted to inline parenthetical muted text.
• Configure-outputs modal — visible feedback: Auto-pick and Test write access were silently swallowing errors. Both are now four-state (idle → working → success | error) with inline status lines, spinner, toast, and error-envelope surfacing.
• Clearer step labels in the designer: "Link members via a shared entity" (was "When are two members linked?"), "Conditions every member must satisfy" (was "Compatibility policies"). Terminology switched from "class" to "entity" throughout user-facing strings.
• Cohort explain fix — namespace drift: CohortBuilder._members_of_class now checks all URI variants (ontology form, data form, raw) so explain_membership works regardless of which normalisation path the loader used. Enhanced "not in class" diagnostics report typed-as, untyped, or URI not found with actionable advice.
• Rule summary card: removed the redundant rule_id chip (equal to label for camelCase names); fixed binary UC/graph output display to enumerate all four states (graph + UC / graph only / UC only / no outputs).

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Digital Twin Build

• Live build log panel (#syncBuildLogCard): appears on Build click, grows row-by-row with icon, description, live sub-message, and per-step elapsed timer. Step labels rewritten to plain English ("Preparing mappings…", "Detecting what changed since last build", etc.).
• TaskManager.skip_step() marks a step skipped and advances current_step so the label array stays aligned with execution when phases are conditionally bypassed (e.g. Detecting what changed on first build, Checking source tables on forced full rebuild).
• Export build log: one-click export to digital-twin-build_<timestamp>.log (plain text with a header block, per-step table, and result block). Button enabled from the first poll onwards.
• Fast gzip + background archive: GraphSyncService.sync_to_volume now uses compresslevel=1 (≈ 6–10× faster than the previous level 9). For session builds the Volume upload runs in a daemon thread; the build task completes immediately after the snapshot step with the note "Registry backup continues in the background."
• Archive checkbox: new "Archive graph to registry" checkbox on the Build page (default on); when off, the archive step is marked skipped with a plain-English reason.
• Honest timing: archive row shows "Continues after build" with a tooltip instead of a misleading 0ms duration when the upload is backgrounded.
• Background archive task tracked as a separate registry_archive TaskManager task with its own navbar hourglass entry.

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Task Manager & Notifications

• Task.duration_seconds() — computed live for running/pending, frozen at completed_at − started_at for terminal tasks; serialised in to_dict().
• TaskManager lifecycle log lines unified to START task <id> [<type>] — <name> / END task <id> [<type>] completed|failed|cancelled in <duration>.
• _format_duration produces compact strings: 450ms, 2.40s, 1m 23.5s, 1h 5m.
• Navbar hourglass: running rows show a live 1 s ticking elapsed time; bell toasts append (in 1m 23s).
• All task/step timestamps emitted in UTC-aware ISO format (+00:00); duration_seconds() tolerates mixed naive/aware legacy timestamps.
• Removed the broken "Open" link from terminal task completion toasts.

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Health & Observability

/health readiness probe (replaces static {"status":"healthy"})

11 probes, each timed and wrapped in _safely_run so one failure never breaks the overall response:

Probe	What it checks
runtime	Python + OntoBricks version
filesystem.tmp	Write sentinel + shutil.disk_usage thresholds (warn < 1 GB, error < 100 MB)
filesystem.session_dir	Same check against the session directory
filesystem.log_dir	Same check against the log directory
databricks.auth	has_valid_auth + OAuth token mint in App mode
databricks.warehouse	SELECT 1 against the configured warehouse
databricks.cloudfetch	Real SQL probe with use_cloud_fetch=True; cached 5 min
registry.cfg	Resolved catalog / schema / volume
registry.volume_read	VolumeFileService.list_directory on the registry volume
registry.volume_write	Write + delete of a sentinel file via the Files API
registry.uc_schema_ddl	CREATE OR REPLACE VIEW … AS SELECT 1 + DROP VIEW
lakebase	init_status() with fine-grained warning/error mapping
lakebase.permissions	Schema USAGE/CREATE, table DML, sequence grants

• /health/detailed retired; its information is included in the unified response.
• HTTP 200 is intentional even when status: error — load-balancers should inspect summary.errors.

Settings → Health tab

• Admin-only tab calls GET /health on open (lazy-load) and on Refresh.
• KPI tiles (Total / Passed / Warnings / Errors) + sortable table (errors → warnings → ok) with status icon, label, name, detail (long details collapse into <details>), and per-check duration badge.

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Mapping Diagnostics — source table permissions

• New third accordion section Source table permissions probes every distinct UC table referenced by the mapping with SELECT * FROM … LIMIT 0.
• Classifies warehouse errors as PERMISSION_DENIED, TABLE_OR_VIEW_NOT_FOUND, SCHEMA_NOT_FOUND, CATALOG_NOT_FOUND, or "Probe failed".
• When no warehouse client is available (local dev without PAT), returns a warning advisory row so the section explains the gap rather than appearing broken.
• Global KPI tiles at the top of Mapping Diagnostics now include permission check results.
• 23 new tests in test_mapping_service.py.

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Knowledge Graph

• Right-click Expand neighbours: new context-menu entry on any non-cluster node. Fetches the N-hop induced subgraph via GET /dtwin/neighbors, de-duplicates against existing results, highlights newly-added nodes for 6 s, and frames the camera around them. Default depth reads the current slider value.
• Non-blocking expand spinner (#sgExpandSpinner): replaces the blocking "Expanding…" toast; positioned top-right over the canvas with pointer-events: none.
• Depth slider default lowered from 3 to 2.
• KG preview / expand hardening:
  • _fetchWithTimeout with AbortController applied to preview and expand requests — users see a clear timeout message instead of an indefinite spinner.
  • find_seed_subjects now accepts an optional limit so the API requests at most max_preview + 1 subjects, avoiding unbounded scans.
  • In Apps mode: expansion depth capped to 3, max entities capped to 3000, triple fetch batched (250 subjects/batch), 40 s time budget returning partial results rather than failing.
  • 502 error path now shows an actionable message ("reduce Depth / Max entities and retry").
  • _parseJsonResponse safely handles non-JSON upstream errors that previously caused Unexpected token 'u'.

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Deployment & Infrastructure

Single source of truth

• scripts/deploy.config.sh (new): one file for app names, DAB target, warehouse ID, registry coords, Lakebase project/branch/database, and app.yaml runtime fallbacks. Four sections; DEFAULT_* block at the top so changing a default is a one-line edit.
• app.yaml.template (new): app.yaml is now generated by scripts/_render-app-yaml.py from the template and config. app.yaml added to .gitignore.
• deploy.sh sources deploy.config.sh before doing anything; prints a config summary before validation; accepts --skip-app-yaml and --no-bootstrap.
• Makefile slimmed: removed hard-coded APP_NAME variable; deploy* targets just call deploy.sh; new make render-app-yaml target.
• databricks.yml app name unified to ontobricks-030 (was ontobricks-020 in the DAB resource but ontobricks-030 in the Makefile — now consistent everywhere).
• bootstrap-app-permissions.sh and bootstrap-lakebase-perms.sh read APP_NAME / MCP_APP_NAME from env with documented override patterns; bootstrap-app-permissions.sh automatically grants CAN_USE from the MCP SP to the main app.
• bootstrap-lakebase-perms.sh gains --branch support for branch-accurate grant targeting.
• Post-deploy resource-binding verification for both apps (warehouse, volume, postgres branch/database on lakebase targets).

Dependency / startup hardening

• requirements.txt reduced to uv + pydantic-settings>=2.1.0 bootstrap + -e ".[lakebase]" editable install so pyproject.toml remains the single source of Python dependencies.
• docs/ and *.md excluded from Databricks bundle sync via .databricksignore and databricks.yml sync exclusions.
• Credential helpers (get_databricks_client, get_databricks_host_and_token, resolve_warehouse_id) now accept domain=None via _domain_databricks() helper — fixes /health warehouse probe crash.
• 4 new regression tests in test_helpers.py for the domain=None safety contract.

Scripts cleanup

• Deleted orphaned scripts/run_tests.sh and scripts/test_UI.sh (superseded by make test).
• Deleted stale tests/reports/ artifacts (2026-02-25 snapshots when the suite was 306 tests).

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CloudFetch

• DatabricksAuth initially disabled CloudFetch unconditionally in Apps mode to fix a Connection refused crash on the *.storage.cloud.databricks.com storage host.
• Replaced with a runtime capability probe (probe_cloud_fetch_capability()) that issues a bounded SELECT 1 with use_cloud_fetch=True and caches the (capable, reason) outcome for ~5 minutes. can_use_cloud_fetch() reads the cached verdict; get_sql_connection_params() sets the flag accordingly.
• cloud_fetch_status(force=False) for diagnostic callers.
• /health probe databricks.cloudfetch calls the real probe and surfaces the actual outcome.
• New Settings → Global → "Enable CloudFetch for SQL queries" toggle persisted via GlobalConfigService; propagated to DatabricksClient and DatabricksAuth through a new resolve_use_cloud_fetch helper.
• DATABRICKS_DISABLE_CLOUD_FETCH / DATABRICKS_FORCE_CLOUD_FETCH env vars for CI isolation.

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Lakebase connection resilience

• TCP keepalives added to LakebaseAuth.kwargs() / conninfo(): keepalives_idle=10, keepalives_interval=5, keepalives_count=3. Zombie sockets now surface in ~25 s instead of ~130 s.
• Stale cache on Lakebase failure: GlobalConfigService.load() now returns the previously-cached config (up to 30-minute stale window) instead of falling back to _empty() on a blip. _CACHE_TTL bumped from 60 s → 300 s.
• Cohort preview() wrapped in a 60 s AbortController budget with a clear "Preview timed out" message.

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Documentation

• docs/cohort_discovery.md (new) — mental model, 5-section UX walkthrough, output destinations, persistence in both registry backends, 6-stage algorithm summary, 4 worked examples, API summary, Stage 2 walkthrough.
• docs/deployment.md — updated for deploy.config.sh, app.yaml.template, Lakebase --branch bootstrap, and the real /health probe payload.
• docs/development.md — TestHealthRoutes row updated; /health/detailed retirement noted.
• docs/user-guide.md — "Right-click on a node (Expand neighbours)" section added.
• README.md — new bullet for cohort discovery + right-click expand.

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Upgrade notes

• App name: the dev sandbox is now ontobricks-030 in all tooling (databricks.yml, deploy.config.sh, scripts/bootstrap-*.sh, Makefile). Update any scripts or docs that still reference ontobricks-020.
• app.yaml is generated: do not edit it directly — it is gitignored. Edit app.yaml.template and run make render-app-yaml (or make deploy, which runs the renderer automatically). Commit app.yaml.template and scripts/deploy.config.sh instead.
• deploy.config.sh required: scripts/deploy.sh aborts if the config file is missing. Copy scripts/deploy.config.sh.example and fill in your workspace values before the first deploy on a new checkout.
• Cohort predicate migration: graphs that hold the old global <base>/inCohort membership triples (v0.3.0-dev only — the feature was never deployed externally) will not be cleaned up by a re-materialise with the new rule-scoped predicate. Run DELETE FROM … WHERE predicate = '<base>/inCohort' manually before re-running Materialise.
• /health/detailed removed: external probes that hit /health/detailed should switch to GET /health and inspect status + summary.errors. The route returns 404.
• make test: scripts/run_tests.sh and scripts/test_UI.sh are deleted — use make test or uv run pytest directly.
• Lakebase bootstrap: bootstrap-lakebase-perms.sh now accepts --branch <branch> to target the correct Lakebase branch endpoint. Pass LAKEBASE_BOOTSTRAP_BRANCH via env or let deploy.sh handle it automatically.