Practice · Changelog

What Sebrona shipped.

Sebrona s.r.o. was incorporated 22 May 2026. Entries from that date forward are the practice's own ship log. Entries before are founder work that transferred to the practice at incorporation. Kept here with their original ship dates, because the moments work actually shipped are what matters to a procurement reviewer, not the day the legal wrapper landed around them. Curated to ship-relevant work across four active streams: the JARVIS internal lab, the ElektrikPro paying-customer surface, the EU venue-operator pre-launch engagement, and the practice infrastructure that wraps them.

Last updated · 2026-09-21

21 Sept 2026

Practice site · model floor re-verified against current releases and licence files

Every model the site names as part of the practice's stack was re-checked against current vendor releases and against the licence files themselves: Claude Opus 5, Sonnet 5 and Haiku 4.5 hosted; Mistral Small 4 and Qwen3.8-27B on-prem, both Apache 2.0. Only the 27B size of Qwen3.8 is Apache, so the site names the size. The 18 June field note on the Fable 5 withdrawal now carries a dated update on what events overtook. Changelog history and the product pages still state what actually ran.

13 Aug 2026

ElektrikPro · security audit · proposal RPC hardened, RLS baseline in git, headers live

Full audit of the paying-customer surface. The baseline held: row-level security on all eight tables with every policy scoped to auth.uid(), no service-role key in the client, Stripe webhooks HMAC-verified, OTP rate-limited, AI quota enforced server-side. What remained was structural. The public proposal-approval RPC carried a null-token branch that would have let an anonymous caller approve a proposal knowing only its UUID. Latent rather than live, since every proposal row carried a token, and now closed: a token match is required, the column is NOT NULL with a minimum-length CHECK, and two unused public RPCs lost their EXECUTE grants. Supabase security advisors went from 10 lints to 6, all 6 intentional. The RLS policies themselves had only ever existed in the dashboard, so they were transcribed into a migration, and the authorisation boundary is now reviewable and restorable from git. Seven security headers went live on the second attempt. The first deploy shipped none, because an indented comment inside a Cloudflare Pages _headers rule block silently voids the whole block. A curl against production caught it. CSP runs Report-Only for now: the app still has one inline script.

30 Jun 2026

Practice · info@sebrona.com on authenticated mail · DMARC kept at quarantine

Inbound mail for the practice domain routes through Cloudflare Email Routing. Outbound goes through an SMTP relay that signs with two DKIM selectors, published as DNS-only CNAME records. The relay vendor's onboarding suggested relaxing DMARC to p=none. We kept the existing p=quarantine: a policy that only reports does nothing for a recipient deciding whether a message from this domain is real.

28 Jun 2026

Practice site · every route prerendered to static HTML · Worker error 1102 closed

The Worker's CPU budget on our plan is 10 ms per request. At this site's traffic almost every visit lands on a cold isolate, and server-rendering the home page in React on a cold start ran over that budget, so navigations intermittently failed with Cloudflare error 1102 (Worker exceeded resource limits) while static assets, the sitemap and robots.txt stayed up. Every public route is now prerendered to static HTML at build time, one pass per locale, and the Worker serves the prebuilt file by Host header on a render-free path. Anything not prerendered falls back to live SSR, so nothing 404s. Verified in local workerd across both hosts: .com serves EN, .sk serves SK, with the right titles, canonicals and og:locale.

19 Jun 2026

Practice · B2B-distribution case study published · sovereign local AI

Published the second showable case study: custom quoting and procurement software for a CEE B2B distribution operator, with a sovereign local AI on top. A deterministic engine runs the transactional work — best price across vendors, adjustable margins, stock ETAs, demand-based ordering — while a local model grounded in the company's own data via retrieval, on their own hardware, surfaces trends, retunes the system in plain language, reports daily, and answers the team's questions. A frontier model touches only the non-sensitive drafting at the edge. The home page's selected-work card was corrected to the delivered scope and now links straight to the write-up. Client name withheld; figures qualitative under confidentiality.

8 Jun 2026

Practice site · machine-readable layer hardened + baseline security headers

AI assistants and search crawlers read this site without executing JavaScript, so the machine layer got a hardening pass: robots.txt is now rendered per zone by the Worker (each domain advertises only its own sitemap), a plain one-sentence descriptor sits under the hero for content classifiers, blog posts emit BreadcrumbList alongside BlogPosting, and every response carries HSTS, nosniff, Referrer-Policy, and Permissions-Policy headers. Each change verified with a live curl against both zones before close.

7 Jun 2026

Practice · /brief rebuilt as a one-page spec sheet

The engagement brief read as a dense document: the decision facts a buyer actually scans for were buried in prose. It now opens with an at-a-glance panel (based in, engagement length, next opening, capacity, who runs it, languages, model floor, pricing model); the engagement № table stays the centerpiece and the layout prints clean for ⌘P-to-PDF. Every value in the panel restates a fact already on the page. Nothing new is claimed.

29 May 2026

Fleet · Claude Opus 4.8 swapped in everywhere we ran 4.7

Anthropic shipped Opus 4.8 on 28 May at the same price as 4.7. Anthropic reports it is roughly four times less likely to wave its own broken code through. We promoted it across every surface that ran 4.7: JARVIS's hosted routing pool, the model floor in the six-layer reference architecture, and the production agent surfaces. Gated as always on the nightly eval harness greening before sign-off, never on the model card alone. Drop-in: same model-string family (claude-opus-4-8), same price, no contract change for clients. Our full read is in the blog.

25 May 2026

JARVIS · prompt-cache invalidation on tool-schema changes

Adding a new tool to the registry broke the 1-hour cache layer without firing an alert: the tool-definitions block was hashed eagerly, so the cache key matched even when the available tools had changed. Patched the registry loader to emit a cache-bust signal on tool-set changes, with a 5-minute grace window so in-flight conversations drain on their original cache rather than routing to a cold one mid-turn. Hit rate held at 68% across the deploy; no user-visible latency spike.

24 May 2026

ElektrikPro · §69 ods. 12 reverse-charge edge case patched

The construction-services rule (prenesená daňová povinnosť between DPH-payers) was firing on consulting-rate line items because the original heuristic keyed only on the customer's DPH status. Patched with a NACE service-class check (41–43 vs 71.12) before applying §69 ods. 12. Correction invoices backfilled for three accountants in the test cohort whose January quarter touched the bug; test suite expanded with 14 edge cases pulled from their actual line items.

23 May 2026

JARVIS · Claude Opus 4.7 promoted into the production routing pool

Promotion eats one regression up front: a 7-point quality drop on Slovak code-switched dialogue surfaced in the nightly eval pack (240 → 248 instances; 8 new failing cases pulled from real conversation logs). Routing config now pins SK-code-switch traffic to Sonnet 4.6 until the regression closes; cost ledger reflects the per-class shift. Promotion gated on manual sign-off after the harness greens. Never on the model card alone.

22 May 2026

Sebrona s.r.o. incorporated · practice site live

Incorporation registered with the Slovak commercial register (IČO 57 639 272 · OR SR) and the practice surfaces went live the same day: hero, capabilities, selected projects, engagement model (five phases with the fixed-price Diagnostic week), sovereignty position, six-layer reference architecture, build baseline, office, contact. The surfaces the practice opens a conversation with.

16 May 2026

SuperFaktúra two-way sync

Job completion in ElektrikPro fires a draft invoice in SuperFaktúra with materials, labour, and DPH calculated correctly, including §69 ods. 12 reverse-charge cases for construction work between DPH-payers. Reverse webhook flips the job to "uhradené" the moment SuperFaktúra registers payment. Tested against three real accountants' books before ship.

14 May 2026

JARVIS routing layer hits v2

Model selector now picks between Opus 4.7, Sonnet 4.6, and Haiku 4.5 per task class, with Mistral Small 3.2 on Together as the latency-budget fallback. Routing rules live in YAML, every decision logs an OpenTelemetry span, and the cost ledger reconciles back to the routing trace. Representative consulting workload moved 38% cheaper without a measurable quality regression.

13 May 2026

Bookings schema locked with the client team

Three workshops with the venue's ops team to model how their bookings actually flow today. Not how an off-the-shelf PMS would prefer they did. Ten entity types, four state machines, two reporting cuts. The GM and the head of finance signed off the schema before a line of code was written.

12 May 2026

Whisper streaming wired into the JARVIS voice surface

whisper-large-v3-turbo on Groq feeds partials into the agent loop, so tool calls fire mid-utterance for common intents (calendar lookup, customer recall, status check). First-token end-to-end under 380ms on the Slovak audio test set, partials stabilise by word three.

10 May 2026

Pay by Square QR on every invoice

IBAN, variable symbol, amount, and message encoded into a Pay by Square QR rendered on every PDF and HTML invoice. Customer scans once in any Slovak bank app, invoice is paid, no IBAN typing, no wrong variable symbols. Payment-match rate on the test cohort went from 71% to 96%.

9 May 2026

Reference architecture v1.2

Layer responsibilities re-cut after the venue engagement surfaced ambiguity between the orchestration and integration layers. ADR-014 documents the change, the rationale, and the migration that ran on JARVIS.

8 May 2026

Document extraction agent · Slovak PDFs

Layered extraction pipeline for the messy-PDF class we keep seeing: Slovak invoices, ZoZP zápisy, contractor faktúry with scan artifacts. Vision-first when layout matters, layout-aware OCR when text is clean, results pinned against a Pydantic schema, retries once with a stricter prompt on schema failure. 94% field accuracy on our 600-document eval set.

7 May 2026

Asset register imported and reconciled

1,400+ assets imported from three spreadsheets and a legacy Access database, deduplicated against two days of site walkthroughs, re-coded under a single taxonomy. The team has one truth instead of three half-truths, and the maintenance backlog stopped depending on which spreadsheet you opened.

6 May 2026

eKasa-compliant receipt flow

Cash payments route through a certified eKasa virtual register (Bowa integration). One tap on a completed job produces both the eKasa receipt and the matching SuperFaktúra invoice, reference numbers linked, full compliance with Zákon č. 289/2008. The electrician no longer carries two devices.

5 May 2026

JARVIS working-memory layer

Sessions that used to balloon past 80K tokens hold steady around 32K. Active context lives behind prompt-cache breakpoints (5-min and 1-hour), older context demotes to a pgvector store with a small recall agent in front. Recall accuracy verified against a 200-turn synthetic dialogue set before promotion.

2 May 2026

Tool registry refactor

Every internal capability is now an MCP-style tool definition with a JSON Schema and a single handler. Adding a new capability (Outlook lookup, Pohoda export, ETIM lookup) is a YAML entry and a function, not an agent refactor. Cut the time-to-new-tool from an afternoon to under twenty minutes.

30 Apr 2026

Materials catalogue rebuilt against ETIM SK

Catalogue now uses the same ETIM SK product codes wholesalers like Elektro-Centrum, SEZ-Krompachy, and Elektro Haramia already publish. Quotes and invoices reference codes a supplier can fulfil directly. Quote prep on a typical bytový rozvádzač moved from ~25 minutes to under 5.

29 Apr 2026

Closed alpha · internal cohort 1

First cohort of six venue staff running the platform in parallel with the legacy system for two weeks. Daily standups, written change requests, no informal Slack changes. Twelve adjustments folded back into the build, three of them schema-level. Exactly what cohort 1 is for.

28 Apr 2026

Nightly eval harness against routing config

240 task instances across the four classes we sell: extraction, classification, summarisation, agentic action. Runs nightly, blocks deploy on regression. First pass caught a 12-point drop on Slovak summarisation that would have shipped otherwise. Now the deploy gate stops it before main.

24 Apr 2026

Revízna správa templating per STN 33 2000-6

Pre-filled revízna správa templates with measurement fields auto-populated from a tethered Eurotest reader over Bluetooth. The revízny technik signs with KEP, the PDF lands in the customer's inbox within seconds, a copy goes to the archived inspection register. The compliance paperwork stopped being the bottleneck.

22 Apr 2026

Slovak-language eval pack

Public Slovak benchmarks don't cover the domains we actually serve, so we built our own: hospitality bookings, electrical permit prose, invoice line items, ZoZP excerpts. Rankings on extraction: Opus 4.7 first, Sonnet 4.6 within two points, Mistral Small 3.2 surprisingly strong on classification, Haiku 4.5 the budget pick for high-volume routing.

21 Apr 2026

Reporting packs for finance, ops, and leadership

Three pre-built reporting packs, each rendered as a printable PDF and a live dashboard. Finance gets P&L by asset class. Ops gets utilisation and maintenance backlog. Leadership gets the same numbers without having to ask anyone. The "I'll get back to you tomorrow" loop is closed.

20 Apr 2026

Photo-doc coverage check

Every completed job carries a structured photo set: pred, po, závadové miesta, štítok rozvádzača. Haiku 4.5 runs a coverage check and refuses to let the job close if the required shots aren't present. Post-hoc scope disputes dropped to near zero in the cohort that ran it for a month.

18 Apr 2026

Prompt-cache plumbing made explicit

cache_control breakpoints wired into system prompt, retrieved context, and tool definitions: 5-min on conversation state, 1-hour on stable instructions. Hit rate is now 68% on multi-turn sessions in production. Cost dropped roughly proportional; latency dropped more than expected on first-turn time-to-token.

17 Apr 2026

Per-iteration capture pipeline extended to client microsites

The Playwright × three viewports × two themes capture that runs against our own work now runs against client microsites too. Every audit report ships with the screenshots that justified its conclusions, in the same commit, under `.design/`.

15 Apr 2026

Audit log on every mutation

Every write operation logs actor, timestamp, before/after diff, and a 7-year retention matched to the Slovak record-keeping requirements that apply to the client's category. Procurement asked for this in writing before any code was written. They have it.

14 Apr 2026

Monthly accounting export pack

One folder per month for the účtovník: SuperFaktúra invoices, eKasa receipts, materials write-offs, KM log, and a DPH summary mapped to the right boxes of the Slovak VAT return. Drop-in. No follow-up emails. The accountants we tested with asked when it would ship for their other clients.

11 Apr 2026

Cost ledger with Slovak DPH treatment

Per-conversation rollup of input, output, cache reads/writes, and tool calls, aggregated into a monthly statement that maps cleanly onto a Slovak DPH-payer's bookkeeping. Lets us hand clients an exact answer to "what does this workload cost" instead of an estimate.

8 Apr 2026

Pohoda and Kros export added

Customers on legacy accounting tools no longer forced to switch. ElektrikPro now exports to Pohoda (XML) and Kros (CSV) alongside SuperFaktúra. Both formats round-tripped through real accountant test files before shipping. Onboarding objection that came up in five of six discovery calls is now gone.

1 Apr 2026

Multi-fakturant support

Larger firms can run multiple fakturanti under one account, each with their own IBAN, signature image, and number series. Audit log records who issued what, when, and from where. Two five-person companies migrated off shared logins in the first week.

25 Mar 2026

AI quote draft from customer description

Customer descriptions in plain Slovak ("rekonštrukcia 3-izbáku, panelák, hliník na meď, bez zmeny rozvádzača") produce a draft quote with line items priced from the ETIM catalogue. Electrician reviews and ships. The model never sends a quote on its own. It removes the blank-page tax, not the judgement.

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