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Design
oto — System Design ProposalDomain Research: Prometheus Alertmanager + Slackoto — Red-Team Memooto — SCOPE BOUNDARY (the doctrine)oto — BINDING SPECIFICATION v1
ADRs
0001 — PostgreSQL is the sole datastore; River is the job queue0002 — `internal/<domain>/{api,service,repository,domain}` with three model sets0003 — Alert, AlertOccurrence and AlertEvent are three distinct entities0004 — oto owns alert identity; Alertmanager's fingerprint is recomputed, not trusted0005 — A durable group key, and the AlertGroup generation owns the Slack thread0006 — The Alertmanager API v2 reconciler is mandatory, not optional0007 — Webhook response contract: 202 or 503. Never 4xx, never 429.0008 — Slack: `chat.update` in place is primary; threads are secondary; one colour attachment0009 — Rule definitions are snapshotted and versioned at fire time0010 — Server-Sent Events with durable resume, not WebSocket0011 — Validation is seven layers with two opposite trust models0012 — Pastel product chrome, saturated colour reserved exclusively for state0013 — oto is alert-first: the Flight Recorder Test defines the scope boundary0014 — Postgres is the only store; no TSDB or column store in v10015 — No stream processor; River in Postgres is the pipeline0016 — Cluster context arrives via MCP, on demand; never the Kubernetes event firehose0017 — Alertmanager-style matchers, not CEL; and a filter AST that keeps the door open0018 — Slack distribution: a customer-built internal app, credentials in config0019 — MIT licence0020 — Broadcast the transitions that must be seen0021 — Correctness and testing strategy0022 — Length-prefixed identity pre-images0023 — Terminal thread states are decided first, and the send is three phases0024 — Retention defaults, what each boundary destroys, and cold storage0025 — The alert list resolves rule snapshots in a batch, not per row0026 — `refire_grace` and the flap thresholds, derived from a real rule corpus0027 — Delivery drills: a synthetic alert through the real pipeline, and the mark that keeps it out of the numbers0028 — Non-urgency motion: one-shot events, honest activity loops, and nothing else0029 — Type and radius scales, read off the product rather than drawn for it0030 — Tier A repainted as Washi & Ink / Konshi Sutra; accent moves to beni0031 — Sharp corners and higher-contrast grid lines within Washi & Ink; colours unchanged0032 — Dark-theme accent moves from beni to plum-blossom blue-and-white; light untouched0033 — The alert filters are a toolbar above the table, not a panel in the rail0034 — Notifications is a destination, and the record it keeps is readable0035 — Decorative ink as a masked wash: one primitive, four motifs, and the placements it is refused0036 — AlertOccurrence becomes AlertCase, and `case` is argued against FR-1 by name0037 — A Wording is Liquid, and the structure around it stays oto's0038 — The group key is derived from the alert's own labels0039 — Group close stays activity-driven0040 — A Case is `open` or `closed`, and it is never reopened0041 — The Alert/Case allocation, and the one rule that decides it0042 — Storm damping is removed, because the defence was built before its object0043 — The Slack action row renders five elements, and the fifth is the snooze pair0044 — A count condition is a silence the operator asked for, and `below_threshold` is how oto says so0045 — A Case is a conversation, and one Slack thread per alert is the accepted cost0046 — Corners round again: ADR 0031's radius override is reversed0047 — A channel answers to a connection, and Slack gets two scopes back0048 — A Wording is spelled by its channel, and the marks in between are oto's0049 — A Wording is selected by its own clause, not by a route0050 — A NotificationTemplate is one whole message, and its policy says which one0051 — A `raw` template owns the whole message, and a template may carry its replies0052 — An Incident is drawn over Cases, and its response is handed off0053 — An Investigator reads, proposes, and never decides delivery0054 — A Remedy earns the write path0055 — An incident-tool integration is data or a bridge, never code inside oto0056 — A Case the upstream stopped speaking about expires, and says why
Setup
Configuration referenceReaching an incident tool: the envelope, a mapping, or a bridgeInvestigatorsRemediesConnecting oto to SlackThe live Slack verification runTuning otoConnecting oto to VictoriaMetrics (vmalert)The generic webhook and `oto.notification.v1`
Runbooks
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Alert search — optional partial/substring matching on alert names

This is not a metric page like the rest of this directory — it is a one-time, operator-run, fully optional SQL snippet. oto never runs it itself and never requires it.

What this closes

Section titled “What this closes”

?q= free-text alert search always runs a full-text query (websearch_to_tsquery) over alertname, annotations->>'summary' and annotations->>'description', backed by the alerts_text_idx GIN index (db/migrations/00007_alerts.sql). That gets you negation (-word), phrase search ("exact phrase") and OR (word1 OR word2) for free, but it cannot do one specific thing: real alert names are often PascalCase compound identifiers with no word boundaries — CheckoutErrorRateHigh is an actual value from a test fixture — and Postgres’s text-search parser tokenizes that as one lexeme. No tsquery variant can ever substring-match “error” inside it; tsquery matches whole lexemes, never fragments of one.

pg_trgm (trigram similarity, which is what accelerates ILIKE '%...%') is the tool for exactly that gap. Enabling it lets alert search also match alertname ILIKE '%error%' against CheckoutErrorRateHigh.

Why oto does not do this for you

Section titled “Why oto does not do this for you”

internal/platform/migrate runs oto’s own migrations, all-or-nothing: any one step failing fails the whole oto migrate run. Attempting CREATE EXTENSION pg_trgm there would hard-fail startup on any managed Postgres that does not permit extensions — the exact failure mode ADR 0014 rejected TimescaleDB over. pg_trgm is far more widely available than TimescaleDB (it ships in Postgres’s own contrib), but the reasoning still holds: a migration oto controls must never bet the boot sequence on a privilege the operator may not have granted.

Instead, oto detects the capability with a single privilege-free query — SELECT EXISTS(SELECT 1 FROM pg_extension WHERE extname = 'pg_trgm'), readable by any connected role, no elevated grant needed (internal/platform/db/capabilities.go, TrigramAvailable). It runs once at process startup and is cached for the process lifetime. The result is threaded into alerts/repository.AlertRepository (which branches ?q= on it) and surfaced on GET /api/v1/me as search.partial_match_enabled, so the UI can tell whether to advertise substring search at all.

Enabling it

Section titled “Enabling it”

Run this once, whenever is convenient — it needs no maintenance window:

CREATE EXTENSION IF NOT EXISTS pg_trgm;
CREATE INDEX CONCURRENTLY IF NOT EXISTS alerts_alertname_trgm_idx ON alerts USING GIN (alertname gin_trgm_ops);
  • Safe to run on any Postgres that permits extensions at all — a fresh install, an existing one, a managed service that allows pg_trgm (most do; it is a standard contrib module, unlike TimescaleDB).
  • oto picks it up automatically at the next process restart — the check runs once at boot, not on a timer.
  • If you enable the extension but skip the index (or CREATE INDEX CONCURRENTLY is still building), search still works correctly — the ILIKE '%...%' clause just runs as an unindexed sequential scan on alertname instead of an index scan, which is slower but not wrong.
  • Disabling it later (DROP EXTENSION pg_trgm) is equally safe: the next restart’s detector reports false again and search falls back to the tsquery-only clause, exactly as it behaved before you opted in.