Signals

Verified against commit 942a18727c on 2026-09-26 (UTC). Re-verify: git grep -n "Map\(Get\|Post\|Group\)(\|AddHostedService" -- src/Signals/StellaOps.Signals and ls src/Signals/__Libraries/StellaOps.Signals.Persistence/Migrations.

Service rows (host project, image, database and role, compose file, bundle presence, Doctor registration) are generated in docs/architecture/service-inventory.md; where this page and the inventory differ, the inventory is authoritative.

Purpose

Signals is the reachability and runtime-evidence service. It ingests and serves call graphs, reachability facts, runtime facts, unknown symbols, execution evidence and verification beacons, receives SCM and CI webhooks, owns the unified-score API and its history, and publishes reachability-fact change events.

Deployables

Libraries composed by the host: StellaOps.Signals.Persistence and StellaOps.Signals.EvidenceWeightedScore (under src/Signals/__Libraries/). StellaOps.Signals.Ebpf exists in the solution but no production host composes it (see architecture.md). StellaOps.Signals.Scheduler and StellaOps.Signals.RuntimeAgent are withdrawn (below).

Database

• Own database stellaops_signals, schema signals (src/Signals/__Libraries/StellaOps.Signals.Persistence/SignalsSchemaTopology.cs).
• Connection: STELLAOPS_POSTGRES_SIGNALS_CONNECTION (key Postgres:Signals:ConnectionString). No shared-connection fallback; the bundle fails closed when the variable is unset.
• Migrations: src/Signals/__Libraries/StellaOps.Signals.Persistence/Migrations/ (001 to 005), applied on startup by AddSignalsPersistence (AddStartupMigrations).

API surface

Withdrawn 2026-09-27 (SPRINT_20260927_003 PCD-44). The never-served MVC controllers HotSymbolsController (/api/v1/signals/hot-symbols*), RuntimeAgentController and RuntimeFactsController (/api/v1/agents*), the unknowns rescan worker and StellaOps.Signals.Scheduler are withdrawn to src/__Obsoleted/Signals/. Their routes answer 404. The unknowns rescan schedule the worker was meant to act on was retired on 2026-09-29 (below).

Withdrawn 2026-09-29 (SPRINT_20260928_001 PCD-159). The StellaOps.Signals.RuntimeAgent library and its tests, referenced by no deploying host, are frozen at src/__Obsoleted/Signals/. Its EventPipe agent never collected events. Runtime facts arrive over POST /signals/runtime-facts.

Route and scope detail: architecture.md and the generated api-reference.md.

Configuration

Root section Signals (Options/SignalsOptions.cs): Authority, Storage, AirGap, Scoring, Cache, Events, OpenApi, Retention, Scm; separate sections Signals:UnknownsScoring, Signals:UnknownsDecay, Signals:ExecutionEvidence, Signals:Beacon. Environment variables use the SIGNALS_ prefix. Optional YAML files ../etc/signals.yaml and signals.yaml are read relative to the content root; the sample is devops/etc/signals.yaml.sample.

Installation posture replication: Catalog:Replication:EnvironmentState (Enabled, FeedBaseAddress, AuthTenant, AuthMode) enables the drain of Platform’s environment-state catalog into Signals’ own database (Hosting/SignalsPostureReplication.cs). The release bundle on this commit does not set it; see the posture note in architecture.md.

Doctor checks

doctor.signals.database.own-database-cutover, doctor.signals.schema.table-census, doctor.signals.persistence.local-harness-escape-hatch, doctor.signals.retention.overdue-rows (StellaOps.Signals/Doctor/), plus the standard service checks. Registered only when the Signals connection resolves.

The endpoint requires ops.health and nothing else. The Doctor policy never includes resource-server default scopes, so no signals:* scope is combined into it. Signals accepts the estate audience stellaops in addition to api://signals, including when a deployment lists only api://signals. Platform’s Doctor aggregation pull authenticates as stellaops-platform-doctor, whose tokens carry audience stellaops and scope ops.health, so the pull reaches the checks. Before SPRINT_20260926_002 PCD-4 the same pull was refused with 401 (audience) and, once past that, 403 (default scopes).

Retired predecessors

• The unknowns rescan schedule (nextScheduledRescan, rescanAttempts, lastRescanResult, the three rescan-cadence scoring options and their columns): retired by 006_v1_signals_retire_unknowns_rescan_schedule.sql (SPRINT_20260928_001 PCD-158, owner ruling of 2026-09-29). Nothing acted on it.
• signals.graph_metrics and its view high_centrality_nodes: retired by 005_v1_signals_retire_graph_metrics.sql (RFC-12, owner ruling Q-40). The unknowns centrality factor is reported as unavailable.
• Eight baseline tables with no production writer: retired by 003_v1_signals_retire_unused_tables.sql (RFC-12).
• The pre-window connection keys (ConnectionStrings:Signals, Signals:Postgres:ConnectionString and their environment forms): no longer read (SPRINT_20260722_020 W3-06).

Subordinate documents