Maple Telemetry Conventions

Reference for the language-agnostic OpenTelemetry conventions Maple uses across TypeScript (apps/api, Cloudflare workers in packages/effect-sdk/), Rust (apps/ingest), and future Python services. These conventions are load-bearing — Tinybird materialized views pre-extract certain attribute keys into columns, dashboards filter on Title Case status strings, and sampling-aware throughput math relies on the SampleRate column. Use the exact attribute spellings here in every language.

When to apply

• Adding setAttribute / Effect.annotateCurrentSpan / Span::current().record(...) / #[instrument(fields(...))] to any code path
• Setting span status (Ok / Error / Unset)
• Wiring a new query through WarehouseQueryService.compiledQuery() (the context and profile options become span attributes)
• Configuring an OTLP exporter, tracer provider, or resource builder
• Introducing a new pre-extracted MV column or a new vendor attribute under maple.*
• Reviewing a PR that touches apps/api/src/services/WarehouseQueryService.ts, apps/ingest/src/main.rs, apps/api/src/app.ts, packages/effect-sdk/src/cloudflare/, or packages/domain/src/tinybird/materializations.ts

Index

• rules/span-attributes.md — Master reference of every custom attribute key Maple emits, grouped by namespace, with file:line citations.
• rules/status-and-kind.md — Title Case status code rule (Ok/Error/Unset) and span kind conventions (Server / Client / Internal).
• rules/resource-attributes.md — service.* identity, deployment.environment.name resolution order, the deprecated deployment.environment dual-emit and read-side coalesce, and maple_org_id.
• rules/language-bindings.md — Parallel TypeScript / Rust / Python snippets that emit the same attribute keys.
• rules/mv-first-class-columns.md — Which span and resource attributes Tinybird MVs pre-extract into columns (and the rule for adding new ones).
• rules/service-map-attribution.md — Required span and resource attributes for the service map to render edges, runtime icons, and platform badges. Includes the canonical peer.service registry.
• rules/loop-prevention.md — The three guards that prevent Maple's self-traffic from creating a feedback loop: API TracerDisabledWhen, ingest loopback guard, sampling.

Quick reference

Topic	Rule
Status codes	Always Title Case: "Ok", "Error", "Unset". Never OK, ERROR, SUCCESS, FAILED.
Vendor namespace	Custom attributes go under maple.*. Sub-namespaces: maple.ingest.*, maple.cloudflare.*.
Standard semconv	Use OTel semconv keys verbatim: service.name, http.request.method, db.system.name, error.type.
Org identity	orgId (camelCase) in TypeScript spans, maple.org_id (dotted) in Rust spans. Don't unify until MVs migrate.
Deployment env	Emit deployment.environment.name (we dual-emit the deprecated deployment.environment too). Read both via DEPLOYMENT_ENV_SQL / deploymentEnvExpr — never a bare map lookup.
Warehouse SQL spans	Every span from WarehouseQueryService.executeSql carries db.system.name, peer.service, db.query.text, db.query.fingerprint, db.duration_ms, result.rowCount, orgId, query.context, query.profile. Legacy spans (pre 2026-06) use db.statement*/db.system; warehouse readers coalesce both.
Service map	Outbound spans need peer.service (HTTP/RPC) or db.system.name (DB) on a Client/Producer span. Resource attrs need process.runtime.name, cloud.platform, maple.sdk.type for runtime icon + platform badge. See rules/service-map-attribution.md.
Loop prevention	Never remove HttpMiddleware.TracerDisabledWhen (apps/api/src/app.ts:169-175) or the ingest loopback guard (apps/ingest/src/main.rs:499-514).

Canonical references (do not modify from this skill)

• apps/api/src/services/WarehouseQueryService.ts:441-510 — executeSql span emission (the canonical example for TS).
• apps/ingest/src/otel.rs — Resource builder + platform detection + forward-span helper for Rust. The canonical example for Rust resource and outbound-span attribution.
• apps/ingest/src/main.rs — handle_signal and handle_cloudflare_logpush (search for tracing::info_span! with otel.kind = "server") — Server-kind span macros for OTLP inbound.
• apps/api/src/app.ts:169-175 — TracerDisabledWhen filter.
• packages/effect-sdk/src/cloudflare/index.ts — MapleCloudflareSDK tracer setup.
• packages/domain/src/tinybird/materializations.ts — MV SELECT lists that pre-extract attribute keys into columns.