domainspec-instrument-otel

Imported from Zezolas2798/stackblitz-starters-lvhktmos (domainspec/.claude/skills/domainspec-instrument-otel/SKILL.md). Install upstream with npx skills add Zezolas2798/stackblitz-starters-lvhktmos --skill domainspec-instrument-otel. Copyright stays with the author.

Outputs:

• Modified use-case and infrastructure files with OTel metric recording
• Optional feature-specific instrument file at backend/src/infrastructure/telemetry/{feature}.ts
• Compilation verification via tsc --noEmit

import {
  operationInvocation,
  operationDuration,
} from "../../infrastructure/telemetry/instruments";

export const myOperation =
  (deps: Deps) =>
  async (input: Input): Promise<Output> => {
    const start = performance.now();
    try {
      // ... original logic ...
      operationInvocation.add(1, {
        feature: "my-feature",
        operation: "MyOperation",
        result: "success",
      });
      return result;
    } catch (err) {
      operationInvocation.add(1, {
        feature: "my-feature",
        operation: "MyOperation",
        result: "error",
      });
      throw err;
    } finally {
      operationDuration.record((performance.now() - start) / 1000, {
        feature: "my-feature",
        operation: "MyOperation",
      });
    }
  };

O5: Rule violation (catch at use-case boundary)

import { ruleViolation } from "../../infrastructure/telemetry/instruments";

// In the catch block or validation result check:
ruleViolation.add(1, {
  feature: "my-feature",
  operation: "MyOperation",
  rule_id: "R1",
});

O1: State transition (after successful transition)

import { stateTransition } from "../../infrastructure/telemetry/instruments";

stateTransition.add(1, {
  feature: "my-feature",
  entity: "MyEntity",
  from: previousState,
  to: newState,
  event: "EventName",
});

O10: Event emission (after event is dispatched)

import { eventEmit } from "../../infrastructure/telemetry/instruments";

eventEmit.add(1, { feature: "my-feature", event_type: "MyEvent" });

O13: Business KPI (feature-specific counter)

// In backend/src/infrastructure/telemetry/my-feature.ts
import { createCounter } from "./instruments";

export const businessMyKpi = createCounter("business.my_kpi", {
  unit: "{unit}",
  description: "What this KPI measures (O13)",
});