feat(observability): honor an OpenTelemetry kill switch in the environment

[yordis]

• A machine that turns telemetry off for every other process on it expects one more process to join in without being told twice. T3 Code kept exporting anyway, because OTEL_SDK_DISABLED is only read inside the Effect library's layerFromConfig, and T3 Code builds each exporter explicitly instead.
• Inheriting OTEL_SDK_DISABLED from a shell profile is common, so T3 Code's own name is read first. Without a name of its own the only way to get T3 Code's telemetry back would be to unset a variable the rest of the machine depends on.
• The specification recognizes only the string true and forbids implementations from extending that, so OTEL_SDK_DISABLED=1 has to leave export running. It also asks for a warning when that happens, because a value being read as the opposite of what it looks like is the whole hazard of these variables. T3 Code's own name is not bound by that and accepts the same values as every other T3CODE_* boolean.
• The server and the desktop main process are separate producers, and a switch that stopped only one of them would be the more confusing half of a feature.
• Carved out of feat(observability): honor the standard OTEL_* environment variables #12621, which is the same reader grown to the rest of the standard variables. This part stands alone: it decides nothing about endpoints, so it needs no precedence rules and makes no new egress decision.

Summary by CodeRabbit

• New Features

  • Added environment-variable controls to disable OpenTelemetry exports across desktop, server, and WSL processes.
  • Added support for T3CODE_OTEL_SDK_DISABLED, which takes precedence over OTEL_SDK_DISABLED.
  • When disabled, configured OTLP endpoints are ignored.

• Bug Fixes

  • Ensured telemetry disablement is consistently propagated across WSL boundaries.
  • Added startup warnings for unsupported or invalid switch values.

• Documentation

  • Documented supported values, precedence rules, and behavior of the observability kill switches.

[macroscopeapp]

Approvability

Verdict: Not approved

Macroscope's review found this PR not approvable — This PR adds a cross-cutting environment-controlled kill switch that changes existing server and desktop telemetry export behavior and propagates across the WSL boundary. It also introduces static-analysis suppression directives, warranting human review.

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📥 Commits

Reviewing files that changed from the base of the PR and between 1de563c and ab2824a.

📒 Files selected for processing (17)

• apps/desktop/src/app/DesktopObservability.test.ts
• apps/desktop/src/app/DesktopObservability.ts
• apps/desktop/src/backend/DesktopBackendConfiguration.test.ts
• apps/desktop/src/backend/DesktopBackendConfiguration.ts
• apps/server/src/bin.test.ts
• apps/server/src/cli/config.test.ts
• apps/server/src/cli/config.ts
• apps/server/src/cli/pair.ts
• apps/server/src/config.ts
• apps/server/src/environment/ServerEnvironment.test.ts
• apps/server/src/observability/Layers/Observability.ts
• apps/server/src/server.test.ts
• apps/server/src/serverLogger.test.ts
• docs/operations/observability.md
• packages/shared/package.json
• packages/shared/src/otelEnvironment.test.ts
• packages/shared/src/otelEnvironment.ts

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📝 Walkthrough

Walkthrough

The pull request adds shared OpenTelemetry kill-switch parsing. Server and desktop endpoint resolution now honor the disabled state, log parsing warnings, forward the variables through WSL, and include test coverage and operational documentation.

Changes

OpenTelemetry export kill switch

Layer / File(s)	Summary
Shared OpenTelemetry environment loader packages/shared/src/otelEnvironment.ts, packages/shared/src/otelEnvironment.test.ts, packages/shared/package.json	The shared module reads T3CODE_OTEL_SDK_DISABLED and OTEL_SDK_DISABLED, applies precedence and boolean parsing rules, returns warnings, and exposes the new module entry point.
Server configuration and observability integration apps/server/src/config.ts, apps/server/src/cli/config.ts, apps/server/src/observability/Layers/Observability.ts, apps/server/src/cli/pair.ts, apps/server/src/*test.ts	Server configuration stores the resolved OpenTelemetry environment. Disabled environments omit OTLP endpoints. Observability logs warnings. Pairing and test configurations provide OtelEnvironment.none.
Desktop export suppression and WSL propagation apps/desktop/src/app/DesktopObservability.ts, apps/desktop/src/app/DesktopObservability.test.ts, apps/desktop/src/backend/DesktopBackendConfiguration.ts, apps/desktop/src/backend/DesktopBackendConfiguration.test.ts, docs/operations/observability.md	Desktop endpoint resolution omits all OTLP endpoints when disabled. WSL forwards both kill-switch variables. Tests and documentation cover precedence, accepted values, warnings, and persisted endpoint handling.

Priority: ⬇️ Low

Estimated code review effort: 4 (Complex) | ~45 minutes

Change: Feature

Sequence Diagram(s)

sequenceDiagram
  participant Environment
  participant ServerConfig
  participant ObservabilityLive
  participant OTLPExporter
  Environment->>ServerConfig: Provide OpenTelemetry kill-switch variables
  ServerConfig->>ServerConfig: Resolve disabled state and OTLP URLs
  ServerConfig->>ObservabilityLive: Provide otelEnvironment and endpoints
  ObservabilityLive->>ObservabilityLive: Log warnings
  ObservabilityLive-->>OTLPExporter: Configure enabled or omitted exports

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Suggested reviewers: juliusmarminge, t3dotgg

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Description check	⚠️ Warning	The description explains the motivation and key behavior, but it does not follow the required template. It omits the What Changed and Why headings and the Checklist section.	Rewrite the description using the required What Changed, Why, and Checklist sections. Include the checklist items and state that UI Changes are not applicable, or remove that section as permitted by the template.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 1…
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title clearly and concisely describes the primary change: support for an OpenTelemetry environment kill switch.

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[macroscopeapp]

All clear

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[macroscopeapp]

All clear

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[yordis]

@juliusmarminge send the 🐶 doggy out!