feat(observability): honor OTEL_*_EXPORTER=none per signal

[yordis]

• The OpenTelemetry spec defines OTEL_TRACES_EXPORTER, OTEL_METRICS_EXPORTER, and OTEL_LOGS_EXPORTER as the way to turn off one signal, and T3 Code ignored them, so the only way to stop, say, log export was OTEL_SDK_DISABLED, which also stops traces and metrics.
• A machine-wide OTEL_LOGS_EXPORTER=none (common when a collector only accepts some signals) silently had no effect on T3 Code, unlike every other SDK on that machine.
• The spec requires an unrecognized exporter name to warn and be ignored rather than change behavior silently.

Summary by CodeRabbit

• New Features

  • Added support for OTEL exporter settings to selectively enable or disable trace, metric, and log export. The none setting disables only its corresponding signal, while otlp uses the default behavior.
  • Exporter settings are forwarded when running through WSL.

• Documentation

  • Clarified how exporter settings interact with endpoints and how unsupported values are handled.

[macroscopeapp]

Approvability

Verdict: Approved at 7a8b16e

Macroscope's review found this PR approvable — The PR adds a small, operator-controlled per-signal OTEL exporter setting while preserving existing behavior when the settings are absent. Its impact is limited to remote telemetry routing, includes focused coverage for precedence and disabling behavior, and does not alter schemas, deployment, or product defaults.

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ℹ️ Recent review info

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Plan: Advanced

Run ID: c800f8eb-b94a-4a50-ba58-4ad34c0debc7

📥 Commits

Reviewing files that changed from the base of the PR and between 6530de0 and 7a8b16e.

📒 Files selected for processing (4)

• apps/desktop/src/backend/DesktopBackendConfiguration.ts
• docs/operations/observability.md
• packages/shared/src/otelEnvironment.test.ts
• packages/shared/src/otelEnvironment.ts

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📝 Walkthrough

Walkthrough

The OTEL environment loader now supports per-signal exporter settings. A none setting disables its signal, while otlp and endpoint resolution retain the documented behavior. The desktop backend forwards the exporter variables to WSL.

Changes

Per-signal OTEL exporter selection

Layer / File(s)	Summary
Parse exporter settings and resolve signals packages/shared/src/otelEnvironment.ts, packages/shared/src/otelEnvironment.test.ts	The loader parses case-insensitive, comma-separated exporter values for traces, metrics, and logs. none disables the signal before endpoint resolution; otlp takes precedence when both recognized values are present. Tests cover parsing, warnings, and endpoint resolution.
Forward and document exporter settings apps/desktop/src/backend/DesktopBackendConfiguration.ts, docs/operations/observability.md	The desktop backend forwards all three exporter variables to WSL. The observability documentation describes per-signal disabling and exporter defaults.

Priority: ⬇️ Low

Estimated code review effort: 2 (Simple) | ~10 minutes

Change: Feature

Suggested reviewers: juliusmarminge

Merge Risk: ⚪ Minimal · up to 7a8b1

The per-signal exporter behavior appears mergeable after normal checks.

Security Architecture Review

Security architecture risk: 🔵 Low · up to 7a8b1

The change lets operators disable individual telemetry exports without adding a new exporter or destination. It uses an existing configuration boundary, though environment ownership in every deployment has not been verified.

Retained concerns
No architecture-level concerns identified.

Security review details

Security Blast Radius

• inferred — An actor able to set a process’s telemetry environment can now suppress one OTLP signal, including in the WSL child when the desktop forwards that setting. This does not by itself confer control of a new destination.

Security Findings and Attack Paths

• inferred — No PR-introduced privilege escalation or new export sink was established: the same environment boundary already carried endpoint controls and a global disable setting. Who can set that environment in production remains unverified.

Trust Boundaries and Controls

• observed — Exporter names are restricted to otlp and none, while WSL bootstrap authority remains with the desktop launcher. An explicit T3 export URL can still send a signal despite none; that precedence is documented rather than a newly introduced bypass.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Description check	⚠️ Warning	The description clearly explains the problem and motivation, but it omits the required What Changed and Why headings and does not include the checklist. It also does not explicitly summarize the imple…	Add the template sections. Describe the implementation under What Changed, explain the motivation under Why, state that UI Changes are not applicable, and complete the Checklist.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly identifies the main change: per-signal handling of OTEL_*_EXPORTER=none settings.
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 3…
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.

Full details: Description check

Explanation

The description clearly explains the problem and motivation, but it omits the required What Changed and Why headings and does not include the checklist. It also does not explicitly summarize the implementation changes.

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✨ Finishing Touches

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