fix(desktop): detect installed Spectre libs for Windows builds

[juliusmarminge]

Windows desktop artifact builds rejected current Visual Studio Build Tools installs because the preflight required the stale generic Spectre component id. Current VS 2022 Build Tools exposes the selected Spectre libraries under versioned toolset components while still placing the actual libraries under the MSVC toolset directory.

This keeps the C++ tool and Windows SDK checks through vswhere, then validates the Spectre libraries by checking the installed MSVC toolset directory for lib\spectre\. That matches the real installed layout for current Build Tools without weakening the prerequisite guard.

Verified:

• vp run --filter @t3tools/scripts typecheck
• vpr dist:desktop:win --skip-build --keep-stage

Model: GPT-5 Codex
Harness: Codex CLI

---

Note

Low Risk
Build-time prerequisite detection only; no runtime or packaging behavior changes, and Spectre libs are still required via a more accurate filesystem check.

Overview
Fixes Windows desktop build preflight falsely failing on current Visual Studio 2022 Build Tools installs that no longer register the old Spectre workload component IDs in vswhere.

The PowerShell probe in windowsVswherePrerequisiteScript still requires VC toolset and Windows SDK via vswhere, but Spectre is now verified by checking the latest installed MSVC toolset folder for lib\spectre\arm64 or lib\spectre\x64 instead of -requires on deprecated *.Spectre components.

^{Reviewed by Cursor Bugbot for commit 6a07bee. Bugbot is set up for automated code reviews on this repo. Configure here.}

[github-actions]

Thread transfer impact

✅ Thread transfer remains within every enforced ceiling.

Provider	Metric	Main baseline	This PR	Impact	PR ceiling
Codex	Total thread wire	13.3 KiB	13.2 KiB	−48 B (−0.4%)	15.1 KiB	✅
Codex	Thread snapshot wire	6.9 KiB	6.9 KiB	+2 B (+0.0%)	7.3 KiB	✅
Codex	Live turn WebSocket wire	6.4 KiB	6.3 KiB	−50 B (−0.8%)	7.8 KiB	✅
Codex	Live turn WebSocket decoded	55.6 KiB	55.5 KiB	−88 B (−0.2%)	66.4 KiB	✅
Codex	Live turn messages	10	8	−2 (−20.0%)	21	✅
Claude	Total thread wire	13.2 KiB	13.5 KiB	+317 B (+2.4%)	15.1 KiB	✅
Claude	Thread snapshot wire	6.9 KiB	6.9 KiB	+2 B (+0.0%)	7.3 KiB	✅
Claude	Live turn WebSocket wire	6.3 KiB	6.6 KiB	+315 B (+4.9%)	7.8 KiB	✅
Claude	Live turn WebSocket decoded	55.5 KiB	57.8 KiB	+2.3 KiB (+4.2%)	66.4 KiB	✅
Claude	Live turn messages	8	10	+2 (+25.0%)	21	✅

Baseline: 994bd73 · PR result: 6a07bee · Source CI: success

Scenario and decoded snapshot size

10 historical turns, 5 command tools per turn, 878.9 KiB retained MCP result per historical turn, and a 1.05 MiB retained result in the measured turn.

• Codex decoded thread snapshot: 109.4 KiB
• Claude decoded thread snapshot: 110.1 KiB

Updated in place by a trusted workflow. PR artifacts are strictly validated and never executed.

[cursor]

Cursor Bugbot has reviewed your changes using high effort and found 1 potential issue.

^{Bugbot Autofix is ON, but a cloud agent failed to start.}

^{Reviewed by Cursor Bugbot for commit 49d7d46. Configure here.}

[macroscopeapp]

Approvability

Verdict: Would Approve

Macroscope's review found this PR approvable — This is a one-file, build-time Windows prerequisite fix that replaces an obsolete Visual Studio component lookup with an architecture-specific Spectre library check. It does not change shipped product behavior, defaults, APIs, or deployment configuration.

Not approved because:

• Monthly spending limit reached (workspace setting). Approvability relies on correctness review in order to determine eligibility

^{Review your spending limits in Billing settings. You can add or adjust custom eligibility rules. Learn more.}

[juliusmarminge]

Windows desktop artifact builds rejected current Visual Studio Build Tools installs because the preflight required the stale generic Spectre component id. Current VS 2022 Build Tools exposes the selected Spectre libraries under versioned toolset components while still placing the actual libraries under the MSVC toolset directory.

This keeps the C++ tool and Windows SDK checks through vswhere, then validates the Spectre libraries by checking the installed MSVC toolset directory for lib\spectre\. That matches the real installed layout for current Build Tools without weakening the prerequisite guard.

Verified:

• vp run --filter @t3tools/scripts typecheck
• vpr dist:desktop:win --skip-build --keep-stage

Model: GPT-5 Codex
Harness: Codex CLI

---

Note

Low Risk
Build-time prerequisite detection only; no runtime or packaging behavior changes, and Spectre libs are still required via a more accurate filesystem check.

Overview
Fixes Windows desktop build preflight falsely failing on current Visual Studio 2022 Build Tools installs that no longer register the old Spectre workload component IDs in vswhere.

The PowerShell probe in windowsVswherePrerequisiteScript still requires VC toolset and Windows SDK via vswhere, but Spectre is now verified by checking the latest installed MSVC toolset folder for lib\spectre\arm64 or lib\spectre\x64 instead of -requires on deprecated *.Spectre components.

^{Reviewed by Cursor Bugbot for commit 6a07bee. Bugbot is set up for automated code reviews on this repo. Configure here.}

[github-actions]

Thread transfer impact

✅ Thread transfer remains within every enforced ceiling.

Provider	Metric	Main baseline	This PR	Impact	PR ceiling
Codex	Total thread wire	13.3 KiB	13.2 KiB	−48 B (−0.4%)	15.1 KiB	✅
Codex	Thread snapshot wire	6.9 KiB	6.9 KiB	+2 B (+0.0%)	7.3 KiB	✅
Codex	Live turn WebSocket wire	6.4 KiB	6.3 KiB	−50 B (−0.8%)	7.8 KiB	✅
Codex	Live turn WebSocket decoded	55.6 KiB	55.5 KiB	−88 B (−0.2%)	66.4 KiB	✅
Codex	Live turn messages	10	8	−2 (−20.0%)	21	✅
Claude	Total thread wire	13.2 KiB	13.5 KiB	+317 B (+2.4%)	15.1 KiB	✅
Claude	Thread snapshot wire	6.9 KiB	6.9 KiB	+2 B (+0.0%)	7.3 KiB	✅
Claude	Live turn WebSocket wire	6.3 KiB	6.6 KiB	+315 B (+4.9%)	7.8 KiB	✅
Claude	Live turn WebSocket decoded	55.5 KiB	57.8 KiB	+2.3 KiB (+4.2%)	66.4 KiB	✅
Claude	Live turn messages	8	10	+2 (+25.0%)	21	✅

Baseline: 994bd73 · PR result: 6a07bee · Source CI: success

Scenario and decoded snapshot size

10 historical turns, 5 command tools per turn, 878.9 KiB retained MCP result per historical turn, and a 1.05 MiB retained result in the measured turn.

• Codex decoded thread snapshot: 109.4 KiB
• Claude decoded thread snapshot: 110.1 KiB

Updated in place by a trusted workflow. PR artifacts are strictly validated and never executed.

[cursor]

Cursor Bugbot has reviewed your changes using high effort and found 1 potential issue.

^{Bugbot Autofix is ON, but a cloud agent failed to start.}

^{Reviewed by Cursor Bugbot for commit 49d7d46. Configure here.}

[macroscopeapp]

Approvability

Verdict: Would Approve

Macroscope's review found this PR approvable — This is a one-file, build-time Windows prerequisite fix that replaces an obsolete Visual Studio component lookup with an architecture-specific Spectre library check. It does not change shipped product behavior, defaults, APIs, or deployment configuration.

Not approved because:

• Monthly spending limit reached (workspace setting). Approvability relies on correctness review in order to determine eligibility

^{Review your spending limits in Billing settings. You can add or adjust custom eligibility rules. Learn more.}

[juliusmarminge]

Windows desktop artifact builds rejected current Visual Studio Build Tools installs because the preflight required the stale generic Spectre component id. Current VS 2022 Build Tools exposes the selected Spectre libraries under versioned toolset components while still placing the actual libraries under the MSVC toolset directory.

This keeps the C++ tool and Windows SDK checks through vswhere, then validates the Spectre libraries by checking the installed MSVC toolset directory for lib\spectre\. That matches the real installed layout for current Build Tools without weakening the prerequisite guard.

Verified:

• vp run --filter @t3tools/scripts typecheck
• vpr dist:desktop:win --skip-build --keep-stage

Model: GPT-5 Codex
Harness: Codex CLI

---

Note

Low Risk
Build-time prerequisite detection only; no runtime or packaging behavior changes, and Spectre libs are still required via a more accurate filesystem check.

Overview
Fixes Windows desktop build preflight falsely failing on current Visual Studio 2022 Build Tools installs that no longer register the old Spectre workload component IDs in vswhere.

The PowerShell probe in windowsVswherePrerequisiteScript still requires VC toolset and Windows SDK via vswhere, but Spectre is now verified by checking the latest installed MSVC toolset folder for lib\spectre\arm64 or lib\spectre\x64 instead of -requires on deprecated *.Spectre components.

^{Reviewed by Cursor Bugbot for commit 6a07bee. Bugbot is set up for automated code reviews on this repo. Configure here.}

[github-actions]

Thread transfer impact

✅ Thread transfer remains within every enforced ceiling.

Provider	Metric	Main baseline	This PR	Impact	PR ceiling
Codex	Total thread wire	13.3 KiB	13.2 KiB	−48 B (−0.4%)	15.1 KiB	✅
Codex	Thread snapshot wire	6.9 KiB	6.9 KiB	+2 B (+0.0%)	7.3 KiB	✅
Codex	Live turn WebSocket wire	6.4 KiB	6.3 KiB	−50 B (−0.8%)	7.8 KiB	✅
Codex	Live turn WebSocket decoded	55.6 KiB	55.5 KiB	−88 B (−0.2%)	66.4 KiB	✅
Codex	Live turn messages	10	8	−2 (−20.0%)	21	✅
Claude	Total thread wire	13.2 KiB	13.5 KiB	+317 B (+2.4%)	15.1 KiB	✅
Claude	Thread snapshot wire	6.9 KiB	6.9 KiB	+2 B (+0.0%)	7.3 KiB	✅
Claude	Live turn WebSocket wire	6.3 KiB	6.6 KiB	+315 B (+4.9%)	7.8 KiB	✅
Claude	Live turn WebSocket decoded	55.5 KiB	57.8 KiB	+2.3 KiB (+4.2%)	66.4 KiB	✅
Claude	Live turn messages	8	10	+2 (+25.0%)	21	✅

Baseline: 994bd73 · PR result: 6a07bee · Source CI: success

Scenario and decoded snapshot size

10 historical turns, 5 command tools per turn, 878.9 KiB retained MCP result per historical turn, and a 1.05 MiB retained result in the measured turn.

• Codex decoded thread snapshot: 109.4 KiB
• Claude decoded thread snapshot: 110.1 KiB

Updated in place by a trusted workflow. PR artifacts are strictly validated and never executed.

[cursor]

Cursor Bugbot has reviewed your changes using high effort and found 1 potential issue.

^{Bugbot Autofix is ON, but a cloud agent failed to start.}

^{Reviewed by Cursor Bugbot for commit 49d7d46. Configure here.}

[macroscopeapp]

Approvability

Verdict: Would Approve

Macroscope's review found this PR approvable — This is a one-file, build-time Windows prerequisite fix that replaces an obsolete Visual Studio component lookup with an architecture-specific Spectre library check. It does not change shipped product behavior, defaults, APIs, or deployment configuration.

Not approved because:

• Monthly spending limit reached (workspace setting). Approvability relies on correctness review in order to determine eligibility

^{Review your spending limits in Billing settings. You can add or adjust custom eligibility rules. Learn more.}

[juliusmarminge]

Windows desktop artifact builds rejected current Visual Studio Build Tools installs because the preflight required the stale generic Spectre component id. Current VS 2022 Build Tools exposes the selected Spectre libraries under versioned toolset components while still placing the actual libraries under the MSVC toolset directory.

This keeps the C++ tool and Windows SDK checks through vswhere, then validates the Spectre libraries by checking the installed MSVC toolset directory for lib\spectre\. That matches the real installed layout for current Build Tools without weakening the prerequisite guard.

Verified:

• vp run --filter @t3tools/scripts typecheck
• vpr dist:desktop:win --skip-build --keep-stage

Model: GPT-5 Codex
Harness: Codex CLI

---

Note

Low Risk
Build-time prerequisite detection only; no runtime or packaging behavior changes, and Spectre libs are still required via a more accurate filesystem check.

Overview
Fixes Windows desktop build preflight falsely failing on current Visual Studio 2022 Build Tools installs that no longer register the old Spectre workload component IDs in vswhere.

The PowerShell probe in windowsVswherePrerequisiteScript still requires VC toolset and Windows SDK via vswhere, but Spectre is now verified by checking the latest installed MSVC toolset folder for lib\spectre\arm64 or lib\spectre\x64 instead of -requires on deprecated *.Spectre components.

^{Reviewed by Cursor Bugbot for commit 6a07bee. Bugbot is set up for automated code reviews on this repo. Configure here.}

[github-actions]

Thread transfer impact

✅ Thread transfer remains within every enforced ceiling.

Provider	Metric	Main baseline	This PR	Impact	PR ceiling
Codex	Total thread wire	13.3 KiB	13.2 KiB	−48 B (−0.4%)	15.1 KiB	✅
Codex	Thread snapshot wire	6.9 KiB	6.9 KiB	+2 B (+0.0%)	7.3 KiB	✅
Codex	Live turn WebSocket wire	6.4 KiB	6.3 KiB	−50 B (−0.8%)	7.8 KiB	✅
Codex	Live turn WebSocket decoded	55.6 KiB	55.5 KiB	−88 B (−0.2%)	66.4 KiB	✅
Codex	Live turn messages	10	8	−2 (−20.0%)	21	✅
Claude	Total thread wire	13.2 KiB	13.5 KiB	+317 B (+2.4%)	15.1 KiB	✅
Claude	Thread snapshot wire	6.9 KiB	6.9 KiB	+2 B (+0.0%)	7.3 KiB	✅
Claude	Live turn WebSocket wire	6.3 KiB	6.6 KiB	+315 B (+4.9%)	7.8 KiB	✅
Claude	Live turn WebSocket decoded	55.5 KiB	57.8 KiB	+2.3 KiB (+4.2%)	66.4 KiB	✅
Claude	Live turn messages	8	10	+2 (+25.0%)	21	✅

Baseline: 994bd73 · PR result: 6a07bee · Source CI: success

Scenario and decoded snapshot size

10 historical turns, 5 command tools per turn, 878.9 KiB retained MCP result per historical turn, and a 1.05 MiB retained result in the measured turn.

• Codex decoded thread snapshot: 109.4 KiB
• Claude decoded thread snapshot: 110.1 KiB

Updated in place by a trusted workflow. PR artifacts are strictly validated and never executed.

[cursor]

Cursor Bugbot has reviewed your changes using high effort and found 1 potential issue.

^{Bugbot Autofix is ON, but a cloud agent failed to start.}

^{Reviewed by Cursor Bugbot for commit 49d7d46. Configure here.}

[macroscopeapp]

Approvability

Verdict: Would Approve

Macroscope's review found this PR approvable — This is a one-file, build-time Windows prerequisite fix that replaces an obsolete Visual Studio component lookup with an architecture-specific Spectre library check. It does not change shipped product behavior, defaults, APIs, or deployment configuration.

Not approved because:

• Monthly spending limit reached (workspace setting). Approvability relies on correctness review in order to determine eligibility

^{Review your spending limits in Billing settings. You can add or adjust custom eligibility rules. Learn more.}

[juliusmarminge]

Windows desktop artifact builds rejected current Visual Studio Build Tools installs because the preflight required the stale generic Spectre component id. Current VS 2022 Build Tools exposes the selected Spectre libraries under versioned toolset components while still placing the actual libraries under the MSVC toolset directory.

This keeps the C++ tool and Windows SDK checks through vswhere, then validates the Spectre libraries by checking the installed MSVC toolset directory for lib\spectre\. That matches the real installed layout for current Build Tools without weakening the prerequisite guard.

Verified:

• vp run --filter @t3tools/scripts typecheck
• vpr dist:desktop:win --skip-build --keep-stage

Model: GPT-5 Codex
Harness: Codex CLI

---

Note

Low Risk
Build-time prerequisite detection only; no runtime or packaging behavior changes, and Spectre libs are still required via a more accurate filesystem check.

Overview
Fixes Windows desktop build preflight falsely failing on current Visual Studio 2022 Build Tools installs that no longer register the old Spectre workload component IDs in vswhere.

The PowerShell probe in windowsVswherePrerequisiteScript still requires VC toolset and Windows SDK via vswhere, but Spectre is now verified by checking the latest installed MSVC toolset folder for lib\spectre\arm64 or lib\spectre\x64 instead of -requires on deprecated *.Spectre components.

^{Reviewed by Cursor Bugbot for commit 6a07bee. Bugbot is set up for automated code reviews on this repo. Configure here.}

[github-actions]

Thread transfer impact

✅ Thread transfer remains within every enforced ceiling.

Provider	Metric	Main baseline	This PR	Impact	PR ceiling
Codex	Total thread wire	13.3 KiB	13.2 KiB	−48 B (−0.4%)	15.1 KiB	✅
Codex	Thread snapshot wire	6.9 KiB	6.9 KiB	+2 B (+0.0%)	7.3 KiB	✅
Codex	Live turn WebSocket wire	6.4 KiB	6.3 KiB	−50 B (−0.8%)	7.8 KiB	✅
Codex	Live turn WebSocket decoded	55.6 KiB	55.5 KiB	−88 B (−0.2%)	66.4 KiB	✅
Codex	Live turn messages	10	8	−2 (−20.0%)	21	✅
Claude	Total thread wire	13.2 KiB	13.5 KiB	+317 B (+2.4%)	15.1 KiB	✅
Claude	Thread snapshot wire	6.9 KiB	6.9 KiB	+2 B (+0.0%)	7.3 KiB	✅
Claude	Live turn WebSocket wire	6.3 KiB	6.6 KiB	+315 B (+4.9%)	7.8 KiB	✅
Claude	Live turn WebSocket decoded	55.5 KiB	57.8 KiB	+2.3 KiB (+4.2%)	66.4 KiB	✅
Claude	Live turn messages	8	10	+2 (+25.0%)	21	✅

Baseline: 994bd73 · PR result: 6a07bee · Source CI: success

Scenario and decoded snapshot size

10 historical turns, 5 command tools per turn, 878.9 KiB retained MCP result per historical turn, and a 1.05 MiB retained result in the measured turn.

• Codex decoded thread snapshot: 109.4 KiB
• Claude decoded thread snapshot: 110.1 KiB

Updated in place by a trusted workflow. PR artifacts are strictly validated and never executed.

[cursor]

Cursor Bugbot has reviewed your changes using high effort and found 1 potential issue.

^{Bugbot Autofix is ON, but a cloud agent failed to start.}

^{Reviewed by Cursor Bugbot for commit 49d7d46. Configure here.}

[macroscopeapp]

Approvability

Verdict: Would Approve

Macroscope's review found this PR approvable — This is a one-file, build-time Windows prerequisite fix that replaces an obsolete Visual Studio component lookup with an architecture-specific Spectre library check. It does not change shipped product behavior, defaults, APIs, or deployment configuration.

Not approved because:

• Monthly spending limit reached (workspace setting). Approvability relies on correctness review in order to determine eligibility

^{Review your spending limits in Billing settings. You can add or adjust custom eligibility rules. Learn more.}

[juliusmarminge]

Windows desktop artifact builds rejected current Visual Studio Build Tools installs because the preflight required the stale generic Spectre component id. Current VS 2022 Build Tools exposes the selected Spectre libraries under versioned toolset components while still placing the actual libraries under the MSVC toolset directory.

This keeps the C++ tool and Windows SDK checks through vswhere, then validates the Spectre libraries by checking the installed MSVC toolset directory for lib\spectre\. That matches the real installed layout for current Build Tools without weakening the prerequisite guard.

Verified:

• vp run --filter @t3tools/scripts typecheck
• vpr dist:desktop:win --skip-build --keep-stage

Model: GPT-5 Codex
Harness: Codex CLI

---

Note

Low Risk
Build-time prerequisite detection only; no runtime or packaging behavior changes, and Spectre libs are still required via a more accurate filesystem check.

Overview
Fixes Windows desktop build preflight falsely failing on current Visual Studio 2022 Build Tools installs that no longer register the old Spectre workload component IDs in vswhere.

The PowerShell probe in windowsVswherePrerequisiteScript still requires VC toolset and Windows SDK via vswhere, but Spectre is now verified by checking the latest installed MSVC toolset folder for lib\spectre\arm64 or lib\spectre\x64 instead of -requires on deprecated *.Spectre components.

^{Reviewed by Cursor Bugbot for commit 6a07bee. Bugbot is set up for automated code reviews on this repo. Configure here.}

[github-actions]

Thread transfer impact

✅ Thread transfer remains within every enforced ceiling.

Provider	Metric	Main baseline	This PR	Impact	PR ceiling
Codex	Total thread wire	13.3 KiB	13.2 KiB	−48 B (−0.4%)	15.1 KiB	✅
Codex	Thread snapshot wire	6.9 KiB	6.9 KiB	+2 B (+0.0%)	7.3 KiB	✅
Codex	Live turn WebSocket wire	6.4 KiB	6.3 KiB	−50 B (−0.8%)	7.8 KiB	✅
Codex	Live turn WebSocket decoded	55.6 KiB	55.5 KiB	−88 B (−0.2%)	66.4 KiB	✅
Codex	Live turn messages	10	8	−2 (−20.0%)	21	✅
Claude	Total thread wire	13.2 KiB	13.5 KiB	+317 B (+2.4%)	15.1 KiB	✅
Claude	Thread snapshot wire	6.9 KiB	6.9 KiB	+2 B (+0.0%)	7.3 KiB	✅
Claude	Live turn WebSocket wire	6.3 KiB	6.6 KiB	+315 B (+4.9%)	7.8 KiB	✅
Claude	Live turn WebSocket decoded	55.5 KiB	57.8 KiB	+2.3 KiB (+4.2%)	66.4 KiB	✅
Claude	Live turn messages	8	10	+2 (+25.0%)	21	✅

Baseline: 994bd73 · PR result: 6a07bee · Source CI: success

Scenario and decoded snapshot size

10 historical turns, 5 command tools per turn, 878.9 KiB retained MCP result per historical turn, and a 1.05 MiB retained result in the measured turn.

• Codex decoded thread snapshot: 109.4 KiB
• Claude decoded thread snapshot: 110.1 KiB

Updated in place by a trusted workflow. PR artifacts are strictly validated and never executed.

[cursor]

Cursor Bugbot has reviewed your changes using high effort and found 1 potential issue.

^{Bugbot Autofix is ON, but a cloud agent failed to start.}

^{Reviewed by Cursor Bugbot for commit 49d7d46. Configure here.}

[macroscopeapp]

Approvability

Verdict: Would Approve

Macroscope's review found this PR approvable — This is a one-file, build-time Windows prerequisite fix that replaces an obsolete Visual Studio component lookup with an architecture-specific Spectre library check. It does not change shipped product behavior, defaults, APIs, or deployment configuration.

Not approved because:

• Monthly spending limit reached (workspace setting). Approvability relies on correctness review in order to determine eligibility

^{Review your spending limits in Billing settings. You can add or adjust custom eligibility rules. Learn more.}

[juliusmarminge]

Windows desktop artifact builds rejected current Visual Studio Build Tools installs because the preflight required the stale generic Spectre component id. Current VS 2022 Build Tools exposes the selected Spectre libraries under versioned toolset components while still placing the actual libraries under the MSVC toolset directory.

This keeps the C++ tool and Windows SDK checks through vswhere, then validates the Spectre libraries by checking the installed MSVC toolset directory for lib\spectre\. That matches the real installed layout for current Build Tools without weakening the prerequisite guard.

Verified:

• vp run --filter @t3tools/scripts typecheck
• vpr dist:desktop:win --skip-build --keep-stage

Model: GPT-5 Codex
Harness: Codex CLI

---

Note

Low Risk
Build-time prerequisite detection only; no runtime or packaging behavior changes, and Spectre libs are still required via a more accurate filesystem check.

Overview
Fixes Windows desktop build preflight falsely failing on current Visual Studio 2022 Build Tools installs that no longer register the old Spectre workload component IDs in vswhere.

The PowerShell probe in windowsVswherePrerequisiteScript still requires VC toolset and Windows SDK via vswhere, but Spectre is now verified by checking the latest installed MSVC toolset folder for lib\spectre\arm64 or lib\spectre\x64 instead of -requires on deprecated *.Spectre components.

^{Reviewed by Cursor Bugbot for commit 6a07bee. Bugbot is set up for automated code reviews on this repo. Configure here.}

[github-actions]

Thread transfer impact

✅ Thread transfer remains within every enforced ceiling.

Provider	Metric	Main baseline	This PR	Impact	PR ceiling
Codex	Total thread wire	13.3 KiB	13.2 KiB	−48 B (−0.4%)	15.1 KiB	✅
Codex	Thread snapshot wire	6.9 KiB	6.9 KiB	+2 B (+0.0%)	7.3 KiB	✅
Codex	Live turn WebSocket wire	6.4 KiB	6.3 KiB	−50 B (−0.8%)	7.8 KiB	✅
Codex	Live turn WebSocket decoded	55.6 KiB	55.5 KiB	−88 B (−0.2%)	66.4 KiB	✅
Codex	Live turn messages	10	8	−2 (−20.0%)	21	✅
Claude	Total thread wire	13.2 KiB	13.5 KiB	+317 B (+2.4%)	15.1 KiB	✅
Claude	Thread snapshot wire	6.9 KiB	6.9 KiB	+2 B (+0.0%)	7.3 KiB	✅
Claude	Live turn WebSocket wire	6.3 KiB	6.6 KiB	+315 B (+4.9%)	7.8 KiB	✅
Claude	Live turn WebSocket decoded	55.5 KiB	57.8 KiB	+2.3 KiB (+4.2%)	66.4 KiB	✅
Claude	Live turn messages	8	10	+2 (+25.0%)	21	✅

Baseline: 994bd73 · PR result: 6a07bee · Source CI: success

Scenario and decoded snapshot size

10 historical turns, 5 command tools per turn, 878.9 KiB retained MCP result per historical turn, and a 1.05 MiB retained result in the measured turn.

• Codex decoded thread snapshot: 109.4 KiB
• Claude decoded thread snapshot: 110.1 KiB

Updated in place by a trusted workflow. PR artifacts are strictly validated and never executed.

[cursor]

Cursor Bugbot has reviewed your changes using high effort and found 1 potential issue.

^{Bugbot Autofix is ON, but a cloud agent failed to start.}

^{Reviewed by Cursor Bugbot for commit 49d7d46. Configure here.}

[macroscopeapp]

Approvability

Verdict: Would Approve

Macroscope's review found this PR approvable — This is a one-file, build-time Windows prerequisite fix that replaces an obsolete Visual Studio component lookup with an architecture-specific Spectre library check. It does not change shipped product behavior, defaults, APIs, or deployment configuration.

Not approved because:

• Monthly spending limit reached (workspace setting). Approvability relies on correctness review in order to determine eligibility

^{Review your spending limits in Billing settings. You can add or adjust custom eligibility rules. Learn more.}

[juliusmarminge]

Windows desktop artifact builds rejected current Visual Studio Build Tools installs because the preflight required the stale generic Spectre component id. Current VS 2022 Build Tools exposes the selected Spectre libraries under versioned toolset components while still placing the actual libraries under the MSVC toolset directory.

This keeps the C++ tool and Windows SDK checks through vswhere, then validates the Spectre libraries by checking the installed MSVC toolset directory for lib\spectre\. That matches the real installed layout for current Build Tools without weakening the prerequisite guard.

Verified:

• vp run --filter @t3tools/scripts typecheck
• vpr dist:desktop:win --skip-build --keep-stage

Model: GPT-5 Codex
Harness: Codex CLI

---

Note

Low Risk
Build-time prerequisite detection only; no runtime or packaging behavior changes, and Spectre libs are still required via a more accurate filesystem check.

Overview
Fixes Windows desktop build preflight falsely failing on current Visual Studio 2022 Build Tools installs that no longer register the old Spectre workload component IDs in vswhere.

The PowerShell probe in windowsVswherePrerequisiteScript still requires VC toolset and Windows SDK via vswhere, but Spectre is now verified by checking the latest installed MSVC toolset folder for lib\spectre\arm64 or lib\spectre\x64 instead of -requires on deprecated *.Spectre components.

^{Reviewed by Cursor Bugbot for commit 6a07bee. Bugbot is set up for automated code reviews on this repo. Configure here.}

[github-actions]

Thread transfer impact

✅ Thread transfer remains within every enforced ceiling.

Provider	Metric	Main baseline	This PR	Impact	PR ceiling
Codex	Total thread wire	13.3 KiB	13.2 KiB	−48 B (−0.4%)	15.1 KiB	✅
Codex	Thread snapshot wire	6.9 KiB	6.9 KiB	+2 B (+0.0%)	7.3 KiB	✅
Codex	Live turn WebSocket wire	6.4 KiB	6.3 KiB	−50 B (−0.8%)	7.8 KiB	✅
Codex	Live turn WebSocket decoded	55.6 KiB	55.5 KiB	−88 B (−0.2%)	66.4 KiB	✅
Codex	Live turn messages	10	8	−2 (−20.0%)	21	✅
Claude	Total thread wire	13.2 KiB	13.5 KiB	+317 B (+2.4%)	15.1 KiB	✅
Claude	Thread snapshot wire	6.9 KiB	6.9 KiB	+2 B (+0.0%)	7.3 KiB	✅
Claude	Live turn WebSocket wire	6.3 KiB	6.6 KiB	+315 B (+4.9%)	7.8 KiB	✅
Claude	Live turn WebSocket decoded	55.5 KiB	57.8 KiB	+2.3 KiB (+4.2%)	66.4 KiB	✅
Claude	Live turn messages	8	10	+2 (+25.0%)	21	✅

Baseline: 994bd73 · PR result: 6a07bee · Source CI: success

Scenario and decoded snapshot size

10 historical turns, 5 command tools per turn, 878.9 KiB retained MCP result per historical turn, and a 1.05 MiB retained result in the measured turn.

• Codex decoded thread snapshot: 109.4 KiB
• Claude decoded thread snapshot: 110.1 KiB

Updated in place by a trusted workflow. PR artifacts are strictly validated and never executed.

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Approvability

Verdict: Would Approve

Macroscope's review found this PR approvable — This is a one-file, build-time Windows prerequisite fix that replaces an obsolete Visual Studio component lookup with an architecture-specific Spectre library check. It does not change shipped product behavior, defaults, APIs, or deployment configuration.

Not approved because:

• Monthly spending limit reached (workspace setting). Approvability relies on correctness review in order to determine eligibility

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