diff --git a/docs/crash-reports.md b/docs/crash-reports.md
index adcd00c4..a9c22bb8 100644
--- a/docs/crash-reports.md
+++ b/docs/crash-reports.md
@@ -12,6 +12,33 @@ Coverage limits: a Windows unhandled-exception filter attempts a fixed, allocati
 
 For manual UI validation, run the executable with `--crash-report-preview`. This generates a clearly synthetic report and opens the popup without initializing the game, setup, Steam or assets. Check Copy report, clipboard text, Open folder, saved UTF-8 text and Close. Static tests do not validate desktop presentation.
 
+## Mixed-worktree dependency in f96be1d (2026-09-09)
+
+The DownTown report at tick1020 repeats the nonfinite walking result before
+the swept-line rejection. The full local stderr retains the finite GroundJob
+and tiny surface components omitted from the bounded report.
+
+The matching shipped PDB establishes that `movement_velocity/math.rs` was
+compiled from worktree `8186`, with SHA-256
+`4652072df4a51a6bf8eb2dd837e61d4fb6e01710d984334af8073deb4c4449ac`.
+That source lacks the earlier subnormal refinement fix. The intended source
+in this worktree has SHA-256
+`76de0780adb5ea015c57fa4118105669f1897ef01eafb611eed14cc829c5eda1`.
+The game build ID identified the game crate, but did not establish the identity
+of reused path dependencies. Matching EXE/PDB GUIDs alone did not catch this.
+
+`tools/build_verified_windows.ps1` now builds into a private
+`target/verified-windows` under the current worktree. Its verification step
+reads PDB source checksums and requires both current-worktree paths and matching
+SHA-256 for referenced project crates and vendored Bevy sources. It fails closed
+when required game/core/data source records are missing. The old shipped PDB
+fails this check (619 mismatched path/checksum entries).
+
+Use this build script for subsequent crash-test builds and retain its
+`source-checks.json` with the staged EXE/PDB and existing import/hash manifest.
+Do not share Cargo artifact directories between independently edited worktrees.
+This repair changes build provenance, not gameplay rules or collision validation.
+
 ## Walking velocity convergence (2026-09-09)
 
 Observed user failure: clean revision `dff672a`, build timestamp
diff --git a/tools/build_verified_windows.ps1 b/tools/build_verified_windows.ps1
new file mode 100644
index 00000000..4ac15539
--- /dev/null
+++ b/tools/build_verified_windows.ps1
@@ -0,0 +1,19 @@
+param([Parameter(Mandatory=$true)][string]$OutputDirectory)
+$ErrorActionPreference = 'Stop'
+$sourceRoot = Split-Path -Parent $PSScriptRoot
+$outputPath = [IO.Path]::GetFullPath($OutputDirectory)
+if (Test-Path -LiteralPath $outputPath) { throw "Build output already exists: $outputPath" }
+New-Item -ItemType Directory -Path $outputPath | Out-Null
+# Never share path-dependency artifacts between concurrently edited worktrees.
+$targetPath = Join-Path $sourceRoot 'target/verified-windows'
+$previousFlags = $env:CARGO_TARGET_X86_64_PC_WINDOWS_MSVC_RUSTFLAGS
+Push-Location $sourceRoot
+try {
+    $env:CARGO_TARGET_X86_64_PC_WINDOWS_MSVC_RUSTFLAGS = '-C target-feature=+crt-static'
+    cargo rustc --release --locked --target x86_64-pc-windows-msvc --target-dir $targetPath -p skate-game --bin skate3rust --no-default-features -- -C extra-filename= -o "$outputPath/skate3rust.exe" -C "link-arg=/PDB:$outputPath/skate3rust.pdb" *> "$outputPath/compile.log"
+    if ($LASTEXITCODE -ne 0) { Get-Content "$outputPath/compile.log" -Tail 40; throw 'Game build failed' }
+    & "$PSScriptRoot/verify_windows_build_sources.ps1" -Pdb "$outputPath/skate3rust.pdb" -SourceRoot $sourceRoot -ReportPath "$outputPath/source-checks.json"
+} finally {
+    $env:CARGO_TARGET_X86_64_PC_WINDOWS_MSVC_RUSTFLAGS = $previousFlags
+    Pop-Location
+}
diff --git a/tools/verify_windows_build_sources.ps1 b/tools/verify_windows_build_sources.ps1
new file mode 100644
index 00000000..9907d992
--- /dev/null
+++ b/tools/verify_windows_build_sources.ps1
@@ -0,0 +1,40 @@
+param(
+    [Parameter(Mandatory=$true)][string]$Pdb,
+    [string]$SourceRoot = (Split-Path -Parent $PSScriptRoot),
+    [string]$ReportPath
+)
+$ErrorActionPreference = 'Stop'
+$sourcePrefix = [IO.Path]::GetFullPath($SourceRoot).TrimEnd('\', '/') + '\'
+$pdbutil = Join-Path $env:ProgramFiles 'LLVM/bin/llvm-pdbutil.exe'
+$dump = & $pdbutil dump --files $Pdb
+if ($LASTEXITCODE -ne 0) { throw 'PDB source inspection failed' }
+$checked = @{}
+$failures = [Collections.Generic.List[string]]::new()
+foreach ($line in $dump) {
+    if ($line -notmatch '^- \(SHA-256: ([0-9A-Fa-f]{64})\) (.+)$') { continue }
+    $compiledHash = $Matches[1]
+    $compiledPath = $Matches[2].Replace('/', '\')
+    if ($compiledPath -notmatch '\\((?:crates\\skate-[^\\]+|vendor\\bevy_[^\\]+)\\.+)$') { continue }
+    $relative = $Matches[1]
+    $key = "$compiledPath|$compiledHash"
+    if ($checked.ContainsKey($key)) { continue }
+    $expectedPath = Join-Path $sourcePrefix $relative
+    $sourceHash = if (Test-Path -LiteralPath $expectedPath -PathType Leaf) {
+        (Get-FileHash -LiteralPath $expectedPath -Algorithm SHA256).Hash
+    } else { $null }
+    $matchesRoot = $compiledPath.StartsWith($sourcePrefix, [StringComparison]::OrdinalIgnoreCase)
+    $matchesHash = $sourceHash -eq $compiledHash
+    $checked[$key] = [ordered]@{ file=$relative; compiledPath=$compiledPath; compiledSha256=$compiledHash; sourceSha256=$sourceHash; matchesRoot=$matchesRoot; matchesHash=$matchesHash }
+    if (-not $matchesRoot -or -not $matchesHash) { $failures.Add($relative) }
+}
+foreach ($crate in @('skate-core', 'skate-data', 'skate-game')) {
+    if (-not ($checked.Values | Where-Object { $_.file.StartsWith("crates\$crate\") })) {
+        $failures.Add("No source checksums found for $crate")
+    }
+}
+if ($ReportPath) {
+    [ordered]@{ pdb=[IO.Path]::GetFullPath($Pdb); sourceRoot=$sourcePrefix; passed=($failures.Count -eq 0); files=@($checked.Values | Sort-Object file,compiledPath) } |
+        ConvertTo-Json -Depth 5 | Set-Content -LiteralPath $ReportPath -Encoding utf8
+}
+if ($failures.Count) { throw "PDB source provenance failed for $($failures.Count) entries: $(($failures | Select-Object -First 8) -join ', ')" }
+Write-Output "Verified $($checked.Count) workspace source checksums and paths in $Pdb"