diff --git a/docs/ROADMAP.md b/docs/ROADMAP.md
index 92a0e8a..4e585a2 100644
--- a/docs/ROADMAP.md
+++ b/docs/ROADMAP.md
@@ -79,10 +79,8 @@
 
 ## Known Issues
 - `->>` threading macro with nested `map`/`reduce` requires proper macro expansion context
-- REPL definitions are re-compiled from scratch on each evaluation (slow but correct — interpreter path handles most cases in <0.1ms now)
-- ffi/interop examples fail — `sin` symbol not found (Nim module import issue, pre-existing)
 
 ## Recent Bug Fixes (2026-05-08)
+- Fixed: ffi/interop examples — temp files now use isolated subdirectories to avoid shadowing Nim stdlib modules (e.g., `math.nim` shadowing `import math`)
 - Fixed: `quot`/`rem` — added `cljQuot`/`cljRem` to runtime + interpreter support
-- Fixed: `rem` — interpreter and compiled path both now handle `(rem n d)`
 - Cleanup: removed unused `processAgentActions` proc, unused `sequtils` import in repl.nim
diff --git a/src/cljnim.nim b/src/cljnim.nim
index 5fcada9..521f615 100644
--- a/src/cljnim.nim
+++ b/src/cljnim.nim
@@ -111,11 +111,17 @@ proc nimCompile(nimPath: string, binPath: string, release: bool = false): int =
   echo "Compiling: ", cmd
   execCmd(cmd)
 
+proc makeTempDir(): string =
+  let pid = getCurrentProcessId()
+  let ts = epochTime().int
+  result = getTempDir() / "cljnim_build_" & $pid & "_" & $ts
+  createDir(result)
+
 proc runFile*(inputPath: string) =
-  let tmpDir = getTempDir()
   let baseName = inputPath.splitFile.name
-  let nimPath = tmpDir / baseName & "_generated.nim"
-  let binPath = tmpDir / baseName & "_generated"
+  let buildDir = makeTempDir()
+  let nimPath = buildDir / baseName & ".nim"
+  let binPath = buildDir / baseName
 
   # Resolve project dependencies
   let inputDir = inputPath.parentDir
@@ -124,8 +130,9 @@ proc runFile*(inputPath: string) =
   # Check nimcache for cached output
   let projectDir = inputPath.parentDir
   let cacheDir = projectDir / "nimcache"
-  let cacheNimPath = cacheDir / baseName & ".nim"
-  let cacheBinPath = cacheDir / baseName
+  let cacheSubDir = cacheDir / baseName
+  let cacheNimPath = cacheSubDir / baseName & ".nim"
+  let cacheBinPath = cacheSubDir / baseName
 
   var useCache = false
   if fileExists(cacheNimPath) and fileExists(cacheBinPath):
@@ -140,6 +147,7 @@ proc runFile*(inputPath: string) =
     if compileResult != 0:
       stderr.writeLine("Compilation failed (cached)")
       quit(1)
+    try: removeDir(buildDir) except: discard
     let runResult = execCmd(cacheBinPath)
     quit(runResult)
 
@@ -148,11 +156,12 @@ proc runFile*(inputPath: string) =
   let compileResult = nimCompile(nimPath, binPath)
   if compileResult != 0:
     stderr.writeLine("Compilation failed")
+    try: removeDir(buildDir) except: discard
     quit(1)
 
   # Save to cache
   try:
-    createDir(cacheDir)
+    createDir(cacheSubDir)
     copyFile(nimPath, cacheNimPath)
     copyFile(binPath, cacheBinPath)
     echo "Cached: ", cacheNimPath
@@ -160,6 +169,7 @@ proc runFile*(inputPath: string) =
     discard
 
   let runResult = execCmd(binPath)
+  try: removeDir(buildDir) except: discard
   if runResult != 0:
     stderr.writeLine("Execution failed")
     quit(1)
@@ -199,17 +209,19 @@ proc main() =
       stderr.writeLine("Error: Missing expression after -e")
       quit(1)
     let code = args[1]
-    let tmpDir = getTempDir()
-    let nimPath = tmpDir / "cljnim_expr.nim"
-    let binPath = tmpDir / "cljnim_expr"
+    let buildDir = makeTempDir()
+    let nimPath = buildDir / "expr.nim"
+    let binPath = buildDir / "expr"
     let forms = reader.readAll(code)
     let nimCode = emitter.emitProgram(forms)
     writeFile(nimPath, nimCode)
     let compileResult = nimCompile(nimPath, binPath)
     if compileResult != 0:
       stderr.writeLine("Compilation failed")
+      try: removeDir(buildDir) except: discard
       quit(1)
     let runResult = execCmd(binPath)
+    try: removeDir(buildDir) except: discard
     quit(runResult)
   
   case cmd