PDF-Viewer Extension Errors #783

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1. sgilstrap015

   added

   bugSomething isn't workingSomething isn't working

   on Sep 22, 2026
2. tzipora-rose commented on Oct 20, 2026

   

   tzipora-rose

   on Oct 20, 2026

   More actions

   Defect A, the empty allowedDirectories, has three causes. We traced them on Windows with pdf-viewer 2.0.0 and the current desktop app (2.42304.0.0):

   1. The default does reach the server, but unexpanded. The app puts the manifest's default, ${HOME}/Documents, into the arguments as written, without substituting ${HOME}, so the server gets the literal text and drops it. The app's main.log shows it: [pdf-server] Warning: File not found: C:\Users\<user>\${HOME}\Documents. The MCPB manifest spec says a default supports variable substitution, so this one is the app's: [BUG] pdf-viewer opens no local PDF on Windows: roots become C:\C:\..., configured folders are wiped, and ${HOME} in their default is never expanded anthropics/claude-code#103692.
   2. A folder chosen in the setting is wiped. It reaches the server, one argument per folder, and is registered at startup; then refreshRoots() empties the list when the app sends its roots: v1.7.0 refreshRoots() clears allowedLocalDirs when host advertises roots capability but returns empty list — wipes CLI-arg directories #644, with a fix in fix(pdf-server): keep CLI-arg directories across client roots refreshes #805.
   3. The app's roots are dropped. The app does send roots (for a Code session, its folder), but as file:///C:/... URLs, which the server's fileUrlToPath() turns into C:\C:\... and skips: fix(pdf-server): resolve Windows file:// URLs to the right path #816.

   So the list ends up empty whatever the setting holds. Until fixed versions ship, https://github.com/tzipora-rose/pdf-local-read patches the installed extension in place, reversibly.

   Investigated and written in collaboration with Claudia in Claude Code.