Windows: set %ProgramData%/%ALLUSERSPROFILE% so spawned ssh/scp work under Claude Desktop (fixes #10)

CHANGELOG.md

@@ -15,6 +15,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Verified after the bumps: full suite green, `npm ci` reproducible from the lockfile, and the real server answers `initialize` and `tools/list` correctly over STDIO.
 
 ### Fixed
+- **Windows/Claude Desktop: every SSH command failed with exit 255 (fixes #10)**: Claude Desktop launches the extension with a stripped, allow-listed environment that omits `%ProgramData%` and `%ALLUSERSPROFILE%`. Win32-OpenSSH resolves `%ProgramData%` at startup to locate its global config (`%ProgramData%\ssh\`) and exits 255 **before producing any output** when it is unset — so every spawned `ssh`/`scp` failed with empty stdout/stderr while the identical command succeeded from a normal shell. Both spawn paths were affected: key-auth hosts get no env override and inherit `process.env` implicitly, and password hosts spread a `process.env` that is itself missing the variable. Both variables are now normalized once at module load, Windows only. Reported by @Krolikfarm with an environment bisection, independently reproduced by @pa-bmundt, and contributed by @pa-bmundt.
+  - The fallback derives from `%SystemDrive%` instead of hardcoding `C:`, so a Windows install on another drive still gets a valid path (`SystemDrive` is one of the variables Claude Desktop does pass through), and tolerates a trailing separator.
 - **Multi-alias hosts (fixes #12)**: A host declared under several aliases (`Host docker-lxc hlab`) was unreachable under *any* of its names. `ssh-config@5` returns a plain string for a single-token value but an array of token objects (`{val, separator, quoted}`) once a directive carries more than one token; `extractHostsFromConfig` stored that array in `alias` verbatim, so every strict comparison downstream (`_assertKnownHostAlias`, `getHostInfo`, `getPasswordForHost`, `getAllKnownHosts`) compared a string against an array and never matched. The host was listed by `listKnownHosts` but rejected by the known-host gate before `ssh` was ever spawned. ssh-config values are now normalized once at parse time: `alias` keeps the first alias (output shape unchanged), a new `aliases` field carries the full list, and matching goes through a shared `hostMatchesAlias()` helper. Contributed by @badigit.
 - **Wildcard blocks with negations**: `Host * !bastion` was emitted as a connectable host if it carried a `HostName`. The old `section.value !== '*'` check could not match a multi-token value, which is an array. Blocks consisting only of wildcards and negated patterns are now skipped as the defaults blocks they are.
 - **Multi-token directives**: `ProxyCommand`, `SendEnv`, `IPQoS` and friends were surfaced in `listKnownHosts` output as arrays of token objects instead of readable strings. They are now flattened.

server.mjs

@@ -27,6 +27,25 @@ const execFileAsync = promisify(execFile);
 
 const isWindows = process.platform === 'win32';
 
+// Windows + Claude Desktop: extensions are launched with a stripped, allow-listed
+// environment that omits %ProgramData% and %ALLUSERSPROFILE%. Win32-OpenSSH needs
+// %ProgramData% to locate its global config (%ProgramData%\ssh\) at startup and
+// exits 255 with no output before it produces anything when the variable is unset,
+// which makes every spawned ssh/scp fail. Normalize the vars once at module load so
+// every spawned child inherits them. See issue #10.
+if (isWindows) {
+  if (!process.env.ProgramData) {
+    // Derive the last-resort default from %SystemDrive% rather than hardcoding
+    // C:, so a Windows install on another drive still gets a valid path.
+    // SystemDrive is part of the environment Claude Desktop does pass through.
+    const systemDrive = (process.env.SystemDrive || 'C:').replace(/[\\/]+$/, '');
+    process.env.ProgramData = process.env.ALLUSERSPROFILE || `${systemDrive}\\ProgramData`;
+  }
+  if (!process.env.ALLUSERSPROFILE) {
+    process.env.ALLUSERSPROFILE = process.env.ProgramData;
+  }
+}
+
 // Resolve an executable's absolute path on Windows by walking PATH and PATHEXT.
 // This lets us call spawn() with shell:false on Windows — without it we would
 // need shell:true to find ssh.exe/scp.exe via PATH, which would route every

server.test.mjs

@@ -33,10 +33,19 @@ import { SSHConfigParser, SSHClient, main, SSH_BIN, SCP_BIN } from './server.mjs
 // Without this, ~14 tests silently assert POSIX-only behaviour (chmod 600
 // checks, the /bin/sh askpass helper, `detached`, a bare 'ssh' argv[0]) and fail
 // when the suite runs on Windows.
+// Variables server.mjs writes to process.env at import time (the Windows
+// ProgramData normalization). They are always saved and restored, whether or not
+// a test overrides them — otherwise the first Windows-flavoured import leaks its
+// mutation into every later test and makes those branches look covered when
+// nothing asserted them.
+const ENV_MUTATED_AT_IMPORT = ['ProgramData', 'ALLUSERSPROFILE'];
+
 async function loadServerAs(platform, envOverrides = {}) {
   const realPlatform = Object.getOwnPropertyDescriptor(process, 'platform');
   const realEnv = {};
 
+  for (const key of ENV_MUTATED_AT_IMPORT) realEnv[key] = process.env[key];
+
   for (const [key, value] of Object.entries(envOverrides)) {
     realEnv[key] = process.env[key];
     if (value === undefined) delete process.env[key];
@@ -51,10 +60,16 @@ async function loadServerAs(platform, envOverrides = {}) {
     // resetModules re-runs the vi.mock factory, so these are new spies — not the
     // ones bound by the static import above.
     const fs = await import('fs/promises');
-    return { ...server, fs };
+    // Snapshot the variables the module writes at import time. The finally block
+    // below restores process.env immediately, so a test that wants to assert on
+    // the normalization has to read it from here.
+    const envAfterImport = Object.fromEntries(
+      ENV_MUTATED_AT_IMPORT.map(key => [key, process.env[key]])
+    );
+    return { ...server, fs, envAfterImport };
   } finally {
     Object.defineProperty(process, 'platform', realPlatform);
-    for (const key of Object.keys(envOverrides)) {
+    for (const key of new Set([...ENV_MUTATED_AT_IMPORT, ...Object.keys(envOverrides)])) {
       if (realEnv[key] === undefined) delete process.env[key];
       else process.env[key] = realEnv[key];
     }
@@ -1852,3 +1867,116 @@ describe('output truncation', () => {
     expect(markers).toHaveLength(1);
   });
 });
+
+// =============================================================================
+// Windows ProgramData normalization (issue #10)
+//
+// Claude Desktop launches the extension with a stripped, allow-listed
+// environment that omits %ProgramData%. Win32-OpenSSH resolves it at startup to
+// find its global config (%ProgramData%\ssh\) and exits 255 with no output when
+// it is unset, so every spawned ssh/scp fails while the same command works from
+// a normal shell. server.mjs restores the variable at import time; these tests
+// pin that behaviour, including that it stays out of the way on POSIX.
+// =============================================================================
+
+describe('Windows ProgramData normalization', () => {
+  it('should default ProgramData and ALLUSERSPROFILE when both are missing', async () => {
+    const win = await loadServerAs('win32', {
+      ProgramData: undefined,
+      ALLUSERSPROFILE: undefined,
+      SystemDrive: 'C:',
+    });
+
+    expect(win.envAfterImport.ProgramData).toBe('C:\\ProgramData');
+    expect(win.envAfterImport.ALLUSERSPROFILE).toBe('C:\\ProgramData');
+  });
+
+  it('should derive the default from %SystemDrive% rather than hardcoding C:', async () => {
+    const win = await loadServerAs('win32', {
+      ProgramData: undefined,
+      ALLUSERSPROFILE: undefined,
+      SystemDrive: 'D:',
+    });
+
+    expect(win.envAfterImport.ProgramData).toBe('D:\\ProgramData');
+  });
+
+  it('should tolerate a %SystemDrive% that carries a trailing separator', async () => {
+    const win = await loadServerAs('win32', {
+      ProgramData: undefined,
+      ALLUSERSPROFILE: undefined,
+      SystemDrive: 'E:\\',
+    });
+
+    expect(win.envAfterImport.ProgramData).toBe('E:\\ProgramData');
+  });
+
+  it('should fall back to C: when %SystemDrive% is missing too', async () => {
+    const win = await loadServerAs('win32', {
+      ProgramData: undefined,
+      ALLUSERSPROFILE: undefined,
+      SystemDrive: undefined,
+    });
+
+    expect(win.envAfterImport.ProgramData).toBe('C:\\ProgramData');
+  });
+
+  it('should prefer an existing ALLUSERSPROFILE over the drive-based default', async () => {
+    const win = await loadServerAs('win32', {
+      ProgramData: undefined,
+      ALLUSERSPROFILE: 'X:\\CustomProgramData',
+    });
+
+    expect(win.envAfterImport.ProgramData).toBe('X:\\CustomProgramData');
+  });
+
+  it('should leave an already-set ProgramData untouched and backfill ALLUSERSPROFILE', async () => {
+    const win = await loadServerAs('win32', {
+      ProgramData: 'Q:\\Existing',
+      ALLUSERSPROFILE: undefined,
+    });
+
+    expect(win.envAfterImport.ProgramData).toBe('Q:\\Existing');
+    expect(win.envAfterImport.ALLUSERSPROFILE).toBe('Q:\\Existing');
+  });
+
+  it('should not touch either variable when both are already set', async () => {
+    const win = await loadServerAs('win32', {
+      ProgramData: 'Q:\\Existing',
+      ALLUSERSPROFILE: 'R:\\Other',
+    });
+
+    expect(win.envAfterImport.ProgramData).toBe('Q:\\Existing');
+    expect(win.envAfterImport.ALLUSERSPROFILE).toBe('R:\\Other');
+  });
+
+  it('should not invent the variables on POSIX', async () => {
+    const posix = await loadServerAs('linux', {
+      ProgramData: undefined,
+      ALLUSERSPROFILE: undefined,
+    });
+
+    expect(posix.envAfterImport.ProgramData).toBeUndefined();
+    expect(posix.envAfterImport.ALLUSERSPROFILE).toBeUndefined();
+  });
+
+  it('should reach the spawned ssh process through the inherited environment', async () => {
+    // The whole point of issue #10: key-auth hosts get no env override, so the
+    // child inherits process.env and must find ProgramData there.
+    const win = await loadServerAs('win32', {
+      ProgramData: undefined,
+      ALLUSERSPROFILE: undefined,
+      SystemDrive: 'C:',
+    });
+    const client = new win.SSHClient();
+    win.fs.readFile.mockResolvedValue(`Host test\n    HostName 1.2.3.4\n`);
+    client._spawn = createMockSpawn({ stdout: 'ok\n', code: 0 });
+
+    await client.runRemoteCommand('test', 'echo ok');
+
+    // No password -> no explicit env, so the child inherits the parent's, which
+    // the import-time normalization has already repaired.
+    expect(client._spawn.mock.calls[0][2].env).toBeUndefined();
+    expect(win.envAfterImport.ProgramData).toBe('C:\\ProgramData');
+  });
+});