diff --git a/src/servers/sidecar/claude/claude-manager.ts b/src/servers/sidecar/claude/claude-manager.ts
index f76f397e..391fab58 100644
--- a/src/servers/sidecar/claude/claude-manager.ts
+++ b/src/servers/sidecar/claude/claude-manager.ts
@@ -1,4 +1,4 @@
-import { existsSync } from 'node:fs';
+import { closeSync, existsSync, openSync, readSync, readdirSync, statSync } from 'node:fs';
 import { spawn } from 'node:child_process';
 import { homedir } from 'node:os';
 import { join } from 'node:path';
@@ -543,6 +543,19 @@ function createSession(
   const cleanEnv = envWithoutParentSession();
 
   const resumeId = getClaudeSession(sessionKey, params.userId) ?? params.resumeSessionId;
+  /*
+    Where that transcript actually lives, because `--resume` is scoped to the WORKING DIRECTORY.
+
+    Claude Code files transcripts per cwd (`~/.claude/projects/<slugged path>/<id>.jsonl`), so resuming
+    from a different directory fails with "No conversation found with session ID" — exit 1, before any
+    output. Conversations created before the New Chat directory picker carry no cwd, fall back to
+    HOST_HOME, and could therefore NEVER resume: every message died the same way, and the exit line said
+    `stderr=<silent>` while the CLI had printed the reason.
+
+    The transcript knows its own directory — every line carries `cwd` — so it is read from the file
+    rather than guessed. An explicit cwd from the caller still wins; this only fills the gap.
+  */
+  const resumeCwd = resumeId && !params.cwd ? cwdOfTranscript(resumeId) : undefined;
   const subModel = params.model?.split('/')[1];
   session.resumeId = resumeId;
   session.model = params.model;
@@ -559,7 +572,7 @@ function createSession(
    * disagree, and only this line can show that they have.
    */
   console.log(
-    `[claude:spawn:${sessionKey}] resume=${resumeId ?? 'none'} cwd=${params.cwd ?? 'default'} ` +
+    `[claude:spawn:${sessionKey}] resume=${resumeId ?? 'none'} cwd=${params.cwd ?? resumeCwd ?? 'default'} ` +
       `as=${params.member?.osUser ?? 'owner'} model=${params.model ?? 'default'}`,
   );
 
@@ -572,7 +585,7 @@ function createSession(
     options: {
       // HOST_HOME is this process's home — the owner's. Defaulting a member's turn to it would start them in
       // a directory they cannot read, and the failure would look like a broken agent rather than a wrong cwd.
-      cwd: params.cwd ?? params.member?.home ?? HOST_HOME,
+      cwd: params.cwd ?? resumeCwd ?? params.member?.home ?? HOST_HOME,
       // `bypassPermissions` unless the conversation opened in plan mode. CLAUDE.md is explicit that the
       // unsandboxed default is deliberate — this is the owner's own machine — so plan mode is the only
       // thing that may ever move it, and it moves back the moment a plan is approved.
@@ -904,6 +917,49 @@ const QUESTION_ANSWER_TIMEOUT_MS = 20 * 60 * 1000;
  * returned here is the harness's permission answer, so every path out of it must resolve — a throw or a
  * forgotten branch is a wedged turn, and the symptom would be a chat that shows a plan and then nothing.
  */
+/**
+ * The working directory a transcript belongs to, read from the transcript itself.
+ *
+ * `--resume` only finds a session when the process starts in the directory it was recorded in, and the
+ * id alone does not say which that is. Every line of a transcript carries its own `cwd`, so the file
+ * answers the question — no path-slug decoding, which is lossy the moment a directory name contains a
+ * dash.
+ *
+ * Only the FIRST line is read. These files reach 100 MB (one on this machine already has), and the
+ * answer is in the first few hundred bytes.
+ *
+ * The same id can exist under two project directories when a checkout has moved — `…/officerdev/platform`
+ * and `…/officer-dev/platform` both hold one here. The newest wins, and a directory that no longer
+ * exists is skipped, because resuming into a path that is gone fails exactly the way this is fixing.
+ */
+function cwdOfTranscript(sessionId: string): string | undefined {
+  try {
+    const root = join(homedir(), '.claude', 'projects');
+    const candidates = readdirSync(root)
+      .map((dir) => join(root, dir, `${sessionId}.jsonl`))
+      .filter((file) => existsSync(file))
+      .map((file) => ({ file, at: statSync(file).mtimeMs }))
+      .sort((a, b) => b.at - a.at);
+
+    for (const { file } of candidates) {
+      const fd = openSync(file, 'r');
+      try {
+        const buf = Buffer.alloc(8192);
+        const read = readSync(fd, buf, 0, buf.length, 0);
+        const line = buf.subarray(0, read).toString('utf8').split('\n')[0];
+        const cwd: unknown = line ? (JSON.parse(line) as { cwd?: unknown }).cwd : undefined;
+        if (typeof cwd === 'string' && cwd && existsSync(cwd)) return cwd;
+      } finally {
+        closeSync(fd);
+      }
+    }
+  } catch {
+    // A missing projects dir, an unreadable file, a first line that is not JSON — all mean "no answer",
+    // and the caller falls back to the default cwd exactly as it did before this existed.
+  }
+  return undefined;
+}
+
 async function planGate(
   session: PersistentSession,
   toolInput: Record<string, unknown>,