diff --git a/apps/server/agent/manager.ts b/apps/server/agent/manager.ts
index 152ac3c..0d650de 100644
--- a/apps/server/agent/manager.ts
+++ b/apps/server/agent/manager.ts
@@ -239,8 +239,18 @@ export class MultiProviderAgentManager implements AgentManager {
       log.debug({ alias, initiativeId, baseBranch, branchName }, 'creating initiative-based worktrees');
       agentCwd = await this.processManager.createProjectWorktrees(alias, initiativeId, baseBranch, branchName);
 
-      // Log projects linked to the initiative
+      // Verify each project worktree subdirectory actually exists
       const projects = await this.projectRepository.findProjectsByInitiativeId(initiativeId);
+      for (const project of projects) {
+        const projectWorktreePath = join(agentCwd, project.name);
+        if (!existsSync(projectWorktreePath)) {
+          throw new Error(
+            `Worktree subdirectory missing after createProjectWorktrees: ${projectWorktreePath}. ` +
+            `Agent ${alias} cannot run without an isolated worktree.`
+          );
+        }
+      }
+
       log.info({
         alias,
         initiativeId,
@@ -255,11 +265,12 @@ export class MultiProviderAgentManager implements AgentManager {
     }
 
     // Verify the final agentCwd exists
-    const cwdVerified = existsSync(agentCwd);
+    if (!existsSync(agentCwd)) {
+      throw new Error(`Agent workdir does not exist after creation: ${agentCwd}`);
+    }
     log.info({
       alias,
       agentCwd,
-      cwdVerified,
       initiativeBasedAgent: !!initiativeId
     }, 'agent workdir setup completed');
 
diff --git a/apps/server/dispatch/manager.ts b/apps/server/dispatch/manager.ts
index 4ef2f35..554dff3 100644
--- a/apps/server/dispatch/manager.ts
+++ b/apps/server/dispatch/manager.ts
@@ -327,8 +327,13 @@ export class DefaultDispatchManager implements DispatchManager {
             }
           }
         }
-      } catch {
-        // Non-fatal: fall back to default branching
+      } catch (err) {
+        if (!isPlanningCategory(task.category)) {
+          // Execution tasks MUST have correct branches — fail loudly
+          throw new Error(`Failed to compute branches for execution task ${task.id}: ${err}`);
+        }
+        // Planning tasks: non-fatal, fall back to default branching
+        log.debug({ taskId: task.id, err }, 'branch computation skipped for planning task');
       }
 
       // Ensure branches exist in project clones before spawning worktrees
@@ -350,7 +355,10 @@ export class DefaultDispatchManager implements DispatchManager {
             }
           }
         } catch (err) {
-          log.warn({ taskId: task.id, err }, 'failed to ensure branches for task dispatch');
+          if (!isPlanningCategory(task.category)) {
+            throw new Error(`Failed to ensure branches for execution task ${task.id}: ${err}`);
+          }
+          log.warn({ taskId: task.id, err }, 'failed to ensure branches for planning task dispatch');
         }
       }
     }
diff --git a/docs/agent.md b/docs/agent.md
index 38f55db..15503bf 100644
--- a/docs/agent.md
+++ b/docs/agent.md
@@ -32,7 +32,7 @@
 
 1. **tRPC procedure** calls `agentManager.spawn(options)`
 2. Manager generates alias (adjective-animal), creates DB record. Appends inter-agent communication and preview instructions unless `skipPromptExtras: true` (used by conflict-resolution agents to keep prompts lean).
-3. `AgentProcessManager.createWorktree()` — creates git worktree at `.cw-worktrees/agent/<alias>/`
+3. `AgentProcessManager.createProjectWorktrees()` — creates git worktrees at `agent-workdirs/<alias>/<project>/`. After creation, each project subdirectory is verified to exist; missing worktrees throw immediately to prevent agents running in the wrong directory.
 4. `file-io.writeInputFiles()` — writes `.cw/input/` with assignment files (initiative, pages, phase, task) and read-only context dirs (`context/phases/`, `context/tasks/`)
 5. Provider config builds spawn command via `buildSpawnCommand()`
 6. `spawnDetached()` — launches detached child process with file output redirection
diff --git a/docs/dispatch-events.md b/docs/dispatch-events.md
index d9e336d..7f0ffd6 100644
--- a/docs/dispatch-events.md
+++ b/docs/dispatch-events.md
@@ -69,6 +69,7 @@ InitiativeChangesRequestedEvent { initiativeId, phaseId, taskId }
 7. **Summary propagation** — `completeTask()` reads the completing agent's `result.message` and stores it on the task's `summary` column. Dependent tasks see this summary in `context/tasks/<id>.md` frontmatter.
 8. **Spawn failure** — If `agentManager.spawn()` throws, the task is blocked via `blockTask()` with the error message. The dispatch cycle continues instead of crashing.
 9. **Retry blocked** — `retryBlockedTask(taskId)` resets a blocked task to pending and re-queues it. Exposed via tRPC `retryBlockedTask` mutation. The UI shows a Retry button in the task slide-over when status is `blocked`.
+10. **Branch validation** — Branch computation and `ensureBranch` errors are fatal for execution tasks (execute, verify, merge, review) but non-fatal for planning tasks. This prevents agents from spawning without proper branch isolation.
 
 ### DispatchManager Methods