diff --git a/mcp-server/src/tools/reviewTools.ts b/mcp-server/src/tools/reviewTools.ts
index 08293ca4..bf8b6e43 100644
--- a/mcp-server/src/tools/reviewTools.ts
+++ b/mcp-server/src/tools/reviewTools.ts
@@ -2,7 +2,7 @@ import type { FastMCP } from 'fastmcp';
 import { z } from 'zod';
 
 import { getController } from '../controller';
-import { jsonTextContent } from '../utils/format';
+import { jsonTextContent, slimTask } from '../utils/format';
 
 const toolContextSchema = {
   teamName: z.string().min(1),
@@ -23,11 +23,13 @@ export function registerReviewTools(server: Pick<FastMCP, 'addTool'>) {
     execute: async ({ teamName, claudeDir, taskId, from, reviewer, leadSessionId }) =>
       await Promise.resolve(
         jsonTextContent(
-          getController(teamName, claudeDir).review.requestReview(taskId, {
-            ...(from ? { from } : {}),
-            ...(reviewer ? { reviewer } : {}),
-            ...(leadSessionId ? { leadSessionId } : {}),
-          })
+          slimTask(
+            getController(teamName, claudeDir).review.requestReview(taskId, {
+              ...(from ? { from } : {}),
+              ...(reviewer ? { reviewer } : {}),
+              ...(leadSessionId ? { leadSessionId } : {}),
+            }) as Record<string, unknown>
+          )
         )
       ),
   });
@@ -46,12 +48,14 @@ export function registerReviewTools(server: Pick<FastMCP, 'addTool'>) {
     execute: async ({ teamName, claudeDir, taskId, from, note, notifyOwner, leadSessionId }) =>
       await Promise.resolve(
         jsonTextContent(
-          getController(teamName, claudeDir).review.approveReview(taskId, {
-            ...(from ? { from } : {}),
-            ...(note ? { note } : {}),
-            ...(notifyOwner !== false ? { 'notify-owner': true } : {}),
-            ...(leadSessionId ? { leadSessionId } : {}),
-          })
+          slimTask(
+            getController(teamName, claudeDir).review.approveReview(taskId, {
+              ...(from ? { from } : {}),
+              ...(note ? { note } : {}),
+              ...(notifyOwner !== false ? { 'notify-owner': true } : {}),
+              ...(leadSessionId ? { leadSessionId } : {}),
+            }) as Record<string, unknown>
+          )
         )
       ),
   });
@@ -69,11 +73,13 @@ export function registerReviewTools(server: Pick<FastMCP, 'addTool'>) {
     execute: async ({ teamName, claudeDir, taskId, from, comment, leadSessionId }) =>
       await Promise.resolve(
         jsonTextContent(
-          getController(teamName, claudeDir).review.requestChanges(taskId, {
-            ...(from ? { from } : {}),
-            ...(comment ? { comment } : {}),
-            ...(leadSessionId ? { leadSessionId } : {}),
-          })
+          slimTask(
+            getController(teamName, claudeDir).review.requestChanges(taskId, {
+              ...(from ? { from } : {}),
+              ...(comment ? { comment } : {}),
+              ...(leadSessionId ? { leadSessionId } : {}),
+            }) as Record<string, unknown>
+          )
         )
       ),
   });
diff --git a/mcp-server/src/tools/taskTools.ts b/mcp-server/src/tools/taskTools.ts
index a8eae60a..c3f893bc 100644
--- a/mcp-server/src/tools/taskTools.ts
+++ b/mcp-server/src/tools/taskTools.ts
@@ -2,7 +2,7 @@ import type { FastMCP } from 'fastmcp';
 import { z } from 'zod';
 
 import { agentBlocks, getController } from '../controller';
-import { jsonTextContent, taskWriteResult, slimTask } from '../utils/format';
+import { jsonTextContent, taskWriteResult, slimTask, slimTaskForList } from '../utils/format';
 
 /** stripAgentBlocks from canonical agentBlocks module — single source of truth for the tag format. */
 const { stripAgentBlocks } = agentBlocks;
@@ -228,7 +228,11 @@ export function registerTaskTools(server: Pick<FastMCP, 'addTool'>) {
       ...toolContextSchema,
     }),
     execute: async ({ teamName, claudeDir }) =>
-      await Promise.resolve(jsonTextContent(getController(teamName, claudeDir).tasks.listTasks())),
+      await Promise.resolve(
+        jsonTextContent(
+          (getController(teamName, claudeDir).tasks.listTasks() as Record<string, unknown>[]).map(slimTaskForList)
+        )
+      ),
   });
 
   server.addTool({
diff --git a/mcp-server/src/utils/format.ts b/mcp-server/src/utils/format.ts
index 180237f1..3d5a6c79 100644
--- a/mcp-server/src/utils/format.ts
+++ b/mcp-server/src/utils/format.ts
@@ -25,21 +25,53 @@ export function taskWriteResult(result: Record<string, unknown>): Record<string,
 }
 
 /**
- * Strips heavy fields from a raw task object returned directly by status/owner
- * mutations (not wrapped in `{ task: ... }`).
+ * Minimal task confirmation for write operations (status changes, owner
+ * assignment, comments, etc.). Uses an allowlist — only fields the caller
+ * needs to verify the mutation succeeded. Agents already know what they
+ * modified, so description/prompt/timestamps are unnecessary here.
  */
 export function slimTask(full: Record<string, unknown>): Record<string, unknown> {
-  const slim: Record<string, unknown> = {
+  return {
     id: full.id,
     displayId: full.displayId,
     subject: full.subject,
     status: full.status,
     owner: full.owner,
+    reviewState: full.reviewState,
+    needsClarification: full.needsClarification,
+    blockedBy: full.blockedBy,
+    blocks: full.blocks,
+    commentCount: Array.isArray(full.comments) ? full.comments.length : 0,
   };
+}
 
-  const comments = full.comments;
-  if (Array.isArray(comments)) {
-    slim.commentCount = comments.length;
+/**
+ * Fields that grow unboundedly and dominate context usage.
+ * Everything else passes through — new task fields are included by default.
+ */
+const HEAVY_TASK_FIELDS = new Set(['comments', 'historyEvents', 'workIntervals']);
+
+/**
+ * Lightweight task representation for task_list.
+ *
+ * Uses a BLOCKLIST approach: strips only known heavy array fields and replaces
+ * `comments` with `commentCount`. All other fields (including any future ones)
+ * pass through automatically. This avoids silently dropping new fields when
+ * the task schema evolves.
+ */
+export function slimTaskForList(full: Record<string, unknown>): Record<string, unknown> {
+  const slim: Record<string, unknown> = {};
+
+  for (const [key, value] of Object.entries(full)) {
+    if (!HEAVY_TASK_FIELDS.has(key)) {
+      slim[key] = value;
+    }
+  }
+
+  if (Array.isArray(full.comments)) {
+    slim.commentCount = full.comments.length;
+  } else {
+    slim.commentCount = 0;
   }
 
   return slim;
diff --git a/mcp-server/test/tools.test.ts b/mcp-server/test/tools.test.ts
index dd631492..60536214 100644
--- a/mcp-server/test/tools.test.ts
+++ b/mcp-server/test/tools.test.ts
@@ -918,6 +918,98 @@ describe('agent-teams-mcp tools', () => {
     expect(reloaded.comments[0].text).toBe('Comment should persist despite broken inbox');
   });
 
+  it('write operations return slim task (no comments/historyEvents arrays)', async () => {
+    const claudeDir = makeClaudeDir();
+    const teamName = 'slim-check';
+
+    fs.mkdirSync(path.join(claudeDir, 'tasks', teamName), { recursive: true });
+    writeTeamConfig(claudeDir, teamName, { members: [{ name: 'lead' }] });
+
+    const task = parseJsonToolResult(
+      await getTool('task_create').execute({
+        claudeDir,
+        teamName,
+        subject: 'Slim task test',
+        owner: 'lead',
+        notifyOwner: false,
+      })
+    );
+
+    // task_create returns full task (read operation)
+    expect(task.historyEvents).toBeDefined();
+
+    // Add a comment so commentCount > 0
+    const commented = parseJsonToolResult(
+      await getTool('task_add_comment').execute({
+        claudeDir,
+        teamName,
+        taskId: task.id,
+        text: 'test comment',
+        from: 'lead',
+      })
+    );
+
+    // task_add_comment: nested task should be slim
+    expect(commented.commentId).toBeTruthy();
+    expect(commented.comment.text).toBe('test comment');
+    expect(commented.task.commentCount).toBe(1);
+    expect(commented.task.comments).toBeUndefined();
+    expect(commented.task.historyEvents).toBeUndefined();
+
+    // task_start: returns slim task directly
+    const started = parseJsonToolResult(
+      await getTool('task_start').execute({
+        claudeDir,
+        teamName,
+        taskId: task.id,
+        actor: 'lead',
+      })
+    );
+    expect(started.status).toBe('in_progress');
+    expect(started.commentCount).toBe(1);
+    expect(started.comments).toBeUndefined();
+    expect(started.historyEvents).toBeUndefined();
+    expect(started.workIntervals).toBeUndefined();
+
+    // task_complete: returns slim task directly
+    const completed = parseJsonToolResult(
+      await getTool('task_complete').execute({
+        claudeDir,
+        teamName,
+        taskId: task.id,
+        actor: 'lead',
+      })
+    );
+    expect(completed.status).toBe('completed');
+    expect(completed.comments).toBeUndefined();
+
+    // task_list: uses blocklist, includes description but not comments array
+    const listed = parseJsonToolResult(
+      await getTool('task_list').execute({ claudeDir, teamName })
+    );
+    const listedTask = listed.find((t: { id: string }) => t.id === task.id);
+    expect(listedTask).toBeDefined();
+    expect(listedTask.subject).toBe('Slim task test');
+    expect(listedTask.commentCount).toBe(1);
+    expect(listedTask.comments).toBeUndefined();
+    expect(listedTask.historyEvents).toBeUndefined();
+    expect(listedTask.workIntervals).toBeUndefined();
+    // task_list preserves non-heavy fields
+    expect(listedTask.status).toBeDefined();
+    expect(listedTask.id).toBeDefined();
+
+    // task_get: still returns full task with comments
+    const full = parseJsonToolResult(
+      await getTool('task_get').execute({
+        claudeDir,
+        teamName,
+        taskId: task.id,
+      })
+    );
+    expect(full.comments).toHaveLength(1);
+    expect(full.historyEvents).toBeDefined();
+  });
+
   describe('task_create_from_message', () => {
     function writeSentMessage(
       claudeDir: string,
diff --git a/src/main/services/team/TeamProvisioningService.ts b/src/main/services/team/TeamProvisioningService.ts
index 96b6c71f..9129bdb0 100644
--- a/src/main/services/team/TeamProvisioningService.ts
+++ b/src/main/services/team/TeamProvisioningService.ts
@@ -407,7 +407,7 @@ function buildTeammateAgentBlockReminder(): string {
   ].join('\n');
 }
 
-function buildMemberBootstrapPrompt(
+function buildMemberSpawnPrompt(
   member: TeamCreateRequest['members'][number],
   displayName: string,
   teamName: string,
@@ -438,7 +438,7 @@ ${buildTeammateAgentBlockReminder()}
 ${actionModeProtocol}`;
 }
 
-function buildReconnectMemberBootstrapPrompt(
+function buildReconnectMemberSpawnPrompt(
   member: TeamCreateRequest['members'][number],
   teamName: string,
   leadName: string,
@@ -482,24 +482,6 @@ ${actionModeProtocol}
      - If you have no tasks, wait for new assignments.`;
 }
 
-function buildMemberSpawnPrompt(
-  member: TeamCreateRequest['members'][number],
-  displayName: string,
-  teamName: string,
-  leadName: string
-): string {
-  return buildMemberBootstrapPrompt(member, displayName, teamName, leadName);
-}
-
-function buildReconnectMemberSpawnPrompt(
-  member: TeamCreateRequest['members'][number],
-  teamName: string,
-  leadName: string,
-  hasTasks: boolean
-): string {
-  return buildReconnectMemberBootstrapPrompt(member, teamName, leadName, hasTasks);
-}
-
 export function buildAddMemberSpawnMessage(
   teamName: string,
   displayName: string,
@@ -515,7 +497,7 @@ export function buildAddMemberSpawnMessage(
       ? ` Their workflow: ${member.workflow.trim()}`
       : '';
 
-  const prompt = buildMemberBootstrapPrompt(
+  const prompt = buildMemberSpawnPrompt(
     {
       name: member.name,
       ...(member.role ? { role: member.role } : {}),
@@ -866,12 +848,7 @@ ${request.members
     (m) => `   For “${m.name}”:
    - name: “${m.name}”
    - prompt:
-${buildMemberSpawnPrompt(
-  m,
-  displayName,
-  request.teamName,
-  leadName
-)
+${buildMemberSpawnPrompt(m, displayName, request.teamName, leadName)
   .split('\n')
   .map((line) => `     ${line}`)
   .join('\n')}`