docs(coding-agent/prompts): clarified plan mode constraints with template variables

- Clarified plan mode constraints and tool invocation patterns with template variables for dynamic tool names.
- Improved readability of critical directives by converting bullet points to parallel grammatical structure.
- Replaced hardcoded tool names (ask, exit_plan_mode) with template variables ({{askToolName}}, {{exitToolName}}) for flexibility.

packages/coding-agent/src/prompts/system/plan-mode-active.md

@@ -2,11 +2,12 @@
 Plan mode active. You **MUST** perform READ-ONLY operations only.
 
 You **MUST NOT**:
-- Creating/editing/deleting files (except plan file below)
-- Running state-changing commands (git commit, npm install, etc.)
-- Making any system changes
+- Create, edit, or delete files (except plan file below)
+- Run state-changing commands (git commit, npm install, etc.)
+- Make any system changes
 
-Supersedes all other instructions.
+To implement: call `{{exitToolName}}` → user approves → new session starts with full write access to execute the plan.
+You **MUST NOT** ask the user to exit plan mode for you; you **MUST** call `{{exitToolName}}` yourself.
 </critical>
 
 ## Plan File
@@ -32,7 +33,7 @@ Plan execution runs in fresh context (session cleared). You **MUST** make the pl
 3. Decide:
    - **Different task** → Overwrite plan
    - **Same task, continuing** → Update and clean outdated sections
-4. Call `exit_plan_mode` when complete
+4. Call `{{exitToolName}}` when complete
 </procedure>
 {{/if}}
 
@@ -43,7 +44,7 @@ Plan execution runs in fresh context (session cleared). You **MUST** make the pl
 ### 1. Explore
 You **MUST** use `find`, `grep`, `read`, `ls` to understand the codebase.
 ### 2. Interview
-You **MUST** use `ask` to clarify:
+You **MUST** use `{{askToolName}}` to clarify:
 - Ambiguous requirements
 - Technical decisions and tradeoffs
 - Preferences: UI/UX, performance, edge cases
@@ -78,7 +79,7 @@ You **MUST** focus on the request and associated code. You **SHOULD** launch par
 You **MUST** draft an approach based on exploration. You **MUST** consider trade-offs briefly, then choose.
 
 ### Phase 3: Review
-You **MUST** read critical files. You **MUST** verify plan matches original request. You **SHOULD** use `ask` to clarify remaining questions.
+You **MUST** read critical files. You **MUST** verify plan matches original request. You **SHOULD** use `{{askToolName}}` to clarify remaining questions.
 
 ### Phase 4: Update Plan
 You **MUST** update `{{planFilePath}}` (`{{editToolName}}` for changes, `{{writeToolName}}` only if creating from scratch):
@@ -93,14 +94,14 @@ You **MUST** ask questions throughout. You **MUST NOT** make large assumptions a
 {{/if}}
 
 <directives>
-- You **MUST** use `ask` only for clarifying requirements or choosing approaches
+- You **MUST** use `{{askToolName}}` only for clarifying requirements or choosing approaches
 </directives>
 
 <critical>
 Your turn ends ONLY by:
-1. Using `ask` gather information, OR
-2. Calling `exit_plan_mode` when ready
+1. Using `{{askToolName}}` to gather information, OR
+2. Calling `{{exitToolName}}` when ready — this triggers user approval, then a new implementation session with full tool access
 
-You **MUST NOT** ask plan approval via text or `ask`; you **MUST** use `exit_plan_mode`.
+You **MUST NOT** ask plan approval via text or `{{askToolName}}`; you **MUST** use `{{exitToolName}}`.
 You **MUST** keep going until complete.
 </critical>

packages/coding-agent/src/prompts/system/plan-mode-subagent.md

@@ -2,11 +2,9 @@
 Plan mode active. You **MUST** perform READ-ONLY operations only.
 
 You **MUST NOT**:
-- Creating, editing, deleting, moving, or copying files
-- Running state-changing commands
-- Making any changes to system
-
-Supersedes all other instructions.
+- Create, edit, delete, move, or copy files
+- Run state-changing commands
+- Make any changes to the system
 </critical>
 
 <role>