diff --git a/src/bcbench/agent/shared/config.yaml b/src/bcbench/agent/shared/config.yaml
index 2f271f326..4494ba7f4 100644
--- a/src/bcbench/agent/shared/config.yaml
+++ b/src/bcbench/agent/shared/config.yaml
@@ -78,7 +78,7 @@ skills:
 #    - Claude: copies to repo/.claude/agents/
 # 2. whether to pass --agent=<agent-name> to copilot or claude
 agents:
-  enabled: false
+  enabled: true
   name: ALTest
 
 mcp:
diff --git a/src/bcbench/agent/shared/instructions/microsoft-BCApps/agents/ALTest.agent.md b/src/bcbench/agent/shared/instructions/microsoft-BCApps/agents/ALTest.agent.md
index d27e038ff..ccc907197 100644
--- a/src/bcbench/agent/shared/instructions/microsoft-BCApps/agents/ALTest.agent.md
+++ b/src/bcbench/agent/shared/instructions/microsoft-BCApps/agents/ALTest.agent.md
@@ -17,6 +17,10 @@ Your task is to implement automated tests in the AL language for Microsoft Dynam
 - Your job is ONLY to fix formatting, structure, and coding standard violations - NOT to change test logic.
 - If code seems unnecessary or wrong, LEAVE IT - the human developer approved it.
 
+**CRITICAL: BUILD MUST SUCCEED**
+- Your output must compile and publish in the target test project.
+- Avoid introducing new objects (new codeunits/files) unless absolutely required (see Build Robustness rules).
+
 <structure_rules>
 ### Test Structure
 
@@ -56,6 +60,38 @@ end;
 - Use rounded amounts without decimals
 </structure_rules>
 
+<build_robustness_rules>
+### Build Robustness (NEW — MUST FOLLOW)
+
+**Primary rule: prefer edits over new objects**
+1) Prefer adding a new `[Test]` procedure to an EXISTING test codeunit in the same app/test project.
+2) Avoid creating new test codeunits/files unless:
+   - no suitable existing test codeunit exists, AND
+   - the project’s object ID ranges and dependencies are known and satisfied.
+
+**Object identifiers**
+- If a new object is unavoidable:
+  - Object name must be <= 30 characters (AL object identifier constraint).
+  - Object ID must be within the allowed ranges for that project.
+  - Object ID must be unused (search before choosing).
+  - If ranges are unknown, do NOT create a new object; instead, add the test to an existing codeunit.
+
+**Dependencies (critical)**
+- Do NOT reference codeunits/libraries that are not available in the target test project.
+- Specifically: `Library - Variable Storage` is OPTIONAL and must only be used if it exists in the project.
+
+**Symbol correctness**
+- Do NOT call procedures/fields that do not exist in the target branch/project.
+- If you use a helper procedure (e.g., `SomeRec.SomeHelper()`), it must exist in the codebase.
+
+**Build preflight checklist (must pass mentally before finalizing)**
+- No new codeunit IDs unless absolutely required
+- No object name > 30 chars
+- No duplicate object IDs
+- No “missing codeunit/library” references
+- No invented procedures/fields
+</build_robustness_rules>
+
 <library_rules>
 ### Test Library Usage Requirements
 
@@ -86,11 +122,11 @@ end;
 | Library Text File Validation | Reading, searching, validating values in text files |
 | Library Lower Permissions | Setting, adding, managing permission sets |
 
-3. **Library Variable Storage**
+3. **Library - Variable Storage**
    - Use to pass data between test and handler procedures.
    - If used, MUST add `LibraryVariableStorage.AssertEmpty()` at the end of test.
 
-4. **Library Setup Storage**
+4. **Library - Setup Storage**
    - Use in Initialize procedure if any setup table is modified in tests.
 </library_rules>
 
diff --git a/src/bcbench/agent/shared/instructions/microsoftInternal-NAV/agents/ALTest.agent.md b/src/bcbench/agent/shared/instructions/microsoftInternal-NAV/agents/ALTest.agent.md
index d27e038ff..ccc907197 100644
--- a/src/bcbench/agent/shared/instructions/microsoftInternal-NAV/agents/ALTest.agent.md
+++ b/src/bcbench/agent/shared/instructions/microsoftInternal-NAV/agents/ALTest.agent.md
@@ -17,6 +17,10 @@ Your task is to implement automated tests in the AL language for Microsoft Dynam
 - Your job is ONLY to fix formatting, structure, and coding standard violations - NOT to change test logic.
 - If code seems unnecessary or wrong, LEAVE IT - the human developer approved it.
 
+**CRITICAL: BUILD MUST SUCCEED**
+- Your output must compile and publish in the target test project.
+- Avoid introducing new objects (new codeunits/files) unless absolutely required (see Build Robustness rules).
+
 <structure_rules>
 ### Test Structure
 
@@ -56,6 +60,38 @@ end;
 - Use rounded amounts without decimals
 </structure_rules>
 
+<build_robustness_rules>
+### Build Robustness (NEW — MUST FOLLOW)
+
+**Primary rule: prefer edits over new objects**
+1) Prefer adding a new `[Test]` procedure to an EXISTING test codeunit in the same app/test project.
+2) Avoid creating new test codeunits/files unless:
+   - no suitable existing test codeunit exists, AND
+   - the project’s object ID ranges and dependencies are known and satisfied.
+
+**Object identifiers**
+- If a new object is unavoidable:
+  - Object name must be <= 30 characters (AL object identifier constraint).
+  - Object ID must be within the allowed ranges for that project.
+  - Object ID must be unused (search before choosing).
+  - If ranges are unknown, do NOT create a new object; instead, add the test to an existing codeunit.
+
+**Dependencies (critical)**
+- Do NOT reference codeunits/libraries that are not available in the target test project.
+- Specifically: `Library - Variable Storage` is OPTIONAL and must only be used if it exists in the project.
+
+**Symbol correctness**
+- Do NOT call procedures/fields that do not exist in the target branch/project.
+- If you use a helper procedure (e.g., `SomeRec.SomeHelper()`), it must exist in the codebase.
+
+**Build preflight checklist (must pass mentally before finalizing)**
+- No new codeunit IDs unless absolutely required
+- No object name > 30 chars
+- No duplicate object IDs
+- No “missing codeunit/library” references
+- No invented procedures/fields
+</build_robustness_rules>
+
 <library_rules>
 ### Test Library Usage Requirements
 
@@ -86,11 +122,11 @@ end;
 | Library Text File Validation | Reading, searching, validating values in text files |
 | Library Lower Permissions | Setting, adding, managing permission sets |
 
-3. **Library Variable Storage**
+3. **Library - Variable Storage**
    - Use to pass data between test and handler procedures.
    - If used, MUST add `LibraryVariableStorage.AssertEmpty()` at the end of test.
 
-4. **Library Setup Storage**
+4. **Library - Setup Storage**
    - Use in Initialize procedure if any setup table is modified in tests.
 </library_rules>