fix(core): enforce maxSubtasks limit in createPlan and reviseCurrentPlan by JGoP-L · Pull Request #656 · agentscope-ai/agentscope-java

JGoP-L · 2026-01-25T15:25:15Z

AgentScope-Java Version

1.0.8-SNAPSHOT

Description

Fixes #631

The maxSubtasks parameter of PlanNotebook was not being enforced.
Users could set maxSubtasks(5) but still create plans with more than 5 subtasks or add unlimited subtasks via reviseCurrentPlan.

Changes:

Added validation in createPlan method to reject plan creation when subtask count exceeds maxSubtasks
Added validation in reviseCurrentPlan method (action="add") to
reject adding subtasks when the current plan has reached the limit

Testing:

Created a plan with 6 subtasks when maxSubtasks=5 → correctly rejected
Created a plan with 5 subtasks when maxSubtasks=5 → correctly allowed
Added a subtask when plan already has 5 subtasks and maxSubtasks=5 → correctly rejected
Added a subtask when plan has 4 subtasks and maxSubtasks=5 → correctly allowed
Historical plan recovery and session load are not affected (by design)

Checklist

Code has been formatted with mvn spotless:apply
All tests are passing (mvn test)
Javadoc comments are complete and follow project conventions
Related documentation has been updated (e.g. links, examples, etc.)
Code is ready for review

gemini-code-assist · 2026-01-25T15:25:27Z

Summary of Changes

Hello @JGoP-L, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request addresses a critical bug where the maxSubtasks parameter in PlanNotebook was not being properly enforced. The changes introduce robust validation checks within both the createPlan and reviseCurrentPlan methods. This ensures that users cannot create plans with more subtasks than allowed or add additional subtasks beyond the specified maximum, thereby upholding the integrity of the plan structure and adhering to configured limits.

Highlights

Enforce maxSubtasks in createPlan: Added validation in the createPlan method to reject plan creation if the number of subtasks exceeds the configured maxSubtasks limit.
Enforce maxSubtasks in reviseCurrentPlan: Implemented validation in the reviseCurrentPlan method (specifically for the 'add' action) to prevent adding new subtasks if the current plan has already reached the maxSubtasks limit.

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Code Review

This pull request correctly implements the maxSubtasks limit enforcement in createPlan and reviseCurrentPlan. The validation logic is sound and placed appropriately to prevent the creation of plans or addition of subtasks beyond the configured limit. My review includes a couple of suggestions to improve the readability of the error messages. Additionally, while manual testing was performed, I highly recommend adding automated unit tests to cover these new validation scenarios to safeguard against future regressions.

gemini-code-assist · 2026-01-25T15:26:18Z

agentscope-core/src/main/java/io/agentscope/core/plan/PlanNotebook.java

+                            "Cannot create plan: the number of subtasks (%d) exceeds the maximum"
+                                    + " limit of %d. Please reduce the number of subtasks.",


For improved readability and maintainability, it's better to define this long string on a single line rather than concatenating it across multiple lines.

Suggested change

"Cannot create plan: the number of subtasks (%d) exceeds the maximum"

+ " limit of %d. Please reduce the number of subtasks.",

"Cannot create plan: the number of subtasks (%d) exceeds the maximum limit of %d. Please reduce the number of subtasks.",

gemini-code-assist · 2026-01-25T15:26:18Z

agentscope-core/src/main/java/io/agentscope/core/plan/PlanNotebook.java

+                                "Cannot add more subtasks: the current plan has reached the"
+                                        + " maximum limit of %d subtasks. Please delete some"
+                                        + " existing subtasks first.",


For better readability, this multi-line string concatenation can be simplified into a single line.

Suggested change

"Cannot add more subtasks: the current plan has reached the"

+ " maximum limit of %d subtasks. Please delete some"

+ " existing subtasks first.",

"Cannot add more subtasks: the current plan has reached the maximum limit of %d subtasks. Please delete some existing subtasks first.",

Copilot

Pull request overview

This PR fixes the bug where the PlanNotebook.maxSubtasks configuration was not actually enforced, allowing plans to exceed the configured subtask limit. It adds validation to both plan creation and incremental plan revision so the maximum subtask count is consistently respected.

Changes:

In createPlan, validate the number of requested subtasks against maxSubtasks and return a descriptive error message when the limit is exceeded, without creating or replacing the current plan.
In reviseCurrentPlan (for action="add"), prevent adding new subtasks when the current plan has already reached maxSubtasks, returning a clear limit-reached message instead.
Keep existing behavior unchanged when maxSubtasks is null, maintaining the “unlimited subtasks” configuration.

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Copilot · 2026-01-25T15:30:38Z

agentscope-core/src/main/java/io/agentscope/core/plan/PlanNotebook.java

+        if (maxSubtasks != null && subtaskList.size() > maxSubtasks) {
+            return Mono.just(
+                    String.format(
+                            "Cannot create plan: the number of subtasks (%d) exceeds the maximum"
+                                    + " limit of %d. Please reduce the number of subtasks.",
+                            subtaskList.size(), maxSubtasks));
+        }


The new maxSubtasks validation path in createPlan (when subtaskList.size() > maxSubtasks) is not covered by tests, even though PlanNotebookToolTest already exercises createPlanWithSubTasks and related tool flows. Please add tests that configure a PlanNotebook with a finite maxSubtasks value and verify that creating a plan with more subtasks than allowed returns the expected error message and does not set currentPlan or trigger plan change side effects.

Copilot · 2026-01-25T15:30:38Z

agentscope-core/src/main/java/io/agentscope/core/plan/PlanNotebook.java

+            if (maxSubtasks != null && subtasks.size() >= maxSubtasks) {
+                return Mono.just(
+                        String.format(
+                                "Cannot add more subtasks: the current plan has reached the"
+                                        + " maximum limit of %d subtasks. Please delete some"
+                                        + " existing subtasks first.",
+                                maxSubtasks));


The new maxSubtasks guard in reviseCurrentPlan for action "add" (rejecting additions when subtasks.size() >= maxSubtasks) is not currently exercised by automated tests, while other PlanNotebook tool behaviors are covered in PlanNotebookToolTest. To prevent regressions for this bugfix, consider adding tests that: (1) create a plan at the subtask limit and verify that an "add" action returns the new limit-reached message and leaves the subtask list unchanged, and (2) confirm that adding a subtask is still allowed just below the limit.

codecov · 2026-01-25T15:31:50Z

Codecov Report

❌ Patch coverage is 85.71429% with 1 line in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...ain/java/io/agentscope/core/plan/PlanNotebook.java	85.71%	0 Missing and 1 partial ⚠️

📢 Thoughts on this report? Let us know!

AlbumenJ · 2026-01-26T02:21:57Z

@LearningGp PTAL

maxSubtasks limit not enforced in PlanNotebook

d638789

JGoP-L requested review from a team and Copilot January 25, 2026 15:25

Copilot started reviewing on behalf of JGoP-L January 25, 2026 15:25 View session

gemini-code-assist bot reviewed Jan 25, 2026

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Copilot AI reviewed Jan 25, 2026

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JGoP-L added 3 commits January 25, 2026 23:31

maxSubtasks limit not enforced in PlanNotebook

5cff379

maxSubtasks limit not enforced in PlanNotebook

ec17da3

add test

d5a57e0

AlbumenJ approved these changes Jan 26, 2026

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AlbumenJ merged commit 42b3b0b into agentscope-ai:main Jan 26, 2026
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fix(core): enforce maxSubtasks limit in createPlan and reviseCurrentPlan #656

fix(core): enforce maxSubtasks limit in createPlan and reviseCurrentPlan #656
AlbumenJ merged 4 commits intoagentscope-ai:mainfrom
JGoP-L:fix/maxSubtasks-parameter-now-works-correctly

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		"Cannot create plan: the number of subtasks (%d) exceeds the maximum"
		+ " limit of %d. Please reduce the number of subtasks.",

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JGoP-L commented Jan 25, 2026

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