feat: human in the loop (confirmation) by supreme-gg-gg · Pull Request #1398 · kagent-dev/kagent

supreme-gg-gg · 2026-02-27T18:14:42Z

Supports confirmation flow for HITL (single and parallel tool use). Flow documented in docs/architecture/human-in-the-loop.md

Todo: custom payload so the agent can invoke tools that require user input

Add per-tool approval configuration to the Agent CRD so that specific MCP tools can require human approval before execution. When a tool marked with `requireApproval` is invoked, the agent pauses and sends an `input_required` event. The chat UI renders inline Approve/Reject buttons, and the user's decision is sent back as a structured A2A message to resume or redirect the agent. Changes across all layers: - CRD: `requireApproval` field on `McpServerTool` with CEL validation - Go ADK types + translator: pass `require_approval` through to config - Python `_approval.py`: `before_tool_callback` that blocks tools needing approval via a session-state-based one-time approval flow - Python executor: detects approval markers, sends `input_required` interrupt, handles approve/reject continuation on next message - UI: `pending_approval` status on ToolDisplay with approve/reject buttons, message handler detection of tool approval interrupts, `sendApprovalDecision()` in ChatInterface - Tests: golden translator test, 11 Python unit tests for callback - Docs: design doc and implementation reference Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com> Signed-off-by: Eitan Yarmush <eitan.yarmush@solo.io>

Bug 1: Approve/Reject buttons appeared to do nothing when clicked. The sendApprovalDecision function was moving messages from streaming to stored state, causing ToolCallDisplay components to unmount/remount. A race condition with the global toolCallCache prevented remounted components from re-registering their tool call IDs, making the approval card disappear without feedback. Fix: keep messages in place so the ToolDisplay's isSubmitting state is preserved naturally. Bug 2: Reloading the page lost the approval dialog. Messages were loaded from task history via extractMessagesFromTasks, but input_required status messages with tool_approval data were not reconstructed as ToolApprovalRequest messages. Fix: add extractApprovalMessagesFromTasks that detects tasks in input_required state with tool_approval data and reconstructs proper ToolApprovalRequest messages with approval buttons. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com> Signed-off-by: Eitan Yarmush <eitan.yarmush@solo.io>

Signed-off-by: Eitan Yarmush <eitan.yarmush@solo.io>

Signed-off-by: Jet Chiang <pokyuen.jetchiang-ext@solo.io>

supreme-gg-gg · 2026-02-28T03:55:46Z

Screen.Recording.2026-02-27.at.10.48.58.PM.mov

Added support for parallel tool calls (confirmation are gathered and batched sent). Some agents will not use parallel tool calls (from my experience Copilot and Antigravity don't do it, Cursor does it intermittently), meaning that they wait until one tool is approved and completed before generating another tool call, but apparently Kagent agents like calling parallel tools so they're supported in HITL now

Signed-off-by: Jet Chiang <pokyuen.jetchiang-ext@solo.io>

Copilot

Pull request overview

Implements ADK-native Human-in-the-Loop (HITL) tool approval end-to-end: adds requireApproval to the Agent CRD/tool configs, wires an ADK before_tool_callback to request confirmation, and updates the UI to render approval cards and send approval decisions back to resume execution.

Changes:

Add requireApproval to MCP server tool configuration (CRD → Go translator/types → Python agent config).
Add ADK-native approval callback + executor resume logic (uniform + batch decisions).
Update UI message handling and tool call rendering to display approval status and approval controls (including reload recovery), plus new documentation.

Reviewed changes

Copilot reviewed 28 out of 28 changed files in this pull request and generated 12 comments.

Show a summary per file

File	Description
ui/src/types/index.ts	Adds `requireApproval` to MCP server tool type for UI consumption.
ui/src/lib/statusUtils.ts	Updates input-required UI text to “Awaiting approval…”.
ui/src/lib/messageHandlers.ts	Detects ADK confirmation parts, builds approval messages, and marks HITL rejections in tool results.
ui/src/components/sidebars/AgentDetailsSidebar.tsx	Shows “requires approval” indicator for tools based on `requireApproval`.
ui/src/components/chat/ToolCallDisplay.tsx	Adds ToolApprovalRequest handling, optimistic approve/reject UI, and HITL terminal states.
ui/src/components/chat/ChatMessage.tsx	Routes ToolApprovalRequest messages to ToolCallDisplay with approval callbacks.
ui/src/components/chat/ChatInterface.tsx	Adds pending decision collection + decision submission via A2A streaming.
ui/src/components/ToolDisplay.tsx	Adds approval/rejection UI and new statuses (pending/approved/rejected).
python/packages/kagent-core/tests/test_hitl_utils.py	Updates HITL parsing tests for structured DataPart decisions + batch.
python/packages/kagent-core/tests/test_hitl_handlers.py	Removes tests for old interrupt handler path.
python/packages/kagent-core/tests/test_hitl_consts.py	Removes tests for old HITL constants/keywords.
python/packages/kagent-core/src/kagent/core/a2a/_hitl.py	Simplifies HITL decision extraction + adds batch decision extraction.
python/packages/kagent-core/src/kagent/core/a2a/_consts.py	Adds batch decision constants; removes old interrupt/keyword constants.
python/packages/kagent-core/src/kagent/core/a2a/init.py	Updates public exports to the new HITL helpers/constants.
python/packages/kagent-adk/tests/unittests/test_approval.py	Adds tests for ADK-native approval callback behavior.
python/packages/kagent-adk/src/kagent/adk/types.py	Adds `require_approval` to tool configs; wires `before_tool_callback`.
python/packages/kagent-adk/src/kagent/adk/_approval.py	New ADK `before_tool_callback` that requests confirmation and blocks/exits accordingly.
python/packages/kagent-adk/src/kagent/adk/_agent_executor.py	Adds HITL resume path: converts A2A decision messages into ADK FunctionResponse confirmations; breaks on long-running confirmation events.
python/packages/kagent-adk/src/kagent/adk/_a2a.py	Enables ADK resumability and passes task_store into executor.
helm/kagent-crds/templates/kagent.dev_agents.yaml	CRD schema update to include `requireApproval`.
go/pkg/adk/types.go	Adds `require_approval` to ADK config JSON types.
go/internal/controller/translator/agent/testdata/outputs/agent_with_require_approval.json	Adds golden output for require_approval translation.
go/internal/controller/translator/agent/testdata/inputs/agent_with_require_approval.yaml	Adds translator input fixture covering `requireApproval`.
go/internal/controller/translator/agent/adk_api_translator.go	Propagates `RequireApproval` from CRD tool spec into ADK config structs.
go/config/crd/bases/kagent.dev_agents.yaml	Base CRD schema update to include `requireApproval`.
go/api/v1alpha2/zz_generated.deepcopy.go	Adds deepcopy support for `RequireApproval`.
go/api/v1alpha2/agent_types.go	Adds `RequireApproval` field on `McpServerTool`.
docs/architecture/human-in-the-loop.md	New architecture doc describing ADK-native HITL flow and UI/backend responsibilities.

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docs/architecture/human-in-the-loop.md

go/api/v1alpha2/agent_types.go

ui/src/components/chat/ChatInterface.tsx

python/packages/kagent-core/src/kagent/core/a2a/__init__.py

ui/src/lib/messageHandlers.ts

python/packages/kagent-core/src/kagent/core/a2a/_hitl.py

python/packages/kagent-adk/src/kagent/adk/_agent_executor.py

ui/src/components/chat/ChatInterface.tsx

ui/src/lib/messageHandlers.ts

ui/src/components/chat/ToolCallDisplay.tsx

Signed-off-by: Jet Chiang <pokyuen.jetchiang-ext@solo.io>

EItanya and others added 5 commits February 27, 2026 17:07

fixed a couple bus, but it's still in a rough state

7e648b7

Signed-off-by: Eitan Yarmush <eitan.yarmush@solo.io>

use adk native approach

c35e376

Signed-off-by: Jet Chiang <pokyuen.jetchiang-ext@solo.io>

fixed tests and golden

a974155

Signed-off-by: Jet Chiang <pokyuen.jetchiang-ext@solo.io>

supreme-gg-gg force-pushed the eitanya/hitl branch from b99d3f7 to a974155 Compare February 27, 2026 22:22

supreme-gg-gg changed the title ~~feat: human in the loop - confirmation~~ feat: human in the loop (confirmation) Feb 27, 2026

supreme-gg-gg added 4 commits February 27, 2026 17:41

Merge branch 'main' into eitanya/hitl

0c17c54

Signed-off-by: Jet Chiang <pokyuen.jetchiang-ext@solo.io>

oops

e351ae4

Signed-off-by: Jet Chiang <pokyuen.jetchiang-ext@solo.io>

parallel tool call hitl flow is finally working

3971da9

Signed-off-by: Jet Chiang <pokyuen.jetchiang-ext@solo.io>

change color of border since i'm bad at arts

8f7b667

Signed-off-by: Jet Chiang <pokyuen.jetchiang-ext@solo.io>

removed accidentally committed local docs

df457c0

Signed-off-by: Jet Chiang <pokyuen.jetchiang-ext@solo.io>

supreme-gg-gg marked this pull request as ready for review February 28, 2026 03:58

Copilot AI review requested due to automatic review settings February 28, 2026 03:58

supreme-gg-gg requested review from EItanya, ilackarms, peterj and yuval-k as code owners February 28, 2026 03:58

Copilot started reviewing on behalf of supreme-gg-gg February 28, 2026 03:58 View session

Copilot AI reviewed Feb 28, 2026

View reviewed changes

supreme-gg-gg added 2 commits February 27, 2026 23:56

meditate with copilot

6468705

Signed-off-by: Jet Chiang <pokyuen.jetchiang-ext@solo.io>

remove unused vars from linter warnings

08e6290

Signed-off-by: Jet Chiang <pokyuen.jetchiang-ext@solo.io>

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feat: human in the loop (confirmation)#1398

feat: human in the loop (confirmation)#1398
supreme-gg-gg wants to merge 12 commits intomainfrom
eitanya/hitl

supreme-gg-gg commented Feb 27, 2026 •

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supreme-gg-gg commented Feb 27, 2026 •

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