improvement(hitl): add webhook notification and resume, add webhook block by Sg312 · Pull Request #2673 · simstudioai/sim

Sg312 · 2026-01-03T22:20:56Z

Summary

Adds webhook block and webhook resume functionality to hitl block

Type of Change

New feature

Testing

Manual

Checklist

Code follows project style guidelines
Self-reviewed my changes
Tests added/updated and passing
No new warnings introduced
I confirm that I have read and agree to the terms outlined in the Contributor License Agreement (CLA)

vercel · 2026-01-03T22:21:00Z

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1 Skipped Deployment

Project	Deployment	Review	Updated (UTC)
docs	Skipped		Jan 3, 2026 10:25pm

greptile-apps · 2026-01-03T22:27:33Z

Greptile Summary

Adds a new webhook request block and tool to send HTTP requests with HMAC-SHA256 signing and standard webhook headers
Enhances the human-in-the-loop block to expose resumeEndpoint API URLs alongside existing UI URLs for programmatic workflow resumption
Updates the resume page client with modernized styling using CSS variables and improved block identification using optional blockId fields

Important Files Changed

Filename	Overview
`tools/http/webhook_request.ts`	New webhook tool with HMAC signature generation and webhook-specific headers; requires review for security implementation
`blocks/blocks/webhook_request.ts`	New webhook request block configuration with AI-powered payload generation and comprehensive webhook functionality
`app/api/resume/[workflowId]/[executionId]/[contextId]/route.ts`	Modified resume API endpoint to allow dashboard access without deployment validation; check authentication logic
`executor/handlers/human-in-the-loop/human-in-the-loop-handler.ts`	Exposes resume API endpoints in HITL block outputs for webhook-based resumption; verify proper endpoint exposure

Confidence score: 4/5

This PR introduces significant new webhook functionality with proper integration across the codebase but requires careful security review
Score reflects well-structured implementation following established patterns, but deducted one point due to authentication bypass logic in resume endpoints and HMAC security implementation that needs verification
Pay close attention to the webhook tool's HMAC signature generation and the resume API's authentication bypass logic for dashboard access

Sequence Diagram

sequenceDiagram
    participant User
    participant HumanInTheLoopBlock
    participant NotificationTools
    participant WebhookRequest
    participant Database
    participant ResumeAPI
    participant PauseResumeManager

    User->>HumanInTheLoopBlock: Execute workflow with HITL block
    HumanInTheLoopBlock->>Database: Generate pause context and persist execution
    HumanInTheLoopBlock->>HumanInTheLoopBlock: Generate resume URLs (UI and API)
    HumanInTheLoopBlock->>NotificationTools: Execute notification tools with resume links
    NotificationTools->>WebhookRequest: Send webhook with resume endpoint
    WebhookRequest->>External Service: POST webhook payload with signature
    External Service-->>WebhookRequest: Acknowledge webhook
    HumanInTheLoopBlock-->>User: Return pause response with resume URLs

    User->>ResumeAPI: POST resume with input data
    ResumeAPI->>Database: Validate workflow access and pause context
    ResumeAPI->>PauseResumeManager: Enqueue or start resume execution
    PauseResumeManager->>Database: Update pause status to resuming
    PauseResumeManager->>PauseResumeManager: Execute workflow from pause point
    PauseResumeManager->>Database: Update execution status to completed
    PauseResumeManager-->>ResumeAPI: Return execution result
    ResumeAPI-->>User: Return resume confirmation

greptile-apps

_{16 files reviewed, 5 comments}

_{Edit Code Review Agent Settings | Greptile}

greptile-apps · 2026-01-03T22:27:30Z

apps/sim/tools/http/types.ts

+
+export interface WebhookRequestParams {
+  url: string
+  body?: any


style: Consider using unknown instead of any for better type safety

Suggested change

body?: any

body?: unknown

Context Used: Context from dashboard - TypeScript conventions and type safety (source)

_{Note: If this suggestion doesn't match your team's coding style, reply to this and let me know. I'll remember it for next time!}

Prompt To Fix With AI

This is a comment left during a code review. Path: apps/sim/tools/http/types.ts Line: 23:23 Comment: **style:** Consider using `unknown` instead of `any` for better type safety ```suggestion body?: unknown ``` **Context Used:** Context from `dashboard` - TypeScript conventions and type safety ([source](https://app.greptile.com/review/custom-context?memory=b4f0be8d-a787-4d5a-9098-a66b1449df25)) Note: If this suggestion doesn't match your team's coding style, reply to this and let me know. I'll remember it for next time! How can I resolve this? If you propose a fix, please make it concise.

greptile-apps · 2026-01-03T22:27:31Z

apps/sim/app/api/resume/[workflowId]/[executionId]/[contextId]/route.ts

-  const workflow = access.workflow!
+  const workflow = access.workflow

  let payload: any = {}


style: Consider using unknown instead of any for better type safety

Suggested change

let payload: any = {}

let payload: unknown = {}

Context Used: Context from dashboard - TypeScript conventions and type safety (source)

_{Note: If this suggestion doesn't match your team's coding style, reply to this and let me know. I'll remember it for next time!}

Prompt To Fix With AI

This is a comment left during a code review. Path: apps/sim/app/api/resume/[workflowId]/[executionId]/[contextId]/route.ts Line: 32:32 Comment: **style:** Consider using `unknown` instead of `any` for better type safety ```suggestion let payload: unknown = {} ``` **Context Used:** Context from `dashboard` - TypeScript conventions and type safety ([source](https://app.greptile.com/review/custom-context?memory=b4f0be8d-a787-4d5a-9098-a66b1449df25)) Note: If this suggestion doesn't match your team's coding style, reply to this and let me know. I'll remember it for next time! How can I resolve this? If you propose a fix, please make it concise.

greptile-apps · 2026-01-03T22:27:32Z

apps/sim/lib/workflows/blocks/block-outputs.ts

+      if (!fieldName) continue
+
+      hitlOutputs[fieldName] = {
+        type: (field?.type || 'any') as any,


style: Type assertion as any bypasses TypeScript's type checking. Consider defining a proper union type for supported field types instead of using any.

Context Used: Context from dashboard - TypeScript conventions and type safety (source)

_{Note: If this suggestion doesn't match your team's coding style, reply to this and let me know. I'll remember it for next time!}

Prompt To Fix With AI

This is a comment left during a code review. Path: apps/sim/lib/workflows/blocks/block-outputs.ts Line: 244:244 Comment: **style:** Type assertion `as any` bypasses TypeScript's type checking. Consider defining a proper union type for supported field types instead of using `any`. **Context Used:** Context from `dashboard` - TypeScript conventions and type safety ([source](https://app.greptile.com/review/custom-context?memory=b4f0be8d-a787-4d5a-9098-a66b1449df25)) Note: If this suggestion doesn't match your team's coding style, reply to this and let me know. I'll remember it for next time! How can I resolve this? If you propose a fix, please make it concise.

greptile-apps · 2026-01-03T22:27:32Z

...onents/panel/components/editor/components/sub-block/components/tag-dropdown/tag-dropdown.tsx

+            blockTags = isSelfReference
+              ? allTags.filter((tag) => tag.endsWith('.url') || tag.endsWith('.resumeEndpoint'))
+              : allTags


style: Consider extracting the tag filtering logic into a helper function since this pattern is now used for both approval and human_in_the_loop blocks

_{Note: If this suggestion doesn't match your team's coding style, reply to this and let me know. I'll remember it for next time!}

Prompt To Fix With AI

This is a comment left during a code review. Path: apps/sim/app/workspace/[workspaceId]/w/[workflowId]/components/panel/components/editor/components/sub-block/components/tag-dropdown/tag-dropdown.tsx Line: 765:767 Comment: **style:** Consider extracting the tag filtering logic into a helper function since this pattern is now used for both approval and human_in_the_loop blocks Note: If this suggestion doesn't match your team's coding style, reply to this and let me know. I'll remember it for next time! How can I resolve this? If you propose a fix, please make it concise.

greptile-apps · 2026-01-03T22:27:33Z

apps/sim/app/resume/[workflowId]/[executionId]/resume-page-client.tsx

+                            <Label>Pause Data</Label>
+                          </div>
+                          <div style={{ padding: '16px' }}>
+                            <Code.Viewer code={pauseResponsePreview} language='json' />


style: using Code.Viewer with dot notation instead of importing from barrel

Context Used: Context from dashboard - Import patterns for the Sim application (source)

_{Note: If this suggestion doesn't match your team's coding style, reply to this and let me know. I'll remember it for next time!}

Prompt To Fix With AI

This is a comment left during a code review. Path: apps/sim/app/resume/[workflowId]/[executionId]/resume-page-client.tsx Line: 1161:1161 Comment: **style:** using Code.Viewer with dot notation instead of importing from barrel **Context Used:** Context from `dashboard` - Import patterns for the Sim application ([source](https://app.greptile.com/review/custom-context?memory=a1041767-1a8e-44e0-9ec7-7efb79eb749b)) Note: If this suggestion doesn't match your team's coding style, reply to this and let me know. I'll remember it for next time! How can I resolve this? If you propose a fix, please make it concise.

…lock (#2673) * Add api blcok as tool * Add webhook block * Hitl v1 * Cleanup * Fix * Update names for fields in hitl * Fix hitl tag dropdown * Update hitl dashboard * Lint

Sg312 changed the base branch from main to staging January 3, 2026 22:21

Sg312 added 9 commits January 3, 2026 14:24

Add api blcok as tool

0bb71f7

Add webhook block

173b3e6

Hitl v1

2565200

Cleanup

bed3935

Fix

51a00b2

Update names for fields in hitl

b612e35

Fix hitl tag dropdown

97882c8

Update hitl dashboard

fb4f35e

Lint

90e8db1

vercel bot deployed to Preview January 3, 2026 22:24 View deployment

Sg312 force-pushed the improvement/hitl-resume branch from 87d8a79 to 90e8db1 Compare January 3, 2026 22:25

vercel bot temporarily deployed to Preview January 3, 2026 22:25 Inactive

greptile-apps bot reviewed Jan 3, 2026

View reviewed changes

Sg312 merged commit 8215a81 into staging Jan 6, 2026
11 checks passed

waleedlatif1 mentioned this pull request Jan 6, 2026

v0.5.51: triggers, kb, condition block improvements, supabase and grain integration updates #2693

Merged

waleedlatif1 deleted the improvement/hitl-resume branch January 6, 2026 22:39

This was referenced Jan 16, 2026

[BUG] Human in the Loop Webhook #2379

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feat(blocks): add Webhook tool for sending HTTP requests #2400

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improvement(hitl): add webhook notification and resume, add webhook block#2673

improvement(hitl): add webhook notification and resume, add webhook block#2673
Sg312 merged 9 commits intostagingfrom
improvement/hitl-resume

Sg312 commented Jan 3, 2026

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Sg312 commented Jan 3, 2026

Summary

Type of Change

Testing

Checklist

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greptile-apps bot commented Jan 3, 2026

Greptile Summary

Important Files Changed

Confidence score: 4/5

Sequence Diagram

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