feat(mcp): add sim tab and json config input for mcp servers by waleedlatif1 · Pull Request #3377 · simstudioai/sim

waleedlatif1 · 2026-02-27T21:13:26Z

Summary

Add "Sim" tab to workflow MCP server details for one-click adding to workspace
Add JSON config toggle to MCP add-server form (paste standard mcpServers JSON)

Type of Change

New feature

Testing

Tested manually

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)

…keyboard shortcuts, audit logs

…rects to rewrites

…stash, algolia tools; isolated-vm robustness improvements, tables backend (#3271) * feat(tools): advanced fields for youtube, vercel; added cloudflare and dataverse tools (#3257) * refactor(vercel): mark optional fields as advanced mode Move optional/power-user fields behind the advanced toggle: - List Deployments: project filter, target, state - Create Deployment: project ID override, redeploy from, target - List Projects: search - Create/Update Project: framework, build/output/install commands - Env Vars: variable type - Webhooks: project IDs filter - Checks: path, details URL - Team Members: role filter - All operations: team ID scope Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com> * style(youtube): mark optional params as advanced mode Hide pagination, sort order, and filter fields behind the advanced toggle for a cleaner default UX across all YouTube operations. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com> * added advanced fields for vercel and youtube, added cloudflare and dataverse block * addded desc for dataverse * add more tools * ack comment * more * ops --------- Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com> * feat(tables): added tables (#2867) * updates * required * trashy table viewer * updates * updates * filtering ui * updates * updates * updates * one input mode * format * fix lints * improved errors * updates * updates * chages * doc strings * breaking down file * update comments with ai * updates * comments * changes * revert * updates * dedupe * updates * updates * updates * refactoring * renames & refactors * refactoring * updates * undo * update db * wand * updates * fix comments * fixes * simplify comments * u[dates * renames * better comments * validation * updates * updates * updates * fix sorting * fix appearnce * updating prompt to make it user sort * rm * updates * rename * comments * clean comments * simplicifcaiton * updates * updates * refactor * reduced type confusion * undo * rename * undo changes * undo * simplify * updates * updates * revert * updates * db updates * type fix * fix * fix error handling * updates * docs * docs * updates * rename * dedupe * revert * uncook * updates * fix * fix * fix * fix * prepare merge * readd migrations * add back missed code * migrate enrichment logic to general abstraction * address bugbot concerns * adhere to size limits for tables * remove conflicting migration * add back migrations * fix tables auth * fix permissive auth * fix lint * reran migrations * migrate to use tanstack query for all server state * update table-selector * update names * added tables to permission groups, updated subblock types --------- Co-authored-by: Vikhyath Mondreti <vikhyath@simstudio.ai> Co-authored-by: waleed <walif6@gmail.com> * fix(snapshot): changed insert to upsert when concurrent identical child workflows are running (#3259) * fix(snapshot): changed insert to upsert when concurrent identical child workflows are running * fixed ci tests failing * fix(workflows): disallow duplicate workflow names at the same folder level (#3260) * feat(tools): added redis, upstash, algolia, and revenuecat (#3261) * feat(tools): added redis, upstash, algolia, and revenuecat * ack comment * feat(models): add gemini-3.1-pro-preview and update gemini-3-pro thinking levels (#3263) * fix(audit-log): lazily resolve actor name/email when missing (#3262) * fix(blocks): move type coercions from tools.config.tool to tools.config.params (#3264) * fix(blocks): move type coercions from tools.config.tool to tools.config.params Number() coercions in tools.config.tool ran at serialization time before variable resolution, destroying dynamic references like <block.result.count> by converting them to NaN/null. Moved all coercions to tools.config.params which runs at execution time after variables are resolved. Fixed in 15 blocks: exa, arxiv, sentry, incidentio, wikipedia, ahrefs, posthog, elasticsearch, dropbox, hunter, lemlist, spotify, youtube, grafana, parallel. Also added mode: 'advanced' to optional exa fields. Closes #3258 * fix(blocks): address PR review — move remaining param mutations from tool() to params() - Moved field mappings from tool() to params() in grafana, posthog, lemlist, spotify, dropbox (same dynamic reference bug) - Fixed parallel.ts excerpts/full_content boolean logic - Fixed parallel.ts search_queries empty case (must set undefined) - Fixed elasticsearch.ts timeout not included when already ends with 's' - Restored dropbox.ts tool() switch for proper default fallback * fix(blocks): restore field renames to tool() for serialization-time validation Field renames (e.g. personalApiKey→apiKey) must be in tool() because validateRequiredFieldsBeforeExecution calls selectToolId()→tool() then checks renamed field names on params. Only type coercions (Number(), boolean) stay in params() to avoid destroying dynamic variable references. * improvement(resolver): resovled empty sentinel to not pass through unexecuted valid refs to text inputs (#3266) * fix(blocks): add required constraint for serviceDeskId in JSM block (#3268) * fix(blocks): add required constraint for serviceDeskId in JSM block * fix(blocks): rename custom field values to request field values in JSM create request * fix(trigger): add isolated-vm support to trigger.dev container builds (#3269) Scheduled workflow executions running in trigger.dev containers were failing to spawn isolated-vm workers because the native module wasn't available in the container. This caused loop condition evaluation to silently fail and exit after one iteration. - Add isolated-vm to build.external and additionalPackages in trigger config - Include isolated-vm-worker.cjs via additionalFiles for child process spawning - Add fallback path resolution for worker file in trigger.dev environment * fix(tables): hide tables from sidebar and block registry (#3270) * fix(tables): hide tables from sidebar and block registry * fix(trigger): add isolated-vm support to trigger.dev container builds (#3269) Scheduled workflow executions running in trigger.dev containers were failing to spawn isolated-vm workers because the native module wasn't available in the container. This caused loop condition evaluation to silently fail and exit after one iteration. - Add isolated-vm to build.external and additionalPackages in trigger config - Include isolated-vm-worker.cjs via additionalFiles for child process spawning - Add fallback path resolution for worker file in trigger.dev environment * lint * fix(trigger): update node version to align with main app (#3272) * fix(build): fix corrupted sticky disk cache on blacksmith (#3273) --------- Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com> Co-authored-by: Lakee Sivaraya <71339072+lakeesiv@users.noreply.github.com> Co-authored-by: Vikhyath Mondreti <vikhyath@simstudio.ai> Co-authored-by: Vikhyath Mondreti <vikhyathvikku@gmail.com>

…t support

… fixes, removed retired models, hex integration

…mprovements

…ogle tasks and bigquery integrations, workflow lock

vercel · 2026-02-27T21:13:30Z

The latest updates on your projects. Learn more about Vercel for GitHub.

1 Skipped Deployment

Project	Deployment	Actions	Updated (UTC)
docs	Skipped		Feb 27, 2026 10:13pm

greptile-apps · 2026-02-27T21:16:23Z

Greptile Summary

This PR adds two convenient features for MCP server management: a JSON config input mode and a "Sim" tab for one-click workspace integration.

Key changes:

Added toggle between form and JSON input modes in MCP server settings
Implemented extractStringHeaders helper that properly validates header values are strings (addresses previous validation concerns)
Added JSON parsing for both mcpServers format and direct { url, headers } format
Created "Sim" tab in workflow MCP server details for direct workspace integration
Fixed timer cleanup with proper useEffect unmount handling (resolves previous memory leak issue)

Code quality improvements:

Good separation of concerns with dedicated validation functions
Proper error handling and user feedback
Clean state management and cleanup

Confidence Score: 4/5

Safe to merge with one minor UX improvement suggested
Solid implementation that properly fixes previous validation and memory leak issues. Code is well-structured with proper error handling. One minor UX improvement suggested for multi-server JSON handling, but not a blocker.
No files require special attention - both changes are well-implemented

Important Files Changed

Filename	Overview
apps/sim/app/workspace/[workspaceId]/w/components/sidebar/components/settings-modal/components/mcp/mcp.tsx	Added JSON config input mode with proper validation and string-only header extraction. Addresses previous header validation issues. Minor UX concern: multiple servers in JSON silently ignored.
apps/sim/app/workspace/[workspaceId]/w/components/sidebar/components/settings-modal/components/workflow-mcp-servers/workflow-mcp-servers.tsx	Added "Sim" tab with one-click workspace integration. Properly implements timer cleanup with useEffect, resolving previous memory leak concern. Clean implementation.

_{Last reviewed commit: 463ef80}

greptile-apps

_{2 files reviewed, 4 comments}

_{Edit Code Review Agent Settings | Greptile}

...orkspace/[workspaceId]/w/components/sidebar/components/settings-modal/components/mcp/mcp.tsx

...s/sidebar/components/settings-modal/components/workflow-mcp-servers/workflow-mcp-servers.tsx

…header

waleedlatif1 · 2026-02-27T21:53:42Z

@cursor review

waleedlatif1 · 2026-02-27T21:53:48Z

@greptile

...s/sidebar/components/settings-modal/components/workflow-mcp-servers/workflow-mcp-servers.tsx

...orkspace/[workspaceId]/w/components/sidebar/components/settings-modal/components/mcp/mcp.tsx

… clean up timer

waleedlatif1 · 2026-02-28T00:06:23Z

@greptile

waleedlatif1 · 2026-02-28T00:06:27Z

@cursor review

greptile-apps · 2026-02-28T00:11:20Z

...orkspace/[workspaceId]/w/components/sidebar/components/settings-modal/components/mcp/mcp.tsx

+          const entries = Object.entries(parsed.mcpServers)
+          if (entries.length === 0) {
+            setJsonError('No servers found in mcpServers')
+            return null
+          }
+          const [name, config] = entries[0] as [string, Record<string, unknown>]


if JSON contains multiple servers, only the first is used without warning users

Suggested change

const entries = Object.entries(parsed.mcpServers)

if (entries.length === 0) {

setJsonError('No servers found in mcpServers')

return null

}

const [name, config] = entries[0] as [string, Record<string, unknown>]

const entries = Object.entries(parsed.mcpServers)

if (entries.length === 0) {

setJsonError('No servers found in mcpServers')

return null

}

if (entries.length > 1) {

setJsonError(`Found ${entries.length} servers. Please provide only one server at a time.`)

return null

}

const [name, config] = entries[0] as [string, Record<string, unknown>]

cursor

Cursor Bugbot has reviewed your changes and found 1 potential issue.

^{Bugbot Autofix is OFF. To automatically fix reported issues with cloud agents, enable autofix in the Cursor dashboard.}

cursor · 2026-02-28T00:19:09Z

...orkspace/[workspaceId]/w/components/sidebar/components/settings-modal/components/mcp/mcp.tsx

+            return null
+          }
+          const [name, config] = entries[0] as [string, Record<string, unknown>]
+          if (!config.url || typeof config.url !== 'string') {


Unsafe type assertion causes misleading error for null config

Low Severity

The as [string, Record<string, unknown>] type assertion on entries[0] bypasses TypeScript's null safety. If a user pastes valid JSON where the server config value is null (e.g., {"mcpServers": {"name": null}}), accessing config.url throws a TypeError. The catch block handles it but displays "Invalid JSON", which is misleading since the JSON is syntactically valid. A null/type guard on config before property access would produce a more accurate error message.

Additional Locations (1)

apps/sim/app/workspace/[workspaceId]/w/components/sidebar/components/settings-modal/components/mcp/mcp.tsx#L710-L713

waleedlatif1 and others added 12 commits February 16, 2026 00:36

v0.5.91: docs i18n, turborepo upgrade

b7e377e

v0.5.92: shortlinks, copilot scrolling stickiness, pagination

da46a38

v0.5.93: NextJS config changes, MCP and Blocks whitelisting, copilot …

fdca736

…keyboard shortcuts, audit logs

v0.5.94: vercel integration, folder insertion, migrated tracking redi…

15ace5e

…rects to rewrites

v0.5.96: sim oauth provider, slack ephemeral message tool and blockki…

34d92fa

…t support

v0.5.97: oidc discovery for copilot mcp

115f04e

v0.5.98: change detection improvements, rate limit and code execution…

0d86ea0

… fixes, removed retired models, hex integration

v0.5.99: local dev improvements, live workflow logs in terminal

af59234

v0.5.100: multiple credentials, 40% speedup, gong, attio, audit log i…

67f8a68

…mprovements

v0.5.101: circular dependency mitigation, confluence enhancements, go…

4fd0989

…ogle tasks and bigquery integrations, workflow lock

feat(mcp): add sim tab and json config input for mcp servers

e41fbcc

greptile-apps bot reviewed Feb 27, 2026

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...orkspace/[workspaceId]/w/components/sidebar/components/settings-modal/components/mcp/mcp.tsx Outdated Show resolved Hide resolved

...orkspace/[workspaceId]/w/components/sidebar/components/settings-modal/components/mcp/mcp.tsx Outdated Show resolved Hide resolved

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...orkspace/[workspaceId]/w/components/sidebar/components/settings-modal/components/mcp/mcp.tsx Show resolved Hide resolved

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fix(mcp): validate json headers, add domain check, fix empty api key …

9b72b5c

…header

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...orkspace/[workspaceId]/w/components/sidebar/components/settings-modal/components/mcp/mcp.tsx Show resolved Hide resolved

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fix(mcp): deduplicate json validation, remove redundant state resets,…

6a3e350

… clean up timer

vercel bot temporarily deployed to Preview February 27, 2026 22:10 Inactive

improvement(mcp): extract extractStringHeaders helper for DRY

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Conversation

waleedlatif1 commented Feb 27, 2026

Summary

Type of Change

Testing

Checklist

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Greptile Summary

Confidence Score: 4/5

Important Files Changed

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Unsafe type assertion causes misleading error for null config

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