feat(linq): add Linq iMessage/SMS/RCS integration

[waleedlatif1]

Summary

• Add a complete Linq integration (iMessage / SMS / RCS messaging) with 34 tools spanning chats, messages, attachments, phone numbers, capability checks, contact cards, and webhook subscriptions
• Single linq block (API-key auth, Communication) with an operation dropdown, conditional fields, and full param wiring
• Attachments use the canonical Sim file-upload pattern: a file-upload subBlock → internal /api/tools/linq/upload route (withRouteHandler + contract + downloadFileFromStorage) that performs Linq's two-step pre-upload + presigned PUT
• Official Linq icon on a black background; generated docs with a hand-written intro section
• Verified every tool, request/response shape, and field name against Linq's live API docs (https://docs.linqapp.com/api)

Type of Change

• New feature (integration)

Testing

Tested manually. bun run lint clean; bun run check:api-validation:strict passes (route baseline bumped 758→759 for the new upload route, counted as Zod-backed via contract). Each tool independently re-audited against live docs via parallel review.

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)

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Project	Deployment	Actions	Updated (UTC)
docs	Ready	Preview, Comment	Jun 1, 2026 8:03pm

[cursor]

PR Summary

Medium Risk
Large additive surface area and external messaging API calls; attachment upload handles user files and API keys but follows existing integration patterns with auth on the upload route.

Overview
Adds a Linq integration so workflows can send and manage iMessage, SMS, and RCS via API key.

The PR introduces 34 linq_* tools (chats, messages, attachments, phone numbers, iMessage/RCS checks, contact cards, webhooks) wired through a single linq workflow block with an operation dropdown and conditional fields. Attachment uploads go through a new authenticated /api/tools/linq/upload route (Zod contract, storage download, Linq pre-upload + presigned PUT) instead of calling Linq directly from the client.

Docs and discovery get a new linq.mdx page, LinqIcon in icon maps, a landing integrations.json entry, and block/tool registry entries. The API validation script baseline is bumped by one route for the upload endpoint.

^{Reviewed by Cursor Bugbot for commit 88bf28c. Configure here.}

[greptile-apps]

Greptile Summary

This PR adds a complete Linq iMessage/SMS/RCS integration to Sim — 34 tools covering chats, messages, attachments, phone numbers, capability checks, contact cards, and webhook subscriptions — all wired through a single linq block with API-key auth and an operation dropdown.

• The file-upload flow (create_attachment) correctly proxies through an internal /api/tools/linq/upload route that enforces internal auth, file-access authorization, and Linq's 100 MB cap before executing the two-step presigned-PUT protocol.
• buildMessageContent and the send_voice_memo body builder both include runtime guards that surface clear errors when no content is supplied, addressing concerns raised in prior review rounds.
• The block's field-remapping layer (e.g. webhookTargetUrl→targetUrl, contactPhoneNumber→phoneNumber) is consistent with tool param names across all 34 operations.

Confidence Score: 5/5

This PR is safe to merge; the new Linq integration is well-scoped, follows established patterns, and carries no changes to existing functionality.

All 34 tools follow the same auth, error-handling, and response-mapping conventions as existing integrations. The file-upload proxy route correctly chains auth, access authorization, size validation, and the two-step Linq presigned-PUT flow. Prior review concerns around empty-body messages and voice-memo double-dereference were resolved in the earlier commit. The one remaining suggestion (guarding against empty PUT bodies in update_chat and update_webhook_subscription) is a defensive-coding improvement, not a current defect.

apps/sim/tools/linq/update_chat.ts and apps/sim/tools/linq/update_webhook_subscription.ts — both PUT endpoints can receive an empty body when all optional fields are omitted.

Important Files Changed

Filename	Overview
apps/sim/app/api/tools/linq/upload/route.ts	New internal route implementing Linq's two-step pre-upload flow; validates auth, size limit, and file presence; correctly uses assertToolFileAccess and downloadFileFromStorage.
apps/sim/blocks/blocks/linq.ts	Single block with 34 operations and complex params-mapping function; field remapping is consistent with tool param names; update_chat and update_webhook_subscription can produce empty PUT bodies when all optional fields are omitted.
apps/sim/tools/linq/utils.ts	Shared utilities; buildMessageContent correctly throws when no content parts are assembled; error extraction handles both nested and flat response shapes.
apps/sim/tools/linq/create_attachment.ts	Delegates to the internal /api/tools/linq/upload route; correctly unwraps data.output.
apps/sim/tools/linq/update_webhook_subscription.ts	Uses PUT with all-optional body fields; empty body possible when no optional fields are provided.
apps/sim/tools/linq/types.ts	Comprehensive type definitions for all 34 tools.
apps/sim/lib/api/contracts/tools/communication/messaging.ts	Adds linqUploadAttachmentBodySchema and contract correctly.
apps/sim/tools/registry.ts	All 34 Linq tools correctly registered under linq_* keys.

Sequence Diagram

sequenceDiagram
    participant Block as Linq Block (UI)
    participant Tool as linq_create_attachment tool
    participant Route as /api/tools/linq/upload
    participant Auth as checkInternalAuth
    participant Storage as File Storage
    participant LinqReg as Linq POST /attachments
    participant S3 as Presigned PUT URL

    Block->>Tool: "params { apiKey, file, filename, contentType }"
    Tool->>Route: POST /api/tools/linq/upload (JSON body)
    Route->>Auth: checkInternalAuth(request)
    Auth-->>Route: "{ success, userId }"
    Route->>Route: parseRequest(linqUploadAttachmentContract)
    alt file provided (UserFile reference)
        Route->>Storage: downloadFileFromStorage(userFile)
        Storage-->>Route: buffer
    else fileContent provided (base64)
        Route->>Route: Buffer.from(fileContent, 'base64')
    end
    Route->>Route: validate size ≤ 100MB
    Route->>LinqReg: "POST /attachments { filename, content_type, size_bytes }"
    LinqReg-->>Route: "{ attachment_id, upload_url, required_headers, http_method }"
    Route->>S3: PUT upload_url (file bytes, required_headers)
    S3-->>Route: 200 OK
    Route-->>Tool: "{ success: true, output: { attachmentId, downloadUrl, … } }"
    Tool-->>Block: output.attachmentId

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^{Reviewed by Cursor Bugbot for commit 88bf28c. Configure here.}