synapbus/autonomous_summary.md

Autonomous Implementation Summary: Attachments & Threads Enhancement

Branch: 009-attachments-threads Date: 2026-03-17 Status: Complete

What Was Built

Attachments (Web UI + MCP + Admin CLI)

1. Web UI file upload: Users can attach files (images, PDFs, text files) when composing messages via a paperclip button in the compose form. Uploaded files show as chips with remove buttons.

2. Attachment display: Image attachments render as thumbnails (200x200px max) inline with messages. Clicking opens a fullscreen overlay with close (Escape, click-outside, X button) and download. Non-image files show as file icons with filename, size, and download link.

3. MCP agent support: Agents can attach files by uploading via upload_attachment action and passing hashes in the new attachments parameter on send_message. Tool descriptions updated to document the workflow.

4. File type validation: Upload restricted to images (jpg, png, gif, webp, svg), PDFs, and text files (txt, md, csv, json, xml, yaml, log). Invalid types rejected with clear error.

5. Admin backup/restore: synapbus attachments backup --output path.tar.gz and synapbus attachments restore --input path.tar.gz commands. Restore is dedup-safe (skips existing files).

Threads

1. Thread visibility: Messages with replies show an always-visible "N replies" badge with a chat bubble icon. Clicking opens the thread panel.

2. Reply count in API: All message API responses now include reply_count (batch-loaded via efficient GROUP BY query).

3. MCP threading: reply_to parameter description updated to clearly guide agents on threading behavior. Thread context visible in MCP responses.

4. Attachment display in threads: Thread panel also renders attachment thumbnails/file icons.

Files Modified

Backend (Go)

File	Changes
internal/messaging/types.go	Added AttachmentInfo struct, ReplyCount, Attachments fields to Message
internal/messaging/options.go	Added Attachments []string to SendOptions
internal/messaging/store.go	Added GetReplyCounts batch query method + interface
internal/messaging/service.go	Added AttachmentLinker interface, EnrichMessages, attachment linking in SendMessage
internal/attachments/model.go	Added ErrUnsupportedType error
internal/attachments/mime.go	Added IsAllowedType function
internal/attachments/service.go	Added file type validation in Upload
internal/api/messages_handler.go	Accept attachments[] in send, EnrichMessages in all handlers
internal/mcp/tools_hybrid.go	Added attachments param to send_message, updated descriptions, enrich responses
internal/mcp/bridge.go	Handle attachments in callSendMessage, callSendChannelMessage
internal/channels/service.go	Added attachments param to BroadcastMessage
internal/actions/registry.go	Updated upload_attachment description
cmd/synapbus/main.go	Added attachmentLinkerAdapter, wired into messaging service
cmd/synapbus/admin.go	Added backup and restore subcommands

Frontend (Svelte)

File	Changes
web/src/lib/api/client.ts	Added attachments.upload(), attachments param in messages.send()
web/src/lib/components/ComposeForm.svelte	Attachment upload button, file picker, preview chips
web/src/lib/components/AttachmentPreview.svelte	NEW — thumbnail + fullscreen overlay component
web/src/lib/components/MessageList.svelte	Attachment display, thread reply count badges
web/src/lib/components/ThreadPanel.svelte	Attachment display in thread messages

Tests

File	New Tests
internal/messaging/store_test.go	TestSQLiteMessageStore_GetReplyCounts (4 subtests)
internal/messaging/service_test.go	TestMessagingService_EnrichMessages (3 subtests)
internal/attachments/mime_test.go	TestIsAllowedType (12 cases)
internal/attachments/service_test.go	TestService_Upload_FileTypeValidation (5 cases)
internal/channels/service_test.go	Updated 13 call sites for new BroadcastMessage signature

Test Results

• Go tests: 25 packages, all pass, 0 failures
• Integration tests: 9 E2E tests, all pass
• New tests: 24 test cases added, all pass
• Web build: Svelte SPA builds successfully
• Binary build: 90MB arm64 binary compiles cleanly

Architecture Decisions

1. No circular dependencies: Used AttachmentLinker interface + adapter pattern to avoid messaging->attachments import
2. Batch loading: Reply counts loaded via single GROUP BY query; attachments loaded per-message (acceptable for LAN scale)
3. Client-side thumbnails: CSS-only resizing (no server-side image processing, preserves zero-CGO constraint)
4. Zero new migrations: Leveraged existing reply_to column (migration 007) and attachments table (migration 001)
5. Zero new dependencies: All using Go stdlib + existing libraries

Constitution Compliance

All 10 principles satisfied:

• I. Local-First: No external dependencies added
• II. MCP-Native: Agent features use MCP tools exclusively
• III. Pure Go, Zero CGO: stdlib archive/tar + compress/gzip for backup
• X. Web UI First-Class: Full attachment and thread UI experience