Desktop connected to a remote gateway can now attach images and PDFs and
display agent-written images. Previously the desktop passed a LOCAL file path
to image.attach; on a remote gateway that path doesn't exist, so the image was
silently dropped ("skipped unreadable path") and the vision model never saw it.
The reverse direction was also broken — images the agent wrote on the gateway
rendered as dead links in the remote client.
Gateway (tui_gateway/server.py):
- image.attach_bytes: base64 byte upload written into the gateway's own images
dir and queued via the existing native-image-attach pipeline. Magic-byte
extension sniffing, data-URL prefix + whitespace tolerance, 25 MB cap,
structured error codes. Accepts content_base64/filename (canonical) and
data/ext (older-desktop aliases).
- pdf.attach: renders each page to PNG via pdftoppm (poppler-utils) at 150 DPI
and queues the pages as images; 50 MB / 25-page caps. Accepts host path or
base64 upload.
- Shared helpers (_decode_attach_base64, _sniff_image_ext, _queue_attached_image)
so the two methods and the existing image.attach don't duplicate logic.
Gateway (hermes_cli/web_server.py):
- GET /api/media: returns a gateway-local image as a base64 data URL so remote
clients can display it. Auth-gated like every /api route, extension
allowlist + size cap, AND confined to the gateway's own media roots
(images/screenshots/cache, resolved symlink-safe) so an authed caller can't
read image-extension files anywhere on disk.
Desktop (apps/desktop):
- syncImageAttachmentsForSubmit uploads bytes via image.attach_bytes when the
connection mode is 'remote'; the local fast path is unchanged.
- media.ts gains isRemoteGateway() + gatewayMediaDataUrl(); directive-text and
markdown-text fetch images over /api/media in remote mode.
Consolidates the competing remote-media PRs (#38876, #40317, #21908, #39437)
into one coherent implementation, taking the strongest parts of each and adding
shared-helper cleanup plus the /api/media root-confinement hardening on top.
The per-profile gateway switching from #38876 is intentionally left out as a
separable feature. TUI file uploads (#40492) remain a separate surface.
Tested: 11 new tui_gateway tests + 5 /api/media endpoint tests + desktop
media.remote unit tests; full tui_gateway + web_server suites green (472
passed); tsc -b clean; E2E verified the full attach→disk→queue and
gateway-path→data-URL display round-trip plus the out-of-root security block.
Co-authored-by: Max Mitcham <maxmitcham@mac.home>
Co-authored-by: Justlrnal4 <Justlrnal4@users.noreply.github.com>
Co-authored-by: Chris Cook <ccook@nvms.com>
Co-authored-by: Thomas Paquette <thomas.paquette@gmail.com>
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