Images and file references

Zuno admits local images as typed prompt content and bounded UTF-8 files as explicit text context. The TUI, child-session composer, durable inbox, replay, headless run command, and provider request path share the same rich-content model; clients do not create a private image-only agent loop.

Paste an image in the TUI

Paste one existing image path as the complete paste payload. Zuno validates the file and replaces the visible path with a draft handle:

[Image #1]

The handle is presentation state. The image filename, detected MIME type, and base64 bytes travel separately as a typed image block when the prompt is sent. Deleting the handle before submission drops that image from the draft. A typed path is ordinary text; automatic attachment occurs only for a paste event that resolves to a supported local image.

Accepted path forms include an ordinary platform path, a matching quoted path, file:// URLs, ~/..., and POSIX paths with escaped spaces. Native Windows drive and UNC paths are resolved by Windows. Under WSL, an existing path such as C:\\Users\\me\\image.png may resolve through /mnt/c/....

When the terminal clipboard backend supplies image bytes directly, pasting the clipboard image creates the same [Image #N] draft attachment. Clipboard MIME and detected file content must agree.

Zuno detects content by magic bytes rather than filename extension. Supported formats are:

• PNG (image/png);
• JPEG (image/jpeg);
• GIF (image/gif);
• WebP (image/webp).

Each decoded image is limited to 20 MiB. Direct image pastes are not written to prompt recall history because the display handle alone cannot reconstruct the bytes; after submission, the actual rich input is stored in durable session parts and survives replay and child-session continuation.

Reference project files

In the TUI, type @ and select a project file, or enter a project-relative token such as:

Review @src/main.rs and compare it with @docs/architecture.png

References are resolved below the active project root after canonicalization. Absolute paths, missing files, directories, and paths that escape the project are refused. One prompt may reference at most 16 distinct files.

• A supported image becomes a typed image block and uses the 20 MiB image limit.
• Any other reference must be UTF-8 text no larger than 51,200 bytes and 2,000 lines. Its bounded contents are inserted with explicit begin/end markers.
• Unsupported binary files, including PDFs, are not silently converted or uploaded.

An image path paste and one or more @file references can be combined in the same prompt. Queue and steer submissions preserve the same typed content.

Attach files in headless mode

zuno run -f/--file is repeatable:

zuno run "Explain the evidence" \
  --file ./screenshot.png \
  --file ./notes.txt

Images use the same format detection and 20 MiB limit as the TUI. Other files must be bounded UTF-8 text under 51,200 bytes and 2,000 lines. A regular file is required. --command and --file cannot be combined because custom-command expansion does not yet carry typed attachments; Zuno fails explicitly instead of dropping them.

Durable and provider behavior

Before a model request, each image is persisted as a durable file part with its filename, MIME type, data URL, and base64 payload. Reopening a session rebuilds the same typed image block. Child sessions accept the same rich prompt shape as root sessions.

Compaction never sends historical image bytes to the compaction model. It replaces each image in the summary input with a label such as [Attached diagram.png (image/png)]; the original durable session record is unchanged.

The selected model route must advertise an image input modality. A generic attachment flag without image input is not enough. A text-only model fails with a typed permanent unsupported_capability error before a compatible transport call, rather than silently omitting the image or retrying the same invalid request.

Local attachment paths are read by the client process under the operating system account running Zuno. A pasted http:// or https:// URL is text, not a download request.