IdeA/.ideai/tickets/155/carnet.md

issueRef, version, updatedBy, updatedAt

issueRef	version	updatedBy	updatedAt
#155	4	kind agent_id agent a6c6ea12-bfc6-4bdc-8031-324102dfa34d	1786007117827

Objective

Allow the user to paste an image directly from the clipboard into the custom agent chat composer (for example after a screenshot) and send it as a proper attachment.

Dependency

This ticket depends on #154 because clipboard image paste must reuse the durable agent/chat attachment pipeline rather than reintroduce a local-only workaround.

User expectation

The experience should feel close to Codex / Claude Code:

• user focuses the custom chat composer;
• presses paste after taking a screenshot or copying an image;
• sees an attachment chip and, if practical, a lightweight preview;
• sends the message normally;
• the target agent can actually access the attached image in its sandbox.

Product constraints

• This is for the custom structured chat UI, not the raw PTY/TUI path.
• The feature must ride on first-class attachments, not on embedding base64 in the prompt or on temporary browser-only objects.
• If the message text is empty but an image attachment is present, product behavior should be explicitly decided: either allow send with attachment-only or require text. Recommendation: allow attachment-only send.

UX scope

Recommended MVP:

• intercept paste on the custom chat composer textarea;
• detect image MIME types from clipboard data (image/png, image/jpeg, potentially image/webp if stable);
• materialize the image through the foundation pipeline from #154;
• show an attachment chip with filename, MIME, and size if available;
• show a thumbnail preview when cheap and reliable;
• allow removing the pasted attachment before send;
• send through the same structured attachment contract as picked files.

Possible follow-ups, not required in this ticket unless cheap:

• multiple pasted images in one operation;
• drag-and-drop onto the composer;
• richer preview lightbox;
• file progress UI for large payloads.

Edge cases

• clipboard contains both text and image;
• clipboard contains unsupported binary data;
• paste permission / browser-webview limitations;
• pasted image too large;
• rapid repeated pastes;
• session recovery / resend after structured session NOT_FOUND;
• removing/replacing an attachment before send.

Expected technical direction

Frontend

• handle onPaste on the composer;
• inspect clipboard items and prefer image payloads when present;
• route pasted binary data through the attachment creation/import API from #154;
• keep attachment state typed and separate from message text;
• render attachment chip/preview in the composer area;
• keep keyboard behavior intact: Enter sends, Shift+Enter newline.

Backend

• no bespoke clipboard-only path; use the generic attachment pipeline from #154;
• if a dedicated import endpoint is needed for raw bytes from the frontend, it should still create the same attachment entity/store record as picked files.

Sandbox / runtime

• the agent must read the resulting stored image through the managed attachment location;
• no dependence on the clipboard source continuing to exist after paste.

Acceptance criteria

• Pasting an image into the custom chat composer creates a real attachment entry.
• The composer shows the attachment before send and lets the user remove it.
• Sending the turn makes the attachment available to the target agent through the first-class attachment pipeline.
• The feature works for a typical screenshot flow on supported desktop targets.
• Failure states are explicit and recoverable (unsupported clipboard content, too large, import failed).

QA expectations

• verify screenshot paste on the supported desktop platform(s);
• verify pasted image is readable by the agent in practice, not just visible in UI;
• verify send with attachment-only if product accepts it;
• verify no regression on plain text send, picked-file attach, and session recovery.

Quality bar

No workaround such as:

• adding a fake path string to the prompt without importing the file;
• storing only a browser blob URL;
• embedding the whole image inline in prompt text;
• relying on arbitrary external paths that the sandbox may or may not read.

This ticket is considered done only if the UX is good and the underlying file-access model is solid.