Bug: macOS screenshot thumbnails dropped into terminal fail to attach (TemporaryItems race)

Environment
• OS: macOS (any version with screenshot drag-to-thumbnail)
• Kimi CLI version: 1.40.0
• Install method: uv tool install kimi-cli
Reproduction

1. Take a macOS screenshot (Cmd+Shift+4) but don't save it — drag the floating thumbnail directly into the Kimi CLI t
   inal.
2. The path appears in the prompt, e.g.:
   /var/folders/hx/.../TemporaryItems/NSIRD_screencaptureui_abc123/Screenshot 2026-05-07 at 5.47.51 PM.png
3. Submit the message.
4. Result: The agent calls ReadMediaFile and gets:
   Error: File not found — /var/folders/hx/.../Screenshot ... PM.png
   By the time the tool runs, macOS has already reaped the TemporaryItems/NSIRD_* directory (cleanup window is ~1–3 s
   nds).
   Root cause
   The image path is read lazily (via ReadMediaFile tool call inside the agent loop), but the path lifecycle is eager (≤
   3 seconds). The two clocks don't agree.
   Claude Code CLI and Cursor solve this the same way: scan the user's input string at submit time, detect image-extensi
   on paths, read them synchronously before the message goes to the model, and attach the bytes as multimodal content bl
   ocks. The agent never sees a path it has to chase.
   Fix
   The fix is localized to the input-handling module (kimi_cli/ui/shell/placeholders.py) plus a small catch-block in the
   shell event router.
   What changed
   File Change
   ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
   kimi_cli/ui/shell/placeholders.py Added synchronous image-path scanning in PromptPlaceholderManager.resolve_comma
   nd(): detects .png/.jpg/.jpeg/.webp/.gif/.heic/.bmp/.svg paths in literal text,
   reads them at submit time, validates size (≤ 20 MB), sniffs MIME from magic byt
   es, and attaches ImageURLPart content blocks.
   kimi_cli/ui/shell/init.py Catches ImagePathResolutionError in _route_prompt_events() and prints a user-fa
   cing error before resuming the prompt loop.
   kimi_cli/ui/shell/prompt.py Threads model_capabilities into PromptPlaceholderManager so image attachment is
   skipped when the model doesn't support image_in.
   tests/ 26 tests covering drag-and-drop, spaces, quotes, Unicode, ~, relative paths, de
   duplication, size cap, missing files, non-image extensions, URLs, and capabilit
   y gating.
   Key behaviors
   • Drag macOS screenshot thumbnail → image visible to model on first turn, zero tool calls.
   • Path with spaces / quotes / Unicode / ~ → all resolve correctly.
   • Two images in one message → both attached as separate content blocks.
   • Same path twice → deduplicated to one attachment.
   • 50 MB image → rejected with inline size-cap error.
   • Missing explicit path (e.g., reaped temp file) → clear error: "Image at was no longer accessible (macOS Temp
   aryItems likely reaped); save to a persistent location and try again."
   • .txt / .pdf / .json path → NOT auto-read; flows through normal text path.
   • https://... URL → left as text, not treated as a missing local file.
   • file:///path/to/image.png → stripped to /path/to/image.png and attached.
   Patch

Tests
All 26 new tests pass:
platform darwin -- Python 3.13.12, pytest-9.0.3
collected 26 items

test_placeholders.py::TestFindImagePathCandidates::test_basic_absolute PASSED
test_placeholders.py::TestFindImagePathCandidates::test_escaped_spaces PASSED
test_placeholders.py::TestFindImagePathCandidates::test_quoted_paths PASSED
test_placeholders.py::TestFindImagePathCandidates::test_no_candidates PASSED
test_placeholders.py::TestFindImagePathCandidates::test_path_with_spaces PASSED
test_placeholders.py::TestExpandImagePath::test_unescape_spaces PASSED
test_placeholders.py::TestExpandImagePath::test_tilde PASSED
test_placeholders.py::TestReadImageSync::test_valid_png PASSED
test_placeholders.py::TestReadImageSync::test_svg PASSED
test_placeholders.py::TestReadImageSync::test_size_cap PASSED
test_placeholders.py::TestReadImageSync::test_fake_png PASSED
test_placeholders.py::TestReadImageSync::test_missing_file PASSED
test_placeholders.py::TestResolveImagePathsInText::test_valid_png PASSED
test_placeholders.py::TestResolveImagePathsInText::test_two_images PASSED
test_placeholders.py::TestResolveImagePathsInText::test_duplicate_path PASSED
test_placeholders.py::TestResolveImagePathsInText::test_missing_explicit_path PASSED
test_placeholders.py::TestResolveImagePathsInText::test_missing_simple_filename_treated_as_text PASSED
test_placeholders.py::TestResolveImagePathsInText::test_text_not_auto_read PASSED
test_placeholders.py::TestResolveImagePathsInText::test_quoted_path PASSED
test_placeholders.py::TestResolveImagePathsInText::test_escaped_spaces PASSED
test_placeholders.py::TestResolveImagePathsInText::test_relative_path PASSED
test_placeholders.py::TestResolveImagePathsInText::test_unicode_filename PASSED
test_placeholders.py::TestResolveImagePathsInText::test_url_left_as_text PASSED
test_placeholders.py::TestPromptPlaceholderManager::test_resolve_command_with_image PASSED
test_placeholders.py::TestPromptPlaceholderManager::test_resolve_command_with_pasted_text_and_image PASSED
test_placeholders.py::TestPromptPlaceholderManager::test_capability_gating_no_image_in PASSED

============================== 26 passed in 0.51s ==============================
Prior art
• Claude Code CLI ships this exact behavior. Drag a macOS screenshot thumbnail directly into the prompt and it works
the first turn — no ReadMediaFile, no TemporaryItems race.
• Cursor implements the same for Finder drag-and-drop.
Impact
This is table-stakes UX for any terminal-based coding agent on macOS. The screenshot-thumbnail workflow is too common
to lose to a 1-second cleanup race.
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I'm happy to open this as a proper PR if the maintainers prefer — just let me know and I'll fork + branch.

Start with kimi_cli/ui/shell/placeholders.py and trace PromptPlaceholderManager.resolve_command(), then review the related routing in kimi_cli/ui/shell/init.py and capability wiring in kimi_cli/ui/shell/prompt.py. Run the 26 tests listed for test_placeholders.py; done means macOS temporary image paths are attached before model handling, errors are user-facing, and capability gating remains covered.