feat: handle images sent to non-vision models in Slack, Linear, and web UI (#1560)

* feat: handle images sent to non-vision models in Slack, Linear, and web UI

Add vision capability checks across all image input paths. When a user
sends images to a text-only model (e.g. GLM 5.2, DeepSeek V4 Pro), the
images are now skipped and a warning is injected into the prompt instead
of sending unsupported content to the model.

- Slack: resolve model at webhook time, skip image fetch + add warning
- Linear: same pattern as Slack
- Queued message middleware: read resolved model from thread metadata,
  strip images from queued payloads for text-only models
- Web UI: disable submit + show inline warning when images are attached
  to a non-vision model selection
- Shared: resolve_agent_model_id helper + vision_not_supported_warning

Co-authored-by: open-swe[bot] <open-swe@users.noreply.github.com>

* test: mock resolve_agent_model_id in Slack mention test

The test_process_slack_mention_queues_active_thread_message test was
missing a mock for the new resolve_agent_model_id call added to the
Slack webhook handler, causing a TypeError when image URLs triggered
the model resolution path.

Co-authored-by: open-swe[bot] <open-swe@users.noreply.github.com>

* fix: include vision warning in queued payload for text-only models

Update the prompt variable (not just content_blocks) before clearing
image_urls so the queued payload also carries the warning text when a
Slack/Linear follow-up arrives while the thread is busy.

Co-authored-by: open-swe[bot] <open-swe@users.noreply.github.com>

---------

Co-authored-by: open-swe[bot] <open-swe@users.noreply.github.com>

agent/dashboard/agent_overrides.py

@@ -10,6 +10,7 @@ from langgraph_sdk import get_client
 
 from .options import SUPPORTED_MODEL_IDS, model_supports_effort, provider_fallback_pair
 from .profiles import PROFILES_NAMESPACE
+from .team_settings import get_team_default_model
 from .user_mappings import cached_login_for_email, login_for_email
 
 logger = logging.getLogger(__name__)
@@ -135,3 +136,23 @@ def normalize_profile_subagent_overrides(
         model_key="default_subagent_model",
         effort_key="subagent_reasoning_effort",
     )
+
+
+async def resolve_agent_model_id(
+    github_login: str | None,
+    per_thread_model_id: str | None = None,
+) -> str:
+    """Resolve the agent model ID using the same precedence as ``get_agent``.
+
+    Order: per-thread override → profile override → team default.
+    """
+    model_id, _effort = await get_team_default_model("agent")
+    if github_login:
+        profile = await load_profile(github_login)
+        if profile:
+            overridden_model, _ = normalize_profile_overrides(profile)
+            if overridden_model:
+                model_id = overridden_model
+    if isinstance(per_thread_model_id, str) and per_thread_model_id in SUPPORTED_MODEL_IDS:
+        model_id = per_thread_model_id
+    return model_id

agent/middleware/check_message_queue.py

@@ -14,8 +14,10 @@ import httpx
 from langchain.agents.middleware import AgentState, before_model
 from langgraph.config import get_config, get_store
 from langgraph.runtime import Runtime
+from langgraph_sdk import get_client
 
-from ..utils.multimodal import fetch_image_block
+from ..dashboard.options import model_supports_images
+from ..utils.multimodal import fetch_image_block, vision_not_supported_warning
 
 logger = logging.getLogger(__name__)
 
@@ -34,8 +36,25 @@ class LinearNotifyState(AgentState):
     linear_messages_sent_count: int
 
 
+async def _resolve_thread_model_id(thread_id: str) -> str | None:
+    """Read the resolved model from thread metadata (set by ``get_agent``)."""
+    try:
+        client = get_client()
+        thread = await client.threads.get(thread_id)
+        metadata = thread.get("metadata") if isinstance(thread, dict) else None
+        if not isinstance(metadata, dict):
+            return None
+        model = metadata.get("model")
+        return model if isinstance(model, str) and model else None
+    except Exception:
+        logger.debug("Could not read thread metadata for model resolution", exc_info=True)
+        return None
+
+
 async def _build_blocks_from_payload(
     payload: dict[str, Any],
+    *,
+    model_id: str | None = None,
 ) -> list[dict[str, Any]]:
     text = payload.get("text", "")
     image_urls = payload.get("image_urls", []) or []
@@ -48,6 +67,18 @@ async def _build_blocks_from_payload(
 
     if not image_urls:
         return blocks
+    if model_id and not model_supports_images(model_id):
+        logger.warning(
+            "Skipping %d queued image(s): model %s does not support images",
+            len(image_urls),
+            model_id,
+        )
+        if text:
+            blocks[0] = {
+                "type": "text",
+                "text": text + vision_not_supported_warning(model_id, len(image_urls)),
+            }
+        return blocks
     async with httpx.AsyncClient() as client:
         for image_url in image_urls:
             image_block = await fetch_image_block(image_url, client)
@@ -117,6 +148,15 @@ async def check_message_queue_before_model(  # noqa: PLR0911
             thread_id,
         )
 
+        has_images = any(
+            isinstance(msg.get("content"), dict)
+            and (msg["content"].get("image_urls") or msg["content"].get("images"))
+            for msg in queued_messages
+        )
+        resolved_model_id: str | None = None
+        if has_images:
+            resolved_model_id = await _resolve_thread_model_id(thread_id)
+
         content_blocks: list[dict[str, Any]] = []
         for msg in queued_messages:
             content = msg.get("content")
@@ -126,7 +166,7 @@ async def check_message_queue_before_model(  # noqa: PLR0911
                 "text" in content or "image_urls" in content or "images" in content
             ):
                 logger.debug("Queued message contains text + image URLs")
-                blocks = await _build_blocks_from_payload(content)
+                blocks = await _build_blocks_from_payload(content, model_id=resolved_model_id)
                 content_blocks.extend(blocks)
                 continue
             if isinstance(content, list):

agent/utils/multimodal.py

@@ -37,6 +37,15 @@ def extract_image_urls(text: str) -> list[str]:
     return deduped
 
 
+def vision_not_supported_warning(model_id: str, image_count: int) -> str:
+    """Build a prompt-visible warning when images are sent to a text-only model."""
+    return (
+        f"\n\n**Note:** {image_count} image(s) were attached but the current model "
+        f"({model_id}) does not support image input. The images were not included. "
+        "Please switch to a vision-enabled model to process images."
+    )
+
+
 async def fetch_image_block(
     image_url: str,
     client: httpx.AsyncClient,

agent/webapp.py

@@ -24,11 +24,13 @@ from .ci_autofix import handle_ci_failure, handle_review_feedback
 from .dashboard import router as dashboard_router
 from .dashboard.agent_overrides import (
     get_profile_default_repo,
+    resolve_agent_model_id,
     resolve_login_from_email_async,
 )
 from .dashboard.autofix_state import set_pr_autofix_disabled
 from .dashboard.enabled_repos import is_review_repo_enabled
 from .dashboard.oauth import build_settings_url
+from .dashboard.options import model_supports_images
 from .dashboard.profiles import get_profile, get_valid_access_token, has_access_token_record
 from .dashboard.team_settings import (
     get_team_default_repo,
@@ -96,7 +98,12 @@ from .utils.github_token import (
 )
 from .utils.linear import post_linear_trace_comment
 from .utils.linear_team_repo_map import LINEAR_TEAM_TO_REPO
-from .utils.multimodal import dedupe_urls, extract_image_urls, fetch_image_block
+from .utils.multimodal import (
+    dedupe_urls,
+    extract_image_urls,
+    fetch_image_block,
+    vision_not_supported_warning,
+)
 from .utils.repo import extract_repo_from_text
 from .utils.slack import (
     GitHubPrRef,
@@ -837,15 +844,27 @@ async def process_linear_issue(  # noqa: PLR0912, PLR0915
     content_blocks: list[dict[str, Any]] = [create_text_block(prompt)]
     if image_urls:
         image_urls = dedupe_urls(image_urls)
-        logger.info("Preparing %d image(s) for multimodal content", len(image_urls))
-        logger.debug("Image URLs: %s", image_urls)
+        linear_login = await resolve_login_from_email_async(user_email) if user_email else None
+        resolved_model_id = await resolve_agent_model_id(linear_login)
+        if model_supports_images(resolved_model_id):
+            logger.info("Preparing %d image(s) for multimodal content", len(image_urls))
+            logger.debug("Image URLs: %s", image_urls)
 
-        async with httpx.AsyncClient() as client:
-            for image_url in image_urls:
-                image_block = await fetch_image_block(image_url, client)
-                if image_block:
-                    content_blocks.append(image_block)
-        logger.info("Built %d content block(s) for prompt", len(content_blocks))
+            async with httpx.AsyncClient() as client:
+                for image_url in image_urls:
+                    image_block = await fetch_image_block(image_url, client)
+                    if image_block:
+                        content_blocks.append(image_block)
+            logger.info("Built %d content block(s) for prompt", len(content_blocks))
+        else:
+            logger.warning(
+                "Skipping %d image(s) for Linear issue: model %s does not support images",
+                len(image_urls),
+                resolved_model_id,
+            )
+            prompt += vision_not_supported_warning(resolved_model_id, len(image_urls))
+            content_blocks[0] = create_text_block(prompt)
+            image_urls = []
 
     linear_project_id = ""
     linear_issue_number = ""
@@ -1068,18 +1087,30 @@ async def process_slack_mention(event_data: dict[str, Any], repo_config: dict[st
         ]
         + image_urls_from_links
     )
-    if image_urls:
-        logger.info("Preparing %d image(s) for Slack mention", len(image_urls))
-        async with httpx.AsyncClient() as http_client:
-            for image_url in image_urls:
-                image_block = await fetch_image_block(image_url, http_client)
-                if image_block:
-                    content_blocks.append(image_block)
 
     mapped_login = await login_for_slack_id(user_id)
     if not mapped_login and user_email:
         mapped_login = await login_for_email(user_email)
 
+    if image_urls:
+        resolved_model_id = await resolve_agent_model_id(mapped_login)
+        if model_supports_images(resolved_model_id):
+            logger.info("Preparing %d image(s) for Slack mention", len(image_urls))
+            async with httpx.AsyncClient() as http_client:
+                for image_url in image_urls:
+                    image_block = await fetch_image_block(image_url, http_client)
+                    if image_block:
+                        content_blocks.append(image_block)
+        else:
+            logger.warning(
+                "Skipping %d image(s) for Slack mention: model %s does not support images",
+                len(image_urls),
+                resolved_model_id,
+            )
+            prompt += vision_not_supported_warning(resolved_model_id, len(image_urls))
+            content_blocks[0] = create_text_block(prompt)
+            image_urls = []
+
     # Open SWE opens PRs as the triggering user, so a run only proceeds when we
     # have a valid user GitHub token. Users who have never signed in with
     # GitHub, and users whose stored authorization is no longer usable, are

tests/test_check_message_queue.py

@@ -7,6 +7,7 @@ import pytest
 
 from agent.middleware.check_message_queue import (
     DASHBOARD_HANDOFF_MARKER,
+    _build_blocks_from_payload,
     check_message_queue_before_model,
 )
 
@@ -53,3 +54,31 @@ async def test_check_message_queue_injects_dashboard_handoff_instruction() -> No
     assert DASHBOARD_HANDOFF_MARKER in message["content"][0]["text"]
     assert message["content"][1] == {"type": "text", "text": "continue in web"}
     assert store.deleted == [(("queue", "thread-1"), "pending_messages")]
+
+
+@pytest.mark.asyncio
+async def test_build_blocks_skips_images_for_text_only_model() -> None:
+    payload = {
+        "text": "see this screenshot",
+        "image_urls": ["https://files.slack.com/fake.png"],
+    }
+    blocks = await _build_blocks_from_payload(
+        payload, model_id="fireworks:accounts/fireworks/models/glm-5p2"
+    )
+    assert len(blocks) == 1
+    assert blocks[0]["type"] == "text"
+    assert "does not support image input" in blocks[0]["text"]
+
+
+@pytest.mark.asyncio
+async def test_build_blocks_includes_images_for_vision_model() -> None:
+    payload: dict[str, Any] = {"text": "see this", "image_urls": []}
+    blocks = await _build_blocks_from_payload(payload, model_id="openai:gpt-5.5")
+    assert blocks == [{"type": "text", "text": "see this"}]
+
+
+@pytest.mark.asyncio
+async def test_build_blocks_no_model_check_fetches_images() -> None:
+    payload: dict[str, Any] = {"text": "see this", "image_urls": []}
+    blocks = await _build_blocks_from_payload(payload)
+    assert blocks == [{"type": "text", "text": "see this"}]

tests/test_dashboard_thread_api.py

@@ -4,6 +4,7 @@ import pytest
 from fastapi import HTTPException
 
 from agent.dashboard import thread_api
+from agent.dashboard.agent_overrides import resolve_agent_model_id
 from agent.dashboard.options import model_supports_images
 
 _TEXT_ONLY_MODEL = "fireworks:accounts/fireworks/models/deepseek-v4-pro"
@@ -79,6 +80,43 @@ async def test_resolve_agent_model_choice_applies_request_before_profile(monkeyp
     assert (model_id, effort) == ("anthropic:claude-opus-4-8", "high")
 
 
+async def test_resolve_agent_model_id_defaults_to_team_default(monkeypatch) -> None:
+    async def fake_team_default(role: str) -> tuple[str, str]:
+        return _TEXT_ONLY_MODEL, "high"
+
+    monkeypatch.setattr("agent.dashboard.agent_overrides.get_team_default_model", fake_team_default)
+    monkeypatch.setattr("agent.dashboard.agent_overrides.load_profile", lambda login: None)
+
+    model_id = await resolve_agent_model_id(None)
+    assert model_id == _TEXT_ONLY_MODEL
+
+
+async def test_resolve_agent_model_id_applies_profile_override(monkeypatch) -> None:
+    async def fake_team_default(role: str) -> tuple[str, str]:
+        return _TEXT_ONLY_MODEL, "high"
+
+    monkeypatch.setattr("agent.dashboard.agent_overrides.get_team_default_model", fake_team_default)
+
+    async def fake_load_profile(login: str) -> dict:
+        return {"default_model": _VISION_MODEL, "reasoning_effort": "medium"}
+
+    monkeypatch.setattr("agent.dashboard.agent_overrides.load_profile", fake_load_profile)
+
+    model_id = await resolve_agent_model_id("someuser")
+    assert model_id == _VISION_MODEL
+
+
+async def test_resolve_agent_model_id_applies_per_thread_override(monkeypatch) -> None:
+    async def fake_team_default(role: str) -> tuple[str, str]:
+        return _TEXT_ONLY_MODEL, "high"
+
+    monkeypatch.setattr("agent.dashboard.agent_overrides.get_team_default_model", fake_team_default)
+    monkeypatch.setattr("agent.dashboard.agent_overrides.load_profile", lambda login: None)
+
+    model_id = await resolve_agent_model_id(None, per_thread_model_id="anthropic:claude-opus-4-8")
+    assert model_id == "anthropic:claude-opus-4-8"
+
+
 def _new_thread_client(created: dict[str, object]) -> object:
     class FakeThreads:
         async def create(

tests/test_multimodal.py

@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-from agent.utils.multimodal import extract_image_urls
+from agent.utils.multimodal import extract_image_urls, vision_not_supported_warning
 
 
 def test_extract_image_urls_empty() -> None:
@@ -96,3 +96,15 @@ def test_extract_image_urls_mixed_markdown_and_direct() -> None:
         "https://example.com/another.gif",
     }
     assert len(result) == 3
+
+
+def test_vision_not_supported_warning_includes_model_and_count() -> None:
+    warning = vision_not_supported_warning("fireworks:.../glm-5p2", 2)
+    assert "glm-5p2" in warning
+    assert "2 image(s)" in warning
+    assert "does not support image input" in warning
+
+
+def test_vision_not_supported_warning_singular() -> None:
+    warning = vision_not_supported_warning("fireworks:.../glm-5p2", 1)
+    assert "1 image(s)" in warning

tests/test_slack_context.py

@@ -709,6 +709,11 @@ def test_process_slack_mention_queues_active_thread_message(
     monkeypatch.setattr(webapp, "refresh_user_mapping_cache", fake_refresh_cache)
     monkeypatch.setattr(webapp, "get_valid_access_token", fake_get_valid_access_token)
 
+    async def fake_resolve_agent_model_id(github_login, per_thread_model_id=None):
+        return "openai:gpt-5.5"
+
+    monkeypatch.setattr(webapp, "resolve_agent_model_id", fake_resolve_agent_model_id)
+
     thread_ts = "1700000000.000100"
     event_ts = "1700000000.000200"
     expected_thread_id = generate_thread_id_from_slack_thread("C123", thread_ts)

ui/src/components/agents/ported/CloudPromptBar.tsx

@@ -187,9 +187,17 @@ export const CloudPromptBar = memo(function CloudPromptBarComponent({
 
   const selectionLabel = formatModelSelection(models, selection)
 
+  const selectedModelSupportsImages = useMemo(() => {
+    if (!selection || pendingImages.length === 0) return true
+    return models.some(
+      (m) => m.id === selection.modelId && m.supports_images
+    )
+  }, [selection, pendingImages.length, models])
+
   const canSubmit =
     !disabled &&
     !isSubmitting &&
+    selectedModelSupportsImages &&
     (value.trim().length > 0 || pendingImages.length > 0)
 
   const handleSubmit = useCallback(async () => {
@@ -389,6 +397,14 @@ export const CloudPromptBar = memo(function CloudPromptBarComponent({
           </div>
         )}
 
+        {!selectedModelSupportsImages && (
+          <div className="mb-2 rounded-md border border-[var(--ui-border)] bg-[var(--ui-panel-2)] px-3 py-1.5 text-xs text-[color:var(--ui-text-muted)]">
+            The selected model does not support image input. Remove the
+            image{pendingImages.length > 1 ? "s" : ""} or switch to a
+            vision-enabled model to send.
+          </div>
+        )}
+
         <textarea
           ref={inputRef}
           rows={1}