diff --git a/src/backend/routers/avatar.py b/src/backend/routers/avatar.py
index 6a5eadaa2..dae371d62 100644
--- a/src/backend/routers/avatar.py
+++ b/src/backend/routers/avatar.py
@@ -27,6 +27,47 @@
 
 AVATAR_DIR = Path("/data/avatars")
 
+
+# #957: Map image-generation error_kind → (HTTP status, user-facing detail).
+# Keeps the Gemini-internal error strings out of the dialog; gives the
+# operator/owner an actionable message per failure mode.
+_AVATAR_ERROR_HTTP = {
+    "not_configured": (
+        501,
+        "Avatar generation isn't configured on this server. Ask an admin "
+        "to set GEMINI_API_KEY.",
+    ),
+    "invalid_input": (400, "Avatar request was rejected by the image service."),
+    "safety_filter": (
+        422,
+        "The prompt was blocked by the image service's safety filters. "
+        "Try rephrasing and avoid descriptions of real people, sensitive "
+        "content, or trademarked characters.",
+    ),
+    "rate_limited": (
+        429,
+        "Image generation is rate-limited right now. Wait a minute and retry.",
+    ),
+    "upstream_error": (
+        502,
+        "Image generation service returned an error. This is usually transient — please retry.",
+    ),
+    "timeout": (
+        504,
+        "Image generation timed out. The model can be slow under load — please retry.",
+    ),
+    "unknown": (
+        422,
+        "Avatar generation failed. Check server logs for details.",
+    ),
+}
+
+
+def _avatar_http_for_result(result) -> tuple[int, str]:
+    """Pick the HTTP status + detail for an unsuccessful ImageGenerationResult."""
+    kind = getattr(result, "error_kind", None) or "unknown"
+    return _AVATAR_ERROR_HTTP.get(kind, _AVATAR_ERROR_HTTP["unknown"])
+
 # Diverse visual styles for default avatars — deterministically assigned from agent name hash
 # so each agent gets a unique look even when they share the same Docker type.
 _DEFAULT_AVATAR_STYLES = [
@@ -374,10 +415,8 @@ async def generate_avatar(
 
     service = get_image_generation_service()
     if not service.available:
-        raise HTTPException(
-            status_code=501,
-            detail="Image generation not available: GEMINI_API_KEY not configured",
-        )
+        status, detail = _AVATAR_ERROR_HTTP["not_configured"]
+        raise HTTPException(status_code=status, detail=detail)
 
     result = await service.generate_image(
         prompt=identity_prompt,
@@ -388,7 +427,8 @@ async def generate_avatar(
     )
 
     if not result.success:
-        raise HTTPException(status_code=422, detail=result.error)
+        status, detail = _avatar_http_for_result(result)
+        raise HTTPException(status_code=status, detail=detail)
 
     # Save optimized display avatar (.webp) and full-quality reference (.png)
     AVATAR_DIR.mkdir(parents=True, exist_ok=True)
@@ -454,10 +494,8 @@ async def regenerate_avatar(
 
     service = get_image_generation_service()
     if not service.available:
-        raise HTTPException(
-            status_code=501,
-            detail="Image generation not available: GEMINI_API_KEY not configured",
-        )
+        status, detail = _AVATAR_ERROR_HTTP["not_configured"]
+        raise HTTPException(status_code=status, detail=detail)
 
     reference_bytes = ref_path.read_bytes()
     result = await service.generate_variation(
@@ -468,7 +506,8 @@ async def regenerate_avatar(
     )
 
     if not result.success:
-        raise HTTPException(status_code=422, detail=result.error)
+        status, detail = _avatar_http_for_result(result)
+        raise HTTPException(status_code=status, detail=detail)
 
     # Save as optimized display avatar only (reference stays the same)
     avatar_path = AVATAR_DIR / f"{agent_name}.webp"
diff --git a/src/backend/services/image_generation_service.py b/src/backend/services/image_generation_service.py
index 6f868ab9b..6c6d4298c 100644
--- a/src/backend/services/image_generation_service.py
+++ b/src/backend/services/image_generation_service.py
@@ -47,6 +47,35 @@ class ImageGenerationResult:
     use_case: str = "general"
     aspect_ratio: str = "1:1"
     error: Optional[str] = None
+    # #957: coarse classification so the router can pick a meaningful HTTP
+    # status and the frontend can render an actionable message instead of a
+    # raw upstream error. Kinds:
+    #   not_configured  — GEMINI_API_KEY missing
+    #   invalid_input   — use_case / aspect_ratio rejected before API call
+    #   safety_filter   — upstream returned no image (prompt blocked)
+    #   rate_limited    — upstream HTTP 429
+    #   upstream_error  — upstream HTTP 5xx or unparseable response
+    #   timeout         — httpx timeout / connect error
+    #   unknown         — anything else
+    error_kind: Optional[str] = None
+
+
+def _classify_exception(exc: BaseException) -> str:
+    """Map a generation-path exception to one of the error_kind values."""
+    if isinstance(exc, httpx.TimeoutException):
+        return "timeout"
+    if isinstance(exc, (httpx.ConnectError, httpx.NetworkError)):
+        return "upstream_error"
+    msg = str(exc)
+    if "no image data" in msg or "safety filter" in msg.lower():
+        return "safety_filter"
+    if "API error 429" in msg:
+        return "rate_limited"
+    if "API error 5" in msg:  # 500/502/503/504
+        return "upstream_error"
+    if "API error 4" in msg:  # 400/401/403 — surfaced as upstream for now
+        return "upstream_error"
+    return "unknown"
 
 
 class ImageGenerationService:
@@ -95,6 +124,7 @@ async def generate_image(
                 use_case=use_case,
                 aspect_ratio=aspect_ratio,
                 error="GEMINI_API_KEY not configured",
+                error_kind="not_configured",
             )
 
         if use_case not in VALID_USE_CASES:
@@ -104,6 +134,7 @@ async def generate_image(
                 use_case=use_case,
                 aspect_ratio=aspect_ratio,
                 error=f"Invalid use_case: {use_case}. Must be one of: {VALID_USE_CASES}",
+                error_kind="invalid_input",
             )
 
         if aspect_ratio not in VALID_ASPECT_RATIOS:
@@ -113,6 +144,7 @@ async def generate_image(
                 use_case=use_case,
                 aspect_ratio=aspect_ratio,
                 error=f"Invalid aspect_ratio: {aspect_ratio}. Must be one of: {VALID_ASPECT_RATIOS}",
+                error_kind="invalid_input",
             )
 
         log_prefix = f"[IMG {agent_name or 'platform'}]"
@@ -145,7 +177,19 @@ async def generate_image(
                 aspect_ratio=aspect_ratio,
             )
         except Exception as e:
-            logger.error(f"{log_prefix} Image generation failed: {e}")
+            kind = _classify_exception(e)
+            logger.error(
+                "image_generation_failed",
+                extra={
+                    "agent_name": agent_name or "platform",
+                    "use_case": use_case,
+                    "aspect_ratio": aspect_ratio,
+                    "error_kind": kind,
+                    "exception_type": type(e).__name__,
+                    "error_message": str(e)[:500],
+                    "prompt_length": len(prompt),
+                },
+            )
             return ImageGenerationResult(
                 success=False,
                 refined_prompt=refined if refined != prompt else None,
@@ -153,6 +197,7 @@ async def generate_image(
                 use_case=use_case,
                 aspect_ratio=aspect_ratio,
                 error=str(e),
+                error_kind=kind,
             )
 
     async def refine_prompt(
@@ -336,6 +381,7 @@ async def generate_variation(
                 original_prompt=prompt,
                 aspect_ratio=aspect_ratio,
                 error="GEMINI_API_KEY not configured",
+                error_kind="not_configured",
             )
 
         log_prefix = f"[IMG {agent_name or 'platform'}]"
@@ -370,13 +416,24 @@ async def generate_variation(
                 aspect_ratio=aspect_ratio,
             )
         except Exception as e:
-            logger.error(f"{log_prefix} Variation generation failed: {e}")
+            kind = _classify_exception(e)
+            logger.error(
+                "image_variation_failed",
+                extra={
+                    "agent_name": agent_name or "platform",
+                    "aspect_ratio": aspect_ratio,
+                    "error_kind": kind,
+                    "exception_type": type(e).__name__,
+                    "error_message": str(e)[:500],
+                },
+            )
             return ImageGenerationResult(
                 success=False,
                 original_prompt=prompt,
                 use_case="avatar",
                 aspect_ratio=aspect_ratio,
                 error=str(e),
+                error_kind=kind,
             )
 
     async def generate_emotion_variation(
@@ -408,6 +465,7 @@ async def generate_emotion_variation(
                 original_prompt=emotion_prompt,
                 aspect_ratio=aspect_ratio,
                 error="GEMINI_API_KEY not configured",
+                error_kind="not_configured",
             )
 
         log_prefix = f"[IMG {agent_name or 'platform'}]"
@@ -433,13 +491,24 @@ async def generate_emotion_variation(
                 aspect_ratio=aspect_ratio,
             )
         except Exception as e:
-            logger.error(f"{log_prefix} Emotion variation generation failed: {e}")
+            kind = _classify_exception(e)
+            logger.error(
+                "image_emotion_variation_failed",
+                extra={
+                    "agent_name": agent_name or "platform",
+                    "aspect_ratio": aspect_ratio,
+                    "error_kind": kind,
+                    "exception_type": type(e).__name__,
+                    "error_message": str(e)[:500],
+                },
+            )
             return ImageGenerationResult(
                 success=False,
                 original_prompt=emotion_prompt,
                 use_case="avatar",
                 aspect_ratio=aspect_ratio,
                 error=str(e),
+                error_kind=kind,
             )
 
     async def close(self):
diff --git a/src/frontend/src/components/AvatarGenerateModal.vue b/src/frontend/src/components/AvatarGenerateModal.vue
index 8c662f0cb..123d821fd 100644
--- a/src/frontend/src/components/AvatarGenerateModal.vue
+++ b/src/frontend/src/components/AvatarGenerateModal.vue
@@ -80,7 +80,7 @@
 
 <script setup>
 import { ref, watch } from 'vue'
-import axios from 'axios'
+import api from '@/api'
 import AgentAvatar from './AgentAvatar.vue'
 
 const props = defineProps({
@@ -105,19 +105,37 @@ watch(() => props.show, (val) => {
   }
 })
 
+// #957: Map axios failures to actionable strings. Backend now sends a
+// friendly `detail` per kind, but we still need a fallback chain for the
+// no-response cases (network, nginx 504 with HTML body) that strip detail.
+function describeAvatarError(err, verb = 'generate') {
+  if (err?.response?.data?.detail && typeof err.response.data.detail === 'string') {
+    return err.response.data.detail
+  }
+  const status = err?.response?.status
+  if (status === 504) return `Avatar ${verb} timed out — please retry.`
+  if (status === 502 || status === 503) {
+    return `Image generation service is unavailable right now — please retry in a few minutes.`
+  }
+  if (!err?.response) {
+    return `Network error while trying to ${verb} avatar — check your connection and retry.`
+  }
+  return `Failed to ${verb} avatar (HTTP ${status}).`
+}
+
 async function generate() {
   if (!identityPrompt.value.trim()) return
   generating.value = true
   error.value = ''
 
   try {
-    await axios.post(`/api/agents/${props.agentName}/avatar/generate`, {
+    await api.post(`/api/agents/${props.agentName}/avatar/generate`, {
       identity_prompt: identityPrompt.value.trim()
-    })
+    }, { timeout: 180000 })
     emit('updated')
     emit('close')
   } catch (err) {
-    error.value = err.response?.data?.detail || 'Failed to generate avatar'
+    error.value = describeAvatarError(err, 'generate')
   } finally {
     generating.value = false
   }
@@ -128,11 +146,11 @@ async function removeAvatar() {
   error.value = ''
 
   try {
-    await axios.delete(`/api/agents/${props.agentName}/avatar`)
+    await api.delete(`/api/agents/${props.agentName}/avatar`)
     emit('updated')
     emit('close')
   } catch (err) {
-    error.value = err.response?.data?.detail || 'Failed to remove avatar'
+    error.value = describeAvatarError(err, 'remove')
   } finally {
     removing.value = false
   }
diff --git a/tests/unit/test_image_generation_service.py b/tests/unit/test_image_generation_service.py
index 04a2ddc4f..b205a797e 100644
--- a/tests/unit/test_image_generation_service.py
+++ b/tests/unit/test_image_generation_service.py
@@ -220,6 +220,64 @@ def test_default_values(self):
         assert result.mime_type == "image/png"
         assert result.use_case == "general"
         assert result.aspect_ratio == "1:1"
+        assert result.error_kind is None  # #957
+
+    def test_error_kind_field_is_settable(self):
+        """#957: error_kind drives router status/detail mapping."""
+        mod = _load_service()
+        result = mod.ImageGenerationResult(
+            success=False,
+            error="GEMINI_API_KEY not configured",
+            error_kind="not_configured",
+        )
+        assert result.error_kind == "not_configured"
+
+
+# =============================================================================
+# #957 — _classify_exception
+# =============================================================================
+
+@pytest.mark.unit
+class TestClassifyException:
+    """Map upstream exceptions to coarse error_kind values for the router."""
+
+    def test_timeout_exception_classified_as_timeout(self):
+        import httpx
+        mod = _load_service()
+        kind = mod._classify_exception(httpx.ReadTimeout("read timed out"))
+        assert kind == "timeout"
+
+    def test_connect_error_classified_as_upstream(self):
+        import httpx
+        mod = _load_service()
+        kind = mod._classify_exception(httpx.ConnectError("nope"))
+        assert kind == "upstream_error"
+
+    def test_safety_filter_runtimeerror(self):
+        mod = _load_service()
+        kind = mod._classify_exception(
+            RuntimeError("Gemini image API returned no image data. ...")
+        )
+        assert kind == "safety_filter"
+
+    def test_rate_limit_runtimeerror(self):
+        mod = _load_service()
+        kind = mod._classify_exception(
+            RuntimeError("Gemini text API error 429: rate limit")
+        )
+        assert kind == "rate_limited"
+
+    def test_upstream_5xx(self):
+        mod = _load_service()
+        kind = mod._classify_exception(
+            RuntimeError("Gemini image API error 503: service unavailable")
+        )
+        assert kind == "upstream_error"
+
+    def test_unknown_default(self):
+        mod = _load_service()
+        kind = mod._classify_exception(ValueError("something else"))
+        assert kind == "unknown"
 
 
 # =============================================================================