diff --git a/pkg/attachment/modelcaps/modelcaps_test.go b/pkg/attachment/modelcaps/modelcaps_test.go
index a473887a6..fc410c86e 100644
--- a/pkg/attachment/modelcaps/modelcaps_test.go
+++ b/pkg/attachment/modelcaps/modelcaps_test.go
@@ -13,6 +13,51 @@ func buildStore(providers map[string]modelsdev.Provider) *modelsdev.Store {
 	return modelsdev.NewDatabaseStore(db)
 }
 
+// TestLoadFromStore_QualifiedIDRequired is the regression test for the bug
+// fixed by pass-fully-qualified-provider-model-ID: modelcaps.Load (and
+// LoadFromStore) requires a "provider/model" key to find a model in the
+// models.dev database.  A bare model name without the provider prefix must
+// NOT resolve to vision capabilities — it falls back to text-only.
+//
+// Before the fix, callers passed c.ModelConfig.Model (e.g. "claude-sonnet-4-6")
+// instead of c.ModelConfig.Provider+"/"+c.ModelConfig.Model; the lookup always
+// missed and all image / PDF attachments were silently dropped.
+func TestLoadFromStore_QualifiedIDRequired(t *testing.T) {
+	store := buildStore(map[string]modelsdev.Provider{
+		"anthropic": {
+			Models: map[string]modelsdev.Model{
+				"claude-sonnet-4-6": {
+					Name: "Claude Sonnet 4.6",
+					Modalities: modelsdev.Modalities{
+						Input:  []string{"text", "image", "pdf"},
+						Output: []string{"text"},
+					},
+				},
+			},
+		},
+	})
+
+	// Bare model name (the original bug): must fall back to conservative text-only caps.
+	bareID := "claude-sonnet-4-6"
+	mcBare := modelcaps.LoadFromStore(store, bareID)
+	if mcBare.Supports("image/jpeg") {
+		t.Errorf("bare model name %q must NOT resolve to vision caps: image/jpeg should be dropped", bareID)
+	}
+	if mcBare.Supports("application/pdf") {
+		t.Errorf("bare model name %q must NOT resolve to vision caps: application/pdf should be dropped", bareID)
+	}
+
+	// Fully-qualified ID (the fix): must resolve to vision+pdf caps.
+	qualifiedID := "anthropic/claude-sonnet-4-6"
+	mcQualified := modelcaps.LoadFromStore(store, qualifiedID)
+	if !mcQualified.Supports("image/jpeg") {
+		t.Errorf("qualified ID %q must resolve to vision caps: image/jpeg should be passed through", qualifiedID)
+	}
+	if !mcQualified.Supports("application/pdf") {
+		t.Errorf("qualified ID %q must resolve to vision caps: application/pdf should be passed through", qualifiedID)
+	}
+}
+
 func TestLoadFromStore_VisionModel(t *testing.T) {
 	store := buildStore(map[string]modelsdev.Provider{
 		"anthropic": {
diff --git a/pkg/model/provider/anthropic/attachments.go b/pkg/model/provider/anthropic/attachments.go
index 773e185c6..62cb81ddd 100644
--- a/pkg/model/provider/anthropic/attachments.go
+++ b/pkg/model/provider/anthropic/attachments.go
@@ -12,18 +12,19 @@ import (
 	"github.com/docker/docker-agent/pkg/attachment"
 	"github.com/docker/docker-agent/pkg/attachment/modelcaps"
 	"github.com/docker/docker-agent/pkg/chat"
+	"github.com/docker/docker-agent/pkg/modelsdev"
 )
 
-// convertDocument converts a chat.Document to standard Anthropic SDK content blocks
-// (not the Beta API).
+// convertDocumentFromStore converts a chat.Document to standard Anthropic SDK content blocks
+// using an explicit modelsdev.Store for capability lookup.
 //
 // Routing:
 //   - image/* with InlineData → ImageBlockParam (base64 source)
 //   - application/pdf with InlineData → DocumentBlockParam (base64)
 //   - text with InlineText → TextBlockParam with TXTEnvelope
 //   - unsupported / no content → nil (logged as warning)
-func convertDocument(ctx context.Context, doc chat.Document, modelID string) ([]anthropic.ContentBlockParamUnion, error) {
-	mc, _ := modelcaps.Load(modelID)
+func convertDocumentFromStore(ctx context.Context, doc chat.Document, modelID string, store *modelsdev.Store) ([]anthropic.ContentBlockParamUnion, error) {
+	mc := modelcaps.LoadFromStore(store, modelID)
 	return convertDocumentWithCaps(ctx, doc, mc)
 }
 
diff --git a/pkg/model/provider/anthropic/attachments_test.go b/pkg/model/provider/anthropic/attachments_test.go
index 6cc8551a6..889089063 100644
--- a/pkg/model/provider/anthropic/attachments_test.go
+++ b/pkg/model/provider/anthropic/attachments_test.go
@@ -9,6 +9,9 @@ import (
 
 	"github.com/docker/docker-agent/pkg/attachment/modelcaps"
 	"github.com/docker/docker-agent/pkg/chat"
+	"github.com/docker/docker-agent/pkg/config/latest"
+	"github.com/docker/docker-agent/pkg/model/provider/base"
+	"github.com/docker/docker-agent/pkg/modelsdev"
 )
 
 // minJPEG is a minimal JPEG magic-byte header for use in tests.
@@ -51,6 +54,58 @@ func TestConvertDocumentAnthropic_StrategyB64_PDF(t *testing.T) {
 	assert.Nil(t, blocks[0].OfText, "expected no text block for PDF")
 }
 
+// TestConvertDocumentAnthropic_QualifiedIDRequired is the regression test for
+// the bug where convertUserMultiContent passed only c.ModelConfig.Model (bare
+// model name) to convertDocument instead of c.ModelConfig.Provider+"/"+c.ModelConfig.Model.
+// When the bare name was used, modelcaps.Load always missed the model and all
+// image/PDF attachments were silently dropped.
+//
+// The test constructs a Client with Provider="anthropic" and Model="claude-sonnet-4-6",
+// injects a fake modelsdev.Store, and calls convertUserMultiContent directly.
+// The image block must be present in the output — which only happens if the
+// fully-qualified "anthropic/claude-sonnet-4-6" was used for the caps lookup.
+func TestConvertDocumentAnthropic_QualifiedIDRequired(t *testing.T) {
+	store := modelsdev.NewDatabaseStore(&modelsdev.Database{
+		Providers: map[string]modelsdev.Provider{
+			"anthropic": {
+				Models: map[string]modelsdev.Model{
+					"claude-sonnet-4-6": {
+						Modalities: modelsdev.Modalities{
+							Input: []string{"text", "image", "pdf"},
+						},
+					},
+				},
+			},
+		},
+	})
+
+	c := &Client{
+		Config: base.Config{
+			ModelConfig: latest.ModelConfig{
+				Provider: "anthropic",
+				Model:    "claude-sonnet-4-6",
+			},
+		},
+		modelsStore: store,
+	}
+
+	parts := []chat.MessagePart{
+		{
+			Type: chat.MessagePartTypeDocument,
+			Document: &chat.Document{
+				Name:     "photo.jpg",
+				MimeType: "image/jpeg",
+				Source:   chat.DocumentSource{InlineData: minJPEG},
+			},
+		},
+	}
+
+	blocks, err := c.convertUserMultiContent(t.Context(), parts)
+	require.NoError(t, err)
+	require.Len(t, blocks, 1, "image must not be dropped when provider+model ID is used for caps lookup")
+	assert.NotNil(t, blocks[0].OfImage, "expected native image block")
+}
+
 func TestConvertDocumentAnthropic_StrategyTXT(t *testing.T) {
 	doc := chat.Document{
 		Name:     "spec.md",
@@ -58,7 +113,7 @@ func TestConvertDocumentAnthropic_StrategyTXT(t *testing.T) {
 		Source:   chat.DocumentSource{InlineText: "## Specification"},
 	}
 
-	blocks, err := convertDocument(t.Context(), doc, "")
+	blocks, err := convertDocumentWithCaps(t.Context(), doc, modelcaps.ModelCapabilities{})
 	require.NoError(t, err)
 	require.Len(t, blocks, 1)
 	require.NotNil(t, blocks[0].OfText)
@@ -74,7 +129,7 @@ func TestConvertDocumentAnthropic_StrategyTXT_Envelope(t *testing.T) {
 		Source:   chat.DocumentSource{InlineText: "some notes"},
 	}
 
-	blocks, err := convertDocument(t.Context(), doc, "")
+	blocks, err := convertDocumentWithCaps(t.Context(), doc, modelcaps.ModelCapabilities{})
 	require.NoError(t, err)
 	require.Len(t, blocks, 1)
 	require.NotNil(t, blocks[0].OfText)
@@ -89,7 +144,7 @@ func TestConvertDocumentAnthropic_Drop_NoContent(t *testing.T) {
 		Source:   chat.DocumentSource{},
 	}
 
-	blocks, err := convertDocument(t.Context(), doc, "")
+	blocks, err := convertDocumentWithCaps(t.Context(), doc, modelcaps.ModelCapabilities{})
 	require.NoError(t, err)
 	assert.Nil(t, blocks, "should be dropped when no inline content")
 }
diff --git a/pkg/model/provider/anthropic/beta_converter.go b/pkg/model/provider/anthropic/beta_converter.go
index 63896a163..252f2f7b3 100644
--- a/pkg/model/provider/anthropic/beta_converter.go
+++ b/pkg/model/provider/anthropic/beta_converter.go
@@ -277,7 +277,7 @@ func (c *Client) convertBetaUserMultiContent(ctx context.Context, parts []chat.M
 
 		case chat.MessagePartTypeDocument:
 			if part.Document != nil {
-				stdBlocks, err := convertDocument(ctx, *part.Document, c.ModelConfig.Model)
+				stdBlocks, err := c.convertDoc(ctx, *part.Document)
 				if err != nil {
 					return nil, fmt.Errorf("failed to convert document attachment %q: %w", part.Document.Name, err)
 				}
diff --git a/pkg/model/provider/anthropic/client.go b/pkg/model/provider/anthropic/client.go
index be1ca1643..b609b6a06 100644
--- a/pkg/model/provider/anthropic/client.go
+++ b/pkg/model/provider/anthropic/client.go
@@ -23,6 +23,7 @@ import (
 	"github.com/docker/docker-agent/pkg/model/provider/base"
 	"github.com/docker/docker-agent/pkg/model/provider/options"
 	"github.com/docker/docker-agent/pkg/model/provider/providerutil"
+	"github.com/docker/docker-agent/pkg/modelsdev"
 	"github.com/docker/docker-agent/pkg/tools"
 )
 
@@ -33,6 +34,7 @@ type Client struct {
 
 	clientFn    func(context.Context) (anthropic.Client, error)
 	fileManager *FileManager
+	modelsStore *modelsdev.Store // initialised in NewClient; overrideable in tests
 }
 
 // NewClient creates a new Anthropic client from the provided configuration
@@ -67,6 +69,13 @@ func NewClient(ctx context.Context, cfg *latest.ModelConfig, env environment.Pro
 		},
 	}
 
+	store, err := modelsdev.NewStore()
+	if err != nil {
+		slog.WarnContext(ctx, "anthropic: failed to load models.dev store, attachments will use conservative caps", "error", err)
+		store = modelsdev.NewDatabaseStore(&modelsdev.Database{}) // empty: conservative text-only
+	}
+	anthropicClient.modelsStore = store
+
 	if gateway := globalOptions.Gateway(); gateway == "" {
 		authOpts, err := buildDirectAuthOptions(ctx, cfg, env)
 		if err != nil {
@@ -313,6 +322,12 @@ func (c *Client) CreateChatCompletionStream(
 	return ad, nil
 }
 
+// convertDoc converts a document attachment using the client's model ID
+// and the store initialized at construction time.
+func (c *Client) convertDoc(ctx context.Context, doc chat.Document) ([]anthropic.ContentBlockParamUnion, error) {
+	return convertDocumentFromStore(ctx, doc, c.ID(), c.modelsStore)
+}
+
 func (c *Client) convertMessages(ctx context.Context, messages []chat.Message) ([]anthropic.MessageParam, error) {
 	var anthropicMessages []anthropic.MessageParam
 	// Track whether the last appended assistant message included tool_use blocks
@@ -553,7 +568,7 @@ func (c *Client) convertUserMultiContent(ctx context.Context, parts []chat.Messa
 
 		case chat.MessagePartTypeDocument:
 			if part.Document != nil {
-				docBlocks, err := convertDocument(ctx, *part.Document, c.ModelConfig.Model)
+				docBlocks, err := c.convertDoc(ctx, *part.Document)
 				if err != nil {
 					return nil, fmt.Errorf("failed to convert document attachment %q: %w", part.Document.Name, err)
 				}
diff --git a/pkg/model/provider/bedrock/attachments.go b/pkg/model/provider/bedrock/attachments.go
index 022235cda..6f37583b3 100644
--- a/pkg/model/provider/bedrock/attachments.go
+++ b/pkg/model/provider/bedrock/attachments.go
@@ -13,6 +13,7 @@ import (
 	"github.com/docker/docker-agent/pkg/attachment"
 	"github.com/docker/docker-agent/pkg/attachment/modelcaps"
 	"github.com/docker/docker-agent/pkg/chat"
+	"github.com/docker/docker-agent/pkg/modelsdev"
 )
 
 // imageFormatFromMIME maps a MIME type to a Bedrock ImageFormat.
@@ -32,15 +33,16 @@ func imageFormatFromMIME(mimeType string) (types.ImageFormat, bool) {
 	}
 }
 
-// convertDocument converts a chat.Document to zero or more Bedrock ContentBlocks.
+// convertDocumentFromStore converts a chat.Document to zero or more Bedrock ContentBlocks
+// using the provided modelsdev.Store for capability lookup.
 //
 // Routing:
 //   - image/* with InlineData → ContentBlockMemberImage
 //   - application/pdf with InlineData → ContentBlockMemberDocument (PDF)
 //   - text/* with InlineText → ContentBlockMemberText with TXTEnvelope
 //   - unsupported / no content → nil (logged as warning)
-func convertDocument(ctx context.Context, doc chat.Document, modelID string) ([]types.ContentBlock, error) {
-	mc, _ := modelcaps.Load(modelID)
+func convertDocumentFromStore(ctx context.Context, doc chat.Document, modelID string, store *modelsdev.Store) ([]types.ContentBlock, error) {
+	mc := modelcaps.LoadFromStore(store, modelID)
 	return convertDocumentWithCaps(ctx, doc, mc)
 }
 
diff --git a/pkg/model/provider/bedrock/attachments_test.go b/pkg/model/provider/bedrock/attachments_test.go
index 976a201a9..3dc766db7 100644
--- a/pkg/model/provider/bedrock/attachments_test.go
+++ b/pkg/model/provider/bedrock/attachments_test.go
@@ -79,7 +79,7 @@ func TestConvertDocumentBedrock_StrategyTXT(t *testing.T) {
 		Source:   chat.DocumentSource{InlineText: "## Notes"},
 	}
 
-	blocks, err := convertDocument(t.Context(), doc, "")
+	blocks, err := convertDocumentWithCaps(t.Context(), doc, modelcaps.ModelCapabilities{})
 	require.NoError(t, err)
 	require.Len(t, blocks, 1)
 	textBlock, ok := blocks[0].(*types.ContentBlockMemberText)
@@ -96,7 +96,7 @@ func TestConvertDocumentBedrock_StrategyTXT_Envelope(t *testing.T) {
 		Source:   chat.DocumentSource{InlineText: "a,b"},
 	}
 
-	blocks, err := convertDocument(t.Context(), doc, "")
+	blocks, err := convertDocumentWithCaps(t.Context(), doc, modelcaps.ModelCapabilities{})
 	require.NoError(t, err)
 	require.Len(t, blocks, 1)
 	textBlock, ok := blocks[0].(*types.ContentBlockMemberText)
@@ -111,7 +111,7 @@ func TestConvertDocumentBedrock_Drop_NoContent(t *testing.T) {
 		Source:   chat.DocumentSource{},
 	}
 
-	blocks, err := convertDocument(t.Context(), doc, "")
+	blocks, err := convertDocumentWithCaps(t.Context(), doc, modelcaps.ModelCapabilities{})
 	require.NoError(t, err)
 	assert.Nil(t, blocks, "should be nil when no inline content")
 }
diff --git a/pkg/model/provider/bedrock/client.go b/pkg/model/provider/bedrock/client.go
index 82d19bc69..e1ea5d1f3 100644
--- a/pkg/model/provider/bedrock/client.go
+++ b/pkg/model/provider/bedrock/client.go
@@ -30,7 +30,8 @@ type Client struct {
 	base.Config
 
 	bedrockClient    *bedrockruntime.Client
-	cachingSupported bool // Cached at init time for efficiency
+	cachingSupported bool             // Cached at init time for efficiency
+	modelsStore      *modelsdev.Store // initialised in NewClient
 }
 
 // bearerTokenTransport adds Authorization header with bearer token to requests
@@ -116,6 +117,12 @@ func NewClient(ctx context.Context, cfg *latest.ModelConfig, env environment.Pro
 	// Uses models.dev cache pricing as proxy for capability detection.
 	cachingSupported := detectCachingSupport(ctx, cfg.Model)
 
+	attachStore, err := modelsdev.NewStore()
+	if err != nil {
+		slog.WarnContext(ctx, "bedrock: failed to load models.dev store, attachments will use conservative caps", "error", err)
+		attachStore = modelsdev.NewDatabaseStore(&modelsdev.Database{})
+	}
+
 	slog.DebugContext(ctx, "Bedrock client created successfully",
 		"model", cfg.Model,
 		"region", awsCfg.Region,
@@ -129,6 +136,7 @@ func NewClient(ctx context.Context, cfg *latest.ModelConfig, env environment.Pro
 		},
 		bedrockClient:    bedrockClient,
 		cachingSupported: cachingSupported,
+		modelsStore:      attachStore,
 	}, nil
 }
 
@@ -236,7 +244,7 @@ func (c *Client) buildConverseStreamInput(ctx context.Context, messages []chat.M
 	enableCaching := c.promptCachingEnabled()
 
 	// Convert and set messages (excluding system)
-	input.Messages, input.System = convertMessages(ctx, messages, c.ModelConfig.Model, enableCaching)
+	input.Messages, input.System = convertMessages(ctx, messages, c.ID(), c.modelsStore, enableCaching)
 
 	// Compute thinking fields first — its presence drives the inference config.
 	additionalFields := c.buildAdditionalModelRequestFields()
diff --git a/pkg/model/provider/bedrock/client_test.go b/pkg/model/provider/bedrock/client_test.go
index 1584f7f61..793f5c2f9 100644
--- a/pkg/model/provider/bedrock/client_test.go
+++ b/pkg/model/provider/bedrock/client_test.go
@@ -14,6 +14,7 @@ import (
 	"github.com/docker/docker-agent/pkg/config/latest"
 	"github.com/docker/docker-agent/pkg/environment"
 	"github.com/docker/docker-agent/pkg/model/provider/base"
+	"github.com/docker/docker-agent/pkg/modelsdev"
 	"github.com/docker/docker-agent/pkg/tools"
 )
 
@@ -25,7 +26,7 @@ func TestConvertMessages_UserText(t *testing.T) {
 		Content: "Hello, world!",
 	}}
 
-	bedrockMsgs, system := convertMessages(t.Context(), msgs, "", false)
+	bedrockMsgs, system := convertMessages(t.Context(), msgs, "", modelsdev.NewDatabaseStore(&modelsdev.Database{}), false)
 
 	require.Len(t, bedrockMsgs, 1)
 	assert.Empty(t, system)
@@ -45,7 +46,7 @@ func TestConvertMessages_SystemExtraction(t *testing.T) {
 		{Role: chat.MessageRoleUser, Content: "Hi"},
 	}
 
-	bedrockMsgs, system := convertMessages(t.Context(), msgs, "", false)
+	bedrockMsgs, system := convertMessages(t.Context(), msgs, "", modelsdev.NewDatabaseStore(&modelsdev.Database{}), false)
 
 	require.Len(t, bedrockMsgs, 1) // Only user message
 	require.Len(t, system, 1)      // System extracted
@@ -70,7 +71,7 @@ func TestConvertMessages_AssistantWithToolCalls(t *testing.T) {
 		}},
 	}}
 
-	bedrockMsgs, _ := convertMessages(t.Context(), msgs, "", false)
+	bedrockMsgs, _ := convertMessages(t.Context(), msgs, "", modelsdev.NewDatabaseStore(&modelsdev.Database{}), false)
 
 	require.Len(t, bedrockMsgs, 1)
 	require.Len(t, bedrockMsgs[0].Content, 1)
@@ -91,7 +92,7 @@ func TestConvertMessages_ToolResult(t *testing.T) {
 		Content:    "Weather is sunny",
 	}}
 
-	bedrockMsgs, _ := convertMessages(t.Context(), msgs, "", false)
+	bedrockMsgs, _ := convertMessages(t.Context(), msgs, "", modelsdev.NewDatabaseStore(&modelsdev.Database{}), false)
 
 	require.Len(t, bedrockMsgs, 1)
 	assert.Equal(t, types.ConversationRoleUser, bedrockMsgs[0].Role)
@@ -115,7 +116,7 @@ func TestConvertMessages_EmptyContent(t *testing.T) {
 		{Role: chat.MessageRoleUser, Content: "   "},
 	}
 
-	bedrockMsgs, _ := convertMessages(t.Context(), msgs, "", false)
+	bedrockMsgs, _ := convertMessages(t.Context(), msgs, "", modelsdev.NewDatabaseStore(&modelsdev.Database{}), false)
 	// Both messages now produce user turns with empty or whitespace content blocks.
 	assert.Len(t, bedrockMsgs, 2)
 }
@@ -181,7 +182,7 @@ func TestConvertMessages_MultiContent(t *testing.T) {
 		},
 	}}
 
-	bedrockMsgs, _ := convertMessages(t.Context(), msgs, "", false)
+	bedrockMsgs, _ := convertMessages(t.Context(), msgs, "", modelsdev.NewDatabaseStore(&modelsdev.Database{}), false)
 
 	require.Len(t, bedrockMsgs, 1)
 	require.Len(t, bedrockMsgs[0].Content, 2)
@@ -205,7 +206,7 @@ func TestConvertMessages_ConsecutiveToolResults(t *testing.T) {
 		{Role: chat.MessageRoleUser, Content: "Continue"},
 	}
 
-	bedrockMsgs, _ := convertMessages(t.Context(), msgs, "", false)
+	bedrockMsgs, _ := convertMessages(t.Context(), msgs, "", modelsdev.NewDatabaseStore(&modelsdev.Database{}), false)
 
 	// Expect: user, assistant, user (grouped tool results), user
 	require.Len(t, bedrockMsgs, 4)
@@ -1136,7 +1137,7 @@ func TestConvertMessages_WithCaching(t *testing.T) {
 		{Role: chat.MessageRoleUser, Content: "How are you?"},
 	}
 
-	bedrockMsgs, system := convertMessages(t.Context(), msgs, "", true)
+	bedrockMsgs, system := convertMessages(t.Context(), msgs, "", modelsdev.NewDatabaseStore(&modelsdev.Database{}), true)
 
 	// System should have text block + cache point
 	require.Len(t, system, 2)
@@ -1167,7 +1168,7 @@ func TestConvertMessages_WithoutCaching(t *testing.T) {
 		{Role: chat.MessageRoleUser, Content: "Hello"},
 	}
 
-	bedrockMsgs, system := convertMessages(t.Context(), msgs, "", false)
+	bedrockMsgs, system := convertMessages(t.Context(), msgs, "", modelsdev.NewDatabaseStore(&modelsdev.Database{}), false)
 
 	// System should only have text block, no cache point
 	require.Len(t, system, 1)
@@ -1258,7 +1259,7 @@ func TestConvertMessages_EmptyWithCaching(t *testing.T) {
 	t.Parallel()
 
 	// Empty message list should not panic with caching enabled
-	bedrockMsgs, system := convertMessages(t.Context(), []chat.Message{}, "", true)
+	bedrockMsgs, system := convertMessages(t.Context(), []chat.Message{}, "", modelsdev.NewDatabaseStore(&modelsdev.Database{}), true)
 
 	assert.Empty(t, bedrockMsgs)
 	assert.Empty(t, system)
@@ -1271,7 +1272,7 @@ func TestConvertMessages_SingleMessageWithCaching(t *testing.T) {
 		{Role: chat.MessageRoleUser, Content: "Hello"},
 	}
 
-	bedrockMsgs, _ := convertMessages(t.Context(), msgs, "", true)
+	bedrockMsgs, _ := convertMessages(t.Context(), msgs, "", modelsdev.NewDatabaseStore(&modelsdev.Database{}), true)
 
 	require.Len(t, bedrockMsgs, 1)
 	// Single message should get a cache point appended
@@ -1291,7 +1292,7 @@ func TestConvertMessages_MultiContentWithCaching(t *testing.T) {
 		},
 	}}
 
-	bedrockMsgs, _ := convertMessages(t.Context(), msgs, "", true)
+	bedrockMsgs, _ := convertMessages(t.Context(), msgs, "", modelsdev.NewDatabaseStore(&modelsdev.Database{}), true)
 
 	require.Len(t, bedrockMsgs, 1)
 	// 2 text blocks + cache point = 3 content blocks
@@ -1314,7 +1315,7 @@ func TestConvertMessages_ToolResultWithCaching(t *testing.T) {
 		{Role: chat.MessageRoleTool, ToolCallID: "tool-1", Content: "Result"},
 	}
 
-	bedrockMsgs, _ := convertMessages(t.Context(), msgs, "", true)
+	bedrockMsgs, _ := convertMessages(t.Context(), msgs, "", modelsdev.NewDatabaseStore(&modelsdev.Database{}), true)
 
 	// Expect: user, assistant, user (tool result)
 	require.Len(t, bedrockMsgs, 3)
diff --git a/pkg/model/provider/bedrock/convert.go b/pkg/model/provider/bedrock/convert.go
index 428246978..d6ab7b988 100644
--- a/pkg/model/provider/bedrock/convert.go
+++ b/pkg/model/provider/bedrock/convert.go
@@ -12,13 +12,14 @@ import (
 	"github.com/aws/aws-sdk-go-v2/service/bedrockruntime/types"
 
 	"github.com/docker/docker-agent/pkg/chat"
+	"github.com/docker/docker-agent/pkg/modelsdev"
 	"github.com/docker/docker-agent/pkg/tools"
 )
 
 // convertMessages handles Bedrock's Converse API constraints:
 // - Tool results must immediately follow the assistant message with tool_use
 // - Multiple consecutive tool results must be grouped into a single user message
-func convertMessages(ctx context.Context, messages []chat.Message, modelID string, enableCaching bool) ([]types.Message, []types.SystemContentBlock) {
+func convertMessages(ctx context.Context, messages []chat.Message, modelID string, store *modelsdev.Store, enableCaching bool) ([]types.Message, []types.SystemContentBlock) {
 	var bedrockMessages []types.Message
 	var systemBlocks []types.SystemContentBlock
 
@@ -43,7 +44,7 @@ func convertMessages(ctx context.Context, messages []chat.Message, modelID strin
 			}
 
 		case chat.MessageRoleUser:
-			contentBlocks := convertUserContent(ctx, msg, modelID)
+			contentBlocks := convertUserContent(ctx, msg, modelID, store)
 			if len(contentBlocks) > 0 {
 				bedrockMessages = append(bedrockMessages, types.Message{
 					Role:    types.ConversationRoleUser,
@@ -120,7 +121,7 @@ func applyCachePointsToMessages(messages []types.Message) {
 	}
 }
 
-func convertUserContent(ctx context.Context, msg *chat.Message, modelID string) []types.ContentBlock {
+func convertUserContent(ctx context.Context, msg *chat.Message, modelID string, store *modelsdev.Store) []types.ContentBlock {
 	var blocks []types.ContentBlock
 
 	if len(msg.MultiContent) > 0 {
@@ -139,7 +140,7 @@ func convertUserContent(ctx context.Context, msg *chat.Message, modelID string)
 				}
 			case chat.MessagePartTypeDocument:
 				if part.Document != nil {
-					docBlocks, err := convertDocument(ctx, *part.Document, modelID)
+					docBlocks, err := convertDocumentFromStore(ctx, *part.Document, modelID, store)
 					if err != nil {
 						slog.WarnContext(ctx, "failed to convert document attachment", "error", err, "doc", part.Document.Name)
 						continue
diff --git a/pkg/model/provider/dmr/client.go b/pkg/model/provider/dmr/client.go
index 2f9887524..f145e067d 100644
--- a/pkg/model/provider/dmr/client.go
+++ b/pkg/model/provider/dmr/client.go
@@ -21,6 +21,7 @@ import (
 	"github.com/docker/docker-agent/pkg/model/provider/base"
 	"github.com/docker/docker-agent/pkg/model/provider/oaistream"
 	"github.com/docker/docker-agent/pkg/model/provider/options"
+	"github.com/docker/docker-agent/pkg/modelsdev"
 	"github.com/docker/docker-agent/pkg/tools"
 )
 
@@ -52,9 +53,10 @@ const (
 type Client struct {
 	base.Config
 
-	client     openai.Client
-	httpClient *http.Client
-	engine     string
+	client      openai.Client
+	httpClient  *http.Client
+	engine      string
+	modelsStore *modelsdev.Store // initialised in NewClient
 }
 
 // NewClient creates a new DMR client from the provided configuration
@@ -132,22 +134,29 @@ func NewClient(ctx context.Context, cfg *latest.ModelConfig, opts ...options.Opt
 
 	slog.DebugContext(ctx, "DMR client created successfully", "model", cfg.Model, "base_url", baseURL)
 
+	store, err := modelsdev.NewStore()
+	if err != nil {
+		slog.WarnContext(ctx, "dmr: failed to load models.dev store, attachments will use conservative caps", "error", err)
+		store = modelsdev.NewDatabaseStore(&modelsdev.Database{})
+	}
+
 	return &Client{
 		Config: base.Config{
 			ModelConfig:  *cfg,
 			ModelOptions: globalOptions,
 			BaseURL:      baseURL,
 		},
-		client:     openai.NewClient(clientOptions...),
-		httpClient: httpClient,
-		engine:     engine,
+		client:      openai.NewClient(clientOptions...),
+		httpClient:  httpClient,
+		engine:      engine,
+		modelsStore: store,
 	}, nil
 }
 
 // convertMessages converts chat messages to OpenAI format and merges consecutive
 // system/user messages, which is needed by some local models run by DMR.
 func (c *Client) convertMessages(ctx context.Context, messages []chat.Message) []openai.ChatCompletionMessageParamUnion {
-	openaiMessages := oaistream.ConvertMessages(ctx, messages, c.ModelConfig.Model)
+	openaiMessages := oaistream.ConvertMessagesFromStore(ctx, messages, c.ID(), c.modelsStore)
 	return oaistream.MergeConsecutiveMessages(openaiMessages)
 }
 
diff --git a/pkg/model/provider/gemini/attachments.go b/pkg/model/provider/gemini/attachments.go
index 9d5b53d00..ce3c5fb6b 100644
--- a/pkg/model/provider/gemini/attachments.go
+++ b/pkg/model/provider/gemini/attachments.go
@@ -10,16 +10,18 @@ import (
 	"github.com/docker/docker-agent/pkg/attachment"
 	"github.com/docker/docker-agent/pkg/attachment/modelcaps"
 	"github.com/docker/docker-agent/pkg/chat"
+	"github.com/docker/docker-agent/pkg/modelsdev"
 )
 
-// convertDocument converts a chat.Document to a Gemini genai.Part.
+// convertDocumentFromStore converts a chat.Document to a Gemini genai.Part
+// using the provided modelsdev.Store for capability lookup.
 //
 // Routing:
 //   - image/* or binary with InlineData → genai.Blob part
 //   - text MIMEs with InlineText → genai.Text part with TXTEnvelope
 //   - unsupported / no content → nil (logged as warning)
-func convertDocument(ctx context.Context, doc chat.Document, modelID string) (*genai.Part, error) {
-	mc, _ := modelcaps.Load(modelID)
+func convertDocumentFromStore(ctx context.Context, doc chat.Document, modelID string, store *modelsdev.Store) (*genai.Part, error) {
+	mc := modelcaps.LoadFromStore(store, modelID)
 	return convertDocumentWithCaps(ctx, doc, mc)
 }
 
diff --git a/pkg/model/provider/gemini/attachments_test.go b/pkg/model/provider/gemini/attachments_test.go
index 634859984..2d705b1ee 100644
--- a/pkg/model/provider/gemini/attachments_test.go
+++ b/pkg/model/provider/gemini/attachments_test.go
@@ -55,7 +55,7 @@ func TestConvertDocumentGemini_StrategyTXT(t *testing.T) {
 		Source:   chat.DocumentSource{InlineText: "# Read Me"},
 	}
 
-	part, err := convertDocument(t.Context(), doc, "")
+	part, err := convertDocumentWithCaps(t.Context(), doc, modelcaps.ModelCapabilities{})
 	require.NoError(t, err)
 	require.NotNil(t, part)
 	assert.Contains(t, part.Text, "readme-md")
@@ -70,7 +70,7 @@ func TestConvertDocumentGemini_StrategyTXT_Envelope(t *testing.T) {
 		Source:   chat.DocumentSource{InlineText: "col1,col2"},
 	}
 
-	part, err := convertDocument(t.Context(), doc, "")
+	part, err := convertDocumentWithCaps(t.Context(), doc, modelcaps.ModelCapabilities{})
 	require.NoError(t, err)
 	require.NotNil(t, part)
 	assert.True(t, strings.HasPrefix(part.Text, "<document"), "should be wrapped in envelope")
@@ -83,7 +83,7 @@ func TestConvertDocumentGemini_Drop_NoContent(t *testing.T) {
 		Source:   chat.DocumentSource{},
 	}
 
-	part, err := convertDocument(t.Context(), doc, "")
+	part, err := convertDocumentWithCaps(t.Context(), doc, modelcaps.ModelCapabilities{})
 	require.NoError(t, err)
 	assert.Nil(t, part, "should be nil when no inline content")
 }
diff --git a/pkg/model/provider/gemini/client.go b/pkg/model/provider/gemini/client.go
index 1c944ee88..c07213202 100644
--- a/pkg/model/provider/gemini/client.go
+++ b/pkg/model/provider/gemini/client.go
@@ -23,6 +23,7 @@ import (
 	"github.com/docker/docker-agent/pkg/model/provider/options"
 	"github.com/docker/docker-agent/pkg/model/provider/providerutil"
 	"github.com/docker/docker-agent/pkg/modelinfo"
+	"github.com/docker/docker-agent/pkg/modelsdev"
 	"github.com/docker/docker-agent/pkg/rag/prompts"
 	"github.com/docker/docker-agent/pkg/rag/types"
 	"github.com/docker/docker-agent/pkg/tools"
@@ -33,7 +34,8 @@ import (
 type Client struct {
 	base.Config
 
-	clientFn func(context.Context) (*genai.Client, error)
+	clientFn    func(context.Context) (*genai.Client, error)
+	modelsStore *modelsdev.Store // initialised in NewClient
 }
 
 // NewClient creates a new Gemini client from the provided configuration
@@ -167,13 +169,20 @@ func NewClient(ctx context.Context, cfg *latest.ModelConfig, env environment.Pro
 
 	slog.DebugContext(ctx, "Gemini client created successfully", "model", cfg.Model)
 
+	store, err := modelsdev.NewStore()
+	if err != nil {
+		slog.WarnContext(ctx, "gemini: failed to load models.dev store, attachments will use conservative caps", "error", err)
+		store = modelsdev.NewDatabaseStore(&modelsdev.Database{})
+	}
+
 	return &Client{
 		Config: base.Config{
 			ModelConfig:  *cfg,
 			ModelOptions: globalOptions,
 			Env:          env,
 		},
-		clientFn: clientFn,
+		clientFn:    clientFn,
+		modelsStore: store,
 	}, nil
 }
 
@@ -193,7 +202,7 @@ func thoughtSignatureOrDefault(sig []byte) []byte {
 }
 
 // convertMessagesToGemini converts chat.Messages into Gemini Contents
-func convertMessagesToGemini(ctx context.Context, messages []chat.Message, modelID string) []*genai.Content {
+func convertMessagesToGemini(ctx context.Context, messages []chat.Message, modelID string, store *modelsdev.Store) []*genai.Content {
 	contents := make([]*genai.Content, 0, len(messages))
 	for i := range messages {
 		msg := &messages[i]
@@ -258,7 +267,7 @@ func convertMessagesToGemini(ctx context.Context, messages []chat.Message, model
 
 		// Handle regular messages
 		if len(msg.MultiContent) > 0 {
-			parts := convertMultiContent(ctx, msg.MultiContent, msg.ThoughtSignature, modelID)
+			parts := convertMultiContent(ctx, msg.MultiContent, msg.ThoughtSignature, modelID, store)
 			if len(parts) > 0 {
 				contents = append(contents, genai.NewContentFromParts(parts, role))
 			}
@@ -288,7 +297,7 @@ func newTextPartWithSignature(text string, signature []byte) *genai.Part {
 }
 
 // convertMultiContent converts multi-part content to Gemini parts
-func convertMultiContent(ctx context.Context, multiContent []chat.MessagePart, thoughtSignature []byte, modelID string) []*genai.Part {
+func convertMultiContent(ctx context.Context, multiContent []chat.MessagePart, thoughtSignature []byte, modelID string, store *modelsdev.Store) []*genai.Part {
 	parts := make([]*genai.Part, 0, len(multiContent))
 	for _, part := range multiContent {
 		switch part.Type {
@@ -301,7 +310,7 @@ func convertMultiContent(ctx context.Context, multiContent []chat.MessagePart, t
 			}
 		case chat.MessagePartTypeDocument:
 			if part.Document != nil {
-				docPart, err := convertDocument(ctx, *part.Document, modelID)
+				docPart, err := convertDocumentFromStore(ctx, *part.Document, modelID, store)
 				if err != nil {
 					slog.WarnContext(ctx, "failed to convert document attachment", "error", err, "doc", part.Document.Name)
 					continue
@@ -601,7 +610,7 @@ func (c *Client) CreateChatCompletionStream(
 		}
 	}
 
-	contents := convertMessagesToGemini(ctx, messages, c.ModelConfig.Model)
+	contents := convertMessagesToGemini(ctx, messages, c.ID(), c.modelsStore)
 
 	// Debug: Log the messages we're sending
 	slog.DebugContext(ctx, "Gemini messages", "count", len(contents))
diff --git a/pkg/model/provider/gemini/client_test.go b/pkg/model/provider/gemini/client_test.go
index 8aeb7b205..a8e83e1c5 100644
--- a/pkg/model/provider/gemini/client_test.go
+++ b/pkg/model/provider/gemini/client_test.go
@@ -10,6 +10,7 @@ import (
 	"github.com/docker/docker-agent/pkg/chat"
 	"github.com/docker/docker-agent/pkg/config/latest"
 	"github.com/docker/docker-agent/pkg/model/provider/base"
+	"github.com/docker/docker-agent/pkg/modelsdev"
 	"github.com/docker/docker-agent/pkg/tools"
 )
 
@@ -365,7 +366,7 @@ func TestConvertMessagesToGemini_ThoughtSignature(t *testing.T) {
 			contents := convertMessagesToGemini(t.Context(), []chat.Message{
 				{Role: chat.MessageRoleUser, Content: "go"},
 				tt.message,
-			}, "")
+			}, "", modelsdev.NewDatabaseStore(&modelsdev.Database{}))
 
 			require.Len(t, contents, 2)
 			assistant := contents[1]
diff --git a/pkg/model/provider/oaistream/attachments.go b/pkg/model/provider/oaistream/attachments.go
index 2a23ce7bb..aa2c573b6 100644
--- a/pkg/model/provider/oaistream/attachments.go
+++ b/pkg/model/provider/oaistream/attachments.go
@@ -12,20 +12,20 @@ import (
 	"github.com/docker/docker-agent/pkg/attachment"
 	"github.com/docker/docker-agent/pkg/attachment/modelcaps"
 	"github.com/docker/docker-agent/pkg/chat"
+	"github.com/docker/docker-agent/pkg/modelsdev"
 )
 
-// convertDocument converts a chat.Document to zero or more
+// convertDocumentFromStore converts a chat.Document to zero or more
 // ChatCompletionContentPartUnionParam values using the OpenAI Chat Completions
-// format.  It is also used by all oaistream-based providers (Mistral, xAI,
-// Ollama, Nebius, MiniMax, GitHub Copilot, Azure, Requesty).
+// format. It uses the provided modelsdev.Store for capability lookups.
 //
 // Routing:
 //   - image/* with InlineData → data-URI image part
-//   - other binary MIMEs with InlineData → text part with TXTEnvelope fallback
+//   - other binary MIMEs with InlineData → drop (no native document block on Chat Completions)
 //   - text MIMEs with InlineText → text part with TXTEnvelope
 //   - unsupported / no content → nil (logged as warning)
-func convertDocument(ctx context.Context, doc chat.Document, modelID string) ([]openai.ChatCompletionContentPartUnionParam, error) {
-	mc, _ := modelcaps.Load(modelID)
+func convertDocumentFromStore(ctx context.Context, doc chat.Document, modelID string, store *modelsdev.Store) ([]openai.ChatCompletionContentPartUnionParam, error) {
+	mc := modelcaps.LoadFromStore(store, modelID)
 	return convertDocumentWithCaps(ctx, doc, mc)
 }
 
diff --git a/pkg/model/provider/oaistream/attachments_test.go b/pkg/model/provider/oaistream/attachments_test.go
index 005a47c54..d3047ee6c 100644
--- a/pkg/model/provider/oaistream/attachments_test.go
+++ b/pkg/model/provider/oaistream/attachments_test.go
@@ -10,6 +10,7 @@ import (
 
 	"github.com/docker/docker-agent/pkg/attachment/modelcaps"
 	"github.com/docker/docker-agent/pkg/chat"
+	"github.com/docker/docker-agent/pkg/modelsdev"
 )
 
 // minJPEG is a minimal JPEG magic-byte header for use in tests.
@@ -53,6 +54,46 @@ func TestConvertDocument_StrategyB64_ImageDropped(t *testing.T) {
 	assert.Nil(t, parts, "image should be dropped for text-only model")
 }
 
+// TestConvertDocument_QualifiedIDRequired is the regression test for the bug
+// where callers passed a bare model name instead of a "provider/model" ID,
+// causing modelcaps to miss the model and silently drop image/PDF attachments.
+//
+// It calls ConvertMultiContentFromStore with an injected fake store, exercising
+// the same path as the production client (which calls ConvertMessages with c.ID()).
+func TestConvertDocument_QualifiedIDRequired(t *testing.T) {
+	store := modelsdev.NewDatabaseStore(&modelsdev.Database{
+		Providers: map[string]modelsdev.Provider{
+			"openai": {
+				Models: map[string]modelsdev.Model{
+					"gpt-4o": {
+						Modalities: modelsdev.Modalities{
+							Input: []string{"text", "image"},
+						},
+					},
+				},
+			},
+		},
+	})
+
+	msgParts := []chat.MessagePart{{
+		Type: chat.MessagePartTypeDocument,
+		Document: &chat.Document{
+			Name:     "photo.jpg",
+			MimeType: "image/jpeg",
+			Source:   chat.DocumentSource{InlineData: minJPEG},
+		},
+	}}
+
+	// Bare model name (the original bug): image must be dropped.
+	partsBare := ConvertMultiContentFromStore(t.Context(), msgParts, "gpt-4o", store)
+	assert.Empty(t, partsBare, "bare model name must not resolve caps: image should be dropped")
+
+	// Qualified ID (the fix, matching what c.ID() returns): image must be preserved.
+	partsQualified := ConvertMultiContentFromStore(t.Context(), msgParts, "openai/gpt-4o", store)
+	require.Len(t, partsQualified, 1, "qualified ID must resolve caps: image should be present")
+	assert.NotNil(t, partsQualified[0].OfImageURL, "expected image URL part for qualified model ID")
+}
+
 func TestConvertDocument_StrategyTXT(t *testing.T) {
 	doc := chat.Document{
 		Name:     "readme.md",
@@ -60,7 +101,7 @@ func TestConvertDocument_StrategyTXT(t *testing.T) {
 		Source:   chat.DocumentSource{InlineText: "# Hello World"},
 	}
 
-	parts, err := convertDocument(t.Context(), doc, "")
+	parts, err := convertDocumentWithCaps(t.Context(), doc, modelcaps.ModelCapabilities{})
 	require.NoError(t, err)
 	require.Len(t, parts, 1)
 	require.NotNil(t, parts[0].OfText)
@@ -76,7 +117,7 @@ func TestConvertDocument_StrategyTXT_Envelope(t *testing.T) {
 		Source:   chat.DocumentSource{InlineText: "a,b,c\n1,2,3"},
 	}
 
-	parts, err := convertDocument(t.Context(), doc, "")
+	parts, err := convertDocumentWithCaps(t.Context(), doc, modelcaps.ModelCapabilities{})
 	require.NoError(t, err)
 	require.Len(t, parts, 1)
 	require.NotNil(t, parts[0].OfText)
@@ -91,7 +132,7 @@ func TestConvertDocument_Drop_NoContent(t *testing.T) {
 		Source:   chat.DocumentSource{},
 	}
 
-	parts, err := convertDocument(t.Context(), doc, "")
+	parts, err := convertDocumentWithCaps(t.Context(), doc, modelcaps.ModelCapabilities{})
 	require.NoError(t, err)
 	assert.Nil(t, parts, "should be dropped when no inline content")
 }
diff --git a/pkg/model/provider/oaistream/messages.go b/pkg/model/provider/oaistream/messages.go
index 7e06e014f..d7e8ae301 100644
--- a/pkg/model/provider/oaistream/messages.go
+++ b/pkg/model/provider/oaistream/messages.go
@@ -14,6 +14,7 @@ import (
 	"github.com/openai/openai-go/v3/packages/param"
 
 	"github.com/docker/docker-agent/pkg/chat"
+	"github.com/docker/docker-agent/pkg/modelsdev"
 )
 
 // JSONSchema is a helper type that implements json.Marshaler for map[string]any.
@@ -25,11 +26,19 @@ func (j JSONSchema) MarshalJSON() ([]byte, error) {
 	return json.Marshal(map[string]any(j))
 }
 
-// ConvertMultiContent converts chat.MessagePart slices to OpenAI content parts.
-// ctx is forwarded to convertDocument for logging and future cancellation support.
-// modelID is used for attachment capability lookups; pass an empty string to
-// skip capability checks (all documents are attempted).
-func ConvertMultiContent(ctx context.Context, multiContent []chat.MessagePart, modelID string) []openai.ChatCompletionContentPartUnionParam {
+// ConvertMultiContentFromStore converts chat.MessagePart slices to OpenAI content
+// parts using the provided modelsdev.Store for capability lookups.
+func ConvertMultiContentFromStore(ctx context.Context, multiContent []chat.MessagePart, modelID string, store *modelsdev.Store) []openai.ChatCompletionContentPartUnionParam {
+	return convertMultiContentWithStore(ctx, multiContent, modelID, store)
+}
+
+// ConvertMessagesFromStore converts chat.Message slices to OpenAI message params
+// using the provided modelsdev.Store for capability lookups.
+func ConvertMessagesFromStore(ctx context.Context, messages []chat.Message, modelID string, store *modelsdev.Store) []openai.ChatCompletionMessageParamUnion {
+	return convertMessagesWithStore(ctx, messages, modelID, store)
+}
+
+func convertMultiContentWithStore(ctx context.Context, multiContent []chat.MessagePart, modelID string, store *modelsdev.Store) []openai.ChatCompletionContentPartUnionParam {
 	parts := make([]openai.ChatCompletionContentPartUnionParam, 0, len(multiContent))
 	for _, part := range multiContent {
 		switch part.Type {
@@ -45,7 +54,7 @@ func ConvertMultiContent(ctx context.Context, multiContent []chat.MessagePart, m
 			}
 		case chat.MessagePartTypeDocument:
 			if part.Document != nil {
-				docParts, err := convertDocument(ctx, *part.Document, modelID)
+				docParts, err := convertDocumentFromStore(ctx, *part.Document, modelID, store)
 				if err != nil {
 					slog.WarnContext(ctx, "failed to convert document attachment", "error", err, "doc", part.Document.Name)
 					continue
@@ -57,11 +66,7 @@ func ConvertMultiContent(ctx context.Context, multiContent []chat.MessagePart, m
 	return parts
 }
 
-// ConvertMessages converts chat.Message slices to OpenAI message params.
-// ctx is forwarded to convertDocument for logging and cancellation support.
-// modelID is forwarded to convertDocument for attachment capability lookups.
-// This is the base conversion without any provider-specific post-processing.
-func ConvertMessages(ctx context.Context, messages []chat.Message, modelID string) []openai.ChatCompletionMessageParamUnion {
+func convertMessagesWithStore(ctx context.Context, messages []chat.Message, modelID string, store *modelsdev.Store) []openai.ChatCompletionMessageParamUnion {
 	openaiMessages := make([]openai.ChatCompletionMessageParamUnion, 0, len(messages))
 	for i := range messages {
 		msg := &messages[i]
@@ -94,7 +99,7 @@ func ConvertMessages(ctx context.Context, messages []chat.Message, modelID strin
 			if len(msg.MultiContent) == 0 {
 				openaiMessage = openai.UserMessage(msg.Content)
 			} else {
-				openaiMessage = openai.UserMessage(ConvertMultiContent(ctx, msg.MultiContent, modelID))
+				openaiMessage = openai.UserMessage(convertMultiContentWithStore(ctx, msg.MultiContent, modelID, store))
 			}
 
 		case chat.MessageRoleAssistant:
diff --git a/pkg/model/provider/oaistream/messages_test.go b/pkg/model/provider/oaistream/messages_test.go
index 3f2cba58c..cb80c4ec0 100644
--- a/pkg/model/provider/oaistream/messages_test.go
+++ b/pkg/model/provider/oaistream/messages_test.go
@@ -8,6 +8,7 @@ import (
 	"github.com/stretchr/testify/require"
 
 	"github.com/docker/docker-agent/pkg/chat"
+	"github.com/docker/docker-agent/pkg/modelsdev"
 	"github.com/docker/docker-agent/pkg/tools"
 )
 
@@ -62,7 +63,7 @@ func TestConvertMultiContent(t *testing.T) {
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
-			result := ConvertMultiContent(t.Context(), tt.multiContent, "")
+			result := ConvertMultiContentFromStore(t.Context(), tt.multiContent, "", modelsdev.NewDatabaseStore(&modelsdev.Database{}))
 			assert.Len(t, result, tt.wantCount)
 		})
 	}
@@ -137,7 +138,7 @@ func TestConvertMessages(t *testing.T) {
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
-			result := ConvertMessages(t.Context(), tt.messages, "")
+			result := ConvertMessagesFromStore(t.Context(), tt.messages, "", modelsdev.NewDatabaseStore(&modelsdev.Database{}))
 			assert.Len(t, result, tt.want)
 		})
 	}
diff --git a/pkg/model/provider/openai/attachments.go b/pkg/model/provider/openai/attachments.go
index 0c13d5be0..77060e766 100644
--- a/pkg/model/provider/openai/attachments.go
+++ b/pkg/model/provider/openai/attachments.go
@@ -13,18 +13,20 @@ import (
 	"github.com/docker/docker-agent/pkg/attachment"
 	"github.com/docker/docker-agent/pkg/attachment/modelcaps"
 	"github.com/docker/docker-agent/pkg/chat"
+	"github.com/docker/docker-agent/pkg/modelsdev"
 )
 
-// convertDocumentToResponseInput converts a chat.Document to zero or more
-// ResponseInputContentUnionParam values for the OpenAI Responses API.
+// convertDocumentToResponseInputFromStore converts a chat.Document to zero or
+// more ResponseInputContentUnionParam values for the OpenAI Responses API,
+// using the provided modelsdev.Store for capability lookup.
 //
 // Routing:
 //   - image/* with InlineData → OfInputImage with a data URI
-//   - other binary with InlineData → OfInputText with TXTEnvelope fallback
+//   - application/pdf with InlineData → OfInputFile (base64)
 //   - text MIMEs with InlineText → OfInputText with TXTEnvelope
 //   - unsupported / no content → nil (logged as warning)
-func convertDocumentToResponseInput(ctx context.Context, doc chat.Document, modelID string) ([]responses.ResponseInputContentUnionParam, error) {
-	mc, _ := modelcaps.Load(modelID)
+func convertDocumentToResponseInputFromStore(ctx context.Context, doc chat.Document, modelID string, store *modelsdev.Store) ([]responses.ResponseInputContentUnionParam, error) {
+	mc := modelcaps.LoadFromStore(store, modelID)
 	return convertDocumentToResponseInputWithCaps(ctx, doc, mc)
 }
 
diff --git a/pkg/model/provider/openai/attachments_test.go b/pkg/model/provider/openai/attachments_test.go
index 6ff9e7c42..e9985fcb1 100644
--- a/pkg/model/provider/openai/attachments_test.go
+++ b/pkg/model/provider/openai/attachments_test.go
@@ -60,7 +60,7 @@ func TestConvertDocumentResponseInput_StrategyTXT(t *testing.T) {
 		Source:   chat.DocumentSource{InlineText: "## API Spec"},
 	}
 
-	parts, err := convertDocumentToResponseInput(t.Context(), doc, "")
+	parts, err := convertDocumentToResponseInputWithCaps(t.Context(), doc, modelcaps.ModelCapabilities{})
 	require.NoError(t, err)
 	require.Len(t, parts, 1)
 	require.NotNil(t, parts[0].OfInputText)
@@ -77,7 +77,7 @@ func TestConvertDocumentResponseInput_StrategyTXT_Envelope(t *testing.T) {
 		Source:   chat.DocumentSource{InlineText: "x,y"},
 	}
 
-	parts, err := convertDocumentToResponseInput(t.Context(), doc, "")
+	parts, err := convertDocumentToResponseInputWithCaps(t.Context(), doc, modelcaps.ModelCapabilities{})
 	require.NoError(t, err)
 	require.Len(t, parts, 1)
 	require.NotNil(t, parts[0].OfInputText)
@@ -92,7 +92,7 @@ func TestConvertDocumentResponseInput_Drop_NoContent(t *testing.T) {
 		Source:   chat.DocumentSource{},
 	}
 
-	parts, err := convertDocumentToResponseInput(t.Context(), doc, "")
+	parts, err := convertDocumentToResponseInputWithCaps(t.Context(), doc, modelcaps.ModelCapabilities{})
 	require.NoError(t, err)
 	assert.Nil(t, parts, "should be nil when no inline content")
 }
diff --git a/pkg/model/provider/openai/client.go b/pkg/model/provider/openai/client.go
index 28e860491..0d278efbe 100644
--- a/pkg/model/provider/openai/client.go
+++ b/pkg/model/provider/openai/client.go
@@ -26,6 +26,7 @@ import (
 	"github.com/docker/docker-agent/pkg/model/provider/oaistream"
 	"github.com/docker/docker-agent/pkg/model/provider/options"
 	"github.com/docker/docker-agent/pkg/modelinfo"
+	"github.com/docker/docker-agent/pkg/modelsdev"
 	"github.com/docker/docker-agent/pkg/rag/prompts"
 	"github.com/docker/docker-agent/pkg/rag/types"
 	"github.com/docker/docker-agent/pkg/tools"
@@ -41,6 +42,8 @@ type Client struct {
 	// wsPool is initialized in NewClient when transport=websocket is configured.
 	// It maintains a persistent WebSocket connection across requests.
 	wsPool *wsPool
+
+	modelsStore *modelsdev.Store // initialised in NewClient
 }
 
 // NewClient creates a new OpenAI client from the provided configuration
@@ -150,13 +153,20 @@ func NewClient(ctx context.Context, cfg *latest.ModelConfig, env environment.Pro
 
 	slog.DebugContext(ctx, "OpenAI client created successfully", "model", cfg.Model)
 
+	store, err := modelsdev.NewStore()
+	if err != nil {
+		slog.WarnContext(ctx, "openai: failed to load models.dev store, attachments will use conservative caps", "error", err)
+		store = modelsdev.NewDatabaseStore(&modelsdev.Database{})
+	}
+
 	client := &Client{
 		Config: base.Config{
 			ModelConfig:  *cfg,
 			ModelOptions: globalOptions,
 			Env:          env,
 		},
-		clientFn: clientFn,
+		clientFn:    clientFn,
+		modelsStore: store,
 	}
 
 	// Pre-create the WebSocket pool when the transport is configured.
@@ -181,7 +191,7 @@ func (c *Client) Close() {
 // convertMessages converts chat.Message to openai.ChatCompletionMessageParamUnion
 // using the shared oaistream implementation.
 func (c *Client) convertMessages(ctx context.Context, messages []chat.Message) []openai.ChatCompletionMessageParamUnion {
-	return oaistream.ConvertMessages(ctx, messages, c.ModelConfig.Model)
+	return oaistream.ConvertMessagesFromStore(ctx, messages, c.ID(), c.modelsStore)
 }
 
 // CreateChatCompletionStream creates a streaming chat completion request
@@ -613,7 +623,7 @@ func (c *Client) convertMessagesToResponseInput(ctx context.Context, messages []
 						}
 					case chat.MessagePartTypeDocument:
 						if part.Document != nil {
-							docParts, err := convertDocumentToResponseInput(ctx, *part.Document, c.ModelConfig.Model)
+							docParts, err := convertDocumentToResponseInputFromStore(ctx, *part.Document, c.ID(), c.modelsStore)
 							if err != nil {
 								slog.WarnContext(ctx, "failed to convert document attachment", "error", err, "doc", part.Document.Name)
 								continue