Send Bedrock inference-profile IDs for on-demand models

Newer Bedrock models (Anthropic Claude 4.x, DeepSeek) reject invocation
by their bare foundation-model ID with on-demand throughput, demanding a
cross-region inference-profile ID instead (HTTP 400). Rewrite such IDs
at request time by prepending the region-matched geo prefix
(us/eu/apac/us-gov), so selecting anthropic.claude-sonnet-4-5-... in a
us-east-1 setup invokes us.anthropic.claude-sonnet-4-5-...

Already-prefixed IDs, ARNs, and families that don't need a profile are
left untouched, preserving explicit choices and custom application
inference profiles.

packages/provider/amazon_bedrock.go

@@ -285,6 +285,94 @@ func (c *bedrockClient) buildRequest(req Request) (*bedrockRequest, error) {
 	return out, nil
 }
 
+// resolveBedrockInferenceProfileID maps a bare foundation-model ID to
+// its region-matched cross-region inference-profile ID.
+//
+// Several newer Bedrock models (Anthropic Claude 4.x, DeepSeek, etc.)
+// cannot be invoked with on-demand throughput by their plain
+// foundation-model ID; Bedrock returns HTTP 400 demanding "the ID or
+// ARN of an inference profile that contains this model". The profile
+// ID is the same model ID with a geographic prefix (us/eu/apac/...).
+//
+// We only rewrite IDs that (a) lack an existing geo prefix and (b)
+// belong to a model family that requires a profile. IDs that already
+// carry a prefix (e.g. "eu.anthropic...", "global.anthropic...") or
+// fully-qualified ARNs are returned unchanged, so explicit user
+// choices and custom application inference profiles still work.
+func resolveBedrockInferenceProfileID(modelID, region string) string {
+	if modelID == "" {
+		return modelID
+	}
+	// ARNs are already inference-profile references; leave untouched.
+	if strings.HasPrefix(modelID, "arn:") {
+		return modelID
+	}
+	// Already geo-prefixed (us. / eu. / apac. / ap. / us-gov. / global.)?
+	if bedrockHasGeoPrefix(modelID) {
+		return modelID
+	}
+	if !bedrockRequiresInferenceProfile(modelID) {
+		return modelID
+	}
+	prefix := bedrockGeoPrefixForRegion(region)
+	if prefix == "" {
+		return modelID
+	}
+	return prefix + "." + modelID
+}
+
+// bedrockGeoPrefixes are the cross-region inference-profile geo
+// prefixes Bedrock uses. A model ID that starts with one of these
+// (followed by a dot) is already a profile reference.
+var bedrockGeoPrefixes = []string{"us-gov", "us", "eu", "apac", "ap", "global", "au"}
+
+func bedrockHasGeoPrefix(modelID string) bool {
+	for _, p := range bedrockGeoPrefixes {
+		if strings.HasPrefix(modelID, p+".") {
+			return true
+		}
+	}
+	return false
+}
+
+// bedrockRequiresInferenceProfile reports whether a bare
+// foundation-model ID is one of the families AWS only exposes through
+// a cross-region inference profile for on-demand throughput.
+func bedrockRequiresInferenceProfile(modelID string) bool {
+	switch {
+	case strings.HasPrefix(modelID, "anthropic.claude-"):
+		return true
+	case strings.HasPrefix(modelID, "deepseek."):
+		return true
+	default:
+		return false
+	}
+}
+
+// bedrockGeoPrefixForRegion maps an AWS region to the geo prefix used
+// by its cross-region inference profiles. Returns "" when the region
+// has no known mapping, in which case the model ID is left unchanged.
+func bedrockGeoPrefixForRegion(region string) string {
+	switch {
+	case region == "":
+		return "us"
+	case strings.HasPrefix(region, "us-gov-"):
+		return "us-gov"
+	case strings.HasPrefix(region, "us-"):
+		return "us"
+	case strings.HasPrefix(region, "eu-"):
+		return "eu"
+	case strings.HasPrefix(region, "ap-"):
+		return "apac"
+	case strings.HasPrefix(region, "ca-"):
+		return "us"
+	case strings.HasPrefix(region, "sa-"):
+		return "us"
+	default:
+		return "us"
+	}
+}
+
 func (c *bedrockClient) Stream(ctx context.Context, req Request) (<-chan Event, error) {
 	wire, err := c.buildRequest(req)
 	if err != nil {
@@ -294,7 +382,8 @@ func (c *bedrockClient) Stream(ctx context.Context, req Request) (<-chan Event,
 	if err != nil {
 		return nil, err
 	}
-	url := c.baseURL + "/model/" + req.Model + "/converse-stream"
+	modelID := resolveBedrockInferenceProfileID(req.Model, c.region)
+	url := c.baseURL + "/model/" + modelID + "/converse-stream"
 	httpReq, err := http.NewRequestWithContext(ctx, "POST", url, bytes.NewReader(body))
 	if err != nil {
 		return nil, err

packages/provider/amazon_bedrock_test.go

@@ -81,3 +81,34 @@ func TestReadAWSCredentialsFile(t *testing.T) {
 		t.Logf("no aws creds available (expected on CI): %v", err)
 	}
 }
+
+func TestResolveBedrockInferenceProfileID(t *testing.T) {
+	cases := []struct {
+		model  string
+		region string
+		want   string
+	}{
+		// Bare Anthropic foundation IDs get the region-matched prefix.
+		{"anthropic.claude-sonnet-4-5-20250929-v1:0", "us-east-1", "us.anthropic.claude-sonnet-4-5-20250929-v1:0"},
+		{"anthropic.claude-sonnet-4-5-20250929-v1:0", "eu-central-1", "eu.anthropic.claude-sonnet-4-5-20250929-v1:0"},
+		{"anthropic.claude-opus-4-6-v1", "ap-southeast-2", "apac.anthropic.claude-opus-4-6-v1"},
+		{"anthropic.claude-opus-4-6-v1", "us-gov-west-1", "us-gov.anthropic.claude-opus-4-6-v1"},
+		{"deepseek.r1-v1:0", "eu-west-1", "eu.deepseek.r1-v1:0"},
+		// Empty region defaults to us.
+		{"anthropic.claude-opus-4-6-v1", "", "us.anthropic.claude-opus-4-6-v1"},
+		// Already-prefixed IDs are left untouched.
+		{"eu.anthropic.claude-sonnet-4-5-20250929-v1:0", "us-east-1", "eu.anthropic.claude-sonnet-4-5-20250929-v1:0"},
+		{"global.anthropic.claude-opus-4-6-v1", "us-east-1", "global.anthropic.claude-opus-4-6-v1"},
+		{"us.anthropic.claude-opus-4-6-v1", "eu-central-1", "us.anthropic.claude-opus-4-6-v1"},
+		// ARNs are passed through verbatim.
+		{"arn:aws:bedrock:us-east-1:123:inference-profile/us.anthropic.claude-opus-4-6-v1", "eu-west-1", "arn:aws:bedrock:us-east-1:123:inference-profile/us.anthropic.claude-opus-4-6-v1"},
+		// Families that don't need a profile are untouched.
+		{"amazon.nova-pro-v1:0", "us-east-1", "amazon.nova-pro-v1:0"},
+		{"", "us-east-1", ""},
+	}
+	for _, c := range cases {
+		if got := resolveBedrockInferenceProfileID(c.model, c.region); got != c.want {
+			t.Errorf("resolveBedrockInferenceProfileID(%q, %q) = %q; want %q", c.model, c.region, got, c.want)
+		}
+	}
+}