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johnstcn merged 7 commits into from
Jul 29, 2026
Merged

fix(aibridge): handle sonnet 5 adaptive thinking in bedrock #27339

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01e186e
fix(aibridge): handle sonnet 5 adaptive thinking
johnstcn Jul 16, 2026
85ccd22
Merge branch 'main' into cian/aigov-510-sonnet-5-adaptive-thinking
johnstcn Jul 26, 2026
0a2a6f3
Merge branch 'main' into cian/aigov-510-sonnet-5-adaptive-thinking
johnstcn Jul 27, 2026
a83a0e2
Merge branch 'main' into cian/aigov-510-sonnet-5-adaptive-thinking
johnstcn Jul 28, 2026
ae03c0e
Merge branch 'main' into cian/aigov-510-sonnet-5-adaptive-thinking
johnstcn Jul 28, 2026
77950c0
Merge branch 'main' into cian/aigov-510-sonnet-5-adaptive-thinking
johnstcn Jul 28, 2026
e6e22d5
assert that an effort was made
johnstcn Jul 29, 2026
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16 changes: 8 additions & 8 deletions aibridge/intercept/messages/base.go
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Original file line number Diff line number Diff line change
Expand Up @@ -424,7 +424,7 @@ func (i *interceptionBase) withBedrockMantleOptions(ctx context.Context) ([]opti
// augmentRequestForBedrockInvokeModel changes the model used for the request since AWS Bedrock doesn't support
// Anthropics' model names. It also converts adaptive thinking to enabled with a budget for models that
// don't support adaptive thinking natively, or enabled thinking to adaptive for models that only support
// adaptive (Opus 4.7+).
// adaptive.
func (i *interceptionBase) augmentRequestForBedrockInvokeModel() {
if i.bedrock == nil {
return
Expand All @@ -440,7 +440,7 @@ func (i *interceptionBase) augmentRequestForBedrockInvokeModel() {

switch {
case bedrockModelRequiresAdaptiveThinking(model):
// Symmetric conversion for adaptive-only models (Opus 4.7+): rewrite
// Symmetric conversion for adaptive-only models: rewrite
// thinking.type "enabled" with budget_tokens to the "adaptive" shape,
// since Bedrock returns 400 for these models when the legacy shape is
// used. Claude Code falls back to the legacy shape when it cannot
Expand Down Expand Up @@ -468,7 +468,7 @@ func (i *interceptionBase) augmentRequestForBedrockInvokeModel() {
}

// Strip body fields that Bedrock does not accept. Adaptive-only models
// (Opus 4.7+) support output_config natively without a beta flag, so
// support output_config natively without a beta flag, so
// keep it for those models even when the effort-2025-11-24 flag is
// absent from the request.
var exemptFields []string
Expand Down Expand Up @@ -496,8 +496,8 @@ func (i *interceptionBase) augmentRequestForBedrockInvokeModel() {
}

// bedrockModelSupportsAdaptiveThinking returns true if the given Bedrock model ID
// supports the "adaptive" thinking type natively (i.e. Claude 4.6 models, and
// adaptive-only models such as Opus 4.7+).
// supports the "adaptive" thinking type natively (i.e. Claude 4.6 models and
// adaptive-only models).
// See https://docs.aws.amazon.com/bedrock/latest/userguide/claude-messages-adaptive-thinking.html
func bedrockModelSupportsAdaptiveThinking(model string) bool {
return strings.Contains(model, "anthropic.claude-opus-4-6") ||
Expand All @@ -507,13 +507,13 @@ func bedrockModelSupportsAdaptiveThinking(model string) bool {

// bedrockModelRequiresAdaptiveThinking returns true if the given Bedrock model
// ID only supports the "adaptive" thinking type and rejects the legacy
// "enabled" + budget_tokens shape with a 400. Claude Opus 4.7 was the first
// model in this category.
// "enabled" + budget_tokens shape with a 400.
//
// See https://docs.aws.amazon.com/bedrock/latest/userguide/model-card-anthropic-claude-opus-4-7.html
func bedrockModelRequiresAdaptiveThinking(model string) bool {
return strings.Contains(model, "anthropic.claude-opus-4-7") ||
strings.Contains(model, "anthropic.claude-opus-4-8")
strings.Contains(model, "anthropic.claude-opus-4-8") ||
strings.Contains(model, "anthropic.claude-sonnet-5")
}

// filterBedrockBetaFlags removes unsupported beta flags from the Anthropic-Beta
Expand Down
17 changes: 16 additions & 1 deletion aibridge/intercept/messages/base_internal_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -716,7 +716,7 @@ func TestAugmentRequestForBedrock_AdaptiveThinking(t *testing.T) {
expectRemovedFields: []string{"output_config", "metadata", "service_tier", "container", "inference_geo", "context_management"},
},

// Adaptive-only models (Opus 4.7+), see coder/aibridge#280. The
// Adaptive-only models, see coder/aibridge#280. The
// conversion drops budget_tokens and flips the type; an explicit
// output_config.effort from the caller is preserved, but none is
// fabricated when absent.
Expand Down Expand Up @@ -765,6 +765,21 @@ func TestAugmentRequestForBedrock_AdaptiveThinking(t *testing.T) {
requestBody: `{"max_tokens":10000,"thinking":{"type":"enabled","budget_tokens":5000}}`,
expectThinkingType: "adaptive",
},
{
name: "sonnet_5_model_with_enabled_thinking_is_converted_to_adaptive_and_drops_budget",
bedrockModel: "anthropic.claude-sonnet-5",
requestBody: `{"max_tokens":10000,"thinking":{"type":"enabled","budget_tokens":5000}}`,
expectThinkingType: "adaptive",
},
{
name: "regional_sonnet_5_model_keeps_adaptive_thinking_and_effort_and_strips_output_config_format",
bedrockModel: "us.anthropic.claude-sonnet-5",
requestBody: `{"max_tokens":10000,"thinking":{"type":"adaptive"},"output_config":{"effort":"medium","format":{"type":"json_schema","schema":{"type":"object"}}}}`,
expectThinkingType: "adaptive",
expectEffort: "medium",
expectKeptFields: []string{"output_config", "output_config.effort"},
expectRemovedFields: []string{"output_config.format"},
},
{
// Opus 4.7 on Bedrock rejects output_config.format (structured
// outputs) with a 400 even though it accepts output_config.effort.
Expand Down
13 changes: 7 additions & 6 deletions aibridge/intercept/messages/reqpayload.go
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Original file line number Diff line number Diff line change
Expand Up @@ -76,7 +76,7 @@ var (
// If the beta flag is present in the (already-filtered) Anthropic-Beta header,
// the field is kept; otherwise it is stripped. Model-specific beta flags must
// be removed from the header before this check (see filterBedrockBetaFlags).
// Adaptive-only models (Opus 4.7+) are exempt for output_config since they
// Adaptive-only models are exempt for output_config since they
// support it natively without a beta flag, see
// bedrockModelRequiresAdaptiveThinking.
bedrockBetaGatedFields = map[string]string{
Expand Down Expand Up @@ -342,8 +342,9 @@ func (RequestPayload) resultToRawMessage(items []gjson.Result) []json.RawMessage
// The two Bedrock thinking-type conversions below are a temporary shim.
// AI Gateway relays the Anthropic Messages API shape to Bedrock, whose Claude
// models accept a disjoint subset on each generation (older models reject
// "adaptive"; Opus 4.7+ rejects "enabled"). A planned native Bedrock provider
// removes the impedance mismatch and lets us delete this whole block. Hopefully.
// "adaptive"; adaptive-only models reject "enabled"). A planned native
// Bedrock provider removes the impedance mismatch and lets us delete this
// whole block. Hopefully.

// bedrockThinkingEffortRatios maps an output_config.effort hint to the fraction
// of max_tokens to allocate as thinking budget. The mapping is a heuristic
Expand Down Expand Up @@ -402,7 +403,7 @@ func (p RequestPayload) convertAdaptiveThinkingForBedrock() (RequestPayload, err

// convertEnabledThinkingForBedrock rewrites thinking.type "enabled" to plain
// "adaptive", dropping budget_tokens. Needed for Bedrock models that only
// support adaptive thinking (Opus 4.7+).
// support adaptive thinking.
//
// We deliberately do not derive output_config.effort from the budget. Any
// such mapping would be invented (no canonical budget-to-effort relationship
Expand All @@ -421,7 +422,7 @@ func (p RequestPayload) convertEnabledThinkingForBedrock() (RequestPayload, erro

// removeBedrockUnsupportedOutputConfigSubFields drops sub-fields of
// output_config that Bedrock rejects even on models where the parent
// output_config object is accepted. Adaptive-only models (Opus 4.7+) accept
// output_config object is accepted. Adaptive-only models accept
// output_config.effort but reject output_config.format (structured outputs)
// with a 400 "Extra inputs are not permitted." The generic field-strip pass
// (removeUnsupportedBedrockFields) operates at top-level granularity only, so
Expand All @@ -444,7 +445,7 @@ func (p RequestPayload) removeBedrockUnsupportedOutputConfigSubFields() (Request
// calling this method (see filterBedrockBetaFlags).
//
// Fields exempted by exemptFields are always kept regardless of beta flag
// state. Adaptive-only Bedrock models (Opus 4.7+) require output_config
// state. Adaptive-only Bedrock models require output_config
// without a beta flag, so callers pass the field through this set to bypass
// the effort-2025-11-24 gate.
func (p RequestPayload) removeUnsupportedBedrockFields(headers http.Header, exemptFields ...string) (RequestPayload, error) {
Expand Down
40 changes: 33 additions & 7 deletions aibridge/internal/integrationtest/bridge_internal_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -460,20 +460,23 @@ func TestAWSBedrockIntegration(t *testing.T) {
}

cases := []struct {
name string
model string
smallFastModel string
expectThinkingType string
expectBudgetTokens int64 // 0 means budget_tokens should not be present
expectKeptFields []string // fields from strippableFields expected to survive
expectedBetaFlags []string // values expected in the anthropic_beta array in the forwarded body
name string
model string
smallFastModel string
expectThinkingType string
expectEffort string
expectBudgetTokens int64 // 0 means budget_tokens should not be present
sendThinkingEnabled bool // send enabled thinking with budget_tokens instead of the fixture's adaptive thinking
expectKeptFields []string // fields from strippableFields expected to survive
expectedBetaFlags []string // values expected in the anthropic_beta array in the forwarded body
}{
// "beddel" matches no model prefix, so adaptive thinking is converted
// to enabled with budget, and all model-gated beta flags are stripped.
{
name: "beddel",
model: "beddel",
smallFastModel: "modrock",
expectEffort: "",
expectThinkingType: "enabled",
expectBudgetTokens: 16000, // 32000 * 0.5 (medium effort)
expectedBetaFlags: []string{"interleaved-thinking-2025-05-14"},
Expand All @@ -483,6 +486,7 @@ func TestAWSBedrockIntegration(t *testing.T) {
name: "opus-4.5",
model: "anthropic.claude-opus-4-5-20250514-v1:0",
smallFastModel: "anthropic.claude-haiku-4-5-20241022-v1:0",
expectEffort: "medium",
expectThinkingType: "enabled",
expectBudgetTokens: 16000,
expectKeptFields: []string{"output_config"},
Expand All @@ -493,6 +497,7 @@ func TestAWSBedrockIntegration(t *testing.T) {
name: "sonnet-4.5",
model: "anthropic.claude-sonnet-4-5-20241022-v2:0",
smallFastModel: "anthropic.claude-haiku-4-5-20241022-v1:0",
expectEffort: "",
expectThinkingType: "enabled",
expectBudgetTokens: 16000,
expectKeptFields: []string{"context_management"},
Expand All @@ -503,10 +508,23 @@ func TestAWSBedrockIntegration(t *testing.T) {
{
name: "opus-4.6",
model: "anthropic.claude-opus-4-6-20260619-v1:0",
expectEffort: "",
smallFastModel: "anthropic.claude-haiku-4-5-20241022-v1:0",
expectThinkingType: "adaptive",
expectedBetaFlags: []string{"interleaved-thinking-2025-05-14"},
},
// Sonnet 5 requires adaptive thinking, so legacy enabled thinking is
// converted and output_config.effort is preserved.
{
name: "sonnet-5",
model: "us.anthropic.claude-sonnet-5",
smallFastModel: "anthropic.claude-haiku-4-5-20241022-v1:0",
expectEffort: "medium",
expectThinkingType: "adaptive",
sendThinkingEnabled: true,
expectKeptFields: []string{"output_config"},
expectedBetaFlags: []string{"interleaved-thinking-2025-05-14"},
},
}

for _, tc := range cases {
Expand Down Expand Up @@ -535,6 +553,13 @@ func TestAWSBedrockIntegration(t *testing.T) {

reqBody, err := sjson.SetBytes(fix.Request(), "stream", streaming)
require.NoError(t, err)
if tc.sendThinkingEnabled {
reqBody, err = sjson.SetBytes(reqBody, "thinking", map[string]any{
"type": "enabled",
"budget_tokens": 16000,
})
require.NoError(t, err)
}

// Send with Anthropic-Beta header containing flags that should be filtered.
resp, err := bridgeServer.makeRequest(t, http.MethodPost, pathAnthropicMessages, reqBody, http.Header{
Expand Down Expand Up @@ -562,6 +587,7 @@ func TestAWSBedrockIntegration(t *testing.T) {
} else {
assert.False(t, gjson.GetBytes(body, "thinking.budget_tokens").Exists(), "budget_tokens should not be present")
}
assert.Equal(t, tc.expectEffort, gjson.GetBytes(body, "output_config.effort").String(), "effort mismatch")

// The Bedrock SDK middleware moves Anthropic-Beta from the header
// into the body as "anthropic_beta".
Expand Down
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