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fix(anthropic): sanitize tool_use/tool_result ids to Anthropic's charset #5096

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Merged
akshaydeo merged 2 commits into from
Jul 12, 2026
+157 −28
Merged

fix(anthropic): sanitize tool_use/tool_result ids to Anthropic's charset #5096

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58f8d2e
fix(anthropic): sanitize tool_use/tool_result ids to Anthropic's charset
Shaik-Sirajuddin Jul 10, 2026
21e7d7a
fix(anthropic): sanitize empty tool_use ids too
Shaik-Sirajuddin Jul 10, 2026
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9 changes: 5 additions & 4 deletions core/providers/anthropic/chat.go
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Original file line number Diff line number Diff line change
Expand Up @@ -682,9 +682,10 @@ func ToAnthropicChatRequest(ctx *schemas.BifrostContext, bifrostReq *schemas.Bif
for i < len(messages) && messages[i].Role == schemas.ChatMessageRoleTool {
toolMsg := messages[i]
if toolMsg.ChatToolMessage != nil && toolMsg.ChatToolMessage.ToolCallID != nil {
sanitizedToolUseID := providerUtils.SanitizeAnthropicToolUseID(*toolMsg.ChatToolMessage.ToolCallID)
toolResult := AnthropicContentBlock{
Type: AnthropicContentBlockTypeToolResult,
ToolUseID: toolMsg.ChatToolMessage.ToolCallID,
ToolUseID: &sanitizedToolUseID,
}

// Convert tool result content
Expand Down Expand Up @@ -783,7 +784,7 @@ func ToAnthropicChatRequest(ctx *schemas.BifrostContext, bifrostReq *schemas.Bif
for _, toolCall := range msg.ChatAssistantMessage.ToolCalls {
toolUse := AnthropicContentBlock{
Type: AnthropicContentBlockTypeToolUse,
ID: toolCall.ID,
ID: providerUtils.SanitizeAnthropicToolUseIDPtr(toolCall.ID),
Name: toolCall.Function.Name,
}

Expand Down Expand Up @@ -1180,7 +1181,7 @@ func ToAnthropicChatResponse(bifrostResp *schemas.BifrostChatResponse) *Anthropi

content = append(content, AnthropicContentBlock{
Type: AnthropicContentBlockTypeToolUse,
ID: toolCall.ID,
ID: providerUtils.SanitizeAnthropicToolUseIDPtr(toolCall.ID),
Name: toolCall.Function.Name,
Input: inputRaw,
})
Expand Down Expand Up @@ -1592,7 +1593,7 @@ func ToAnthropicChatStreamResponse(bifrostResp *schemas.BifrostChatResponse) str
streamResp.Index = &choice.Index
streamResp.ContentBlock = &AnthropicContentBlock{
Type: AnthropicContentBlockTypeToolUse,
ID: toolCall.ID,
ID: providerUtils.SanitizeAnthropicToolUseIDPtr(toolCall.ID),
Name: toolCall.Function.Name,
}
} else if toolCall.Function.Arguments != "" {
Expand Down
54 changes: 30 additions & 24 deletions core/providers/anthropic/responses.go
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Original file line number Diff line number Diff line change
Expand Up @@ -2184,8 +2184,8 @@ func ToAnthropicResponsesStreamResponse(ctx *schemas.BifrostContext, bifrostResp
// Note: Computer tool calls should not be converted to thinking blocks
contentBlock := &AnthropicContentBlock{
Type: AnthropicContentBlockTypeToolUse,
ID: bifrostResp.Item.ID, // The tool use ID
Name: schemas.Ptr(string(AnthropicToolNameComputer)), // "computer"
ID: providerUtils.SanitizeAnthropicToolUseIDPtr(bifrostResp.Item.ID), // The tool use ID
Name: schemas.Ptr(string(AnthropicToolNameComputer)), // "computer"
}

// Always start with empty input for streaming compatibility
Expand All @@ -2203,8 +2203,8 @@ func ToAnthropicResponsesStreamResponse(ctx *schemas.BifrostContext, bifrostResp
// Build the content_block as server_tool_use
contentBlock := &AnthropicContentBlock{
Type: AnthropicContentBlockTypeServerToolUse,
ID: bifrostResp.Item.ID, // The tool use ID
Name: schemas.Ptr(string(AnthropicToolNameWebSearch)), // "web_search"
ID: providerUtils.SanitizeAnthropicToolUseIDPtr(bifrostResp.Item.ID), // The tool use ID
Name: schemas.Ptr(string(AnthropicToolNameWebSearch)), // "web_search"
}

// Deliver the query whole in content_block_start (no input_json_delta),
Expand All @@ -2224,7 +2224,7 @@ func ToAnthropicResponsesStreamResponse(ctx *schemas.BifrostContext, bifrostResp
if tm := bifrostResp.Item.ResponsesToolMessage; tm != nil && tm.Caller != nil {
contentBlock.Caller = &AnthropicToolCaller{
Type: AnthropicToolCallerType(tm.Caller.Type),
ToolID: tm.Caller.ToolID,
ToolID: providerUtils.SanitizeAnthropicToolUseIDPtr(tm.Caller.ToolID),
}
}

Expand All @@ -2240,6 +2240,7 @@ func ToAnthropicResponsesStreamResponse(ctx *schemas.BifrostContext, bifrostResp
if bifrostResp.Item.ResponsesToolMessage != nil && bifrostResp.Item.ResponsesToolMessage.CallID != nil {
toolUseID = bifrostResp.Item.ResponsesToolMessage.CallID
}
toolUseID = providerUtils.SanitizeAnthropicToolUseIDPtr(toolUseID)
streamResp.ContentBlock = &AnthropicContentBlock{
Type: AnthropicContentBlockTypeServerToolUse,
ID: toolUseID,
Expand Down Expand Up @@ -2271,7 +2272,7 @@ func ToAnthropicResponsesStreamResponse(ctx *schemas.BifrostContext, bifrostResp
addedState.codeExecToolNameByItem[reverseStreamItemKey(bifrostResp)] = toolName
streamResp.ContentBlock = &AnthropicContentBlock{
Type: AnthropicContentBlockTypeServerToolUse,
ID: toolUseID,
ID: providerUtils.SanitizeAnthropicToolUseIDPtr(toolUseID),
Name: schemas.Ptr(toolName),
Input: json.RawMessage("{}"),
}
Expand Down Expand Up @@ -2361,7 +2362,7 @@ func ToAnthropicResponsesStreamResponse(ctx *schemas.BifrostContext, bifrostResp
} else {
contentBlock.Type = AnthropicContentBlockTypeToolUse
if bifrostResp.Item.ResponsesToolMessage != nil {
contentBlock.ID = bifrostResp.Item.ResponsesToolMessage.CallID
contentBlock.ID = providerUtils.SanitizeAnthropicToolUseIDPtr(bifrostResp.Item.ResponsesToolMessage.CallID)
contentBlock.Name = bifrostResp.Item.ResponsesToolMessage.Name
// Always start with empty input for streaming compatibility
contentBlock.Input = json.RawMessage("{}")
Expand All @@ -2383,7 +2384,7 @@ func ToAnthropicResponsesStreamResponse(ctx *schemas.BifrostContext, bifrostResp
case schemas.ResponsesMessageTypeMCPCall:
contentBlock.Type = AnthropicContentBlockTypeMCPToolUse
if bifrostResp.Item.ResponsesToolMessage != nil {
contentBlock.ID = bifrostResp.Item.ID
contentBlock.ID = providerUtils.SanitizeAnthropicToolUseIDPtr(bifrostResp.Item.ID)
contentBlock.Name = bifrostResp.Item.ResponsesToolMessage.Name
if bifrostResp.Item.ResponsesToolMessage.ResponsesMCPToolCall != nil {
contentBlock.ServerName = &bifrostResp.Item.ResponsesToolMessage.ResponsesMCPToolCall.ServerLabel
Expand Down Expand Up @@ -2639,14 +2640,14 @@ func ToAnthropicResponsesStreamResponse(ctx *schemas.BifrostContext, bifrostResp

resultBlock := &AnthropicContentBlock{
Type: AnthropicContentBlockTypeWebSearchToolResult,
ToolUseID: bifrostResp.Item.ID, // Link to the server_tool_use block
ToolUseID: providerUtils.SanitizeAnthropicToolUseIDPtr(bifrostResp.Item.ID), // Link to the server_tool_use block
Content: &AnthropicContent{ContentBlocks: resultContentBlocks},
}
// Carry the programmatic-tool-calling caller onto the result too.
if tm != nil && tm.Caller != nil {
resultBlock.Caller = &AnthropicToolCaller{
Type: AnthropicToolCallerType(tm.Caller.Type),
ToolID: tm.Caller.ToolID,
ToolID: providerUtils.SanitizeAnthropicToolUseIDPtr(tm.Caller.ToolID),
}
}
events = append(events,
Expand Down Expand Up @@ -2743,6 +2744,7 @@ func ToAnthropicResponsesStreamResponse(ctx *schemas.BifrostContext, bifrostResp
if bifrostResp.Item.ResponsesToolMessage != nil && bifrostResp.Item.ResponsesToolMessage.CallID != nil {
toolUseID = bifrostResp.Item.ResponsesToolMessage.CallID
}
toolUseID = providerUtils.SanitizeAnthropicToolUseIDPtr(toolUseID)

serverIdx := state.blockIndexFor(reverseStreamItemKey(bifrostResp))

Expand Down Expand Up @@ -5508,7 +5510,7 @@ func convertBifrostFunctionCallToAnthropicToolUse(ctx *schemas.BifrostContext, m
}

if msg.ResponsesToolMessage.CallID != nil {
toolUseBlock.ID = msg.ResponsesToolMessage.CallID
toolUseBlock.ID = providerUtils.SanitizeAnthropicToolUseIDPtr(msg.ResponsesToolMessage.CallID)
}
if msg.ResponsesToolMessage.Name != nil {
toolUseBlock.Name = msg.ResponsesToolMessage.Name
Expand Down Expand Up @@ -5546,7 +5548,7 @@ func convertBifrostFunctionCallOutputToAnthropicToolResultBlock(msg *schemas.Res
if msg.ResponsesToolMessage != nil {
toolResultBlock := AnthropicContentBlock{
Type: AnthropicContentBlockTypeToolResult,
ToolUseID: msg.ResponsesToolMessage.CallID,
ToolUseID: providerUtils.SanitizeAnthropicToolUseIDPtr(msg.ResponsesToolMessage.CallID),
CacheControl: msg.CacheControl,
}

Expand Down Expand Up @@ -5602,7 +5604,7 @@ func convertBifrostComputerCallOutputToAnthropicToolResultBlock(msg *schemas.Res
if msg.ResponsesToolMessage != nil && msg.ResponsesToolMessage.CallID != nil {
toolResultBlock := AnthropicContentBlock{
Type: AnthropicContentBlockTypeToolResult,
ToolUseID: msg.ResponsesToolMessage.CallID,
ToolUseID: providerUtils.SanitizeAnthropicToolUseIDPtr(msg.ResponsesToolMessage.CallID),
}

// Handle output
Expand Down Expand Up @@ -5633,7 +5635,7 @@ func convertBifrostMCPCallOutputToAnthropicToolResultBlock(msg *schemas.Response
if msg.ResponsesToolMessage != nil && msg.ResponsesToolMessage.CallID != nil {
toolResultBlock := AnthropicContentBlock{
Type: AnthropicContentBlockTypeMCPToolResult,
ToolUseID: msg.ResponsesToolMessage.CallID,
ToolUseID: providerUtils.SanitizeAnthropicToolUseIDPtr(msg.ResponsesToolMessage.CallID),
}

// Handle output
Expand Down Expand Up @@ -5688,7 +5690,7 @@ func convertBifrostComputerCallToAnthropicToolUse(msg *schemas.ResponsesMessage)
Name: schemas.Ptr(string(AnthropicToolNameComputer)),
}
if msg.ResponsesToolMessage.CallID != nil {
toolUseBlock.ID = msg.ResponsesToolMessage.CallID
toolUseBlock.ID = providerUtils.SanitizeAnthropicToolUseIDPtr(msg.ResponsesToolMessage.CallID)
}
if msg.ResponsesToolMessage.Name != nil {
toolUseBlock.Name = msg.ResponsesToolMessage.Name
Expand All @@ -5714,7 +5716,7 @@ func convertBifrostMCPCallToAnthropicToolUse(msg *schemas.ResponsesMessage) *Ant
}

if msg.ID != nil {
toolUseBlock.ID = msg.ID
toolUseBlock.ID = providerUtils.SanitizeAnthropicToolUseIDPtr(msg.ID)
}
toolUseBlock.Name = msg.ResponsesToolMessage.Name

Expand All @@ -5741,7 +5743,7 @@ func convertBifrostMCPCallToAnthropicToolUse(msg *schemas.ResponsesMessage) *Ant
func convertBifrostMCPCallOutputToAnthropicMessage(msg *schemas.ResponsesMessage) *AnthropicMessage {
toolResultBlock := AnthropicContentBlock{
Type: AnthropicContentBlockTypeMCPToolResult,
ID: msg.ResponsesToolMessage.CallID,
ID: providerUtils.SanitizeAnthropicToolUseIDPtr(msg.ResponsesToolMessage.CallID),
}

if msg.ResponsesToolMessage.Output != nil {
Expand All @@ -5764,7 +5766,7 @@ func convertBifrostMCPApprovalToAnthropicToolUse(msg *schemas.ResponsesMessage)
}

if msg.ID != nil {
toolUseBlock.ID = msg.ID
toolUseBlock.ID = providerUtils.SanitizeAnthropicToolUseIDPtr(msg.ID)
}
toolUseBlock.Name = msg.ResponsesToolMessage.Name

Expand Down Expand Up @@ -5800,7 +5802,7 @@ func convertBifrostWebSearchCallToAnthropicBlocks(msg *schemas.ResponsesMessage)
// sandbox) must be re-emitted on both the server_tool_use and the result block.
var caller *AnthropicToolCaller
if c := msg.ResponsesToolMessage.Caller; c != nil {
caller = &AnthropicToolCaller{Type: AnthropicToolCallerType(c.Type), ToolID: c.ToolID}
caller = &AnthropicToolCaller{Type: AnthropicToolCallerType(c.Type), ToolID: providerUtils.SanitizeAnthropicToolUseIDPtr(c.ToolID)}
}

// 1. Create server_tool_use block for the web search
Expand All @@ -5811,7 +5813,7 @@ func convertBifrostWebSearchCallToAnthropicBlocks(msg *schemas.ResponsesMessage)
}

if msg.ID != nil {
serverToolUseBlock.ID = msg.ID
serverToolUseBlock.ID = providerUtils.SanitizeAnthropicToolUseIDPtr(msg.ID)
}

// Extract the query from the action
Expand Down Expand Up @@ -5852,6 +5854,7 @@ func convertBifrostWebSearchCallToAnthropicBlocks(msg *schemas.ResponsesMessage)
} else {
toolUseID = msg.ID
}
toolUseID = providerUtils.SanitizeAnthropicToolUseIDPtr(toolUseID)
webSearchResultBlock := AnthropicContentBlock{
Type: AnthropicContentBlockTypeWebSearchToolResult,
ToolUseID: toolUseID,
Expand Down Expand Up @@ -5949,10 +5952,11 @@ func convertBifrostWebFetchCallToAnthropicBlocks(msg *schemas.ResponsesMessage)
} else {
toolUseID = msg.ID
}
toolUseID = providerUtils.SanitizeAnthropicToolUseIDPtr(toolUseID)

var caller *AnthropicToolCaller
if tm.Caller != nil {
caller = &AnthropicToolCaller{Type: AnthropicToolCallerType(tm.Caller.Type), ToolID: tm.Caller.ToolID}
caller = &AnthropicToolCaller{Type: AnthropicToolCallerType(tm.Caller.Type), ToolID: providerUtils.SanitizeAnthropicToolUseIDPtr(tm.Caller.ToolID)}
}

serverToolUseBlock := AnthropicContentBlock{
Expand Down Expand Up @@ -6032,6 +6036,7 @@ func convertBifrostAdvisorCallToAnthropicBlocks(msg *schemas.ResponsesMessage) [
} else {
toolUseID = msg.ID
}
toolUseID = providerUtils.SanitizeAnthropicToolUseIDPtr(toolUseID)

// 1. server_tool_use block — advisor input is always empty.
serverToolUseBlock := AnthropicContentBlock{
Expand Down Expand Up @@ -6277,6 +6282,7 @@ func convertBifrostCodeExecCallToAnthropicBlocks(msg *schemas.ResponsesMessage)
} else {
toolUseID = msg.ID
}
toolUseID = providerUtils.SanitizeAnthropicToolUseIDPtr(toolUseID)

toolName := cec.ToolName
if toolName == "" {
Expand Down Expand Up @@ -6304,7 +6310,7 @@ func convertBifrostCodeExecCallToAnthropicBlocks(msg *schemas.ResponsesMessage)
if cec.Caller != nil {
serverToolUse.Caller = &AnthropicToolCaller{
Type: AnthropicToolCallerType(cec.Caller.Type),
ToolID: cec.Caller.ToolID,
ToolID: providerUtils.SanitizeAnthropicToolUseIDPtr(cec.Caller.ToolID),
}
}

Expand Down Expand Up @@ -6380,7 +6386,7 @@ func convertBifrostCodeExecCallToAnthropicBlocks(msg *schemas.ResponsesMessage)
if cec.Caller != nil {
resultBlock.Caller = &AnthropicToolCaller{
Type: AnthropicToolCallerType(cec.Caller.Type),
ToolID: cec.Caller.ToolID,
ToolID: providerUtils.SanitizeAnthropicToolUseIDPtr(cec.Caller.ToolID),
}
}

Expand Down Expand Up @@ -6418,7 +6424,7 @@ func convertBifrostComputerCallOutputToAnthropicMessage(msg *schemas.ResponsesMe
if msg.ResponsesToolMessage != nil {
toolResultBlock := AnthropicContentBlock{
Type: AnthropicContentBlockTypeToolResult,
ToolUseID: msg.ResponsesToolMessage.CallID,
ToolUseID: providerUtils.SanitizeAnthropicToolUseIDPtr(msg.ResponsesToolMessage.CallID),
}

if msg.ResponsesToolMessage.Output != nil {
Expand Down
52 changes: 52 additions & 0 deletions core/providers/utils/utils.go
View file
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Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,7 @@ import (
"time"

"github.com/bytedance/sonic"
"github.com/cespare/xxhash/v2"
"github.com/maximhq/bifrost/core/network"
"github.com/maximhq/bifrost/core/schemas"
"github.com/tidwall/gjson"
Expand All @@ -40,6 +41,57 @@ import (
// "<baseID>_ts_<signature>".
const ThoughtSignatureSeparator = "_ts_"

// anthropicUnsafeToolUseIDCharRegex matches any character outside Anthropic's
// required tool_use/tool_result id charset (^[a-zA-Z0-9_-]+$).
var anthropicUnsafeToolUseIDCharRegex = regexp.MustCompile(`[^A-Za-z0-9_-]+`)

// maxSanitizedAnthropicToolUseIDLen bounds the sanitized id length, matching the
// 64-char cap this codebase already applies to tool identifiers elsewhere (e.g.
// OpenAI's call_id, Bedrock's tool-name aliasing) so a long, non-conforming
// upstream id can't sanitize into something Anthropic still rejects for length.
const maxSanitizedAnthropicToolUseIDLen = 64

// SanitizeAnthropicToolUseID rewrites a tool_use/tool_result id to satisfy Anthropic's
// ^[a-zA-Z0-9_-]+$ requirement. Some upstream providers (e.g. Kimi/Gemini-compatible
// backends) emit ids containing ':' or '.', which Anthropic's API rejects with a 400
// when such a conversation is replayed through the Anthropic provider. The mapping is
// deterministic (hash of the original id) so a tool_use id and its matching tool_result
// id always sanitize to the same value within a request, matching the alias pattern
// used for Bedrock tool names (see bedrockAliasToolName).
func SanitizeAnthropicToolUseID(id string) string {
// The empty string doesn't match Anthropic's pattern either (it requires at
// least one character), so it needs the same hash-based rewrite as ids with
// disallowed characters rather than being passed through unchanged.
if id != "" && !anthropicUnsafeToolUseIDCharRegex.MatchString(id) {
return id
}
// Use the full 64-bit hash (not a 32-bit truncation) to keep collisions
// between distinct ids astronomically unlikely, since two tool_use blocks
// sharing an id would make Anthropic's replies ambiguous or rejected.
hash := fmt.Sprintf("%016x", xxhash.Sum64String(id))
semantic := strings.Trim(anthropicUnsafeToolUseIDCharRegex.ReplaceAllString(id, "_"), "_")
if semantic == "" {
return hash
}
if maxSemanticLen := maxSanitizedAnthropicToolUseIDLen - len(hash) - 1; len(semantic) > maxSemanticLen {
semantic = strings.Trim(semantic[:maxSemanticLen], "_")
}
if semantic == "" {
return hash
}
return hash + "_" + semantic
}

// SanitizeAnthropicToolUseIDPtr is SanitizeAnthropicToolUseID for an optional id.
// Returns nil unchanged.
func SanitizeAnthropicToolUseIDPtr(id *string) *string {
if id == nil {
return nil
}
sanitized := SanitizeAnthropicToolUseID(*id)
return &sanitized
}

// StripThoughtSignature returns the base tool-call ID without any embedded provider
// reasoning signature. It is deterministic, so a tool call and its matching output strip
// to the same ID. Providers that cannot use the signature (e.g. OpenAI, which caps call_id
Expand Down
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