Anthropic API returns 400 when multiple tool_result blocks share the same
tool_use_id, or when consecutive tool results are sent as separate user
messages. This fix:
1. Adds ToolCallID deduplication in sanitizeHistoryForProvider (context.go)
to drop duplicate tool results before sending to any provider.
2. Merges consecutive tool result messages into a single user message with
multiple tool_result content blocks in Anthropic's buildRequestBody,
for both "user" (with ToolCallID) and "tool" role messages.
3. Adds tests for both behaviors.
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
- add defensive nil check for tool call Arguments field
- replace nil input with empty object to comply with Anthropic spec
- prevent API errors when GLM models return null input in tool_use blocks
Zhipu AI's GLM series models may return tool_use blocks with null input field,
which causes their API to reject subsequent requests with error:
"ClaudeContentBlockToolResult object has no attribute id"
This fix ensures compatibility by converting nil inputs to empty objects {},
matching the Anthropic Messages API specification while maintaining backward
compatibility with other providers.
* feat: add anthropic-messages protocol support
Add native Anthropic Messages API format support to enable
compatibility with custom endpoints that only support Anthropic's
native message format (not OpenAI-compatible format).
Changes:
- Add new pkg/providers/anthropic_messages package with HTTP-based provider
- Implement Anthropic Messages API request/response format conversion
- Add anthropic-messages protocol support in factory_provider.go
- Include comprehensive unit tests (64.2% coverage)
Features:
- Support for system, user, assistant, and tool messages
- Support for tool calls (tool_use blocks)
- Proper header handling (x-api-key, anthropic-version)
- Configurable max_tokens and temperature
- Automatic base URL normalization
Configuration example:
model: "anthropic-messages/claude-opus-4-6"
api_base: "https://api.anthropic.com"
api_key: "sk-..."
Tested with actual API endpoint, verified compatibility
with Anthropic Messages API specification.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
* docs: add anthropic-messages protocol examples to README and config
Add configuration examples and documentation for the new
anthropic-messages protocol:
- config.example.json: Add claude-opus-4.6 example with anthropic-messages
- README.md: Add "Anthropic Messages API (native format)" section
- README.zh.md: Add Chinese version of the documentation
This helps users understand when to use anthropic-messages vs
anthropic protocol and fixes issue #269.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
* fix: format code with gofmt -s
- Align constant definitions in provider.go
- Align struct fields in test cases
- Fix gofmt formatting issues reported in review
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
* fix: address linter errors
- Fix HTTP header canonical form: "x-api-key" → "X-API-Key"
- Fix HTTP header canonical form: "anthropic-version" → "Anthropic-Version"
- Format imports with gci (standard, default, localmodule order)
- Format code with golines (max line length 120)
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
* fix: resolve golangci-lint errors in anthropic-messages provider
- add nolint comment for canonicalheader rule on X-API-Key header (Anthropic API requires exact casing)
- fix golines formatting issues in provider_test.go (split long lines under 120 chars)
- fix long comment line in factory_provider.go (split into two lines)
Resolves CI linter failures for the anthropic-messages protocol implementation.
* fix(providers): address review comments in anthropic-messages provider
- fix normalizeBaseURL edge case that incorrectly appends /v1 to URLs already containing /v1 path (e.g., https://api.example.com/v1/proxy)
- remove dead code for apiBase empty check as normalizeBaseURL() always provides a default value
- update test to use proper constructor instead of direct struct initialization
- add detailed comments explaining the URL normalization logic
Resolves review comments on PR #1284
* fix(providers): remove hardcoded max_tokens in anthropic-messages provider
- remove hardcoded max_tokens value (4096) from buildRequestBody
- read max_tokens directly from options parameter
- add error handling when max_tokens is missing from options
- update test cases to include max_tokens in options
This fix ensures the provider respects the config default value (32768)
or system fallback (8192) instead of always using the hardcoded 4096.
* fix(providers): improve error handling and add edge case tests
- fix ToolCalls nil vs empty slice issue to ensure consistent JSON serialization
- add detailed HTTP error handling for common status codes (401, 429, 400, 404, 500, 503)
- add edge case tests for buildRequestBody and parseResponseBody
- clarify anthropic vs anthropic-messages protocol differences in docs
---------
Co-authored-by: Claude <noreply@anthropic.com>
Kunal Karmakar