fix: uses anthropic endpoints in chat completion and responses in deepseek

[sammaji]

Summary

The DeepSeek provider previously used OpenAI-compatible endpoints for all requests. DeepSeek exposes an Anthropic-compatible API at /anthropic/v1/messages that supports richer features (extended thinking, native tool handling, web search, etc.). This PR migrates the DeepSeek provider to use that Anthropic-compatible endpoint, enabling proper thinking/tool-choice handling and multiple tool calls.

Changes

• Replaced all OpenAI handler calls (HandleOpenAIChatCompletionRequest, HandleOpenAIChatCompletionStreaming) in the DeepSeek provider with their Anthropic equivalents (HandleAnthropicChatCompletionRequest, HandleAnthropicChatCompletionStreaming, HandleAnthropicResponsesRequest, HandleAnthropicResponsesStream).
• Updated the request path from /chat/completions to /anthropic/v1/messages and switched authentication from a Bearer token header to x-api-key.
• The Responses and ResponsesStream methods now call Anthropic handlers directly instead of delegating to ChatCompletion/ChatCompletionStream with a fallback conversion flag.
• Moved the disableThinkingWithToolChoice logic out of the compat plugin and into the Anthropic request builder, which already handles this concern natively for Anthropic-compatible providers. The compat plugin no longer needs to special-case DeepSeek for thinking suppression.
• Enabled MultipleToolCalls in the DeepSeek integration test suite, as the Anthropic-compatible endpoint supports this correctly.
• Added deepseek_anthropic_test.go with unit tests that spin up a local HTTP server to verify: the correct endpoint and x-api-key header are used, web search tools are preserved in the outbound body, and thinking is disabled when a forced tool choice is present (for both chat and responses APIs).

Type of change

• Bug fix
• Feature
• Refactor
• Documentation
• Chore/CI

Affected areas

• Core (Go)
• Transports (HTTP)
• Providers/Integrations
• Plugins
• UI (React)
• Docs

How to test

go test ./core/providers/deepseek/...
go test ./plugins/compat/...
go test ./...

The new deepseek_anthropic_test.go tests use httptest.NewServer and require no external credentials. They verify:

• ChatCompletion and Responses route to /anthropic/v1/messages with x-api-key authentication.
• Web search tools are forwarded correctly in the outbound request body.
• Forced tool choice causes thinking: {type: disabled} to be set in the outbound body for both chat and responses requests.

Breaking changes

• Yes
• No

DeepSeek requests are now sent to the /anthropic/v1/messages endpoint instead of /chat/completions. Any custom BaseURL configurations that pointed to an OpenAI-compatible DeepSeek endpoint will need to be updated to point to a host that serves the Anthropic-compatible API. The BifrostContextKeyPassthroughExtraParams and BifrostContextKeyIsResponsesToChatCompletionFallback context flags are no longer set by the DeepSeek provider.

Related issues

N/A

Security considerations

Authentication now uses x-api-key instead of a Bearer token. The key value handling is unchanged — it is read from schemas.Key and never logged.

Checklist

• I read docs/contributing/README.md and followed the guidelines
• I added/updated tests where appropriate
• I updated documentation where needed
• I verified builds succeed (Go and UI)
• I verified the CI pipeline passes locally if applicable

[coderabbitai]

📝 Walkthrough

Walkthrough

DeepSeek chat and responses operations now support Anthropic-compatible routing alongside OpenAI-compatible fallbacks. The changes add authentication, streaming configuration, feature metadata, forced-tool thinking suppression, and tests for routing, web search, tool choices, and multi-tool calls.

Changes

DeepSeek Anthropic compatibility

Layer / File(s)	Summary
Anthropic provider routing core/providers/deepseek/deepseek.go, core/providers/anthropic/...	DeepSeek chat and responses methods use Anthropic handlers, x-api-key authentication, /anthropic/v1/messages, streaming settings, request defaults, and feature flags.
Forced-tool thinking compatibility core/providers/anthropic/chat.go, core/providers/anthropic/responses.go, plugins/compat/conversion.go	Forced DeepSeek tool choices disable thinking in Anthropic and OpenAI-compatible request handling, while the previous responses conversion override is removed.
Routing and tool-call validation core/providers/deepseek/deepseek_anthropic_test.go, core/providers/deepseek/deepseek_test.go	Tests validate Anthropic and OpenAI endpoint routing, authentication, web search preservation, forced-tool thinking behavior, and multi-tool calling including streaming.

Estimated code review effort: 4 (Complex) | ~45 minutes

Sequence Diagram(s)

sequenceDiagram
  participant Client
  participant DeepSeekProvider
  participant AnthropicHandlers
  participant DeepSeekAPI
  Client->>DeepSeekProvider: Send chat or responses request
  DeepSeekProvider->>AnthropicHandlers: Convert and build Anthropic messages request
  DeepSeekProvider->>DeepSeekAPI: POST /anthropic/v1/messages with x-api-key
  DeepSeekAPI-->>AnthropicHandlers: Return Anthropic response
  AnthropicHandlers-->>Client: Return normalized completion or responses result

Loading

Possibly related PRs

• maximhq/bifrost#5065: Both modify DeepSeek forced-tool handling during ResponsesRequest parameter conversion.
• maximhq/bifrost#5208: Both add or validate DeepSeek routing through the Anthropic-compatible /anthropic/v1/messages endpoint.
• maximhq/bifrost#5305: Both use shared Anthropic endpoint resolution and Anthropic-compatible request routing.

Suggested reviewers: akshaydeo, tejasghatte, danpiths, pratham-mishra04, roroghost17

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 30.77% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title clearly states the main change: switching DeepSeek chat and responses to Anthropic endpoints.
Description check	✅ Passed	The description matches the template well and covers summary, changes, testing, breaking changes, security, and checklist items.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch 07-14-fix_uses_anthropic_endpoints_in_chat_completion_and_responses_in_deepseek

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[sammaji]

• chore: update deepseek provider docs #5177 : 2 dependent PRs (#5187 , #5208 )
• fix: uses anthropic endpoints in chat completion and responses in deepseek #5176 👈 (View in Graphite)
• fix: adds sgl anthropic compatible apis via key level setting #5305
• dev

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[greptile-apps]

Confidence Score: 4/5

This is close, but the raw request path should be fixed before merging.

• Typed DeepSeek requests now handle forced tool choice with thinking.
• Raw Anthropic-compatible bodies can still bypass that handling.
• A raw forced-tool request can still be rejected by DeepSeek.

core/providers/anthropic/requestbuilder.go

Important Files Changed

Filename	Overview
core/providers/deepseek/deepseek.go	Adds Anthropic endpoint routing for DeepSeek while preserving the OpenAI fallback path.
core/providers/anthropic/chat.go	Adds typed DeepSeek thinking suppression for pinned tool choices, while raw bodies still bypass it.
core/providers/anthropic/responses.go	Adds matching typed DeepSeek thinking suppression for responses requests.
core/providers/anthropic/requestbuilder.go	Registers DeepSeek defaults and keeps the raw-body path separate from typed conversion.
core/providers/anthropic/types.go	Adds an explicit DeepSeek capability entry for Anthropic request shaping.
plugins/compat/conversion.go	Removes DeepSeek-specific thinking mutation from compat conversion.
core/providers/deepseek/deepseek_anthropic_test.go	Adds local tests for DeepSeek Anthropic endpoint routing, auth, tools, and typed thinking suppression.
core/providers/deepseek/deepseek_test.go	Enables multiple tool-call coverage for DeepSeek provider scenarios.

_{Reviews (12): Last reviewed commit: "fix: use anthropic endpoints in chat com..." | Re-trigger Greptile}

[coderabbitai]

🧹 Nitpick comments (1)

core/providers/deepseek/deepseek_anthropic_test.go (1)

50-283: 📐 Maintainability & Code Quality | 🔵 Trivial | ⚡ Quick win

Solid new coverage; consider extending to streaming paths.

These tests are clear and deterministic. Since ChatCompletionStream/ResponsesStream route through separate Anthropic streaming handlers (with their own providerName/header-filtering wiring), consider adding equivalent streaming test cases — this would have caught the providerName divergence noted on deepseek.go.

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@core/providers/deepseek/deepseek_anthropic_test.go` around lines 50 - 283,
Extend the DeepSeek Anthropic coverage with equivalent tests for
ChatCompletionStream and ResponsesStream, using the existing httptest setup
patterns in TestChatCompletion_UsesAnthropicEndpoint and
TestResponses_UsesAnthropicEndpointAndKeepsWebSearch. Assert the streaming
requests use /anthropic/v1/messages and x-api-key, and verify streamed responses
succeed; include tool preservation where applicable to cover the separate
streaming handlers’ providerName and header-filtering paths.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Nitpick comments:
In `@core/providers/deepseek/deepseek_anthropic_test.go`:
- Around line 50-283: Extend the DeepSeek Anthropic coverage with equivalent
tests for ChatCompletionStream and ResponsesStream, using the existing httptest
setup patterns in TestChatCompletion_UsesAnthropicEndpoint and
TestResponses_UsesAnthropicEndpointAndKeepsWebSearch. Assert the streaming
requests use /anthropic/v1/messages and x-api-key, and verify streamed responses
succeed; include tool preservation where applicable to cover the separate
streaming handlers’ providerName and header-filtering paths.

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ℹ️ Review info

⚙️ Run configuration

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Run ID: b246dad0-681f-4183-ad45-0a8a466b449e

📥 Commits

Reviewing files that changed from the base of the PR and between ddc26fb and cda389d.

📒 Files selected for processing (4)

• core/providers/deepseek/deepseek.go
• core/providers/deepseek/deepseek_anthropic_test.go
• core/providers/deepseek/deepseek_test.go
• plugins/compat/conversion.go

💤 Files with no reviewable changes (1)

• plugins/compat/conversion.go

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All committers have signed the CLA.

[akshaydeo]

Merge activity

• Jul 18, 4:02 PM UTC: A user started a stack merge that includes this pull request via Graphite.
• Jul 18, 4:03 PM UTC: @akshaydeo merged this pull request with Graphite.

The base branch was changed.