file type mapping bug fix by akshaydeo · Pull Request #5884 · maximhq/bifrost

akshaydeo · 2026-08-06T00:29:24Z

Summary

When a tool result contains a document block (e.g. a PDF returned by Claude Code's Read tool), the Anthropic→Responses converters previously ignored it. This left the function_call_output with an empty content array, causing OpenAI to reject the request with "Missing required parameter: 'input[N].content[0]'". Additionally, URL-sourced files were losing their file_url and file_type fields during chat↔responses conversion, producing equally empty input_file blocks.

Changes

Added AnthropicContentBlockTypeDocument handling inside both convertAnthropicContentBlocksToResponsesMessagesGrouped and convertAnthropicContentBlocksToResponsesMessages, so document blocks nested in tool results are converted to input_file blocks instead of being silently dropped.
Added defaultDocumentFilename to synthesize a filename (e.g. document.pdf) when a document block has no title, since OpenAI rejects inline file_data without a filename.
Propagated FileURL and FileType through all three chat↔responses conversion paths (ToResponsesToolMessage, ToResponsesMessages, ToChatMessages) so URL-sourced files survive round-trips intact.
Added toolresultdocument_test.go covering: document block survival in both converters, title-less documents receiving a synthesized filename, and mixed text+document tool results preserving both blocks in order.
Added fileurlpreservation_test.go covering chat→responses and responses→chat round-trips for URL-sourced files.

Type of change

Affected areas

How to test

go test ./core/providers/anthropic/... ./core/schemas/...

Expected: all tests pass, including TestToolResultDocumentSurvivesGroupedConversion, TestToolResultDocumentSurvivesConversion, TestToolResultDocumentWithoutTitleGetsFilename, TestToolResultDocumentAlongsideText, TestChatToResponsesKeepsFileURL, and TestResponsesToChatKeepsFileURL.

Breaking changes

No

Security considerations

No auth, secrets, or PII implications. The change only affects how document content blocks and file URLs are forwarded to the upstream provider.

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 · 2026-08-06T00:29:30Z

📝 Walkthrough

Summary by CodeRabbit

Bug Fixes
- Preserved document attachments in tool-result content, including placement alongside text.
- Generated filenames for documents without titles using the source media type.
- Preserved file URLs and file types when converting messages between Chat and Responses formats.
Tests
- Added coverage for document handling, filename generation, content ordering, and file metadata preservation.

Walkthrough

Anthropic tool-result conversion preserves nested document blocks and synthesizes filenames for untitled inline files. Chat and Responses file conversions retain file_url and file_type metadata in both directions.

Changes

File content preservation

Layer / File(s)	Summary
Anthropic document conversion `core/providers/anthropic/responses.go`, `core/providers/anthropic/toolresultdocument_test.go`	Grouped and ungrouped tool-result conversion preserves document blocks as `input_file` content. Untitled inline files receive synthesized filenames. Tests cover document-only and mixed text-document results.
File URL round-trip `core/schemas/mux.go`, `core/schemas/fileurlpreservation_test.go`	Chat and Responses conversions preserve `file_url` and `file_type` metadata. Tests cover both conversion directions.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Possibly related PRs

maximhq/bifrost#5662: Extends related Anthropic tool-result document conversion and tests.
maximhq/bifrost#5663: Modifies related Anthropic document conversion and regression tests.
maximhq/bifrost#5450: Modifies Anthropic tool-result conversion and tests for a different tool-result field.

Suggested reviewers: pratham-mishra04, tejasghatte, sammaji

Sequence Diagram(s)

sequenceDiagram
  participant AnthropicToolResult
  participant GroupedConverter
  participant StandardConverter
  participant ResponsesFunctionCallOutput
  AnthropicToolResult->>GroupedConverter: document content block
  AnthropicToolResult->>StandardConverter: document content block
  GroupedConverter->>ResponsesFunctionCallOutput: input_file block
  StandardConverter->>ResponsesFunctionCallOutput: input_file block with filename

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
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 identifies the primary file type mapping bug fix and matches the pull request changes.
Description check	✅ Passed	The description clearly explains the problem, changes, tests, affected areas, breaking changes, and security impact.

✨ 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 08-05-file_type_mapping_bug_fix

_{Comment @coderabbitai help to get the list of available commands.}

akshaydeo · 2026-08-06T00:29:37Z

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coderabbitai

Actionable comments posted: 1

🤖 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.

Inline comments:
In `@core/schemas/mux.go`:
- Around line 620-622: Update the ChatMessageRoleTool branch in
ToResponsesMessages() to propagate block.File.FileURL when constructing the file
input block, preserving URL-only files as complete input_file blocks. Add a
regression test that exercises ToResponsesMessages() with a tool output file
containing only FileURL and verifies the URL is retained.

🪄 Autofix

Fix all unresolved CodeRabbit comments on this PR:

Push a commit to this branch (recommended)
Create a new PR with the fixes

ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro Plus

Run ID: 7d2f52ae-d2b6-472b-9209-fcb8507e6103

📥 Commits

Reviewing files that changed from the base of the PR and between 2e661c5 and 7192207.

📒 Files selected for processing (4)

core/providers/anthropic/responses.go
core/providers/anthropic/toolresultdocument_test.go
core/schemas/fileurlpreservation_test.go
core/schemas/mux.go

coderabbitai · 2026-08-06T09:12:03Z

Note