**Problem:**
GitHub Copilot API returns 400 error "missing required Copilot-Vision-Request
header for vision requests" when requests contain image content blocks, even
though the requests are valid Claude API calls.
**Root Cause:**
The GitHub Copilot executor was not detecting vision content in requests and
did not add the required `Copilot-Vision-Request: true` header.
**Solution:**
- Added `detectVisionContent()` function to check for image_url/image content blocks
- Automatically add `Copilot-Vision-Request: true` header when vision content is detected
- Applied fix to both `Execute()` and `ExecuteStream()` methods
**Testing:**
- Tested with Claude Code IDE requests containing code context screenshots
- Vision requests now succeed instead of failing with 400 errors
- Non-vision requests remain unchanged
Fixes issue where GitHub Copilot executor fails all vision-enabled requests,
causing unnecessary fallback to other providers and 0% utilization.
Co-Authored-By: Claude (claude-sonnet-4.5) <noreply@anthropic.com>
Implement `request_retry` and `disable_cooling` metadata overrides for authentication management. Update retry and cooling logic accordingly across `Manager`, Antigravity executor, and file synthesizer. Add tests to validate new behaviors.
Refactor 401 error handling in both executeWithRetry and
executeStreamWithRetry to always attempt token refresh regardless of
remaining retry attempts. Previously, token refresh was only attempted
when retries remained, which could leave valid refreshed tokens unused.
Also add auth directory resolution in RefreshManager.Initialize to
properly resolve the base directory path before creating the token
repository.
Previously GeminiModels handler unconditionally overwrote displayName
and description with the model name, losing the original values defined
in model definitions (e.g., 'Gemini 3 Pro Preview').
Now only set these fields as fallback when they are missing or empty.
Add support for Imagen 3.0 and 4.0 image generation models in Vertex AI:
- Add 5 Imagen model definitions (4.0, 4.0-ultra, 4.0-fast, 3.0, 3.0-fast)
- Implement :predict action routing for Imagen models
- Convert Imagen request/response format to match Gemini structure like gemini-3-pro-image
- Transform prompts to Imagen's instances/parameters format
- Convert base64 image responses to Gemini-compatible inline data
Update ApplyThinking signature to accept fromFormat and toFormat parameters
instead of a single provider string. This enables:
- Proper level-to-budget conversion when source is level-based (openai/codex)
and target is budget-based (gemini/claude)
- Strict budget range validation when source and target formats match
- Level clamping to nearest supported level for cross-format requests
- Format alias resolution in SDK translator registry for codex/openai-response
Also adds ErrBudgetOutOfRange error code and improves iflow config extraction
to fall back to openai format when iflow-specific config is not present.
- Introduced `payloadModelAliases` and `payloadModelCandidates` functions to support model aliases for improved flexibility.
- Updated rule matching logic to handle multiple model candidates.
- Refactored variable naming in executor to improve code clarity and consistency.
- Added logic to transform `inputResults` into structured JSON for improved processing.
- Removed redundant `safety_identifier` field in executor payload to streamline requests.
