Renames the chat caller to a name that signals its actual purpose, and
factors the reusable cached-system-block + cached-history + cache-usage-log
primitives out to app.core.ai_provider so they can be shared with the
provider-generic path without pulling MCP/beta/images into the abstract
interface.
Helpers added to ai_provider.py:
- `build_anthropic_chat_messages(history, new_message, images, format_reminder)`
— owns: copy history, apply cache_control to last history message,
append format reminder to new message, render images as multimodal blocks.
Anthropic-shaped by design; do not call from Gemini paths.
chat_call_cached keeps exactly the concerns that are unique to the one
MCP/beta/multimodal chat caller:
- Anthropic beta endpoint invocation
- Microsoft Learn MCP server wiring (ENABLE_MCP_MICROSOFT_LEARN)
- Retry-without-MCP fallback
- Format-reminder content string (declared as module constant)
- Phase 0.5 telemetry (mcp.turn, mcp.fallback)
Documents in the module docstring AND at the function site that this is
the ONE MCP/beta chat caller and should not become the general provider
path. MCP/beta/images are features of exactly one optional Anthropic beta
endpoint; routing them through AnthropicProvider would leak a provider-
specific concern into the abstract interface that also serves Gemini.
Behavior change: chat_call_cached now reuses the singleton AnthropicProvider
HTTP client via `_get_anthropic_client(...)` instead of instantiating a new
`anthropic.AsyncAnthropic(...)` per call. Matches the provider's own pattern
and avoids burning connections per-turn. No user-visible difference.
No runtime verification from code-server. TODO(phase0-verify) in
ai_provider.py tracks the cache-hit verification owed on the new dev env.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Michael Chihlas
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