Wraps each static system prompt in a single-block list so Phase 0.1's
AnthropicProvider applies cache_control: ephemeral automatically (policy α,
first block gets marked when no caller-authored cache_control is present).
Call sites:
- ai_tree_generator.scaffold_branches: SCAFFOLD_SYSTEM_PROMPT (~1k tokens)
- ai_tree_generator.generate_branch_detail: BRANCH_DETAIL_SYSTEM_PROMPT
(~2.5k tokens with few-shot example); retries inside the same function
re-read the cached block instead of paying full input cost on each attempt
- kb_conversion.convert_document: TROUBLESHOOTING or PROCEDURAL prompt
(each caches independently by text content)
- ai_fix.generate_fixes: FIX_SYSTEM_PROMPT on first attempt + corrective retry
- script_builder.send_message: SYSTEM_PROMPT_TEMPLATE (per-session language
substitution — same-language sessions share cache entries)
Each edit includes an inline comment explaining why the block is cacheable
(stable-constant, retry-reuse, per-language variant) so a future dev can
see the intent at the cache_control marker site.
script_builder history caching deliberately deferred — per Phase 0.1
decision (option i), AnthropicProvider does not automatically cache the
message list. If script_builder's growing 20-message history turns out
to be a visible cost driver via the anthropic.cache telemetry, route
that caller through the 0.4 chat wrapper which handles history caching.
No runtime verification from code-server; cache-hit behavior will be
confirmed against the new dev environment when it's up, per the inline
TODO(phase0-verify) in ai_provider.py.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
