`effective_cache_ttl` evaluates the generic `is_qwen_model` clamp before any
route-level allowance, so a configured `prompt_caching.cache_ttl: 1h` is
silently rewritten to `5m` for every Qwen model on opencode-go. Reproduced on
this commit's parent, no provider traffic:
effective_cache_ttl('1h', 'opencode-go', 'qwen3.7-plus') -> '5m'
_build_marker('5m') -> {'type': 'ephemeral'}
A repair for this exists historically -- payload d6b33faae1, merged as
a43fe4918d -- but neither commit is reachable from current main
(`git merge-base --is-ancestor` returns non-zero for both), so the regression
is live on this lineage.
Restores the precedence fix: MEASURED_1H_PROVIDERS (an allow-list holding only
opencode-go, the one route measured with a delayed read past five minutes) is
consulted ahead of the generic Qwen clamp, with NO_1H_TIER_MODELS nested inside
it for models measured to ignore the tier even on a capable route.
opencode-go stays in ALIBABA_FAMILY_PROVIDERS. That set is also the
cache-marker-layout opt-in read by
agent_runtime_helpers.anthropic_prompt_cache_policy, so narrowing it would turn
working five-minute caching into *no* caching rather than extending the window.
The two sets are kept separate on purpose and a test pins the separation.
One deliberate divergence from the historical payload, found by independent
review: that patch checked NO_1H_TIER_MODELS globally, ahead of the provider
gate. MiniMax on its own Anthropic-compatible endpoint is a separate and
genuinely cache-eligible route, and the global check regressed its configured
1h to 5m off the back of an opencode-go observation -- an unrelated-provider
change this repair must not make. Measured:
base effective_cache_ttl('1h', 'minimax', 'MiniMax-M2.5') -> '1h'
payload -> '5m'
here -> '1h'
Scope note on the evidence: the delayed-read run covered qwen3.8-max and
glm-5.2. The rule is keyed on the route, not the model, so the deployed
qwen3.7-plus is covered by it but has never itself been measured. This change
restores *sending* the requested 1h marker; it does not establish that the
provider honours 1h retention. Those stay separate claims, and the provider
labels every write `ephemeral_5m_input_tokens` whatever ttl was requested, so
only a delayed read past five minutes with no intervening call can settle it.
Tests: 11 new cases covering the deployed model, marker shape, precedence
against the generic clamp, cache eligibility surviving the repair, negative
controls for unrelated routes, provider case normalization, and a closed-set
audit of every marker-emitting call site. Ten mutations were applied to scratch
copies and each turned the suite red, including hoisting the generic clamp back
above the allowance, dropping opencode-go from ALIBABA_FAMILY_PROVIDERS,
un-nesting the model denial, and adding a new unclamped sender.
Known risk, not discharged here: this marker shape has never been sent on the
Go relay. #77217 records the sibling Zen relay returning HTTP 400 on an
unexpected marker shape, so field validation must check HTTP status before it
looks at any cache counter.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QV9Ld4f5ZTqdZWncpfZcQh
Jack Powrie
d51d66e869