Adds fallbackThinkingLevel plumbing so, when Fusion swaps from a primary model to a configured fallback model (executor, validator/reviewer, merger, planning, title-summarizer, heartbeat, and workflow-step lanes), the fallback's own configured thinking level is applied instead of silently reusing the primary lane's level.
- Add fallbackThinkingLevel option to AgentRuntimeOptions (agent-runtime.ts), AgentOptions (pi.ts), and ReviewOptions (reviewer.ts)
- Add per-lane resolvers: resolveExecutorFallbackThinkingLevel, resolvePlanningFallbackThinkingLevel, resolveValidatorFallbackThinkingLevel, resolveTitleSummarizerFallbackThinkingLevel, resolveMergerFallbackThinkingLevel (agent-session-helpers.ts), each following fallback-provider precedence and falling back to the primary lane/default thinking level when unset
- Export new resolvers from packages/engine/src/index.ts
- Apply the resolved fallback thinking level in createFnAgent's applyThinkingLevelIfSupported once a session has swapped to the fallback model (pi.ts)
- Wire fallbackThinkingLevel through executor session creation (workflow-step, task validator, child-agent, and main executor session paths), merger session creation, and heartbeat session creation
- Promote the fallback thinking level alongside the fallback model/provider when the no-visible-key Grok CLI fallback is promoted to primary, so the cleared fallback pair doesn't leave the session on the superseded primary's thinking level
- Route workflow-step fallback thinking level by which fallback candidate (validatorFallback vs globalFallback) actually matched
- Document fallbackThinkingLevel runtime-swap behavior in docs/settings-reference.md
- Add minor changeset for @runfusion/fusion
- Add regression tests covering fallback thinking-level resolution and application (agent-session-helpers.test.ts, pi.test.ts) and a shared test helper (executor-test-helpers.ts)
Files changed:
.changeset/fn-7794-fallback-thinking-level.md | 7 ++
docs/settings-reference.md | 3 +
.../src/__tests__/agent-session-helpers.test.ts | 38 ++++++
.../engine/src/__tests__/executor-test-helpers.ts | 23 ++++
packages/engine/src/__tests__/pi.test.ts | 136 +++++++++++++++++++++
packages/engine/src/agent-heartbeat.ts | 3 +-
packages/engine/src/agent-runtime.ts | 5 +
packages/engine/src/agent-session-helpers.ts | 54 ++++++++
packages/engine/src/executor.ts | 31 ++++-
packages/engine/src/index.ts | 5 +
packages/engine/src/merger.ts | 7 +-
packages/engine/src/pi.ts | 16 ++-
packages/engine/src/reviewer.ts | 6 +
13 files changed, 327 insertions(+), 7 deletions(-)
Fusion-Task-Id: FN-7794
Fusion-Task-Lineage: c94d621a-ccbd-42b2-9fe6-cb619418ad90
Co-authored-by: Fusion (runfusion.ai) <noreply@runfusion.ai>
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