Two gaps surfaced by a live fan-out smoke in a downstream host (mort):
1) A single-loop run that exhausts its step budget (ErrMaxSteps / ErrToolLoop)
returned empty Output + a hard error, discarding all the reasoning it had
produced — unlike the phased path, which already salvages a partial
transcript and continues. Add opt-in single-loop salvage
(Defaults.SalvageSingleLoopMaxSteps, default off): on budget exhaustion with
empty Output, reconstruct a best-effort answer from the step narration
(reusing salvagePhaseTranscript) and downgrade the run to a successful
partial result. Off by default so a structured-output host keeps its clean
hard error; an interactive host opts in.
2) RunnableAgent carried no tool-call ceiling — MaxIterations bounds STEPS, but
one step can dispatch several tool calls, so a host's "max tool calls" cap
had nowhere to land. Add RunnableAgent.MaxToolCalls (<=0 = unlimited,
backward-compatible): the step observer counts executed calls and, once the
cap is reached, stepCeilingOption forces the loop to exit; the resulting
ErrMaxSteps is relabeled to the new ErrMaxToolCalls sentinel. Enforced
single-loop only for now (phased is a follow-up). A cap hit is budget
exhaustion, so salvage recovers its partial reasoning too.
isPhaseBudgetExhaustion becomes the shared isBudgetExhaustion (now also matching
ErrMaxToolCalls) so the phased and single-loop paths never drift, and the
RunStateAccessor now reports the real tool-call cap (was hardcoded 0).
Additive + backward-compatible: new optional DTO field, new opt-in Defaults
flag, new exported sentinel; unlimited/off reproduce prior behavior exactly. No
new dependencies (go mod tidy clean). Tests cover salvage on/off/no-prose, cap
enforcement + sentinel, cap+salvage, unlimited no-op, and cap-overrides-critic.
Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01Q1eJh5NVR11z6RzyxLANMK
steveandClaude Opus 4.8