run: critic can raise a run's step ceiling mid-flight (CriticHandle.MaxSteps)

Prerequisite for a full-fidelity mort agentcritic adapter (which adjusts a
healthy-but-long run's iteration budget, not just its deadline). executus's
CriticHandle was deadline+steer only; this adds the dynamic step ceiling above
an unchanged majordomo (which already exposes WithMaxStepsFunc).

- run.RunInfo += MaxIterations (the run's base ceiling, so a critic can raise it
  relative to the baseline).
- run.CriticHandle += MaxSteps() int — polled by the executor each step via
  agent.WithMaxStepsFunc; <=0 defers to the base. The executor uses
  WithMaxStepsFunc(critic.MaxSteps) when a critic is active, else WithMaxSteps.
- critic battery: handle.maxSteps (initialised from RunInfo.MaxIterations) +
  MaxSteps(); Decision gains RaiseStepsBy so an Escalator can raise the ceiling
  alongside ExtendBy. ExtendOnce default is unchanged (time-only).

Test: a critic returning MaxSteps=5 lets a base-MaxIterations=1 run complete two
tool-dispatch steps past the base ceiling. Core stays battery-free (run doesn't
import critic).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

critic/critic.go

@@ -10,8 +10,10 @@
 // Mort plugs its LLM critic-agent in as an Escalator; ExtendOnce is the
 // zero-dependency default.
 //
-// NOTE: the executor's call into run.Ports.Critic is a P2 follow-up; this
+// The executor wires run.Ports.Critic (C0b): it feeds the handle activity,
-// battery provides the seam + impl ahead of that wiring.
+// binds the run context to its extendable Deadline, drains its Steer, and polls
+// MaxSteps each step so an Escalator can also raise a long run's step ceiling
+// (Decision.RaiseStepsBy).
 package critic
 
 import (
@@ -38,6 +40,7 @@ type Progress struct {
 type Decision struct {
 	Nudge        []llm.Message // injected before the agent's next turn (a steer)
 	ExtendBy     time.Duration // push the hard deadline out by this much
+	RaiseStepsBy int           // raise the run's tool-dispatch step ceiling by this
 	Kill         bool          // cancel the run now
 	KillReason   string
 }
@@ -136,6 +139,7 @@ func (s *System) Monitor(ctx context.Context, info run.RunInfo, softTimeout time
 		now:          s.now,
 		lastActivity: now,
 		deadline:     now.Add(time.Duration(float64(softTimeout) * s.backstopMul)),
+		maxSteps:     info.MaxIterations, // base ceiling; an Escalator may RaiseStepsBy
 		stopCh:       make(chan struct{}),
 	}
 	go h.watch(ctx, check)
@@ -155,6 +159,7 @@ type handle struct {
 	deadline     time.Time
 	steer        []llm.Message
 	iterations   int
+	maxSteps     int // current tool-dispatch ceiling (base MaxIterations, raised by RaiseStepsBy)
 	lastTool     string
 	killed       bool // sticky: once an Escalator kills, no later decision un-kills it
 	stopped      bool
@@ -192,6 +197,12 @@ func (h *handle) Deadline() time.Time {
 	return h.deadline
 }
 
+func (h *handle) MaxSteps() int {
+	h.mu.Lock()
+	defer h.mu.Unlock()
+	return h.maxSteps
+}
+
 func (h *handle) Stop() {
 	h.mu.Lock()
 	if !h.stopped {
@@ -263,4 +274,7 @@ func (h *handle) tick(ctx context.Context) {
 	if d.ExtendBy > 0 {
 		h.deadline = h.deadline.Add(d.ExtendBy)
 	}
+	if d.RaiseStepsBy > 0 {
+		h.maxSteps += d.RaiseStepsBy
+	}
 }

run/critic.go

@@ -88,6 +88,22 @@ func (b *criticBinding) recordToolStart(name, args string) {
 	}
 }
 
+// maxStepsOption returns the agent step-ceiling Option. With no critic it's a
+// fixed WithMaxSteps(base); with a critic it's a DYNAMIC WithMaxStepsFunc that
+// polls the handle each step (so the critic can raise a long run's budget),
+// falling back to base when the handle defers (MaxSteps() <= 0).
+func (b *criticBinding) maxStepsOption(base int) agent.Option {
+	if b == nil {
+		return agent.WithMaxSteps(base)
+	}
+	return agent.WithMaxStepsFunc(func() int {
+		if n := b.h.MaxSteps(); n > 0 {
+			return n
+		}
+		return base
+	})
+}
+
 // steerOptions returns the agent RunOptions that drain the critic's steer
 // messages into the loop. Empty when there is no critic.
 func (b *criticBinding) steerOptions() []agent.RunOption {

run/critic_test.go

@@ -23,6 +23,7 @@ type fakeCriticHandle struct {
 	mu                  sync.Mutex
 	steps, tools, stops int
 	steered             int
+	maxSteps            int // 0 => defer to the run's base MaxIterations
 }
 
 func (h *fakeCriticHandle) RecordStep(int) { h.mu.Lock(); h.steps++; h.mu.Unlock() }
@@ -33,8 +34,41 @@ func (h *fakeCriticHandle) RecordToolStart(string, string) {
 }
 func (h *fakeCriticHandle) Steer() []llm.Message { h.mu.Lock(); h.steered++; h.mu.Unlock(); return nil }
 func (h *fakeCriticHandle) Deadline() time.Time  { return time.Time{} } // no hard deadline
+func (h *fakeCriticHandle) MaxSteps() int        { h.mu.Lock(); defer h.mu.Unlock(); return h.maxSteps }
 func (h *fakeCriticHandle) Stop()                { h.mu.Lock(); h.stops++; h.mu.Unlock() }
 
+// TestCriticRaisesStepCeiling: a critic returning a higher MaxSteps lets the agent
+// run PAST its base MaxIterations (the dynamic step ceiling). With base=1 and no
+// critic the run would hit ErrMaxSteps after the first tool-dispatch step; the
+// critic raises it to 5 so the run completes.
+func TestCriticRaisesStepCeiling(t *testing.T) {
+	h := &fakeCriticHandle{maxSteps: 5}
+	fp := fake.New("fake")
+	fp.Enqueue("m",
+		// two tool-call steps (unknown tool → tolerated error results), then answer
+		fake.ReplyWith(llm.Response{ToolCalls: []llm.ToolCall{{ID: "c1", Name: "noop", Arguments: []byte(`{}`)}}}),
+		fake.ReplyWith(llm.Response{ToolCalls: []llm.ToolCall{{ID: "c2", Name: "noop", Arguments: []byte(`{}`)}}}),
+		fake.Reply("done after 2 tool steps"),
+	)
+	m, _ := fp.Model("m")
+	ex := run.New(run.Config{
+		Registry: tool.NewRegistry(),
+		Models:   func(ctx context.Context, _ string) (context.Context, llm.Model, error) { return ctx, m, nil },
+		Ports:    run.Ports{Critic: &fakeCritic{h: h}},
+		// large soft timeout so the deadline-watch never interferes in the test
+		Defaults: run.Defaults{CriticSoftTimeout: time.Hour},
+	})
+	res := ex.Run(context.Background(),
+		run.RunnableAgent{Name: "x", ModelTier: "m", MaxIterations: 1, Critic: run.CriticConfig{Enabled: true}},
+		tool.Invocation{RunID: "r"}, "go")
+	if res.Err != nil {
+		t.Fatalf("critic raised the ceiling to 5, run should complete past base=1: %v", res.Err)
+	}
+	if res.Output != "done after 2 tool steps" {
+		t.Errorf("output = %q", res.Output)
+	}
+}
+
 // TestCriticWired: an agent with Critic.Enabled gets monitored — Monitor returns
 // a handle the executor feeds (RecordStep), drains (Steer), and stops.
 func TestCriticWired(t *testing.T) {

run/executor.go

@@ -164,6 +164,7 @@ func (e *Executor) Run(ctx context.Context, ra RunnableAgent, inv tool.Invocatio
 		ParentRunID:   inv.ParentRunID,
 		Inputs:        inv.SkillInputs,
 		StartedAt:     started,
+		MaxIterations: maxIter,
 	}
 	var rec RunRecorder
 	var stateAcc *RunStateAccessor
@@ -243,7 +244,10 @@ func (e *Executor) Run(ctx context.Context, ra RunnableAgent, inv tool.Invocatio
 
 	opts := []agent.Option{
 		agent.WithToolbox(toolbox),
-		agent.WithMaxSteps(maxIter),
+		// Step ceiling: a fixed WithMaxSteps(maxIter) normally, but when a critic is
+		// active it owns a DYNAMIC ceiling (WithMaxStepsFunc) so it can raise a
+		// healthy-but-long run's budget mid-flight. Falls back to maxIter.
+		critic.maxStepsOption(maxIter),
 		agent.WithToolErrorLimits(e.cfg.Defaults.MaxConsecutiveToolErrors, e.cfg.Defaults.MaxSameToolCallRepeats),
 		agent.WithStepObserver(stepObserver),
 	}

run/ports.go

@@ -48,6 +48,9 @@ type RunInfo struct {
 	ParentRunID string
 	Inputs      map[string]any
 	StartedAt   time.Time
+	// MaxIterations is the run's base tool-dispatch step ceiling, so a critic can
+	// raise it relative to the baseline (see CriticHandle.MaxSteps).
+	MaxIterations int
 }
 
 // RunStats is the terminal roll-up a recorder's Close writes. Mirrors mort's
@@ -129,6 +132,11 @@ type CriticHandle interface {
 	// Deadline returns the current hard-kill deadline (the critic may extend
 	// it); the executor binds the run context to it. Zero = no hard deadline.
 	Deadline() time.Time
+	// MaxSteps returns the current tool-dispatch step ceiling, polled by the
+	// executor each step (via majordomo WithMaxStepsFunc) so a critic can raise a
+	// healthy-but-long run's iteration budget mid-flight. Return <= 0 to defer to
+	// the run's base MaxIterations.
+	MaxSteps() int
 	// Stop ends monitoring when the run finishes.
 	Stop()
 }