fix(isolation): preserve task runtime selection and step caps

Problem: worktree task dispatch silently discarded effort, step limits and configured subagent models; parent model aliases also lost live session effort overrides.

Root cause: isolation branched before ordinary task runtime resolution, and alias resolution reloaded config instead of retaining the canonical parent runtime entry.

Fix: reuse shared task/model/effort/budget resolution, pass ephemeral options to the unattended Build, and canonicalize parent aliases to their runtime entry. Existing unsupported isolation restrictions remain refused; best-of keeps its prior policy. No persisted, wire, tool-definition or default changes.

Verification: complete 238-package root inventory passes (217 pass/21 no tests; 23289 test/subtest passes, 215 existing conditional skips, 198 cached packages). Owning delegation/isolation race has 400 passes; real boot focus has 39 passes, no skips. Compiling old owners fail 18 runtime scenarios plus parent, with two automatic-budget controls passing. First-Finish composition race has 32 passes. Gofmt, vet, full lint, make check and diff checks pass. Supplemental required builtin/boot is still running; hosted/native results remain pending.

docs/ISOLATION_RUNTIME_OPTIONS_SECURITY.md

@@ -0,0 +1,115 @@
+---
+owner: @SivanCola
+backup: @esengine
+status: active
+reviewed: 2026-10-25
+---
+
+# Isolated runtime options / 隔离任务运行参数
+
+## Cause and scope / 根因与范围
+
+The task tool dispatched `isolation: "worktree"` before ordinary task-spec
+resolution. That branch forwarded the prompt and explicit model, but silently
+dropped `effort`, `max_steps` and the configured subagent model.
+
+Its separate
+kernel could therefore run with a different model/depth and without the requested
+step cap. This is parameter loss, not evidence of a permission bypass.
+
+An adjacent shared model-resolution defect reloaded a parent-model alias from
+configuration instead of preserving the actual parent entry, losing a session
+effort override. Canonical references already preserved that entry.
+
+任务工具在普通任务规格解析前分流到 worktree，只转发提示与显式模型，遗漏 effort、
+max_steps 和已配置的子代理模型。隔离子内核因此可能使用错误模型、思考深度或步数上限。
+这属于参数丢失，不能据此声称权限绕过。相邻的模型别名解析还会重新读取配置，丢失父
+会话已生效的 effort 覆盖；规范模型引用原本会保留该覆盖。
+
+## Source, owner and sink / 来源、所有者与执行端
+
+- Task arguments and existing task defaults enter the same model/effort and
+  child-budget resolution owners used by ordinary tasks. Vision routing remains
+  in the existing child-runtime resolver.
+- The isolated runner receives ephemeral `Run.Effort` and `Run.MaxSteps` values.
+  Boot resolves a `provider.Selection` through the shared subagent model/effort
+  validation owner, then supplies it and the cap to the unattended child's Build.
+  No extra provider is constructed merely to validate a selection.
+- Parent aliases resolving to the same canonical model reuse the runtime parent
+  entry. A different model keeps its own defaults; explicit effort still wins.
+- Unsupported explicit model/effort combinations remain errors. Existing
+  inherited-effort policy may drop an incompatible inherited setting on a
+  call-selected model, while a configured model/effort pair remains strict.
+  A custom provider resolver retains its existing selection authority.
+- Best-of uses the same private unattended builder. It continues to pass its
+  model with no effort override or explicit cap, preserving its prior policy.
+
+显式参数和默认值通过普通任务已有的解析所有者，执行端将结果传入子内核 Build。
+新增字段只在内存中的 runner 调用传递，不增加额外 provider 构造。
+
+父模型别名保留
+实际会话值，其他模型使用自身默认值；显式 effort 优先。不兼容显式参数继续报错，
+继承值沿用既有逐模型策略，自定义 resolver 的权限不变。共享 unattended builder
+的 best-of 调用继续使用原先无显式 effort/上限的策略。
+
+## Authority and compatibility / 权限与兼容
+
+This does not enable isolation in a session that did not offer it. Profiles,
+tool restrictions, write paths, background execution and continuation/fork
+arguments remain explicitly refused by this isolation path before execution.
+
+They are not silently removed or treated as implemented. Existing approvals,
+workspace selection, sandbox policy and apply/discard behavior are unchanged.
+
+Only the in-process runner and private builder signatures change. Persisted
+result records, config files, wire messages, public tool schemas and tool order
+do not change. The Store Execute signature remains compatible.
+
+Zero MaxSteps
+retains the existing automatic behavior; a positive explicit cap wins, otherwise
+the ordinary child-budget rule derives it from the parent cap. This is a local
+step cap, not a shared root resource or concurrency budget.
+
+不会为原本关闭的会话启用隔离。profile、工具限制、write_paths、后台和续跑/fork
+仍在执行前明确拒绝，不能视为已支持或静默删除。原审批、沙箱、应用/丢弃行为不变。
+
+只改进程内调用，不改持久格式、配置、wire、工具定义及顺序。零上限沿用自动行为，
+显式正值优先，否则复用普通子任务预算规则；这不是根任务共享预算或并发限额。
+
+## Regression boundary / 回归边界
+
+Real `boot.Build` regressions observe actual provider construction and requests
+through both direct task and deferred capability dispatch.
+
+They cover explicit
+and configured models, supported/incompatible effort, parent runtime overrides,
+parent aliases, explicit/derived/automatic step caps and unchanged system/tool
+prefixes over the child run. Finite scripted providers bound the negative
+control even when the old implementation ignores its cap.
+
+The predecessor owners can be compiled with the unchanged public-assembly
+behavior regression. The additional private-helper unit is excluded from that
+overlay because its helper did not exist before this repair; compilation errors
+are not counted as behavior failures.
+
+真实装配测试观察 provider 构造和请求，覆盖直接与动态 capability 入口、模型与 effort
+及三类步数策略，并比较子任务各回合的系统/工具前缀。反向测试保留真实装配行为测试，
+只排除旧版本不存在的私有 helper 单测；编译错误不能算行为反例。
+
+## Remaining work / 后续边界
+
+Automatic isolation, durable Begin/running identity, background/continuation,
+profile/tool/write-path support, nested/root budgets, environment preparation,
+cross-process settlement, recovery journals, snapshot-bound verification and
+automatic integration remain independent series work.
+
+Worktrees do not isolate
+network services, databases, credentials, ports or all shared Git metadata.
+
+This author assessment is not independent security approval or native-platform
+qualification, and does not resolve historical findings from the original large
+PR. Native and hosted evidence must name the tested revision separately.
+
+自动隔离、持久运行身份、后台/续跑、profile/工具/路径支持、根预算、环境准备、
+整合日志和快照验证仍独立推进。worktree 不隔离网络、数据库、凭证、端口及全部
+Git 共享元数据。作者分析不能替代独立安全审查或原生平台验证。

internal/assembly/boot/bestof.go

@@ -73,7 +73,7 @@ func (b *builder) addBestOf() {
 func candidateRunner(parent Options, sink event.Sink, approval *candidateApproval) bestof.Runner {
 	return func(ctx context.Context, run bestof.Run) (bestof.Outcome, error) {
 		cs := &candidateSink{parent: sink}
-		answer, unverified, err := runUnattended(ctx, parent, cs, approval.mode(), run.WorkspaceRoot, run.Prompt, run.Model)
+		answer, unverified, err := runUnattended(ctx, parent, cs, approval.mode(), run.WorkspaceRoot, run.Prompt, provider.Selection{Ref: run.Model}, 0)
 		return bestof.Outcome{Answer: answer, Unverified: unverified, Host: cs.summary()}, err
 	}
 }
@@ -82,7 +82,7 @@ func candidateRunner(parent Options, sink event.Sink, approval *candidateApprova
 // its end. Its transcript lives in a temp dir removed with it; only what sink
 // forwards reaches the parent session. A run that stopped without proving its
 // work is not an error: its readiness reason comes back as unverified.
-func runUnattended(ctx context.Context, parent Options, sink event.Sink, mode, root, prompt, model string) (answer, unverified string, err error) {
+func runUnattended(ctx context.Context, parent Options, sink event.Sink, mode, root, prompt string, selection provider.Selection, maxSteps int) (answer, unverified string, err error) {
 	sessDir, err := os.MkdirTemp("", "reasonix-candidate-")
 	if err != nil {
 		return "", "", err
@@ -92,7 +92,9 @@ func runUnattended(ctx context.Context, parent Options, sink event.Sink, mode, r
 		ComputerDriver:       parent.ComputerDriver,
 		WorkspaceRoot:        root,
 		Home:                 parent.Home,
-		Model:                model,
+		Model:                selection.Ref,
+		EffortOverride:       selection.Effort,
+		MaxSteps:             maxSteps,
 		AgentPreset:          parent.AgentPreset,
 		ProviderResolver:     parent.ProviderResolver,
 		Sink:                 sink,

internal/assembly/boot/computer_scope_test.go

@@ -50,7 +50,7 @@ func TestComputerDriverReachesStudioUnattendedChildSchema(t *testing.T) {
 	approveWorkspace(t, root)
 	driver := computer.NewDriver("/unused", nil)
 	defer driver.Close()
-	_, _, err := runUnattended(t.Context(), Options{ComputerDriver: driver}, event.Discard, "deny", root, "answer briefly", "")
+	_, _, err := runUnattended(t.Context(), Options{ComputerDriver: driver}, event.Discard, "deny", root, "answer briefly", provider.Selection{}, 0)
 	if err != nil {
 		t.Fatal(err)
 	}

internal/assembly/boot/effect_isolation_runtime_test.go

@@ -0,0 +1,196 @@
+package boot
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"os/exec"
+	"strings"
+	"sync"
+	"testing"
+
+	"reasonix/internal/base/testenv"
+	"reasonix/internal/contract/event"
+	"reasonix/internal/contract/provider"
+	"reasonix/internal/session/control"
+)
+
+const isolationRuntimePrompt = "ISOLATED-RUNTIME: inspect a.txt"
+
+type isolationRuntimeRequest struct {
+	model, effort string
+	request       provider.Request
+}
+
+type isolationRuntimeRecorder struct {
+	mu       sync.Mutex
+	requests []isolationRuntimeRequest
+	args     map[string]any
+	deferred bool
+	result   string
+}
+
+type isolationRuntimeProvider struct {
+	recorder      *isolationRuntimeRecorder
+	model, effort string
+}
+
+func (*isolationRuntimeProvider) Name() string { return "boot-isolation-runtime" }
+
+func (p *isolationRuntimeProvider) Stream(_ context.Context, req provider.Request) (<-chan provider.Chunk, error) {
+	r := p.recorder
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	ch := make(chan provider.Chunk, 2)
+	call := func(id, name string, args any) {
+		raw, _ := json.Marshal(args)
+		ch <- provider.Chunk{Type: provider.ChunkToolCall, ToolCall: &provider.ToolCall{ID: id, Name: name, Arguments: string(raw)}}
+	}
+	if strings.Contains(firstUser(req), isolationRuntimePrompt) {
+		r.requests = append(r.requests, isolationRuntimeRequest{model: p.model, effort: p.effort, request: req})
+		// A finite scripted ceiling bounds the negative control even without a cap.
+		if len(r.requests) >= 10 {
+			ch <- provider.Chunk{Type: provider.ChunkText, Text: "inspection finished"}
+		} else {
+			call(fmt.Sprintf("read-%d", len(r.requests)), "read_file", map[string]string{"path": fmt.Sprintf("a-%d.txt", len(r.requests))})
+		}
+	} else if hasToolResult(req) {
+		r.result = lastToolResult(req)
+		ch <- provider.Chunk{Type: provider.ChunkText, Text: "parent done"}
+	} else if r.deferred {
+		call("delegate", "use_capability", map[string]any{"action": "call", "capability_id": "task:subagent", "arguments": r.args})
+	} else {
+		call("delegate", "task", r.args)
+	}
+	ch <- provider.Chunk{Type: provider.ChunkDone}
+	close(ch)
+	return ch, nil
+}
+
+func TestEffectIsolatedTaskHonorsRuntimeSelectionAndBudget(t *testing.T) {
+	if _, err := exec.LookPath("git"); err != nil {
+		t.Skip("git not installed")
+	}
+	cases := []struct {
+		name, configuredModel, inheritedEffort, callModel, callEffort, parentEffort string
+		wantModel, wantEffort                                                       string
+		unsupported, deriveBudget, noParentCap, shared                              bool
+		wantRequests                                                                int
+	}{
+		{name: "explicit", configuredModel: "child-model", callModel: "alternate-model", callEffort: "low", wantModel: "alternate", wantEffort: "low"},
+		{name: "configured-model", configuredModel: "child-model", callEffort: "low", wantModel: "child", wantEffort: "low"},
+		{name: "inherited-effort", configuredModel: "child-model", inheritedEffort: "low", wantModel: "child", wantEffort: "low"},
+		{name: "parent-runtime-effort", parentEffort: "low", wantModel: "parent", wantEffort: "low"},
+		{name: "unsupported-inherited-effort", callModel: "child-model", inheritedEffort: "max", wantModel: "child", wantEffort: "high"},
+		{name: "unsupported-explicit-effort", configuredModel: "child-model", callEffort: "max", unsupported: true},
+		{name: "unsupported-configured-pair", configuredModel: "child-model", inheritedEffort: "max", unsupported: true},
+		{name: "derived-budget", configuredModel: "child-model", wantModel: "child", wantEffort: "high", deriveBudget: true, wantRequests: 7},
+		{name: "automatic-budget", wantModel: "parent", wantEffort: "high", deriveBudget: true, noParentCap: true, wantRequests: 10},
+		{name: "shared-parent-alias", callModel: "parent-model", parentEffort: "low", wantModel: "parent", wantEffort: "low", shared: true},
+	}
+	for _, tc := range cases {
+		for _, deferred := range []bool{false, true} {
+			t.Run(fmt.Sprintf("%s/deferred=%t", tc.name, deferred), func(t *testing.T) {
+				home, root := statedBootHome(t), testenv.TempDir(t)
+				kind := uniqueKind("isolation-runtime")
+				rec := &isolationRuntimeRecorder{deferred: deferred, args: map[string]any{
+					"prompt": isolationRuntimePrompt, "isolation": "worktree", "max_steps": 1,
+				}}
+				if tc.deriveBudget {
+					delete(rec.args, "max_steps")
+				}
+				if tc.shared {
+					delete(rec.args, "isolation")
+				}
+				if tc.callModel != "" {
+					rec.args["model"] = tc.callModel
+				}
+				if tc.callEffort != "" {
+					rec.args["effort"] = tc.callEffort
+				}
+				provider.Register(kind, func(cfg provider.Config) (provider.Provider, error) {
+					effort, _ := cfg.Extra["effort"].(string)
+					return &isolationRuntimeProvider{recorder: rec, model: cfg.Model, effort: effort}, nil
+				})
+				var config strings.Builder
+				fmt.Fprintf(&config, `
+default_model = "parent-model"
+[agent]
+system_prompt = "BASE"
+worktree_isolation = true
+subagent_model = %q
+subagent_effort = %q
+[codegraph]
+enabled = false
+`, tc.configuredModel, tc.inheritedEffort)
+				for _, model := range []string{"parent", "child", "alternate"} {
+					fmt.Fprintf(&config, `
+[[providers]]
+name = %q
+kind = %q
+model = %q
+supported_efforts = ["low", "high"]
+default_effort = "high"
+`, model+"-model", kind, model)
+				}
+				writeFile(t, root, "reasonix.toml", config.String())
+				writeFile(t, root, "a.txt", "read me\n")
+				for i := 1; i <= 10; i++ {
+					writeFile(t, root, fmt.Sprintf("a-%d.txt", i), fmt.Sprintf("round %d\n", i))
+				}
+				gitInDir(t, root, "init", "-q")
+				mirrorToUserConfigAt(t, home, root)
+				gitInDir(t, root, "add", "-A")
+				gitInDir(t, root, "commit", "-q", "-m", "init")
+				opts := Options{Home: home, WorkspaceRoot: root, MaxSteps: 12, Sink: event.Discard}
+				if tc.noParentCap {
+					opts.MaxSteps = 0
+				}
+				if tc.parentEffort != "" {
+					opts.EffortOverride = &tc.parentEffort
+				}
+				ctrl, err := Build(t.Context(), opts)
+				if err != nil {
+					t.Fatal(err)
+				}
+				defer ctrl.Close()
+				ctrl.SetToolApprovalMode(control.ToolApprovalYolo)
+				if err := ctrl.Run(t.Context(), "delegate the inspection"); err != nil {
+					t.Fatal(err)
+				}
+				rec.mu.Lock()
+				defer rec.mu.Unlock()
+				if tc.unsupported {
+					if len(rec.requests) != 0 || !strings.Contains(rec.result, "max") {
+						t.Fatalf("unsupported effort silently executed: requests=%d result=%q", len(rec.requests), rec.result)
+					}
+					return
+				}
+				wantRequests := tc.wantRequests
+				if wantRequests == 0 {
+					wantRequests = 2
+				}
+				if len(rec.requests) != wantRequests {
+					t.Errorf("child request count = %d, want %d; result=%q", len(rec.requests), wantRequests, rec.result)
+				}
+				for _, got := range rec.requests {
+					if got.model != tc.wantModel || got.effort != tc.wantEffort {
+						t.Errorf("child runtime = model %q effort %q; want %q/%q", got.model, got.effort, tc.wantModel, tc.wantEffort)
+					}
+				}
+				if len(rec.requests) > 1 {
+					first, _ := json.Marshal(rec.requests[0].request.Tools)
+					last, _ := json.Marshal(rec.requests[len(rec.requests)-1].request.Tools)
+					if string(first) != string(last) || len(rec.requests[0].request.Tools) == 0 {
+						t.Fatal("child tool definitions changed at finalization")
+					}
+					initial := rec.requests[0].request.Messages[0]
+					final := rec.requests[len(rec.requests)-1].request.Messages[0]
+					if initial.Role != provider.RoleSystem || final.Role != provider.RoleSystem || initial.Content != final.Content {
+						t.Fatal("child system prefix changed during the run")
+					}
+				}
+			})
+		}
+	}
+}

internal/assembly/boot/isolation.go

@@ -56,7 +56,11 @@ func (b *builder) addIsolation() {
 	b.tools.reg.Add(isolation.NewDiscardTool(store))
 	parent, sink := b.opts, b.sink
 	b.tools.taskTool.SetIsolation(store, b.root, func(ctx context.Context, run isolation.Run) (isolation.Outcome, error) {
-		answer, unverified, err := runUnattended(ctx, parent, isolatedUsage{sink}, posture.mode(), run.WorkspaceRoot, run.Prompt, run.Model)
+		_, selection, err := subagentProviderSelection(b.cfg, b.providers.effective, b.model.entry, run.Model, run.Effort)
+		if err != nil {
+			return isolation.Outcome{}, err
+		}
+		answer, unverified, err := runUnattended(ctx, parent, isolatedUsage{sink}, posture.mode(), run.WorkspaceRoot, run.Prompt, selection, run.MaxSteps)
 		return isolation.Outcome{Answer: answer, Unverified: unverified}, err
 	})
 	// The registry canonicalizes a schema when a tool is added, and task was

internal/assembly/boot/subagent_config.go

@@ -99,29 +99,11 @@ func newSubagentConfig(opts Options, cfg *config.Config, entry *config.ProviderE
 	inherited := resolveInheritedSubagentEffort(cfg, entry)
 	return subagentConfig{
 		resolveProvider: func(modelRef, effort string) (provider.Provider, *provider.Pricing, int, error) {
-			me, selectedRef, err := subagentModelEntry(cfg, resolver, entry, modelRef)
+			me, selection, err := subagentProviderSelection(cfg, resolver, entry, modelRef, effort)
 			if err != nil {
 				return nil, nil, 0, err
 			}
-			var effortOverride *string
-			if selectedRef == modelRefFromEntry(entry) {
-				effortOverride = &me.Effort
-			}
-			if strings.TrimSpace(effort) != "" {
-				normalized, err := config.NormalizeEffort(&me, effort)
-				if err != nil {
-					if resolver == nil {
-						return nil, nil, 0, fmt.Errorf("subagent effort %q on %s: %w", effort, selectedRef, err)
-					}
-					normalized = effort
-				}
-				me.Effort = normalized
-				effortOverride = &normalized
-				if me.Kind == "anthropic" && strings.TrimSpace(me.Effort) != "" && strings.TrimSpace(me.Thinking) == "" {
-					me.Thinking = "adaptive"
-				}
-			}
-			p, err := resolveProvider(resolver, cfg, proxy, provider.Selection{Ref: selectedRef, Effort: effortOverride})
+			p, err := resolveProvider(resolver, cfg, proxy, selection)
 			if err != nil {
 				return nil, nil, 0, err
 			}
@@ -148,6 +130,32 @@ func newSubagentConfig(opts Options, cfg *config.Config, entry *config.ProviderE
 	}
 }
 
+func subagentProviderSelection(cfg *config.Config, resolver provider.Resolver, parent *config.ProviderEntry, modelRef, effort string) (config.ProviderEntry, provider.Selection, error) {
+	entry, selectedRef, err := subagentModelEntry(cfg, resolver, parent, modelRef)
+	if err != nil {
+		return entry, provider.Selection{}, err
+	}
+	selection := provider.Selection{Ref: selectedRef}
+	if selectedRef == modelRefFromEntry(parent) {
+		selection.Effort = &entry.Effort
+	}
+	if strings.TrimSpace(effort) != "" {
+		normalized, err := config.NormalizeEffort(&entry, effort)
+		if err != nil {
+			if resolver == nil {
+				return entry, selection, fmt.Errorf("subagent effort %q on %s: %w", effort, selectedRef, err)
+			}
+			normalized = effort
+		}
+		entry.Effort = normalized
+		selection.Effort = &normalized
+		if entry.Kind == "anthropic" && strings.TrimSpace(entry.Effort) != "" && strings.TrimSpace(entry.Thinking) == "" {
+			entry.Thinking = "adaptive"
+		}
+	}
+	return entry, selection, nil
+}
+
 func subagentModelEntry(cfg *config.Config, resolver provider.Resolver, parent *config.ProviderEntry, ref string) (config.ProviderEntry, string, error) {
 	ref = childModelRef(cfg, parent, ref)
 	if parent != nil && (ref == "" || ref == modelRefFromEntry(parent)) {
@@ -155,6 +163,9 @@ func subagentModelEntry(cfg *config.Config, resolver provider.Resolver, parent *
 	}
 	if cfg != nil {
 		if resolved, ok := cfg.ResolveModel(ref); ok {
+			if parent != nil && modelRefFromEntry(resolved) == modelRefFromEntry(parent) {
+				return *parent, modelRefFromEntry(parent), nil
+			}
 			return *resolved, modelRefFromEntry(resolved), nil
 		}
 	}

internal/assembly/boot/subagent_selection_alias_test.go

@@ -0,0 +1,34 @@
+package boot
+
+import (
+	"testing"
+
+	"reasonix/internal/contract/config"
+)
+
+func TestSubagentSelectionPreservesRuntimeForParentAliases(t *testing.T) {
+	cfg := config.Default()
+	cfg.Providers = []config.ProviderEntry{{Name: "parent", Kind: "openai", Models: []string{"p", "q"}, Default: "p",
+		SupportedEfforts: []string{"low", "high"}, DefaultEffort: "high"}}
+	parent, ok := cfg.ResolveModel("parent/p")
+	if !ok {
+		t.Fatal("parent model missing")
+	}
+	parent.Effort = "low"
+	for _, ref := range []string{"", "parent", "parent/p", "p"} {
+		t.Run(ref, func(t *testing.T) {
+			_, selection, err := subagentProviderSelection(cfg, nil, parent, ref, "")
+			if err != nil || selection.Ref != "parent/p" || selection.Effort == nil || *selection.Effort != "low" {
+				t.Fatalf("parent runtime selection for %q = %+v, %v", ref, selection, err)
+			}
+		})
+	}
+	_, other, err := subagentProviderSelection(cfg, nil, parent, "parent/q", "")
+	if err != nil || other.Ref != "parent/q" || other.Effort != nil {
+		t.Fatalf("another model inherited the parent's override: %+v, %v", other, err)
+	}
+	_, explicit, err := subagentProviderSelection(cfg, nil, parent, "parent", "high")
+	if err != nil || explicit.Effort == nil || *explicit.Effort != "high" {
+		t.Fatalf("explicit effort did not narrow the inherited selection: %+v, %v", explicit, err)
+	}
+}

internal/runtime/delegation/isolated_task.go

@@ -35,8 +35,9 @@ func (t *TaskTool) SetIsolation(store *isolation.Store, root string, runner isol
 // isolatedCall is the part of a task call an isolated run reads, and the
 // arguments it has to refuse rather than silently drop.
 type isolatedCall struct {
-	mode, prompt, model string
-	unsupported         []string
+	mode, prompt, model, effort string
+	maxSteps                    int
+	unsupported                 []string
 }
 
 func (t *TaskTool) executeIsolated(ctx context.Context, call isolatedCall) (string, error) {
@@ -50,7 +51,17 @@ func (t *TaskTool) executeIsolated(ctx context.Context, call isolatedCall) (stri
 		return "", tool.Refusal{Code: codeIsolationUnsupported, Message: "an isolated task runs as its own agent and cannot take " +
 			strings.Join(call.unsupported, ", ") + "; drop them or run without isolation"}
 	}
-	return t.isolated.store.Execute(ctx, t.isolated.runner, t.isolated.root, call.prompt, strings.TrimSpace(call.model))
+	model, effort := t.resolveModelEffort("", "", call.model, call.effort, "", "")
+	if model == "" {
+		model = t.baseModel
+	}
+	model, effort = t.childRuntimeRef(ctx, model, effort)
+	steps := t.childMaxStepsForContext(ctx, call.maxSteps)
+	runner := func(ctx context.Context, run isolation.Run) (isolation.Outcome, error) {
+		run.Effort, run.MaxSteps = effort, steps
+		return t.isolated.runner(ctx, run)
+	}
+	return t.isolated.store.Execute(ctx, runner, t.isolated.root, call.prompt, model)
 }
 
 // isolatedUnsupported names the task arguments that were set and that an

internal/runtime/delegation/task.go

@@ -418,7 +418,7 @@ func (t *TaskTool) executeTask(ctx context.Context, args json.RawMessage) (strin
 		return "", fmt.Errorf("prompt is required")
 	}
 	if p.Isolation != "" {
-		return t.executeIsolated(ctx, isolatedCall{mode: p.Isolation, prompt: p.Prompt, model: p.Model,
+		return t.executeIsolated(ctx, isolatedCall{mode: p.Isolation, prompt: p.Prompt, model: p.Model, effort: p.Effort, maxSteps: p.MaxSteps,
 			unsupported: isolatedUnsupported(p.Profile, p.WritePaths, p.Tools, p.ContinueFrom, p.ForkFrom, p.RunInBackground)})
 	}
 

internal/runtime/isolation/run.go

@@ -12,6 +12,8 @@ type Run struct {
 	WorkspaceRoot string
 	Prompt        string
 	Model         string
+	Effort        string
+	MaxSteps      int
 }
 
 // Outcome is what the run ended with. Unverified carries the readiness reason

release-notes/studio/unreleased/14025-isolation-runtime-options.md

@@ -0,0 +1,7 @@
+## 修复
+
+- worktree 隔离任务遵守显式或继承的模型、effort 与步数上限；同模型别名保留
+  父会话实际 effort。原本不支持的工具/路径限制、后台和续跑仍明确拒绝。Refs #14025
+- Worktree tasks honor model, effort and step caps. Parent aliases preserve
+  session effort; unsupported restrictions and lifecycle arguments remain
+  refused. Refs #14025