Merge the EXT-20 shared regulations and web evidence extension point

Why: U9 base public contract for the regulations knowledge base.
Evidence: CI success on f3d2698d (after syncing main) (ci/vet-and-test, governance).
Impact: Additive optional capability; SurfaceVersion 2.15.0-experimental.
Refs: .task/feature-regulations-kb-ext20.md

.task/feature-regulations-kb-ext20.md

@@ -0,0 +1,30 @@
+# feature/regulations-kb-ext20 任务卡
+
+任务主记录：本文件随 PR 描述维护。
+状态：已完成（合入前闭合）；owner：weichen。PR：https://git-home.u1680832.nyat.app:30319/weichen/Agent-System-Backend/pulls/212
+
+## 基线与授权
+
+- 权威仓：ssh://git@git-ssh.u1680832.nyat.app:31411/weichen/Agent-System-Backend.git；root_target：main；immediate_target：main
+- branch_kind：standalone；跨仓总任务：Agent-System-Dev `feature/regulations-kb`（[Dev PR #614](https://git-home.u1680832.nyat.app:30319/weichen/Agent-System-Dev/pulls/614)）
+- R0（initial_main_sha）：cac60c0；工作区：/home/weichen/projects/Agent-System-Backend-wt-feature-regulations-kb-ext20；分支：feature/regulations-kb-ext20
+- 授权与交付终点：用户 2026-10-18 /goal 指示按法规知识库计划实现全部内容；本任务交付 U9 的基座公开契约 EXT-20（提案：Documents `docs/proposals/2026-10-18-ext-20-regulations-provider.md`，分支 `feature/regulations-kb-u9-contract`），经 PR 合入 main。不含法规提供方实现（属 KB 仓）与 RDM 消费（U6）。
+- 实施执行：agent-per-unit（配置：AGENT-EXECUTION.md）
+
+## 目标与非目标
+
+- 目标：`pkg/extension` 新增 `RegulationsProvider`/`RegulationsRegistrar`/`RegulationsHost` 与 DTO；进程内注册槽仅接受插件 `kbreg` 且只注册一次；分发 Host 实现四个方法并强制调用方身份、查询最小化（机密词拒绝、长度限制）、状态透传与无明文审计；快照、边界与契约/兼容测试。
+- 非目标：不实现搜索或语料检索；不改 `KnowledgeSearch` 语义。
+
+## Agent 实施收据
+
+| 单元 ID | 预期范围 | 角色 | 候选顺序 | attempt | CLI/模型 | 终态 | transport | fallback | 源码外收据路径 |
+|---|---|---|---|---|---|---|---|---|---|
+| backend-ext20-regulations-provider | pkg/extension、internal/app | implementation | cursor, antigravity, pi | 1 | cursor-agent-stable / auto（session not-observable，新进程） | success | refs/agent-exec/cfc2e055f212789112cf11716f5649c5/c04b36e76696 → aaed108（apply 快进） | 否 | /tmp/regkb-u9-receipt.json |
+
+## 结果与验证（完成后填写）
+
+- 结果：`pkg/extension/regulations.go`（EXT-20 接口、DTO、状态常量、`ErrRegulationsUnavailable`）、`surface.txt` 与 `SurfaceVersion` 2.15.0-experimental；`internal/app/regulations.go` 注册槽（仅 kbreg、一次、非 nil；声明式拒绝）与 inprocHost 四方法（有效账户检查、调用方取自分发上下文、schema 校验、查询去空白/1–256 字符/排除词拒绝且不调用提供方、状态透传、审计仅含修订/计数/状态/查询 sha256）；单元与兼容测试。
+- 验证（SELF，host 于 HEAD aaed108）：`go vet ./pkg/extension/ ./internal/app/` 与 `go test ./pkg/extension/... ./internal/app/...` PASS；全量 `GOWORK=off go vet ./... && go test -count=1 ./...` 40 包 ok，仅 `pkg/identity TestDSNFileMode` 失败——在未改动基线 cac60c0 上同样失败（本机环境问题，本变更未触及 pkg/identity），以 CI（GATE）为准。
+- Review：host 主模型审阅实际 diff（base 3187a00 / head aaed108），与提案第 2、4、5 节一致，无阻塞项。
+- 影响与剩余项：新增可选能力，未注册提供方时返回不可用，既有行为不变。

internal/app/app.go

@@ -612,7 +612,7 @@ func Run(opt Options) error {
 	if err != nil {
 		return err
 	}
-	caps := hostcaps{projects: projectSlot, directory: directorySlot, st: st, pipe: pipe, set: setSvc, authz: authzSlot, surfaces: surfaceSvc, allowImplicitLocal: !authOn,
+	caps := hostcaps{projects: projectSlot, directory: directorySlot, regulations: &regulationsSlot{}, st: st, pipe: pipe, set: setSvc, authz: authzSlot, surfaces: surfaceSvc, allowImplicitLocal: !authOn,
 		accountGuard: func(owner string) error {
 			valid, err := effectiveAccount(context.Background(), owner)
 			if err != nil {

internal/app/compiled.go

@@ -127,6 +127,17 @@ func (r pluginRegistry) RegisterAccountDirectoryScopeResolver(fn extension.Accou
 	return r.caps.directory.register(r.pluginID, fn)
 }
 
+func (r compiledRegistry) RegisterRegulationsProvider(extension.RegulationsProvider) error {
+	return errors.New("extension: declarative plugins cannot register a regulations provider")
+}
+
+func (r pluginRegistry) RegisterRegulationsProvider(p extension.RegulationsProvider) error {
+	if r.caps.regulations == nil {
+		return errors.New("extension: regulations provider registration unavailable")
+	}
+	return r.caps.regulations.register(r.pluginID, p)
+}
+
 // RegisterResourceAuthorizer 进程内扩展（EXT-1）：填充 EXT-8 适配器槽
 // （hostcaps.authz 共享指针；首个注册者生效，组合根已装配进 Server/runmgr）。
 // 此前 pluginRegistry 未覆盖该方法——进程内插件注册适配器会命中声明式分支的
@@ -169,6 +180,14 @@ func (r recordRegistry) RegisterAccountDirectoryScopeResolver(fn extension.Accou
 	return registrar.RegisterAccountDirectoryScopeResolver(fn)
 }
 
+func (r recordRegistry) RegisterRegulationsProvider(p extension.RegulationsProvider) error {
+	registrar, ok := r.Registry.(extension.RegulationsRegistrar)
+	if !ok {
+		return errors.New("extension: regulations provider registration unavailable")
+	}
+	return registrar.RegisterRegulationsProvider(p)
+}
+
 func (r recordRegistry) AddCommand(spec json.RawMessage) error {
 	if err := r.Registry.AddCommand(spec); err != nil {
 		return err

internal/app/hostcaps.go

@@ -23,6 +23,7 @@ import (
 type hostcaps struct {
 	projects           *projectLifecycleSlot
 	directory          *accountDirectorySlot
+	regulations        *regulationsSlot // EXT-20 法规提供方槽（共享指针；nil/未注册＝不可用）
 	accountGuard       func(string) error
 	allowImplicitLocal bool
 	st                 *store.Store

internal/app/regulations.go

@@ -0,0 +1,220 @@
+package app
+
+import (
+	"context"
+	"crypto/sha256"
+	"encoding/hex"
+	"encoding/json"
+	"errors"
+	"strings"
+	"sync"
+	"unicode/utf8"
+
+	"agent-system-backend/pkg/extension"
+)
+
+// EXT-20：共享法规检索与网络证据。提供方由受信插件 kbreg 进程内注册；基座只
+// 填写调用方身份、做查询最小化校验并审计，不改写提供方返回的状态。
+
+const (
+	regulationsPluginID = "kbreg"
+	maxWebQueryRunes    = 256
+
+	auditRegulationsSearch   = "regulations.search"
+	auditRegulationsEvidence = "regulations.evidence"
+	auditWebSearch           = "web.search"
+	auditWebCapture          = "web.capture"
+
+	regulationsAuditInvalid = "invalid"
+	regulationsAuditError   = "error"
+	regulationsAuditOK      = "ok"
+)
+
+var (
+	errRegulationsSchema = errors.New("extension: unsupported regulations schema version")
+	errWebQueryInvalid   = errors.New("extension: web search query must be 1-256 characters")
+)
+
+type regulationsSlot struct {
+	mu       sync.RWMutex
+	provider extension.RegulationsProvider
+}
+
+func (s *regulationsSlot) register(pluginID string, p extension.RegulationsProvider) error {
+	if p == nil || pluginID != regulationsPluginID {
+		return errors.New("extension: regulations provider requires trusted kbreg registration")
+	}
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if s.provider != nil {
+		return errors.New("extension: regulations provider already registered")
+	}
+	s.provider = p
+	return nil
+}
+
+func (s *regulationsSlot) get() extension.RegulationsProvider {
+	if s == nil {
+		return nil
+	}
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+	return s.provider
+}
+
+// regulationsAudit is the only content written to the audit trail: never the
+// query text, excerpts or captured page text.
+type regulationsAudit struct {
+	Revision    string `json:"revision,omitempty"`
+	Count       int    `json:"count"`
+	State       string `json:"state"`
+	QuerySHA256 string `json:"querySha256,omitempty"`
+}
+
+func regulationsQueryDigest(query string) string {
+	if query == "" {
+		return ""
+	}
+	sum := sha256.Sum256([]byte(query))
+	return hex.EncodeToString(sum[:])
+}
+
+// regulations resolves the provider and the trusted caller. Without an audit
+// store the capability is unavailable: calls must never run unaudited.
+func (h inprocHost) regulations() (extension.RegulationsProvider, extension.RegulationsCaller, error) {
+	if err := h.requireEffective(); err != nil {
+		return nil, extension.RegulationsCaller{}, err
+	}
+	p := h.caps.regulations.get()
+	if p == nil || h.caps.st == nil {
+		return nil, extension.RegulationsCaller{}, extension.ErrRegulationsUnavailable
+	}
+	return p, extension.RegulationsCaller{PluginID: h.pluginID, Actor: h.actor, Owner: h.owner}, nil
+}
+
+// auditRegulations appends one event per call. A call error takes precedence;
+// otherwise an audit failure withholds the result.
+func (h inprocHost) auditRegulations(action string, rec regulationsAudit, callErr error) error {
+	if callErr != nil && rec.State == "" {
+		rec.State = regulationsAuditError
+	}
+	evidence, err := json.Marshal(rec)
+	if err == nil {
+		err = h.Audit(action, regulationsPluginID, string(evidence))
+	}
+	if callErr != nil {
+		return callErr
+	}
+	return err
+}
+
+func (h inprocHost) SearchRegulations(ctx context.Context, req extension.RegulationsSearchRequest) (extension.RegulationsSearchResult, error) {
+	p, caller, err := h.regulations()
+	if err != nil {
+		return extension.RegulationsSearchResult{}, err
+	}
+	rec := regulationsAudit{Revision: req.CorpusRevision, QuerySHA256: regulationsQueryDigest(req.Query)}
+	if req.SchemaVersion != extension.RegulationsSchemaVersion {
+		rec.State = regulationsAuditInvalid
+		return extension.RegulationsSearchResult{}, h.auditRegulations(auditRegulationsSearch, rec, errRegulationsSchema)
+	}
+	res, err := p.SearchRegulations(ctx, caller, req)
+	if err == nil {
+		rec.Revision, rec.Count, rec.State = res.CorpusRevision, len(res.Hits), res.State
+	}
+	if err := h.auditRegulations(auditRegulationsSearch, rec, err); err != nil {
+		return extension.RegulationsSearchResult{}, err
+	}
+	return res, nil
+}
+
+func (h inprocHost) ResolveRegulationEvidence(ctx context.Context, req extension.RegulationEvidenceRequest) (extension.RegulationEvidence, error) {
+	p, caller, err := h.regulations()
+	if err != nil {
+		return extension.RegulationEvidence{}, err
+	}
+	rec := regulationsAudit{Revision: req.CorpusRevision}
+	if req.SchemaVersion != extension.RegulationsSchemaVersion {
+		rec.State = regulationsAuditInvalid
+		return extension.RegulationEvidence{}, h.auditRegulations(auditRegulationsEvidence, rec, errRegulationsSchema)
+	}
+	ev, err := p.ResolveRegulationEvidence(ctx, caller, req)
+	if err == nil {
+		rec.Count, rec.State = 1, regulationsAuditOK
+		if ev.CorpusRevision != "" {
+			rec.Revision = ev.CorpusRevision
+		}
+	}
+	if err := h.auditRegulations(auditRegulationsEvidence, rec, err); err != nil {
+		return extension.RegulationEvidence{}, err
+	}
+	return ev, nil
+}
+
+// webQueryExcluded reports whether query contains any non-empty exclusion
+// term, case-insensitively.
+func webQueryExcluded(query string, exclusions []string) bool {
+	lower := strings.ToLower(query)
+	for _, term := range exclusions {
+		term = strings.ToLower(strings.TrimSpace(term))
+		if term != "" && strings.Contains(lower, term) {
+			return true
+		}
+	}
+	return false
+}
+
+func (h inprocHost) SearchWeb(ctx context.Context, req extension.WebSearchRequest) (extension.WebSearchResult, error) {
+	p, caller, err := h.regulations()
+	if err != nil {
+		return extension.WebSearchResult{}, err
+	}
+	req.Query = strings.TrimSpace(req.Query)
+	rec := regulationsAudit{QuerySHA256: regulationsQueryDigest(req.Query)}
+	if req.SchemaVersion != extension.RegulationsSchemaVersion {
+		rec.State = regulationsAuditInvalid
+		return extension.WebSearchResult{}, h.auditRegulations(auditWebSearch, rec, errRegulationsSchema)
+	}
+	if req.Query == "" || !utf8.ValidString(req.Query) || utf8.RuneCountInString(req.Query) > maxWebQueryRunes {
+		rec.State = regulationsAuditInvalid
+		return extension.WebSearchResult{}, h.auditRegulations(auditWebSearch, rec, errWebQueryInvalid)
+	}
+	if webQueryExcluded(req.Query, req.Exclusions) {
+		res := extension.WebSearchResult{State: extension.WebSearchStateRejected, Reason: "query contains an excluded term"}
+		rec.State = res.State
+		if err := h.auditRegulations(auditWebSearch, rec, nil); err != nil {
+			return extension.WebSearchResult{}, err
+		}
+		return res, nil
+	}
+	res, err := p.SearchWeb(ctx, caller, req)
+	if err == nil {
+		rec.Count, rec.State = len(res.Results), res.State
+	}
+	if err := h.auditRegulations(auditWebSearch, rec, err); err != nil {
+		return extension.WebSearchResult{}, err
+	}
+	return res, nil
+}
+
+func (h inprocHost) CaptureWeb(ctx context.Context, req extension.WebCaptureRequest) (extension.WebCapture, error) {
+	p, caller, err := h.regulations()
+	if err != nil {
+		return extension.WebCapture{}, err
+	}
+	rec := regulationsAudit{QuerySHA256: regulationsQueryDigest(strings.TrimSpace(req.SearchQuery))}
+	if req.SchemaVersion != extension.RegulationsSchemaVersion {
+		rec.State = regulationsAuditInvalid
+		return extension.WebCapture{}, h.auditRegulations(auditWebCapture, rec, errRegulationsSchema)
+	}
+	capture, err := p.CaptureWeb(ctx, caller, req)
+	if err == nil {
+		rec.Count, rec.State = len(capture.Candidates), capture.State
+	}
+	if err := h.auditRegulations(auditWebCapture, rec, err); err != nil {
+		return extension.WebCapture{}, err
+	}
+	return capture, nil
+}
+
+var _ extension.RegulationsHost = inprocHost{}

internal/app/regulations_compat_test.go

@@ -0,0 +1,134 @@
+package app
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"path/filepath"
+	"testing"
+	"time"
+
+	agentcommand "agent-command"
+	"agent-system-backend/internal/cmdbus"
+	"agent-system-backend/internal/store"
+	"agent-system-backend/pkg/extension"
+)
+
+// compatRegulationsPlugin stands in for the external kbreg repository: it uses
+// only pkg/extension types and registers through the optional Registrar.
+type compatRegulationsPlugin struct{ seen []extension.RegulationsCaller }
+
+func (p *compatRegulationsPlugin) Register(reg extension.Registry) error {
+	registrar, ok := reg.(extension.RegulationsRegistrar)
+	if !ok {
+		return errors.New("regulations registrar unavailable")
+	}
+	return registrar.RegisterRegulationsProvider(p)
+}
+
+func (p *compatRegulationsPlugin) SearchRegulations(_ context.Context, c extension.RegulationsCaller, req extension.RegulationsSearchRequest) (extension.RegulationsSearchResult, error) {
+	p.seen = append(p.seen, c)
+	return extension.RegulationsSearchResult{CorpusRevision: "rev-compat", State: extension.RegulationsStateOK,
+		Hits: []extension.RegulationHit{{RegulationID: "r", EditionID: "e", NodeID: "n", Disclosure: extension.RegulationDisclosureExcerpt}}}, nil
+}
+
+func (p *compatRegulationsPlugin) ResolveRegulationEvidence(_ context.Context, c extension.RegulationsCaller, req extension.RegulationEvidenceRequest) (extension.RegulationEvidence, error) {
+	p.seen = append(p.seen, c)
+	return extension.RegulationEvidence{CorpusRevision: req.CorpusRevision, NodeID: req.NodeID, Disclosure: extension.RegulationDisclosureFull, HashVerified: true}, nil
+}
+
+func (p *compatRegulationsPlugin) SearchWeb(_ context.Context, c extension.RegulationsCaller, req extension.WebSearchRequest) (extension.WebSearchResult, error) {
+	p.seen = append(p.seen, c)
+	return extension.WebSearchResult{Provider: "compat", SentQuery: req.Query, State: extension.WebSearchStateEmpty}, nil
+}
+
+func (p *compatRegulationsPlugin) CaptureWeb(_ context.Context, c extension.RegulationsCaller, req extension.WebCaptureRequest) (extension.WebCapture, error) {
+	p.seen = append(p.seen, c)
+	return extension.WebCapture{FinalURL: req.URL, State: extension.WebCaptureStateFailed, Reason: "offline"}, nil
+}
+
+// compatRegulationsConsumer is a second compiled plugin that reaches the
+// provider only through the dispatch Host type assertion.
+func compatRegulationsConsumer(reg extension.Registry) error {
+	return reg.AddCommandHandler(json.RawMessage(`{"id":"consumer.regs","title":"regs"}`),
+		func(ctx context.Context, h extension.Host, req extension.Request) (any, error) {
+			regs, ok := h.(extension.RegulationsHost)
+			if !ok {
+				return nil, errors.New("regulations host capability missing")
+			}
+			search, err := regs.SearchRegulations(ctx, extension.RegulationsSearchRequest{SchemaVersion: extension.RegulationsSchemaVersion, Query: "注册检验"})
+			if err != nil {
+				return nil, err
+			}
+			web, err := regs.SearchWeb(ctx, extension.WebSearchRequest{SchemaVersion: extension.RegulationsSchemaVersion, Query: "注册检验 指导原则"})
+			if err != nil {
+				return nil, err
+			}
+			return map[string]any{"revision": search.CorpusRevision, "webState": web.State}, nil
+		})
+}
+
+func newRegulationsCompatApp(t *testing.T, plugins ...extension.InProc) (*cmdbus.Bus, *store.Store, hostcaps) {
+	t.Helper()
+	extension.ResetCompiled()
+	t.Cleanup(extension.ResetCompiled)
+	for _, p := range plugins {
+		extension.RegisterCompiled(p)
+	}
+	st, err := store.OpenSQLite(filepath.Join(t.TempDir(), "compat.db"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() { st.Close() })
+	if err := st.EnsureUser("alice", ""); err != nil {
+		t.Fatal(err)
+	}
+	bus := cmdbus.New(st, nil, func() time.Time { return time.Unix(1700000000, 0).UTC() })
+	caps := hostcaps{st: st, regulations: &regulationsSlot{}}
+	applyCompiled("", bus, caps)
+	return bus, st, caps
+}
+
+func TestRegulationsCompiledPluginCompatibility(t *testing.T) {
+	provider := &compatRegulationsPlugin{}
+	impostor := &compatRegulationsPlugin{}
+	bus, st, caps := newRegulationsCompatApp(t,
+		extension.InProc{ID: "impostor", Register: impostor.Register},
+		extension.InProc{ID: "kbreg", Register: provider.Register},
+		extension.InProc{ID: "consumer", Register: compatRegulationsConsumer},
+	)
+	if caps.regulations.get() != extension.RegulationsProvider(provider) {
+		t.Fatal("compiled kbreg provider was not the registered provider")
+	}
+	resp := bus.Dispatch(context.Background(), cmdbus.Request{ID: "consumer.regs", Owner: "alice", Actor: "alice", Entrance: "button"})
+	if resp.Receipt.State != agentcommand.StateCommitted {
+		t.Fatalf("dispatch = %+v", resp.Receipt)
+	}
+	payload, _ := resp.Payload.(map[string]any)
+	if payload["revision"] != "rev-compat" || payload["webState"] != extension.WebSearchStateEmpty {
+		t.Fatalf("payload = %+v", resp.Payload)
+	}
+	want := extension.RegulationsCaller{PluginID: "consumer", Actor: "alice", Owner: "alice"}
+	if len(provider.seen) != 2 || provider.seen[0] != want || provider.seen[1] != want || len(impostor.seen) != 0 {
+		t.Fatalf("provider callers = %+v impostor = %+v", provider.seen, impostor.seen)
+	}
+	evs, err := st.ListAuditEvents("alice", 20)
+	if err != nil {
+		t.Fatal(err)
+	}
+	actions := map[string]bool{}
+	for _, ev := range evs {
+		actions[ev.Action] = true
+	}
+	if !actions[auditRegulationsSearch] || !actions[auditWebSearch] {
+		t.Fatalf("host audit missing: %+v", evs)
+	}
+}
+
+func TestRegulationsCompiledConsumerWithoutProvider(t *testing.T) {
+	bus, _, _ := newRegulationsCompatApp(t, extension.InProc{ID: "consumer", Register: compatRegulationsConsumer})
+	resp := bus.Dispatch(context.Background(), cmdbus.Request{ID: "consumer.regs", Owner: "alice", Actor: "alice", Entrance: "button"})
+	if resp.Receipt.State == agentcommand.StateCommitted {
+		t.Fatalf("consumer succeeded without a regulations provider: %+v", resp.Payload)
+	}
+}

internal/app/regulations_test.go

@@ -0,0 +1,347 @@
+package app
+
+import (
+	"context"
+	"crypto/sha256"
+	"encoding/hex"
+	"encoding/json"
+	"errors"
+	"path/filepath"
+	"reflect"
+	"strings"
+	"testing"
+	"time"
+
+	"agent-system-backend/internal/store"
+	"agent-system-backend/pkg/extension"
+)
+
+type fakeRegulationsProvider struct {
+	callers    []extension.RegulationsCaller
+	webQueries []string
+	search     extension.RegulationsSearchResult
+	evidence   extension.RegulationEvidence
+	web        extension.WebSearchResult
+	capture    extension.WebCapture
+	err        error
+}
+
+func (f *fakeRegulationsProvider) SearchRegulations(_ context.Context, c extension.RegulationsCaller, _ extension.RegulationsSearchRequest) (extension.RegulationsSearchResult, error) {
+	f.callers = append(f.callers, c)
+	return f.search, f.err
+}
+
+func (f *fakeRegulationsProvider) ResolveRegulationEvidence(_ context.Context, c extension.RegulationsCaller, _ extension.RegulationEvidenceRequest) (extension.RegulationEvidence, error) {
+	f.callers = append(f.callers, c)
+	return f.evidence, f.err
+}
+
+func (f *fakeRegulationsProvider) SearchWeb(_ context.Context, c extension.RegulationsCaller, req extension.WebSearchRequest) (extension.WebSearchResult, error) {
+	f.callers = append(f.callers, c)
+	f.webQueries = append(f.webQueries, req.Query)
+	return f.web, f.err
+}
+
+func (f *fakeRegulationsProvider) CaptureWeb(_ context.Context, c extension.RegulationsCaller, _ extension.WebCaptureRequest) (extension.WebCapture, error) {
+	f.callers = append(f.callers, c)
+	return f.capture, f.err
+}
+
+func newRegulationsTestHost(t *testing.T) (inprocHost, *store.Store) {
+	t.Helper()
+	st, err := store.OpenSQLite(filepath.Join(t.TempDir(), "regulations.db"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() { st.Close() })
+	if err := st.EnsureUser("alice", ""); err != nil {
+		t.Fatal(err)
+	}
+	caps := hostcaps{st: st, regulations: &regulationsSlot{}}
+	return inprocHost{caps: caps, pluginID: "rdm", owner: "alice", actor: "alice"}, st
+}
+
+func registerFakeRegulations(t *testing.T, h inprocHost) *fakeRegulationsProvider {
+	t.Helper()
+	p := &fakeRegulationsProvider{}
+	if err := (pluginRegistry{pluginID: "kbreg", caps: h.caps}).RegisterRegulationsProvider(p); err != nil {
+		t.Fatal(err)
+	}
+	return p
+}
+
+const regV = extension.RegulationsSchemaVersion
+
+func callAllRegulations(h inprocHost, version int) []error {
+	ctx := context.Background()
+	_, e1 := h.SearchRegulations(ctx, extension.RegulationsSearchRequest{SchemaVersion: version, Query: "医疗器械 临床评价"})
+	_, e2 := h.ResolveRegulationEvidence(ctx, extension.RegulationEvidenceRequest{SchemaVersion: version, CorpusRevision: "rev-1", NodeID: "n1"})
+	_, e3 := h.SearchWeb(ctx, extension.WebSearchRequest{SchemaVersion: version, Query: "临床评价 指导原则"})
+	_, e4 := h.CaptureWeb(ctx, extension.WebCaptureRequest{SchemaVersion: version, URL: "https://www.nmpa.gov.cn/x", SearchQuery: "临床评价 指导原则"})
+	return []error{e1, e2, e3, e4}
+}
+
+func TestRegulationsUnavailableWithoutProvider(t *testing.T) {
+	h, st := newRegulationsTestHost(t)
+	for i, err := range callAllRegulations(h, regV) {
+		if !errors.Is(err, extension.ErrRegulationsUnavailable) {
+			t.Fatalf("method %d without provider: %v", i, err)
+		}
+	}
+	h.caps.regulations = nil
+	for i, err := range callAllRegulations(h, regV) {
+		if !errors.Is(err, extension.ErrRegulationsUnavailable) {
+			t.Fatalf("method %d without slot: %v", i, err)
+		}
+	}
+	if evs, err := st.ListAuditEvents("alice", 10); err != nil || len(evs) != 0 {
+		t.Fatalf("unavailable calls audited: %+v %v", evs, err)
+	}
+}
+
+func TestRegulationsRegistrationOnlyTrustedKbregOnce(t *testing.T) {
+	h, _ := newRegulationsTestHost(t)
+	first, second := &fakeRegulationsProvider{}, &fakeRegulationsProvider{}
+	if err := (pluginRegistry{pluginID: "rdm", caps: h.caps}).RegisterRegulationsProvider(first); err == nil {
+		t.Fatal("non-kbreg plugin registered a regulations provider")
+	}
+	kbreg := pluginRegistry{pluginID: "kbreg", caps: h.caps}
+	if err := kbreg.RegisterRegulationsProvider(nil); err == nil {
+		t.Fatal("nil provider registered")
+	}
+	if err := kbreg.RegisterRegulationsProvider(first); err != nil {
+		t.Fatal(err)
+	}
+	if err := kbreg.RegisterRegulationsProvider(second); err == nil {
+		t.Fatal("duplicate registration accepted")
+	}
+	if h.caps.regulations.get() != first {
+		t.Fatal("duplicate registration replaced the first provider")
+	}
+	if err := (pluginRegistry{pluginID: "kbreg"}).RegisterRegulationsProvider(first); err == nil {
+		t.Fatal("registration without a host slot accepted")
+	}
+}
+
+func TestRegulationsDeclarativeRegistrationRejected(t *testing.T) {
+	h, _ := newRegulationsTestHost(t)
+	p := &fakeRegulationsProvider{}
+	if err := (compiledRegistry{}).RegisterRegulationsProvider(p); err == nil {
+		t.Fatal("declarative registry accepted a regulations provider")
+	}
+	if err := (recordRegistry{Registry: pluginRegistry{pluginID: "kbreg", caps: h.caps}}).RegisterRegulationsProvider(p); err != nil {
+		t.Fatalf("record registry did not forward kbreg registration: %v", err)
+	}
+	if h.caps.regulations.get() != p {
+		t.Fatal("forwarded registration did not fill the slot")
+	}
+}
+
+func TestRegulationsCallerFilledFromDispatchContext(t *testing.T) {
+	h, _ := newRegulationsTestHost(t)
+	h.actor = "alice-session"
+	p := registerFakeRegulations(t, h)
+	p.web.State = extension.WebSearchStateOK
+	for i, err := range callAllRegulations(h, regV) {
+		if err != nil {
+			t.Fatalf("method %d: %v", i, err)
+		}
+	}
+	want := extension.RegulationsCaller{PluginID: "rdm", Actor: "alice-session", Owner: "alice"}
+	if len(p.callers) != 4 {
+		t.Fatalf("provider calls = %d", len(p.callers))
+	}
+	for i, got := range p.callers {
+		if got != want {
+			t.Fatalf("call %d caller = %+v, want %+v", i, got, want)
+		}
+	}
+}
+
+func TestRegulationsRejectsOtherSchemaVersions(t *testing.T) {
+	h, _ := newRegulationsTestHost(t)
+	p := registerFakeRegulations(t, h)
+	for _, version := range []int{0, regV + 1} {
+		for i, err := range callAllRegulations(h, version) {
+			if !errors.Is(err, errRegulationsSchema) {
+				t.Fatalf("schema %d method %d: %v", version, i, err)
+			}
+		}
+	}
+	if len(p.callers) != 0 {
+		t.Fatalf("provider reached with unsupported schema: %d calls", len(p.callers))
+	}
+}
+
+func TestRegulationsWebQueryBounds(t *testing.T) {
+	h, _ := newRegulationsTestHost(t)
+	p := registerFakeRegulations(t, h)
+	ctx := context.Background()
+	for _, q := range []string{"", "   \t\n", strings.Repeat("法", maxWebQueryRunes+1)} {
+		if _, err := h.SearchWeb(ctx, extension.WebSearchRequest{SchemaVersion: regV, Query: q}); !errors.Is(err, errWebQueryInvalid) {
+			t.Fatalf("query of %d runes accepted: %v", len([]rune(q)), err)
+		}
+	}
+	if len(p.callers) != 0 {
+		t.Fatal("provider reached with an invalid query")
+	}
+	maxQuery := strings.Repeat("法", maxWebQueryRunes)
+	if _, err := h.SearchWeb(ctx, extension.WebSearchRequest{SchemaVersion: regV, Query: "  " + maxQuery + " "}); err != nil {
+		t.Fatalf("256-rune query rejected: %v", err)
+	}
+	if len(p.webQueries) != 1 || p.webQueries[0] != maxQuery {
+		t.Fatalf("provider query was not trimmed: %q", p.webQueries)
+	}
+}
+
+func TestRegulationsExclusionRejectedBeforeProvider(t *testing.T) {
+	h, st := newRegulationsTestHost(t)
+	p := registerFakeRegulations(t, h)
+	ctx := context.Background()
+	query := "Project-Falcon 临床评价 指导原则"
+	res, err := h.SearchWeb(ctx, extension.WebSearchRequest{SchemaVersion: regV, Query: query,
+		Exclusions: []string{"", "  ", "project-falcon"}})
+	if err != nil || res.State != extension.WebSearchStateRejected || res.SentQuery != "" || len(res.Results) != 0 {
+		t.Fatalf("excluded query result = %+v %v", res, err)
+	}
+	if len(p.callers) != 0 {
+		t.Fatal("provider received a query containing an excluded term")
+	}
+	evs, err := st.ListAuditEvents("alice", 10)
+	if err != nil || len(evs) != 1 || evs[0].Action != auditWebSearch {
+		t.Fatalf("rejection audit: %+v %v", evs, err)
+	}
+	if strings.Contains(strings.ToLower(evs[0].Evidence), "falcon") || !strings.Contains(evs[0].Evidence, `"state":"rejected"`) {
+		t.Fatalf("rejection audit evidence = %s", evs[0].Evidence)
+	}
+	if _, err := h.SearchWeb(ctx, extension.WebSearchRequest{SchemaVersion: regV, Query: query, Exclusions: []string{"", " "}}); err != nil {
+		t.Fatal(err)
+	}
+	if len(p.callers) != 1 {
+		t.Fatal("blank exclusions blocked an allowed query")
+	}
+}
+
+func TestRegulationsProviderStatesPassThroughUnchanged(t *testing.T) {
+	h, _ := newRegulationsTestHost(t)
+	p := registerFakeRegulations(t, h)
+	at := time.Date(2026, 10, 18, 9, 0, 0, 0, time.UTC)
+	p.search = extension.RegulationsSearchResult{CorpusRevision: "rev-7", State: extension.RegulationsStateDegraded,
+		DegradedReasons: []string{"vector_index_unavailable"},
+		Hits: []extension.RegulationHit{{RegulationID: "r1", EditionID: "e1", NodeID: "n1",
+			Disclosure: extension.RegulationDisclosureWithheld, WithheldReason: "rights"},
+			{RegulationID: "r2", EditionID: "e2", NodeID: "n2", Disclosure: extension.RegulationDisclosureMetadataOnly}}}
+	p.evidence = extension.RegulationEvidence{CorpusRevision: "rev-7", NodeID: "n1",
+		Disclosure: extension.RegulationDisclosureWithheld, WithheldReason: "rights", HashVerified: false}
+	p.web = extension.WebSearchResult{Provider: "fake", SentQuery: "q", SearchedAt: at,
+		State: extension.WebSearchStateRateLimited, Reason: "quota"}
+	p.capture = extension.WebCapture{CaptureID: "c1", FetchedAt: at, Retention: extension.WebRetentionMetadataOnly,
+		State: extension.WebCaptureStateRejected, Reason: "robots"}
+	ctx := context.Background()
+	search, err := h.SearchRegulations(ctx, extension.RegulationsSearchRequest{SchemaVersion: regV, Query: "q"})
+	if err != nil || !reflect.DeepEqual(search, p.search) {
+		t.Fatalf("search = %+v %v", search, err)
+	}
+	evidence, err := h.ResolveRegulationEvidence(ctx, extension.RegulationEvidenceRequest{SchemaVersion: regV, CorpusRevision: "rev-7", NodeID: "n1"})
+	if err != nil || !reflect.DeepEqual(evidence, p.evidence) {
+		t.Fatalf("evidence = %+v %v", evidence, err)
+	}
+	web, err := h.SearchWeb(ctx, extension.WebSearchRequest{SchemaVersion: regV, Query: "q"})
+	if err != nil || !reflect.DeepEqual(web, p.web) {
+		t.Fatalf("web = %+v %v", web, err)
+	}
+	p.web.State = extension.WebSearchStateRejected
+	web, err = h.SearchWeb(ctx, extension.WebSearchRequest{SchemaVersion: regV, Query: "q"})
+	if err != nil || web.State != extension.WebSearchStateRejected {
+		t.Fatalf("provider rejection rewritten: %+v %v", web, err)
+	}
+	capture, err := h.CaptureWeb(ctx, extension.WebCaptureRequest{SchemaVersion: regV, URL: "https://example.org"})
+	if err != nil || !reflect.DeepEqual(capture, p.capture) {
+		t.Fatalf("capture = %+v %v", capture, err)
+	}
+	p.err = errors.New("provider failure")
+	if _, err := h.SearchRegulations(ctx, extension.RegulationsSearchRequest{SchemaVersion: regV, Query: "q"}); !errors.Is(err, p.err) {
+		t.Fatalf("provider failure wrapped as success: %v", err)
+	}
+}
+
+func TestRegulationsAuditEvidenceOmitsQueryAndText(t *testing.T) {
+	h, st := newRegulationsTestHost(t)
+	p := registerFakeRegulations(t, h)
+	const (
+		secretQuery   = "第十七条 secret-query-text"
+		secretExcerpt = "SECRET-EXCERPT 原文片段"
+		secretPage    = "SECRET-PAGE 网页全文"
+	)
+	p.search = extension.RegulationsSearchResult{CorpusRevision: "rev-9", State: extension.RegulationsStateOK,
+		Hits: []extension.RegulationHit{{NodeID: "n1", Excerpt: secretExcerpt, Disclosure: extension.RegulationDisclosureExcerpt}}}
+	p.evidence = extension.RegulationEvidence{CorpusRevision: "rev-9", NodeID: "n1", Excerpt: secretExcerpt,
+		Disclosure: extension.RegulationDisclosureFull, HashVerified: true}
+	p.web = extension.WebSearchResult{SentQuery: secretQuery, State: extension.WebSearchStateOK,
+		Results: []extension.WebSearchHit{{Rank: 1, URL: "https://example.org", Snippet: secretExcerpt}}}
+	p.capture = extension.WebCapture{State: extension.WebCaptureStateCaptured, Retention: extension.WebRetentionFull,
+		Text: secretPage, Candidates: []extension.WebClauseCandidate{{Excerpt: secretExcerpt}}}
+	ctx := context.Background()
+	if _, err := h.SearchRegulations(ctx, extension.RegulationsSearchRequest{SchemaVersion: regV, Query: secretQuery}); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := h.ResolveRegulationEvidence(ctx, extension.RegulationEvidenceRequest{SchemaVersion: regV, CorpusRevision: "rev-9", NodeID: "n1"}); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := h.SearchWeb(ctx, extension.WebSearchRequest{SchemaVersion: regV, Query: " " + secretQuery + " "}); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := h.CaptureWeb(ctx, extension.WebCaptureRequest{SchemaVersion: regV, URL: "https://example.org", SearchQuery: secretQuery}); err != nil {
+		t.Fatal(err)
+	}
+	evs, err := st.ListAuditEvents("alice", 10)
+	if err != nil || len(evs) != 4 {
+		t.Fatalf("audit events = %+v %v", evs, err)
+	}
+	sum := sha256.Sum256([]byte(secretQuery))
+	digest := hex.EncodeToString(sum[:])
+	want := map[string]regulationsAudit{
+		auditRegulationsSearch:   {Revision: "rev-9", Count: 1, State: "ok", QuerySHA256: digest},
+		auditRegulationsEvidence: {Revision: "rev-9", Count: 1, State: "ok"},
+		auditWebSearch:           {Count: 1, State: "ok", QuerySHA256: digest},
+		auditWebCapture:          {Count: 1, State: "captured", QuerySHA256: digest},
+	}
+	for _, ev := range evs {
+		for _, secret := range []string{"secret-query-text", "第十七条", "SECRET-EXCERPT", "原文片段", "SECRET-PAGE", "网页全文"} {
+			if strings.Contains(ev.Evidence, secret) || strings.Contains(ev.Target, secret) {
+				t.Fatalf("%s audit leaks %q: %s", ev.Action, secret, ev.Evidence)
+			}
+		}
+		var fields map[string]any
+		if err := json.Unmarshal([]byte(ev.Evidence), &fields); err != nil {
+			t.Fatal(err)
+		}
+		for k := range fields {
+			if k != "revision" && k != "count" && k != "state" && k != "querySha256" {
+				t.Fatalf("%s audit has unexpected field %q", ev.Action, k)
+			}
+		}
+		var got regulationsAudit
+		if err := json.Unmarshal([]byte(ev.Evidence), &got); err != nil {
+			t.Fatal(err)
+		}
+		if w, ok := want[ev.Action]; !ok || got != w || ev.Owner != "alice" {
+			t.Fatalf("%s audit = %+v owner=%s, want %+v", ev.Action, got, ev.Owner, w)
+		}
+		delete(want, ev.Action)
+	}
+}
+
+func TestRegulationsRequireEffectiveAccount(t *testing.T) {
+	h, _ := newRegulationsTestHost(t)
+	p := registerFakeRegulations(t, h)
+	h.caps.accountGuard = func(string) error { return store.ErrAccountForbidden }
+	for i, err := range callAllRegulations(h, regV) {
+		if !errors.Is(err, store.ErrAccountForbidden) {
+			t.Fatalf("method %d ignored the account guard: %v", i, err)
+		}
+	}
+	if len(p.callers) != 0 {
+		t.Fatal("provider reached for an ineffective account")
+	}
+}

pkg/extension/extension.go

@@ -40,7 +40,9 @@ import (
 // AccountDirectoryRegistrar for scoped, current account candidate decisions.
 // 2.14.0-experimental：InProc.HostOptions / CLIHook，以及 MergeHostOptions、
 // RegisterCLIFlags、RunCLIHooks（组合二进制把插件声明并进基座启动，不覆盖显式参数）。
-const SurfaceVersion = "2.14.0-experimental"
+// 2.15.0-experimental：EXT-20 可选 RegulationsHost 与受信进程内 RegulationsRegistrar
+// （共享法规检索与网络证据；仅插件 kbreg 可注册提供方）。
+const SurfaceVersion = "2.15.0-experimental"
 
 // ErrNotLinked 表示进程没有空白导入 link 包，Main 无法启动服务。
 var ErrNotLinked = errors.New("extension: runner not linked; blank-import agent-system-backend/pkg/extension/link")

pkg/extension/regulations.go

@@ -0,0 +1,209 @@
+package extension
+
+import (
+	"context"
+	"errors"
+	"time"
+)
+
+// RegulationsSchemaVersion is the only request schema the host accepts for
+// EXT-20; any other value is rejected before reaching the provider.
+const RegulationsSchemaVersion = 1
+
+const (
+	RegulationsStateOK          = "ok"
+	RegulationsStateEmpty       = "empty"
+	RegulationsStateDegraded    = "degraded"
+	RegulationsStateUnavailable = "unavailable"
+
+	RegulationDisclosureFull         = "full"
+	RegulationDisclosureExcerpt      = "excerpt"
+	RegulationDisclosureMetadataOnly = "metadata_only"
+	RegulationDisclosureWithheld     = "withheld"
+
+	WebSearchStateOK          = "ok"
+	WebSearchStateEmpty       = "empty"
+	WebSearchStateUnavailable = "unavailable"
+	WebSearchStateRateLimited = "rate_limited"
+	WebSearchStateRejected    = "rejected"
+	WebSearchStateError       = "error"
+
+	WebCaptureStateCaptured = "captured"
+	WebCaptureStateRejected = "rejected"
+	WebCaptureStateFailed   = "failed"
+
+	WebRetentionFull         = "full"
+	WebRetentionExcerpt      = "excerpt"
+	WebRetentionMetadataOnly = "metadata_only"
+)
+
+// ErrRegulationsUnavailable is returned by every RegulationsHost method when no
+// trusted provider is registered. Callers must not fall back to KnowledgeSearch.
+var ErrRegulationsUnavailable = errors.New("extension: regulations provider unavailable")
+
+// RegulationsCaller is filled by the host from the trusted dispatch context.
+// It deliberately has no project ID: shared regulation access neither widens
+// nor narrows with a project.
+type RegulationsCaller struct {
+	PluginID string `json:"pluginId"`
+	Actor    string `json:"actor,omitempty"`
+	Owner    string `json:"owner"`
+}
+
+// RegulationsSearchRequest searches the controlled regulation corpus. An empty
+// CorpusRevision means the current published revision; the result echoes the
+// revision actually searched.
+type RegulationsSearchRequest struct {
+	SchemaVersion  int      `json:"schemaVersion"`
+	Query          string   `json:"query"`
+	CorpusRevision string   `json:"corpusRevision,omitempty"`
+	Kinds          []string `json:"kinds,omitempty"`
+	CurrentOnly    bool     `json:"currentOnly,omitempty"`
+	DocNo          string   `json:"docNo,omitempty"`
+	ClauseNo       string   `json:"clauseNo,omitempty"`
+	Limit          int      `json:"limit,omitempty"`
+}
+
+type RegulationsSearchResult struct {
+	CorpusRevision  string          `json:"corpusRevision"`
+	State           string          `json:"state"` // ok|empty|degraded|unavailable
+	DegradedReasons []string        `json:"degradedReasons,omitempty"`
+	Hits            []RegulationHit `json:"hits"`
+}
+
+type RegulationHit struct {
+	RegulationID      string   `json:"regulationId"`
+	EditionID         string   `json:"editionId"`
+	NodeID            string   `json:"nodeId"`
+	DocNo             string   `json:"docNo,omitempty"`
+	Title             string   `json:"title,omitempty"`
+	EditionLabel      string   `json:"editionLabel,omitempty"`
+	LegalStatus       string   `json:"legalStatus,omitempty"`
+	ClauseNo          string   `json:"clauseNo,omitempty"`
+	HeadingPath       []string `json:"headingPath,omitempty"`
+	Excerpt           string   `json:"excerpt,omitempty"`
+	ExcerptStart      int      `json:"excerptStart,omitempty"`
+	ExcerptEnd        int      `json:"excerptEnd,omitempty"`
+	NodeSHA256        string   `json:"nodeSha256,omitempty"`
+	SourceAssetSHA256 string   `json:"sourceAssetSha256,omitempty"`
+	PageStart         int      `json:"pageStart,omitempty"`
+	PageEnd           int      `json:"pageEnd,omitempty"`
+	Disclosure        string   `json:"disclosure"` // full|excerpt|metadata_only|withheld
+	WithheldReason    string   `json:"withheldReason,omitempty"`
+	IsSummary         bool     `json:"isSummary,omitempty"`
+	MatchKinds        []string `json:"matchKinds,omitempty"`
+	Score             float64  `json:"score,omitempty"`
+}
+
+// RegulationEvidenceRequest retrieves the original text span of a node pinned
+// to a corpus revision.
+type RegulationEvidenceRequest struct {
+	SchemaVersion  int    `json:"schemaVersion"`
+	CorpusRevision string `json:"corpusRevision"`
+	NodeID         string `json:"nodeId"`
+	Start          int    `json:"start,omitempty"`
+	End            int    `json:"end,omitempty"`
+}
+
+type RegulationEvidence struct {
+	CorpusRevision    string `json:"corpusRevision"`
+	RegulationID      string `json:"regulationId,omitempty"`
+	EditionID         string `json:"editionId,omitempty"`
+	NodeID            string `json:"nodeId"`
+	ClauseNo          string `json:"clauseNo,omitempty"`
+	Excerpt           string `json:"excerpt,omitempty"`
+	Start             int    `json:"start,omitempty"`
+	End               int    `json:"end,omitempty"`
+	NodeSHA256        string `json:"nodeSha256,omitempty"`
+	SourceAssetSHA256 string `json:"sourceAssetSha256,omitempty"`
+	PageStart         int    `json:"pageStart,omitempty"`
+	PageEnd           int    `json:"pageEnd,omitempty"`
+	Disclosure        string `json:"disclosure"`
+	WithheldReason    string `json:"withheldReason,omitempty"`
+	HashVerified      bool   `json:"hashVerified"`
+}
+
+// WebSearchRequest performs a real web search. Exclusions are caller-declared
+// confidential terms (project names, numbers, people); a query containing any
+// of them is rejected by the host before the provider sees it.
+type WebSearchRequest struct {
+	SchemaVersion  int      `json:"schemaVersion"`
+	Query          string   `json:"query"`
+	Exclusions     []string `json:"exclusions,omitempty"`
+	PreferOfficial bool     `json:"preferOfficial,omitempty"`
+	Limit          int      `json:"limit,omitempty"`
+}
+
+type WebSearchResult struct {
+	Provider   string         `json:"provider,omitempty"`
+	SentQuery  string         `json:"sentQuery,omitempty"`
+	SearchedAt time.Time      `json:"searchedAt"`
+	State      string         `json:"state"` // ok|empty|unavailable|rate_limited|rejected|error
+	Reason     string         `json:"reason,omitempty"`
+	Results    []WebSearchHit `json:"results,omitempty"`
+}
+
+type WebSearchHit struct {
+	Rank      int    `json:"rank"`
+	URL       string `json:"url"`
+	Title     string `json:"title,omitempty"`
+	Snippet   string `json:"snippet,omitempty"`
+	Publisher string `json:"publisher,omitempty"`
+	Official  bool   `json:"official,omitempty"`
+}
+
+// WebCaptureRequest fetches a page found by a prior SearchWeb call.
+type WebCaptureRequest struct {
+	SchemaVersion  int    `json:"schemaVersion"`
+	URL            string `json:"url"`
+	SearchProvider string `json:"searchProvider,omitempty"`
+	SearchQuery    string `json:"searchQuery,omitempty"`
+	SearchRank     int    `json:"searchRank,omitempty"`
+}
+
+type WebCapture struct {
+	CaptureID   string    `json:"captureId,omitempty"`
+	FinalURL    string    `json:"finalUrl,omitempty"`
+	FetchedAt   time.Time `json:"fetchedAt"`
+	ContentType string    `json:"contentType,omitempty"`
+	ByteSize    int64     `json:"byteSize,omitempty"`
+	SHA256      string    `json:"sha256,omitempty"`
+	Retention   string    `json:"retention,omitempty"` // full|excerpt|metadata_only
+	// Text is present only when the source rights allow full retention.
+	Text       string               `json:"text,omitempty"`
+	Candidates []WebClauseCandidate `json:"candidates,omitempty"`
+	State      string               `json:"state"` // captured|rejected|failed
+	Reason     string               `json:"reason,omitempty"`
+}
+
+type WebClauseCandidate struct {
+	ClauseNo string `json:"clauseNo,omitempty"`
+	Excerpt  string `json:"excerpt"`
+	Start    int    `json:"start"`
+	End      int    `json:"end"`
+}
+
+// RegulationsProvider is implemented and registered by the trusted regulations
+// knowledge plugin (plugin ID "kbreg"); the host ships no implementation.
+type RegulationsProvider interface {
+	SearchRegulations(context.Context, RegulationsCaller, RegulationsSearchRequest) (RegulationsSearchResult, error)
+	ResolveRegulationEvidence(context.Context, RegulationsCaller, RegulationEvidenceRequest) (RegulationEvidence, error)
+	SearchWeb(context.Context, RegulationsCaller, WebSearchRequest) (WebSearchResult, error)
+	CaptureWeb(context.Context, RegulationsCaller, WebCaptureRequest) (WebCapture, error)
+}
+
+// RegulationsRegistrar is optional on a compiled in-process Registry. Only
+// plugin ID "kbreg" may register, and only once.
+type RegulationsRegistrar interface {
+	RegisterRegulationsProvider(RegulationsProvider) error
+}
+
+// RegulationsHost is optional on dispatch Host handles (obtained by type
+// assertion). A missing capability means unavailable; callers must not fall
+// back to KnowledgeSearch.
+type RegulationsHost interface {
+	SearchRegulations(context.Context, RegulationsSearchRequest) (RegulationsSearchResult, error)
+	ResolveRegulationEvidence(context.Context, RegulationEvidenceRequest) (RegulationEvidence, error)
+	SearchWeb(context.Context, WebSearchRequest) (WebSearchResult, error)
+	CaptureWeb(context.Context, WebCaptureRequest) (WebCapture, error)
+}

pkg/extension/regulations_test.go

@@ -0,0 +1,78 @@
+package extension_test
+
+import (
+	"context"
+	"encoding/json"
+	"strings"
+	"testing"
+
+	"agent-system-backend/pkg/extension"
+)
+
+// publicRegulationsProvider is a downstream provider built only from the
+// public extension surface.
+type publicRegulationsProvider struct{}
+
+func (publicRegulationsProvider) SearchRegulations(context.Context, extension.RegulationsCaller, extension.RegulationsSearchRequest) (extension.RegulationsSearchResult, error) {
+	return extension.RegulationsSearchResult{State: extension.RegulationsStateEmpty}, nil
+}
+
+func (publicRegulationsProvider) ResolveRegulationEvidence(context.Context, extension.RegulationsCaller, extension.RegulationEvidenceRequest) (extension.RegulationEvidence, error) {
+	return extension.RegulationEvidence{Disclosure: extension.RegulationDisclosureMetadataOnly}, nil
+}
+
+func (publicRegulationsProvider) SearchWeb(context.Context, extension.RegulationsCaller, extension.WebSearchRequest) (extension.WebSearchResult, error) {
+	return extension.WebSearchResult{State: extension.WebSearchStateUnavailable}, nil
+}
+
+func (publicRegulationsProvider) CaptureWeb(context.Context, extension.RegulationsCaller, extension.WebCaptureRequest) (extension.WebCapture, error) {
+	return extension.WebCapture{State: extension.WebCaptureStateFailed}, nil
+}
+
+var _ extension.RegulationsProvider = publicRegulationsProvider{}
+
+func TestRegulationsContractIsOptional(t *testing.T) {
+	var host extension.Host
+	if _, ok := host.(extension.RegulationsHost); ok {
+		t.Fatal("nil host must not expose regulations")
+	}
+	var registry extension.Registry
+	if _, ok := registry.(extension.RegulationsRegistrar); ok {
+		t.Fatal("nil registry must not expose regulations registration")
+	}
+	if extension.RegulationsSchemaVersion != 1 {
+		t.Fatalf("schema version = %d", extension.RegulationsSchemaVersion)
+	}
+	if extension.ErrRegulationsUnavailable == nil {
+		t.Fatal("unavailable error must be defined")
+	}
+}
+
+func TestRegulationsWireNames(t *testing.T) {
+	states := []string{extension.RegulationsStateOK, extension.RegulationsStateEmpty, extension.RegulationsStateDegraded,
+		extension.RegulationsStateUnavailable, extension.RegulationDisclosureFull, extension.RegulationDisclosureExcerpt,
+		extension.RegulationDisclosureMetadataOnly, extension.RegulationDisclosureWithheld, extension.WebSearchStateOK,
+		extension.WebSearchStateEmpty, extension.WebSearchStateUnavailable, extension.WebSearchStateRateLimited,
+		extension.WebSearchStateRejected, extension.WebSearchStateError, extension.WebCaptureStateCaptured,
+		extension.WebCaptureStateRejected, extension.WebCaptureStateFailed, extension.WebRetentionFull,
+		extension.WebRetentionExcerpt, extension.WebRetentionMetadataOnly}
+	want := "ok empty degraded unavailable full excerpt metadata_only withheld ok empty unavailable rate_limited " +
+		"rejected error captured rejected failed full excerpt metadata_only"
+	if got := strings.Join(states, " "); got != want {
+		t.Fatalf("wire states = %q", got)
+	}
+	raw, err := json.Marshal(extension.WebSearchRequest{SchemaVersion: extension.RegulationsSchemaVersion, Query: "q"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if string(raw) != `{"schemaVersion":1,"query":"q"}` {
+		t.Fatalf("optional fields not omitted: %s", raw)
+	}
+	raw, err = json.Marshal(extension.RegulationsCaller{PluginID: "rdm", Owner: "alice"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if strings.Contains(strings.ToLower(string(raw)), "project") {
+		t.Fatalf("caller must not carry a project: %s", raw)
+	}
+}

pkg/extension/surface.txt

@@ -30,6 +30,7 @@ Compiled
 DelegatedProjectProjectionHost
 DelegatedProjectProjectionHost.ProjectProjectionForCreator
 ErrNotLinked
+ErrRegulationsUnavailable
 Handler
 Host
 Host.ArtifactContent
@@ -78,6 +79,33 @@ Registry.AddSkill
 Registry.Note
 Registry.RegisterResourceAuthorizer
 Registry.RegisterResourceAuthorizerV2
+RegulationDisclosureExcerpt
+RegulationDisclosureFull
+RegulationDisclosureMetadataOnly
+RegulationDisclosureWithheld
+RegulationEvidence
+RegulationEvidenceRequest
+RegulationHit
+RegulationsCaller
+RegulationsHost
+RegulationsHost.CaptureWeb
+RegulationsHost.ResolveRegulationEvidence
+RegulationsHost.SearchRegulations
+RegulationsHost.SearchWeb
+RegulationsProvider
+RegulationsProvider.CaptureWeb
+RegulationsProvider.ResolveRegulationEvidence
+RegulationsProvider.SearchRegulations
+RegulationsProvider.SearchWeb
+RegulationsRegistrar
+RegulationsRegistrar.RegisterRegulationsProvider
+RegulationsSchemaVersion
+RegulationsSearchRequest
+RegulationsSearchResult
+RegulationsStateDegraded
+RegulationsStateEmpty
+RegulationsStateOK
+RegulationsStateUnavailable
 Request
 ResetCompiled
 ResourceAuthorizer
@@ -93,3 +121,21 @@ SurfaceHost.SurfaceList
 SurfaceHost.SurfaceSave
 SurfaceSaveRequest
 SurfaceVersion
+WebCapture
+WebCaptureRequest
+WebCaptureStateCaptured
+WebCaptureStateFailed
+WebCaptureStateRejected
+WebClauseCandidate
+WebRetentionExcerpt
+WebRetentionFull
+WebRetentionMetadataOnly
+WebSearchHit
+WebSearchRequest
+WebSearchResult
+WebSearchStateEmpty
+WebSearchStateError
+WebSearchStateOK
+WebSearchStateRateLimited
+WebSearchStateRejected
+WebSearchStateUnavailable