Serve capabilities through one serializer and add GET /api/v1/executions

The two "refactor later" items from REVIEW-2026-07-30.md; they share the wire
types, so they land together.

A capability had four divergent wire shapes — the HTTP handler, the MCP
adapter, pkg/client, and Maven's vendored copy of it. There is now a single
definition in pkg/client, mapped from domain by internal/wire and used by the
HTTP list/create/get paths and all four MCP surfaces. It lives in pkg/client
rather than internal so external consumers need not vendor internal/domain,
and so producer and consumer are literally the same type.

The unified shape is a strict superset of all four predecessors; nothing was
dropped. It adds enabled and requires_confirmation to the list responses
(never omitempty — an absent bool reads as unknown, not false), capability_id
to the MCP and client shapes, and the timing/attribute/version fields
previously only on get-by-ID. target_types and the list itself now serialize
as [] rather than null.

Both `id` and `capability_id` are deliberately kept, carrying the same value.
Maven decodes `id`; the spec and the rest of the API say `capability_id`.
Bearer auth is already a breaking change for that consumer, and stacking a
second silent one is the wrong trade — the redundancy stays until every
consumer is confirmed on capability_id, then `id` goes in an announced
removal. A test pins this and says so.

GET /api/v1/executions?entity_id=&since=&limit= implements spec §4.5, which
the Command Center needs. `since` reuses the changes-feed cursor convention
rather than inventing a second paging idiom. That cursor is the row's implicit
SQLite rowid, which is safe only while nothing deletes executions and nothing
VACUUMs — both would renumber and silently invalidate outstanding cursors. If
retention is ever added, this must become an explicit monotonic column first;
the constraint is documented at the query site.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Uea55zaiWuEByEDC4UBSdd

internal/api/capability_shape_test.go

@@ -0,0 +1,124 @@
+package api
+
+import (
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+	"time"
+
+	"github.com/kami/hexis/internal/domain"
+	"github.com/kami/hexis/internal/storage"
+)
+
+func seedCapability(t *testing.T, store *storage.Store, entityID string) *domain.Capability {
+	t.Helper()
+	now := time.Now().UTC()
+	c := &domain.Capability{
+		ID:                   domain.NewCapabilityID(),
+		Name:                 "docker.restart_container",
+		Description:          "Restart a container",
+		TargetTypes:          []string{"container"},
+		TargetEntityID:       entityID,
+		Provider:             "workspace_mcp",
+		Operation:            "docker.restart_container",
+		Risk:                 domain.RiskMedium,
+		ReadOnly:             false,
+		RequiresConfirmation: domain.RequiresConfirmationForRisk(domain.RiskMedium),
+		Enabled:              domain.EnabledForRisk(domain.RiskMedium),
+		TimeoutSeconds:       domain.DefaultCapabilityTimeoutSeconds,
+		Attributes:           map[string]any{},
+		CreatedAt:            now,
+		UpdatedAt:            now,
+		Version:              1,
+	}
+	if err := store.CreateCapability(c); err != nil {
+		t.Fatalf("create capability: %v", err)
+	}
+	return c
+}
+
+// TestCapabilityWireShape_ListAndGetAgree pins the unification: the list
+// response and the single-capability response are now produced by the same
+// serializer, so a client cannot see one shape from one endpoint and a
+// different shape from the other. Before this, list emitted a hand-built map
+// (no enabled/requires_confirmation) while get returned the raw domain struct.
+func TestCapabilityWireShape_ListAndGetAgree(t *testing.T) {
+	h, store := newTestHandler(t)
+	c := seedCapability(t, store, "ent_alpha")
+
+	listReq := httptest.NewRequest(http.MethodGet, "/api/v1/capabilities", nil)
+	listW := httptest.NewRecorder()
+	h.listCapabilities(listW, listReq)
+	if listW.Code != http.StatusOK {
+		t.Fatalf("list: expected 200, got %d: %s", listW.Code, listW.Body.String())
+	}
+	var list []map[string]any
+	if err := json.Unmarshal(listW.Body.Bytes(), &list); err != nil {
+		t.Fatalf("decode list: %v", err)
+	}
+	if len(list) != 1 {
+		t.Fatalf("expected 1 capability, got %d", len(list))
+	}
+
+	getW := httptest.NewRecorder()
+	h.getCapability(getW, httptest.NewRequest(http.MethodGet, "/api/v1/capabilities/"+c.ID, nil), c.ID)
+	if getW.Code != http.StatusOK {
+		t.Fatalf("get: expected 200, got %d: %s", getW.Code, getW.Body.String())
+	}
+	var single map[string]any
+	if err := json.Unmarshal(getW.Body.Bytes(), &single); err != nil {
+		t.Fatalf("decode get: %v", err)
+	}
+
+	for k := range single {
+		if _, ok := list[0][k]; !ok {
+			t.Errorf("field %q present on GET by ID but missing from the list response", k)
+		}
+	}
+	for k := range list[0] {
+		if _, ok := single[k]; !ok {
+			t.Errorf("field %q present in the list response but missing from GET by ID", k)
+		}
+	}
+}
+
+// TestListCapabilities_ExposesGuardsAndBothIDAliases pins the two wire
+// decisions at the HTTP boundary: `enabled`/`requires_confirmation` are no
+// longer omitted (the review finding), and `id`/`capability_id` are both
+// emitted for the duration of Maven's migration.
+func TestListCapabilities_ExposesGuardsAndBothIDAliases(t *testing.T) {
+	h, store := newTestHandler(t)
+	c := seedCapability(t, store, "ent_alpha")
+
+	w := httptest.NewRecorder()
+	h.listCapabilities(w, httptest.NewRequest(http.MethodGet, "/api/v1/capabilities", nil))
+
+	var list []map[string]any
+	if err := json.Unmarshal(w.Body.Bytes(), &list); err != nil {
+		t.Fatalf("decode: %v", err)
+	}
+	got := list[0]
+
+	if got["id"] != c.ID || got["capability_id"] != c.ID {
+		t.Errorf("id aliases: id=%v capability_id=%v want %q", got["id"], got["capability_id"], c.ID)
+	}
+	if enabled, ok := got["enabled"].(bool); !ok || !enabled {
+		t.Errorf("enabled: got %#v, want true", got["enabled"])
+	}
+	if rc, ok := got["requires_confirmation"].(bool); !ok || !rc {
+		t.Errorf("requires_confirmation: got %#v, want true (risk=medium)", got["requires_confirmation"])
+	}
+}
+
+// TestListCapabilities_EmptyIsArrayNotNull — clients iterate unconditionally.
+func TestListCapabilities_EmptyIsArrayNotNull(t *testing.T) {
+	h, _ := newTestHandler(t)
+
+	w := httptest.NewRecorder()
+	h.listCapabilities(w, httptest.NewRequest(http.MethodGet, "/api/v1/capabilities", nil))
+
+	if body := w.Body.String(); body != "[]\n" {
+		t.Errorf("expected [], got %q", body)
+	}
+}

internal/api/executions_test.go

@@ -0,0 +1,253 @@
+package api
+
+import (
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"strconv"
+	"testing"
+	"time"
+
+	"github.com/kami/hexis/internal/domain"
+	"github.com/kami/hexis/internal/storage"
+)
+
+// seedExecution inserts a finished execution against targetEntityID.
+func seedExecution(t *testing.T, store *storage.Store, capID, targetEntityID string) *domain.Execution {
+	t.Helper()
+	now := time.Now().UTC()
+	e := &domain.Execution{
+		ID:             domain.NewExecutionID(),
+		CapabilityID:   capID,
+		TargetEntityID: targetEntityID,
+		Status:         domain.ExecutionSucceeded,
+		Arguments:      map[string]any{},
+		CreatedAt:      now,
+		UpdatedAt:      now,
+	}
+	if err := store.CreateExecution(e); err != nil {
+		t.Fatalf("create execution: %v", err)
+	}
+	return e
+}
+
+func getExecutions(t *testing.T, h *Handler, query string) []*domain.Execution {
+	t.Helper()
+	req := httptest.NewRequest(http.MethodGet, "/api/v1/executions"+query, nil)
+	w := httptest.NewRecorder()
+	h.handleExecutions(w, req)
+	if w.Code != http.StatusOK {
+		t.Fatalf("GET /api/v1/executions%s: expected 200, got %d: %s", query, w.Code, w.Body.String())
+	}
+	var out []*domain.Execution
+	if err := json.Unmarshal(w.Body.Bytes(), &out); err != nil {
+		t.Fatalf("decode response: %v", err)
+	}
+	return out
+}
+
+// TestListExecutions_FiltersByEntity pins the entity_id filter from
+// ECOSYSTEM-SPEC.md §4.5 — the Command Center renders per-entity history and
+// must not be shown another entity's executions.
+func TestListExecutions_FiltersByEntity(t *testing.T) {
+	h, store := newTestHandler(t)
+
+	seedExecution(t, store, "cap_a", "ent_alpha")
+	seedExecution(t, store, "cap_b", "ent_beta")
+	wantAlpha := seedExecution(t, store, "cap_c", "ent_alpha")
+
+	all := getExecutions(t, h, "")
+	if len(all) != 3 {
+		t.Fatalf("unfiltered: expected 3 executions, got %d", len(all))
+	}
+
+	alpha := getExecutions(t, h, "?entity_id=ent_alpha")
+	if len(alpha) != 2 {
+		t.Fatalf("entity_id=ent_alpha: expected 2 executions, got %d", len(alpha))
+	}
+	for _, e := range alpha {
+		if e.TargetEntityID != "ent_alpha" {
+			t.Errorf("entity_id filter leaked execution for %s", e.TargetEntityID)
+		}
+	}
+	if alpha[1].ID != wantAlpha.ID {
+		t.Errorf("expected ascending order ending at %s, got %s", wantAlpha.ID, alpha[1].ID)
+	}
+
+	if none := getExecutions(t, h, "?entity_id=ent_nonexistent"); len(none) != 0 {
+		t.Errorf("unknown entity: expected 0 executions, got %d", len(none))
+	}
+}
+
+// TestListExecutions_SinceIsAnExclusiveCursor pins the pagination convention:
+// `since` is the same exclusive integer cursor the /api/v1/changes feed uses,
+// so a client learns one paging idiom. A cursor that returned rows it had
+// already seen would make the Executions surface duplicate history.
+func TestListExecutions_SinceIsAnExclusiveCursor(t *testing.T) {
+	h, store := newTestHandler(t)
+
+	for i := 0; i < 4; i++ {
+		seedExecution(t, store, "cap_a", "ent_alpha")
+	}
+
+	all := getExecutions(t, h, "")
+	if len(all) != 4 {
+		t.Fatalf("expected 4 executions, got %d", len(all))
+	}
+	for i, e := range all {
+		if e.Seq == 0 {
+			t.Fatalf("execution %d has no seq cursor", i)
+		}
+		if i > 0 && e.Seq <= all[i-1].Seq {
+			t.Fatalf("seq not strictly increasing: %d then %d", all[i-1].Seq, e.Seq)
+		}
+	}
+
+	cursor := all[1].Seq
+	page := getExecutions(t, h, "?since="+strconv.FormatInt(cursor, 10))
+	if len(page) != 2 {
+		t.Fatalf("since=%d: expected 2 executions, got %d", cursor, len(page))
+	}
+	for _, e := range page {
+		if e.Seq <= cursor {
+			t.Errorf("execution seq %d should have been excluded by since=%d", e.Seq, cursor)
+		}
+	}
+
+	// Draining the cursor yields an empty array, not null — the Command
+	// Center iterates the response unconditionally.
+	last := all[len(all)-1].Seq
+	if drained := getExecutions(t, h, "?since="+strconv.FormatInt(last, 10)); len(drained) != 0 {
+		t.Errorf("since=%d (latest): expected 0 executions, got %d", last, len(drained))
+	}
+}
+
+// TestListExecutions_CombinesEntityAndSince checks the two filters compose,
+// which is the actual Command Center polling call.
+func TestListExecutions_CombinesEntityAndSince(t *testing.T) {
+	h, store := newTestHandler(t)
+
+	seedExecution(t, store, "cap_a", "ent_alpha")
+	seedExecution(t, store, "cap_b", "ent_beta")
+	third := seedExecution(t, store, "cap_c", "ent_alpha")
+
+	all := getExecutions(t, h, "")
+	cursor := all[0].Seq
+
+	got := getExecutions(t, h, "?entity_id=ent_alpha&since="+strconv.FormatInt(cursor, 10))
+	if len(got) != 1 {
+		t.Fatalf("expected 1 execution, got %d", len(got))
+	}
+	if got[0].ID != third.ID {
+		t.Errorf("expected %s, got %s", third.ID, got[0].ID)
+	}
+}
+
+func TestListExecutions_LimitBoundsThePage(t *testing.T) {
+	h, store := newTestHandler(t)
+
+	for i := 0; i < 5; i++ {
+		seedExecution(t, store, "cap_a", "ent_alpha")
+	}
+
+	got := getExecutions(t, h, "?limit=2")
+	if len(got) != 2 {
+		t.Fatalf("limit=2: expected 2 executions, got %d", len(got))
+	}
+}
+
+func TestListExecutions_RejectsBadCursor(t *testing.T) {
+	h, _ := newTestHandler(t)
+
+	for _, q := range []string{"?since=abc", "?since=-1", "?limit=0", "?limit=nope"} {
+		req := httptest.NewRequest(http.MethodGet, "/api/v1/executions"+q, nil)
+		w := httptest.NewRecorder()
+		h.handleExecutions(w, req)
+		if w.Code != http.StatusBadRequest {
+			t.Errorf("%s: expected 400, got %d: %s", q, w.Code, w.Body.String())
+		}
+	}
+}
+
+func TestListExecutions_RejectsNonGET(t *testing.T) {
+	h, _ := newTestHandler(t)
+
+	req := httptest.NewRequest(http.MethodPost, "/api/v1/executions", nil)
+	w := httptest.NewRecorder()
+	h.handleExecutions(w, req)
+	if w.Code != http.StatusMethodNotAllowed {
+		t.Errorf("expected 405, got %d", w.Code)
+	}
+}
+
+// TestListExecutions_RequiresBearerToken pins that the new endpoint sits
+// behind the same auth as the rest of /api/v1/ rather than being routed
+// around it. Execution history names every entity and capability on the box;
+// it is not public.
+func TestListExecutions_RequiresBearerToken(t *testing.T) {
+	h, store := newTestHandler(t)
+	seedExecution(t, store, "cap_a", "ent_alpha")
+
+	mux := http.NewServeMux()
+	h.Register(mux)
+
+	// No token at all.
+	w := httptest.NewRecorder()
+	mux.ServeHTTP(w, httptest.NewRequest(http.MethodGet, "/api/v1/executions?entity_id=ent_alpha", nil))
+	if w.Code != http.StatusUnauthorized {
+		t.Fatalf("unauthenticated: expected 401, got %d: %s", w.Code, w.Body.String())
+	}
+
+	// Wrong token.
+	req := httptest.NewRequest(http.MethodGet, "/api/v1/executions", nil)
+	req.Header.Set("Authorization", "Bearer wrong-token")
+	w = httptest.NewRecorder()
+	mux.ServeHTTP(w, req)
+	if w.Code != http.StatusUnauthorized {
+		t.Fatalf("wrong token: expected 401, got %d", w.Code)
+	}
+
+	// Correct token.
+	req = httptest.NewRequest(http.MethodGet, "/api/v1/executions", nil)
+	req.Header.Set("Authorization", "Bearer "+testToken)
+	w = httptest.NewRecorder()
+	mux.ServeHTTP(w, req)
+	if w.Code != http.StatusOK {
+		t.Fatalf("authenticated: expected 200, got %d: %s", w.Code, w.Body.String())
+	}
+
+	var out []*domain.Execution
+	if err := json.Unmarshal(w.Body.Bytes(), &out); err != nil {
+		t.Fatalf("decode: %v", err)
+	}
+	if len(out) != 1 {
+		t.Fatalf("expected 1 execution, got %d", len(out))
+	}
+}
+
+// TestListExecutions_RoutedSeparatelyFromGetByID guards the ServeMux split:
+// "/api/v1/executions" (list) and "/api/v1/executions/" (by ID) are distinct
+// patterns, and adding the former must not have shadowed the latter.
+func TestListExecutions_RoutedSeparatelyFromGetByID(t *testing.T) {
+	h, store := newTestHandler(t)
+	exec := seedExecution(t, store, "cap_a", "ent_alpha")
+
+	mux := http.NewServeMux()
+	h.Register(mux)
+
+	req := httptest.NewRequest(http.MethodGet, "/api/v1/executions/"+exec.ID, nil)
+	req.Header.Set("Authorization", "Bearer "+testToken)
+	w := httptest.NewRecorder()
+	mux.ServeHTTP(w, req)
+	if w.Code != http.StatusOK {
+		t.Fatalf("get by id: expected 200, got %d: %s", w.Code, w.Body.String())
+	}
+
+	var single domain.Execution
+	if err := json.Unmarshal(w.Body.Bytes(), &single); err != nil {
+		t.Fatalf("decode: %v", err)
+	}
+	if single.ID != exec.ID {
+		t.Errorf("expected %s, got %s", exec.ID, single.ID)
+	}
+}

internal/api/handler.go

@@ -206,7 +206,7 @@ func (h *Handler) createCapability(w http.ResponseWriter, r *http.Request) {
 		Payload:   map[string]any{"capability_id": cap.ID, "name": cap.Name},
 	})
 
-	writeJSON(w, http.StatusCreated, cap)
+	writeJSON(w, http.StatusCreated, wire.Capability(cap))
 }
 
 func (h *Handler) handleCapabilityByID(w http.ResponseWriter, r *http.Request) {
@@ -232,7 +232,7 @@ func (h *Handler) getCapability(w http.ResponseWriter, r *http.Request, id strin
 		writeJSON(w, http.StatusNotFound, errorResponse(err.Error()))
 		return
 	}
-	writeJSON(w, http.StatusOK, cap)
+	writeJSON(w, http.StatusOK, wire.Capability(cap))
 }
 
 func (h *Handler) deleteCapability(w http.ResponseWriter, r *http.Request, id string) {
@@ -327,19 +327,61 @@ func (h *Handler) handleConfirmations(w http.ResponseWriter, r *http.Request) {
 
 	conf, err := h.engine.CreateConfirmation(req.CapabilityID, req.TargetEntityID, req.Requester, req.Arguments)
 	if err != nil {
-		status := http.StatusBadRequest
+		writeJSON(w, executeErrorStatus(err), errorResponse(err.Error()))
-		if errors.Is(err, domain.ErrCapabilityNotFound) {
-			status = http.StatusNotFound
-		} else if errors.Is(err, domain.ErrCapabilityNotBound) {
-			status = http.StatusForbidden
-		}
-		writeJSON(w, status, errorResponse(err.Error()))
 		return
 	}
 
 	writeJSON(w, http.StatusCreated, conf)
 }
 
+// handleExecutions serves GET /api/v1/executions?entity_id=&since=&limit=
+// (ECOSYSTEM-SPEC.md §4.5) — the execution history the Command Center's
+// Overview and Executions surfaces render.
+//
+// `since` follows the same cursor convention as /api/v1/changes: an integer
+// sequence, exclusive, with results ordered ascending. Callers page by passing
+// the `seq` of the last execution they saw. This deliberately reuses the
+// changes-feed style rather than introducing a timestamp cursor, so a client
+// only has to learn one paging idiom against Hexis.
+func (h *Handler) handleExecutions(w http.ResponseWriter, r *http.Request) {
+	if r.Method != http.MethodGet {
+		writeJSON(w, http.StatusMethodNotAllowed, errorResponse("method not allowed"))
+		return
+	}
+
+	q := r.URL.Query()
+
+	var since int64
+	if s := q.Get("since"); s != "" {
+		parsed, err := strconv.ParseInt(s, 10, 64)
+		if err != nil || parsed < 0 {
+			writeJSON(w, http.StatusBadRequest, errorResponse("since must be a non-negative integer sequence"))
+			return
+		}
+		since = parsed
+	}
+
+	limit := storage.MaxExecutionPageSize
+	if l := q.Get("limit"); l != "" {
+		parsed, err := strconv.Atoi(l)
+		if err != nil || parsed <= 0 {
+			writeJSON(w, http.StatusBadRequest, errorResponse("limit must be a positive integer"))
+			return
+		}
+		limit = parsed
+	}
+
+	execs, err := h.store.ListExecutions(q.Get("entity_id"), since, limit)
+	if err != nil {
+		writeJSON(w, http.StatusInternalServerError, errorResponse(err.Error()))
+		return
+	}
+	if execs == nil {
+		execs = []*domain.Execution{}
+	}
+	writeJSON(w, http.StatusOK, execs)
+}
+
 func (h *Handler) handleExecutionByID(w http.ResponseWriter, r *http.Request) {
 	if r.Method != http.MethodGet {
 		writeJSON(w, http.StatusMethodNotAllowed, errorResponse("method not allowed"))

internal/mcp/adapter.go

@@ -14,6 +14,7 @@ import (
 	"github.com/kami/hexis/internal/execution"
 	"github.com/kami/hexis/internal/nexusclient"
 	"github.com/kami/hexis/internal/storage"
+	"github.com/kami/hexis/internal/wire"
 )
 
 type Adapter struct {
@@ -145,22 +146,12 @@ func (a *Adapter) handleListCapabilities(ctx context.Context, req mcp.CallToolRe
 		return mcp.NewToolResultError(fmt.Sprintf("list capabilities: %v", err)), nil
 	}
 
-	var result []map[string]any
+	// Same serializer as the HTTP API, so an MCP client and an HTTP client see
-	for _, c := range caps {
+	// an identical capability — including `enabled` and
-		result = append(result, map[string]any{
+	// `requires_confirmation`, which this tool previously hid. Tool
-			"id":               c.ID,
+	// availability is not permission (spec §4.5), but a client that can see
-			"name":             c.Name,
+	// the guard fields can at least explain a 403 instead of guessing.
-			"description":      c.Description,
+	data, _ := json.MarshalIndent(wire.Capabilities(caps), "", "  ")
-			"target_types":     c.TargetTypes,
-			"target_entity_id": c.TargetEntityID,
-			"provider":         c.Provider,
-			"operation":        c.Operation,
-			"risk":             c.Risk,
-			"read_only":        c.ReadOnly,
-		})
-	}
-
-	data, _ := json.MarshalIndent(result, "", "  ")
 	return &mcp.CallToolResult{
 		Content: []mcp.Content{
 			mcp.TextContent{Type: "text", Text: string(data)},
@@ -179,7 +170,7 @@ func (a *Adapter) handleInspectCapability(ctx context.Context, req mcp.CallToolR
 		return mcp.NewToolResultError(fmt.Sprintf("capability not found: %v", err)), nil
 	}
 
-	data, _ := json.MarshalIndent(cap, "", "  ")
+	data, _ := json.MarshalIndent(wire.Capability(cap), "", "  ")
 	return &mcp.CallToolResult{
 		Content: []mcp.Content{
 			mcp.TextContent{Type: "text", Text: string(data)},
@@ -317,7 +308,7 @@ func (a *Adapter) handleCapabilitiesResource(ctx context.Context, req mcp.ReadRe
 	if err != nil {
 		return nil, err
 	}
-	data, _ := json.MarshalIndent(caps, "", "  ")
+	data, _ := json.MarshalIndent(wire.Capabilities(caps), "", "  ")
 	return []mcp.ResourceContents{
 		mcp.TextResourceContents{
 			URI:      "hexis://capabilities",
@@ -339,7 +330,7 @@ func (a *Adapter) handleCapabilityResourceTemplate(ctx context.Context, req mcp.
 		return nil, fmt.Errorf("capability %s: %w", id, err)
 	}
 
-	data, _ := json.MarshalIndent(cap, "", "  ")
+	data, _ := json.MarshalIndent(wire.Capability(cap), "", "  ")
 	return []mcp.ResourceContents{
 		mcp.TextResourceContents{
 			URI:      uri,

internal/storage/interface.go

@@ -15,6 +15,7 @@ type Interface interface {
 	UpdateExecution(e *domain.Execution) error
 	GetExecutionByIdempotencyKey(key string) (*domain.Execution, error)
 	GetInFlightExecution(capabilityID, targetEntityID string) (*domain.Execution, error)
+	ListExecutions(entityID string, sinceSeq int64, limit int) ([]*domain.Execution, error)
 
 	CreateConfirmation(c *domain.Confirmation) error
 	GetConfirmation(id string) (*domain.Confirmation, error)

internal/storage/sqlite.go

@@ -467,14 +467,107 @@ func (s *Store) getExecutionLocked(id string) (*domain.Execution, error) {
 	json.Unmarshal([]byte(result), &e.Result)
 	json.Unmarshal([]byte(evidence), &e.ResolutionEvidence)
 	e.IdempotencyKey = idempKey
+	e.ConfirmationID = confID
 	e.Status = domain.ExecutionStatus(status)
 	e.Error = errStr
 	e.CorrelationID = corrID
+	e.CausationID = causID
 	e.CreatedAt = parseTime(createdAt)
 	e.UpdatedAt = parseTime(updatedAt)
 	return e, nil
 }
 
+// executionColumns is the shared SELECT list for execution reads. `rowid` is
+// the insertion sequence and doubles as the pagination cursor for
+// ListExecutions; single-row reads ignore it.
+//
+// Using rowid as the cursor is safe here because executions is an ordinary
+// rowid table (its PRIMARY KEY is TEXT, so rowid is a separate hidden counter)
+// and nothing in this service deletes execution rows or runs VACUUM — both of
+// which could renumber rowids and invalidate outstanding cursors. If either
+// ever becomes true, promote this to an explicit monotonic seq column.
+const executionColumns = `rowid, id, capability_id, capability_version, target_entity_id, entity_version, arguments, requested_by, origin, COALESCE(idempotency_key,''), COALESCE(confirmation_id,''), status, result, COALESCE(error,''), resolution_evidence, COALESCE(correlation_id,''), COALESCE(causation_id,''), created_at, updated_at`
+
+// scanExecution reads one row selected with executionColumns.
+func scanExecution(sc interface{ Scan(...any) error }) (*domain.Execution, error) {
+	e := &domain.Execution{}
+	var args, reqBy, origin, idempKey, confID, status, result, errStr, evidence, corrID, causID, createdAt, updatedAt string
+	err := sc.Scan(&e.Seq, &e.ID, &e.CapabilityID, &e.CapabilityVersion, &e.TargetEntityID, &e.EntityVersion, &args, &reqBy, &origin, &idempKey, &confID, &status, &result, &errStr, &evidence, &corrID, &causID, &createdAt, &updatedAt)
+	if err != nil {
+		return nil, err
+	}
+	json.Unmarshal([]byte(args), &e.Arguments)
+	json.Unmarshal([]byte(reqBy), &e.RequestedBy)
+	json.Unmarshal([]byte(origin), &e.Origin)
+	json.Unmarshal([]byte(result), &e.Result)
+	json.Unmarshal([]byte(evidence), &e.ResolutionEvidence)
+	e.IdempotencyKey = idempKey
+	e.ConfirmationID = confID
+	e.Status = domain.ExecutionStatus(status)
+	e.Error = errStr
+	e.CorrelationID = corrID
+	e.CausationID = causID
+	e.CreatedAt = parseTime(createdAt)
+	e.UpdatedAt = parseTime(updatedAt)
+	if e.Arguments == nil {
+		e.Arguments = map[string]any{}
+	}
+	if e.RequestedBy == nil {
+		e.RequestedBy = map[string]string{}
+	}
+	if e.Origin == nil {
+		e.Origin = map[string]string{}
+	}
+	if e.Result == nil {
+		e.Result = map[string]any{}
+	}
+	return e, nil
+}
+
+// MaxExecutionPageSize bounds a single ListExecutions page, matching the
+// 100-row cap the changes feed uses.
+const MaxExecutionPageSize = 100
+
+// ListExecutions returns executions ordered by ascending insertion sequence.
+//
+// entityID, when non-empty, restricts to that target entity. sinceSeq is an
+// exclusive cursor: only rows with Seq > sinceSeq are returned, the same
+// convention as EventsAfter on /api/v1/changes. limit is clamped to
+// MaxExecutionPageSize.
+func (s *Store) ListExecutions(entityID string, sinceSeq int64, limit int) ([]*domain.Execution, error) {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+
+	if limit <= 0 || limit > MaxExecutionPageSize {
+		limit = MaxExecutionPageSize
+	}
+
+	query := `SELECT ` + executionColumns + ` FROM executions WHERE rowid > ?`
+	args := []any{sinceSeq}
+	if entityID != "" {
+		query += ` AND target_entity_id = ?`
+		args = append(args, entityID)
+	}
+	query += ` ORDER BY rowid ASC LIMIT ?`
+	args = append(args, limit)
+
+	rows, err := s.db.Query(query, args...)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	out := []*domain.Execution{}
+	for rows.Next() {
+		e, err := scanExecution(rows)
+		if err != nil {
+			return nil, err
+		}
+		out = append(out, e)
+	}
+	return out, rows.Err()
+}
+
 // Confirmation operations
 
 func (s *Store) CreateConfirmation(c *domain.Confirmation) error {

internal/wire/capability.go

@@ -0,0 +1,54 @@
+// Package wire converts internal domain objects into the public wire shapes
+// defined in pkg/client. It is the single serialization point: the HTTP
+// handler and the MCP adapter both go through it, so a capability looks the
+// same on every surface Hexis exposes.
+package wire
+
+import (
+	"github.com/kami/hexis/internal/domain"
+	"github.com/kami/hexis/pkg/client"
+)
+
+// Capability converts a domain capability into the public wire shape.
+//
+// Both `capability_id` and `id` are populated with the same value; see the
+// compatibility note on client.Capability for why the alias is retained.
+func Capability(c *domain.Capability) client.Capability {
+	if c == nil {
+		return client.Capability{}
+	}
+	targetTypes := c.TargetTypes
+	if targetTypes == nil {
+		targetTypes = []string{}
+	}
+	return client.Capability{
+		CapabilityID:         c.ID,
+		ID:                   c.ID,
+		Name:                 c.Name,
+		Description:          c.Description,
+		TargetTypes:          targetTypes,
+		TargetEntityID:       c.TargetEntityID,
+		Provider:             c.Provider,
+		Operation:            c.Operation,
+		Risk:                 c.Risk,
+		ReadOnly:             c.ReadOnly,
+		ExpectedSideEffects:  c.ExpectedSideEffects,
+		RequiresConfirmation: c.RequiresConfirmation,
+		Enabled:              c.Enabled,
+		TimeoutSeconds:       c.TimeoutSeconds,
+		Attributes:           c.Attributes,
+		CreatedAt:            c.CreatedAt,
+		UpdatedAt:            c.UpdatedAt,
+		Version:              c.Version,
+	}
+}
+
+// Capabilities converts a slice, never returning nil so the JSON encoding is
+// `[]` rather than `null`.
+func Capabilities(caps []*domain.Capability) []client.Capability {
+	out := make([]client.Capability, 0, len(caps))
+	for _, c := range caps {
+		out = append(out, Capability(c))
+	}
+	return out
+}

internal/wire/capability_test.go

@@ -0,0 +1,207 @@
+package wire
+
+import (
+	"encoding/json"
+	"testing"
+	"time"
+
+	"github.com/kami/hexis/internal/domain"
+	"github.com/kami/hexis/pkg/client"
+)
+
+func sampleCapability() *domain.Capability {
+	now := time.Date(2026, 7, 30, 12, 0, 0, 0, time.UTC)
+	return &domain.Capability{
+		ID:                   "cap_docker_restart",
+		Name:                 "docker.restart_container",
+		Description:          "Restart a container",
+		TargetTypes:          []string{"container"},
+		TargetEntityID:       "",
+		Provider:             "workspace_mcp",
+		Operation:            "docker.restart_container",
+		Risk:                 domain.RiskMedium,
+		ReadOnly:             false,
+		ExpectedSideEffects:  "container restarts",
+		RequiresConfirmation: true,
+		Enabled:              true,
+		TimeoutSeconds:       30,
+		Attributes:           map[string]any{"allowlist": "docker"},
+		CreatedAt:            now,
+		UpdatedAt:            now,
+		Version:              1,
+	}
+}
+
+func marshalCapability(t *testing.T, c *domain.Capability) map[string]any {
+	t.Helper()
+	data, err := json.Marshal(Capability(c))
+	if err != nil {
+		t.Fatalf("marshal: %v", err)
+	}
+	var out map[string]any
+	if err := json.Unmarshal(data, &out); err != nil {
+		t.Fatalf("unmarshal: %v", err)
+	}
+	return out
+}
+
+// TestCapability_EmitsBothIDAliases pins the deliberate redundancy documented
+// on client.Capability. Maven's consumer reads `id`; the spec and the rest of
+// the API say `capability_id`. Hexis is already breaking that consumer with
+// bearer auth, so dropping either alias here would be a second, silent break.
+// If this test is ever changed, it must be as an announced removal, not a
+// tidy-up.
+func TestCapability_EmitsBothIDAliases(t *testing.T) {
+	out := marshalCapability(t, sampleCapability())
+
+	id, hasID := out["id"]
+	capID, hasCapID := out["capability_id"]
+	if !hasID {
+		t.Error("`id` missing — Maven's vendored client decodes this field")
+	}
+	if !hasCapID {
+		t.Error("`capability_id` missing — this is the ECOSYSTEM-SPEC.md §4.1 name")
+	}
+	if id != capID {
+		t.Errorf("aliases disagree: id=%v capability_id=%v", id, capID)
+	}
+	if id != "cap_docker_restart" {
+		t.Errorf("unexpected id %v", id)
+	}
+}
+
+// TestCapability_CarriesServerDerivedGuards pins the review finding that
+// listCapabilities omitted `enabled` and `requires_confirmation`, leaving a
+// client unable to distinguish a callable capability from one that would be
+// refused with 403. Both are always present, even when false.
+func TestCapability_CarriesServerDerivedGuards(t *testing.T) {
+	out := marshalCapability(t, sampleCapability())
+
+	if got, ok := out["enabled"].(bool); !ok || !got {
+		t.Errorf("enabled: expected true, got %#v", out["enabled"])
+	}
+	if got, ok := out["requires_confirmation"].(bool); !ok || !got {
+		t.Errorf("requires_confirmation: expected true, got %#v", out["requires_confirmation"])
+	}
+
+	// Both must be emitted even at their zero value — `omitempty` here would
+	// read to a client as "unknown", not "false".
+	c := sampleCapability()
+	c.Enabled = false
+	c.RequiresConfirmation = false
+	out = marshalCapability(t, c)
+	if _, ok := out["enabled"]; !ok {
+		t.Error("`enabled` omitted when false; it must always be present")
+	}
+	if _, ok := out["requires_confirmation"]; !ok {
+		t.Error("`requires_confirmation` omitted when false; it must always be present")
+	}
+}
+
+// TestCapability_IsASupersetOfEveryPreviousShape guards against a silent field
+// removal for consumers of any of the four shapes this serializer replaced:
+// the HTTP list response, the HTTP get response (raw domain.Capability), the
+// MCP adapter's map, and pkg/client.
+func TestCapability_IsASupersetOfEveryPreviousShape(t *testing.T) {
+	out := marshalCapability(t, sampleCapability())
+
+	required := []string{
+		// union of the old listCapabilities map and the MCP adapter map
+		"id", "capability_id", "name", "description", "target_types",
+		"provider", "operation", "risk", "read_only", "expected_side_effects",
+		// previously only on the raw domain.Capability returned by GET by ID
+		"requires_confirmation", "enabled", "timeout_seconds", "attributes",
+		"created_at", "updated_at", "version",
+	}
+	for _, k := range required {
+		if _, ok := out[k]; !ok {
+			t.Errorf("field %q dropped by the unified serializer", k)
+		}
+	}
+}
+
+// TestCapability_TargetTypesNeverNull — clients range over this array; `null`
+// is a decode hazard for the non-Go consumers the Command Center will add.
+func TestCapability_TargetTypesNeverNull(t *testing.T) {
+	c := sampleCapability()
+	c.TargetTypes = nil
+	out := marshalCapability(t, c)
+
+	tt, ok := out["target_types"].([]any)
+	if !ok {
+		t.Fatalf("target_types is %#v, want []", out["target_types"])
+	}
+	if len(tt) != 0 {
+		t.Errorf("expected empty array, got %v", tt)
+	}
+}
+
+// TestCapabilities_EmptySliceIsNotNull — the HTTP list endpoint must render
+// `[]`, not `null`, when an entity has no capabilities.
+func TestCapabilities_EmptySliceIsNotNull(t *testing.T) {
+	data, err := json.Marshal(Capabilities(nil))
+	if err != nil {
+		t.Fatalf("marshal: %v", err)
+	}
+	if string(data) != "[]" {
+		t.Errorf("expected [], got %s", string(data))
+	}
+}
+
+// TestCapability_RoundTripsThroughPublicClient closes the loop: what the
+// server serializes is exactly what pkg/client — and therefore Maven —
+// decodes. A drift between producer and consumer shape is the whole class of
+// bug this unification exists to remove.
+func TestCapability_RoundTripsThroughPublicClient(t *testing.T) {
+	src := sampleCapability()
+	data, err := json.Marshal(Capability(src))
+	if err != nil {
+		t.Fatalf("marshal: %v", err)
+	}
+
+	var got client.Capability
+	if err := json.Unmarshal(data, &got); err != nil {
+		t.Fatalf("decode into client.Capability: %v", err)
+	}
+
+	if got.ID != src.ID || got.CapabilityID != src.ID {
+		t.Errorf("id round-trip: ID=%q CapabilityID=%q want %q", got.ID, got.CapabilityID, src.ID)
+	}
+	if got.EffectiveID() != src.ID {
+		t.Errorf("EffectiveID() = %q, want %q", got.EffectiveID(), src.ID)
+	}
+	if got.Name != src.Name || got.ReadOnly != src.ReadOnly || got.Risk != src.Risk {
+		t.Errorf("field drift: %+v", got)
+	}
+	if !got.Enabled || !got.RequiresConfirmation {
+		t.Errorf("guard fields lost in round trip: %+v", got)
+	}
+	if got.Version != src.Version || !got.CreatedAt.Equal(src.CreatedAt) {
+		t.Errorf("metadata lost in round trip: %+v", got)
+	}
+}
+
+// TestCapability_EffectiveIDToleratesEitherAlias covers a peer (an older Hexis
+// or a hand-rolled client) that sends only one of the two names.
+func TestCapability_EffectiveIDToleratesEitherAlias(t *testing.T) {
+	cases := map[string]string{
+		`{"id":"cap_x"}`:                         "cap_x",
+		`{"capability_id":"cap_y"}`:              "cap_y",
+		`{"id":"cap_z","capability_id":"cap_z"}`: "cap_z",
+	}
+	for body, want := range cases {
+		var c client.Capability
+		if err := json.Unmarshal([]byte(body), &c); err != nil {
+			t.Fatalf("decode %s: %v", body, err)
+		}
+		if got := c.EffectiveID(); got != want {
+			t.Errorf("%s: EffectiveID() = %q, want %q", body, got, want)
+		}
+	}
+}
+
+func TestCapability_NilIsZeroValue(t *testing.T) {
+	if got := Capability(nil); got.EffectiveID() != "" {
+		t.Errorf("nil capability produced %+v", got)
+	}
+}

pkg/client/capability.go

@@ -0,0 +1,62 @@
+package client
+
+import "time"
+
+// Capability is THE wire shape for a Hexis capability.
+//
+// There is exactly one definition of it, here, and every producer in this
+// repository serializes through it: the HTTP handler (GET/POST
+// /api/v1/capabilities, GET /api/v1/capabilities/{id}), the MCP adapter
+// (hexis.list_capabilities), and this client's decode path. It lives in
+// pkg/client rather than internal/ so that external consumers get the shape
+// without vendoring internal packages; internal/wire holds the
+// domain.Capability -> Capability conversion.
+//
+// Compatibility note — `id` and `capability_id` are BOTH emitted, deliberately.
+// They always carry the same value. Maven's vendored consumer decodes `id`
+// (cmd/mavend/voice.go matches on Capability.ID); the ECOSYSTEM-SPEC.md §4.1
+// schema and the rest of the Hexis API name the column `capability_id`. Hexis
+// is mid-rollout of bearer auth on /api/v1/, which is already one breaking
+// change for that consumer; dropping either alias here would stack a second,
+// silent one on top. Both stay until every consumer is confirmed to read
+// `capability_id`, at which point `id` can be removed in a deliberate,
+// announced change. Do not "clean this up" incidentally.
+type Capability struct {
+	// CapabilityID is the canonical field (ECOSYSTEM-SPEC.md §4.1).
+	CapabilityID string `json:"capability_id"`
+	// ID is a deprecated alias for CapabilityID, kept for wire compatibility.
+	// Always identical to CapabilityID. Prefer CapabilityID in new code.
+	ID string `json:"id"`
+
+	Name                string   `json:"name"`
+	Description         string   `json:"description,omitempty"`
+	TargetTypes         []string `json:"target_types"`
+	TargetEntityID      string   `json:"target_entity_id,omitempty"`
+	Provider            string   `json:"provider"`
+	Operation           string   `json:"operation"`
+	Risk                string   `json:"risk,omitempty"`
+	ReadOnly            bool     `json:"read_only"`
+	ExpectedSideEffects string   `json:"expected_side_effects,omitempty"`
+
+	// RequiresConfirmation and Enabled are server-derived from the risk tier
+	// and are never settable by a caller. listCapabilities used to omit both,
+	// which left clients unable to tell a callable capability from one that
+	// would be rejected with 403; the unified shape always carries them.
+	RequiresConfirmation bool `json:"requires_confirmation"`
+	Enabled              bool `json:"enabled"`
+	TimeoutSeconds       int  `json:"timeout_seconds,omitempty"`
+
+	Attributes map[string]any `json:"attributes,omitempty"`
+	CreatedAt  time.Time      `json:"created_at,omitempty"`
+	UpdatedAt  time.Time      `json:"updated_at,omitempty"`
+	Version    int64          `json:"version,omitempty"`
+}
+
+// EffectiveID returns the capability ID, tolerating a peer that sends only one
+// of the two aliases.
+func (c Capability) EffectiveID() string {
+	if c.CapabilityID != "" {
+		return c.CapabilityID
+	}
+	return c.ID
+}

pkg/client/client.go

@@ -7,6 +7,8 @@ import (
 	"fmt"
 	"io"
 	"net/http"
+	"net/url"
+	"strconv"
 	"time"
 )
 
@@ -42,6 +44,7 @@ func causationIDFrom(ctx context.Context) string {
 type Client struct {
 	baseURL    string
 	httpClient *http.Client
+	token      string
 }
 
 func New(baseURL string) *Client {
@@ -51,6 +54,12 @@ func New(baseURL string) *Client {
 	}
 }
 
+// WithToken sets the shared bearer token sent on every /api/v1/ request.
+func (c *Client) WithToken(token string) *Client {
+	c.token = token
+	return c
+}
+
 func (c *Client) do(ctx context.Context, method, path string, body, result any) error {
 	var reqBody io.Reader
 	if body != nil {
@@ -67,6 +76,9 @@ func (c *Client) do(ctx context.Context, method, path string, body, result any)
 	}
 	req.Header.Set("Content-Type", "application/json")
 	req.Header.Set("X-Hexis-Version", APIVersion)
+	if c.token != "" {
+		req.Header.Set("Authorization", "Bearer "+c.token)
+	}
 	if id := correlationIDFrom(ctx); id != "" {
 		req.Header.Set("X-Correlation-ID", id)
 	}
@@ -97,8 +109,37 @@ func (c *Client) do(ctx context.Context, method, path string, body, result any)
 	return nil
 }
 
-type Capability struct {
+// Capability is defined in capability.go — the single wire shape shared by
-	ID                  string   `json:"id"`
+// the HTTP handler, the MCP adapter and this client.
+
+type Execution struct {
+	// Seq is the pagination cursor for Executions; see the `since` parameter.
+	// Zero on single-execution reads.
+	Seq            int64             `json:"seq,omitempty"`
+	ID             string            `json:"id"`
+	CapabilityID   string            `json:"capability_id"`
+	TargetEntityID string            `json:"target_entity_id"`
+	Status         string            `json:"status"`
+	Result         map[string]any    `json:"result,omitempty"`
+	Error          string            `json:"error,omitempty"`
+	RequestedBy    map[string]string `json:"requested_by,omitempty"`
+	CorrelationID  string            `json:"correlation_id,omitempty"`
+	CausationID    string            `json:"causation_id,omitempty"`
+	IdempotencyKey string            `json:"idempotency_key,omitempty"`
+}
+
+type ExecuteRequest struct {
+	CapabilityID   string            `json:"capability_id"`
+	TargetEntityID string            `json:"target_entity_id"`
+	Arguments      map[string]any    `json:"arguments,omitempty"`
+	RequestedBy    map[string]string `json:"requested_by,omitempty"`
+	Origin         map[string]string `json:"origin,omitempty"`
+	IdempotencyKey string            `json:"idempotency_key,omitempty"`
+	CorrelationID  string            `json:"correlation_id,omitempty"`
+	CausationID    string            `json:"causation_id,omitempty"`
+}
+
+type CreateCapabilityRequest struct {
 	Name                string   `json:"name"`
 	Description         string   `json:"description,omitempty"`
 	TargetTypes         []string `json:"target_types"`
@@ -110,47 +151,11 @@ type Capability struct {
 	ExpectedSideEffects string   `json:"expected_side_effects,omitempty"`
 }
 
-type Execution struct {
-	ID              string            `json:"id"`
-	CapabilityID    string            `json:"capability_id"`
-	TargetEntityID  string            `json:"target_entity_id"`
-	Status          string            `json:"status"`
-	Result          map[string]any    `json:"result,omitempty"`
-	Error           string            `json:"error,omitempty"`
-	RequestedBy     map[string]string `json:"requested_by,omitempty"`
-	CorrelationID   string            `json:"correlation_id,omitempty"`
-	CausationID     string            `json:"causation_id,omitempty"`
-	IdempotencyKey  string            `json:"idempotency_key,omitempty"`
-}
-
-type ExecuteRequest struct {
-	CapabilityID    string            `json:"capability_id"`
-	TargetEntityID  string            `json:"target_entity_id"`
-	Arguments       map[string]any    `json:"arguments,omitempty"`
-	RequestedBy     map[string]string `json:"requested_by,omitempty"`
-	Origin          map[string]string `json:"origin,omitempty"`
-	IdempotencyKey  string            `json:"idempotency_key,omitempty"`
-	CorrelationID   string            `json:"correlation_id,omitempty"`
-	CausationID     string            `json:"causation_id,omitempty"`
-}
-
-type CreateCapabilityRequest struct {
-	Name                string         `json:"name"`
-	Description         string         `json:"description,omitempty"`
-	TargetTypes         []string       `json:"target_types"`
-	TargetEntityID      string         `json:"target_entity_id,omitempty"`
-	Provider            string         `json:"provider"`
-	Operation           string         `json:"operation"`
-	Risk                string         `json:"risk,omitempty"`
-	ReadOnly            bool           `json:"read_only"`
-	ExpectedSideEffects string         `json:"expected_side_effects,omitempty"`
-}
-
 func (c *Client) Capabilities(ctx context.Context, entityID string) ([]Capability, error) {
 	var result []Capability
 	path := "/api/v1/capabilities"
 	if entityID != "" {
-		path += "?entity_id=" + entityID
+		path += "?entity_id=" + url.QueryEscape(entityID)
 	}
 	if err := c.do(ctx, http.MethodGet, path, nil, &result); err != nil {
 		return nil, err
@@ -190,6 +195,33 @@ func (c *Client) GetExecution(ctx context.Context, id string) (*Execution, error
 	return &result, nil
 }
 
+// Executions returns execution history, newest last, ordered by ascending
+// `seq` (ECOSYSTEM-SPEC.md §4.5).
+//
+// entityID, when non-empty, filters to executions against that target entity.
+// since is an exclusive cursor: pass 0 for the first page, then the Seq of the
+// last element returned. The server caps a page at 100 rows, so a full page
+// means "call again with the new cursor".
+func (c *Client) Executions(ctx context.Context, entityID string, since int64) ([]Execution, error) {
+	q := url.Values{}
+	if entityID != "" {
+		q.Set("entity_id", entityID)
+	}
+	if since > 0 {
+		q.Set("since", strconv.FormatInt(since, 10))
+	}
+	path := "/api/v1/executions"
+	if len(q) > 0 {
+		path += "?" + q.Encode()
+	}
+
+	var result []Execution
+	if err := c.do(ctx, http.MethodGet, path, nil, &result); err != nil {
+		return nil, err
+	}
+	return result, nil
+}
+
 func (c *Client) Health(ctx context.Context) error {
 	return c.do(ctx, http.MethodGet, "/health", nil, nil)
 }