From d16bf7a38c7c4dc5eaff64cb4dd3f2ca7b93ab6b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=86gir=20M=C3=A1ni=20Hauksson?=
 <54936225+sourcehawk@users.noreply.github.com>
Date: Wed, 26 Aug 2026 01:08:02 +0200
Subject: [PATCH 1/2] feat(server): let the operator select a playbook at
 session start
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

The new-investigation form gains an optional Playbook picker fed by GET /api/playbooks (locked launcher metas and disabled entries filtered out). When set, the id flows preflight → Investigation → metadata.json → sessions.Options → prompts.Env, and the opening prompt points the agent at that playbook instead of the profile's guided investigation flow, skipping the closing playbook as well. Preflight rejects unknown or disabled ids with 400. The session header shows the selected playbook, and it survives launcher restarts via persisted metadata.

Signal-watch spawns are unchanged and keep the default flow.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Sh4mHX8JUzvrdpWg56iZth
---
 docs/content/investigations.md                |  1 +
 .../app/(main)/investigations/new/page.tsx    |  1 +
 .../investigations/InvestigationForm.test.tsx | 38 ++++++++++
 .../investigations/InvestigationForm.tsx      | 38 +++++++++-
 .../investigations/SessionView.header.tsx     |  8 +++
 frontend/lib/api.ts                           |  7 ++
 frontend/lib/playbook-select.test.ts          | 31 ++++++++
 frontend/lib/playbook-select.ts               | 20 ++++++
 internal/server/handlers.go                   | 26 +++++++
 internal/server/handlers_start_test.go        | 71 +++++++++++++++++++
 internal/server/manager.go                    |  8 +++
 internal/server/manager_test.go               | 17 +++++
 internal/server/persist.go                    |  3 +
 internal/sessions/session.go                  | 38 ++++++----
 internal/sessions/session_test.go             |  7 ++
 prompts/prompts.go                            | 22 ++++--
 prompts/prompts_test.go                       | 21 ++++++
 17 files changed, 338 insertions(+), 19 deletions(-)
 create mode 100644 frontend/lib/playbook-select.test.ts
 create mode 100644 frontend/lib/playbook-select.ts

diff --git a/docs/content/investigations.md b/docs/content/investigations.md
index 3861fb54..992fac50 100644
--- a/docs/content/investigations.md
+++ b/docs/content/investigations.md
@@ -74,6 +74,7 @@ the token falls out of the address bar. The launcher stays alive in the terminal
 3. **Spawn the agent.** Claude is launched with that `mcp.json` plus a system prompt that points the agent at the
    `investigation` playbook. The agent is told nothing product-specific in prose; the playbooks carry the procedural
    knowledge.
+   The form's optional **Playbook** picker overrides this: when the operator selects a playbook (a release-verification runbook, say), the system prompt points the agent at that playbook instead, and the guided flow, including the closing `capture_offer` step, is skipped. The session header shows which playbook was selected.
 4. **Walk the playbook.** The agent calls `list_playbooks`, picks a matching domain playbook, and walks it: read step
    description, make suggested calls, call `step_complete` with findings and the matching goto. The activity panel
    renders every tool call live.
diff --git a/frontend/app/(main)/investigations/new/page.tsx b/frontend/app/(main)/investigations/new/page.tsx
index 97b8a91d..e3e7f355 100644
--- a/frontend/app/(main)/investigations/new/page.tsx
+++ b/frontend/app/(main)/investigations/new/page.tsx
@@ -58,6 +58,7 @@ function InvestigationsHomeInner() {
         inputs: sub.inputs,
         prom: sub.prom,
         auto: sub.auto || undefined,
+        playbook: sub.playbook,
       });
       router.push(`/investigations/?id=${encodeURIComponent(inv.id)}`);
     } catch (e) {
diff --git a/frontend/components/investigations/InvestigationForm.test.tsx b/frontend/components/investigations/InvestigationForm.test.tsx
index dc727423..aacbc549 100644
--- a/frontend/components/investigations/InvestigationForm.test.tsx
+++ b/frontend/components/investigations/InvestigationForm.test.tsx
@@ -144,4 +144,42 @@ describe("InvestigationForm", () => {
       expect.objectContaining({ auto: false }),
     );
   });
+
+  describe("playbook selection", () => {
+    const synced = { status: "synced", reason: "" } as const;
+    function setup() {
+      vi.spyOn(api, "getProfileInputs").mockResolvedValue([
+        { id: "notes", label: "Notes", type: "textarea", optional: true, placeholder: "enter notes" },
+      ]);
+      vi.spyOn(api, "getConnections").mockResolvedValue({ slack: false, incidentio: false, slack_channel_prefix: "" });
+      vi.spyOn(api, "listPlaybooks").mockResolvedValue([
+        { id: "investigation", source: "system", locked: true, nodeCount: 1, yaml: "", syncState: synced, type: "general" },
+        { id: "release_verification", symptom: "Verify a release", source: "user", nodeCount: 1, yaml: "", syncState: synced, type: "general" },
+      ]);
+    }
+
+    it("submits without a playbook by default", async () => {
+      setup();
+      const onSubmit = vi.fn();
+      render(<InvestigationForm onSubmit={onSubmit} />);
+      await screen.findByPlaceholderText("enter notes");
+      await screen.findByRole("option", { name: /release_verification/ });
+
+      fireEvent.click(screen.getByRole("button", { name: /run preflight/i }));
+      expect(onSubmit).toHaveBeenCalledWith(expect.objectContaining({ playbook: undefined }));
+    });
+
+    it("submits the chosen playbook id and hides locked entries", async () => {
+      setup();
+      const onSubmit = vi.fn();
+      render(<InvestigationForm onSubmit={onSubmit} />);
+      await screen.findByPlaceholderText("enter notes");
+      await screen.findByRole("option", { name: /release_verification/ });
+      expect(screen.queryByRole("option", { name: /^investigation/ })).toBeNull();
+
+      fireEvent.change(screen.getByLabelText(/Playbook/i), { target: { value: "release_verification" } });
+      fireEvent.click(screen.getByRole("button", { name: /run preflight/i }));
+      expect(onSubmit).toHaveBeenCalledWith(expect.objectContaining({ playbook: "release_verification" }));
+    });
+  });
 });
diff --git a/frontend/components/investigations/InvestigationForm.tsx b/frontend/components/investigations/InvestigationForm.tsx
index 46f23f8c..9f64b3a6 100644
--- a/frontend/components/investigations/InvestigationForm.tsx
+++ b/frontend/components/investigations/InvestigationForm.tsx
@@ -1,7 +1,8 @@
 "use client";
 
 import { useEffect, useState } from "react";
-import { api, type InputSchema, type PromOverride } from "@/lib/api";
+import { api, type InputSchema, type PlaybookListItem, type PromOverride } from "@/lib/api";
+import { selectablePlaybooks } from "@/lib/playbook-select";
 import { ArrowRightIcon } from "@/components/shared/Icons";
 import { Spinner } from "@/components/shared/Spinner";
 import { TextInput } from "@/components/inputs/TextInput";
@@ -14,6 +15,9 @@ export type FormSubmission = {
   inputs: Record<string, Record<string, unknown>>;
   prom: PromOverride;
   auto: boolean;
+  // playbook: id of the playbook the operator picked, or undefined for
+  // the profile's guided investigation flow.
+  playbook?: string;
 };
 
 type Props = {
@@ -24,6 +28,8 @@ export function InvestigationForm({ onSubmit }: Props) {
   const [schema, setSchema] = useState<InputSchema[] | null>(null);
   const [values, setValues] = useState<Record<string, Record<string, unknown>>>({});
   const [auto, setAuto] = useState(false);
+  const [playbooks, setPlaybooks] = useState<PlaybookListItem[]>([]);
+  const [playbook, setPlaybook] = useState("");
 
   // Prom override panel state — unchanged from today.
   const [showPromOverrides, setShowPromOverrides] = useState(false);
@@ -34,6 +40,12 @@ export function InvestigationForm({ onSubmit }: Props) {
 
   useEffect(() => {
     api.getProfileInputs().then(setSchema).catch(() => setSchema([]));
+    // The picker degrades to "default flow only" when the catalog
+    // can't be fetched; the operator can still start a session.
+    api
+      .listPlaybooks()
+      .then((items) => setPlaybooks(selectablePlaybooks(items)))
+      .catch(() => setPlaybooks([]));
     // Pre-populate prom override fields with the profile's defaults so the
     // operator sees what's currently configured. Functional setters so a
     // late-arriving fetch can't overwrite values the operator typed while
@@ -64,7 +76,7 @@ export function InvestigationForm({ onSubmit }: Props) {
       const portNum = parseInt(promPort, 10);
       if (!Number.isNaN(portNum) && portNum > 0) prom.port = portNum;
     }
-    onSubmit({ inputs: values, prom, auto });
+    onSubmit({ inputs: values, prom, auto, playbook: playbook || undefined });
   }
 
   function setValue(id: string, next: Record<string, unknown>) {
@@ -125,6 +137,28 @@ export function InvestigationForm({ onSubmit }: Props) {
         }
       })}
 
+      {playbooks.length > 0 && (
+        <label className="block">
+          <span className="font-medium">Playbook</span>
+          <span className="block text-sm text-zinc-500">
+            Walk a specific playbook instead of the guided investigation flow.
+          </span>
+          <select
+            value={playbook}
+            onChange={(e) => setPlaybook(e.target.value)}
+            className={inputClass + " mt-2"}
+          >
+            <option value="">Guided investigation (default)</option>
+            {playbooks.map((p) => (
+              <option key={p.id} value={p.id}>
+                {p.id}
+                {p.symptom ? ` — ${p.symptom}` : ""}
+              </option>
+            ))}
+          </select>
+        </label>
+      )}
+
       <label className="flex items-start gap-2 cursor-pointer">
         <input
           type="checkbox"
diff --git a/frontend/components/investigations/SessionView.header.tsx b/frontend/components/investigations/SessionView.header.tsx
index 1e2ae8cb..86da8e88 100644
--- a/frontend/components/investigations/SessionView.header.tsx
+++ b/frontend/components/investigations/SessionView.header.tsx
@@ -165,6 +165,14 @@ function HeaderTitle({ investigation }: { investigation: Investigation }) {
           {investigation.namespace}
         </p>
       )}
+      {investigation.playbook && (
+        <p
+          className="truncate text-xs text-zinc-500"
+          title="Playbook selected at session start"
+        >
+          playbook: <span className="font-mono">{investigation.playbook}</span>
+        </p>
+      )}
     </>
   );
 }
diff --git a/frontend/lib/api.ts b/frontend/lib/api.ts
index 1cff63e2..8730cf19 100644
--- a/frontend/lib/api.ts
+++ b/frontend/lib/api.ts
@@ -327,6 +327,10 @@ export type PreflightRequest = {
   // Omitted on the wire when false thanks to `auto,omitempty` on the
   // server-side struct.
   auto?: boolean;
+  // playbook: optional playbook id to walk instead of the profile's
+  // guided investigation flow. Omitted when the operator keeps the
+  // default.
+  playbook?: string;
 };
 
 export type LinkedRepo = {
@@ -479,6 +483,9 @@ export type Investigation = {
   slackChannelUrl?: string;
   notes?: string;
   label?: string;
+  // playbook: the id the operator selected at session start; absent
+  // when the session runs the guided investigation flow.
+  playbook?: string;
   mcpConfigPath: string;
   docsPrefix?: string;
   sessionDir: string;
diff --git a/frontend/lib/playbook-select.test.ts b/frontend/lib/playbook-select.test.ts
new file mode 100644
index 00000000..d3aec77b
--- /dev/null
+++ b/frontend/lib/playbook-select.test.ts
@@ -0,0 +1,31 @@
+import { describe, it, expect } from "vitest";
+import { selectablePlaybooks } from "./playbook-select";
+import type { PlaybookListItem } from "./playbook";
+
+const synced = { status: "synced", reason: "" } as PlaybookListItem["syncState"];
+
+function item(over: Partial<PlaybookListItem> & { id: string }): PlaybookListItem {
+  return { source: "plugin", nodeCount: 1, yaml: "", syncState: synced, ...over };
+}
+
+describe("selectablePlaybooks", () => {
+  it("drops locked, disabled and broken entries", () => {
+    const out = selectablePlaybooks([
+      item({ id: "investigation", source: "system", locked: true }),
+      item({ id: "off", disabled: true }),
+      item({ id: "bad", source: "broken" }),
+      item({ id: "ok" }),
+    ]);
+    expect(out.map((p) => p.id)).toEqual(["ok"]);
+  });
+
+  it("orders by type (investigation first) then id", () => {
+    const out = selectablePlaybooks([
+      item({ id: "z-general", type: "general" }),
+      item({ id: "b-inv", type: "investigation" }),
+      item({ id: "a-general", type: "general" }),
+      item({ id: "untyped" }),
+    ]);
+    expect(out.map((p) => p.id)).toEqual(["b-inv", "untyped", "a-general", "z-general"]);
+  });
+});
diff --git a/frontend/lib/playbook-select.ts b/frontend/lib/playbook-select.ts
new file mode 100644
index 00000000..39519ff5
--- /dev/null
+++ b/frontend/lib/playbook-select.ts
@@ -0,0 +1,20 @@
+import { DEFAULT_PLAYBOOK_TYPE, type PlaybookListItem } from "./playbook";
+
+// selectablePlaybooks narrows the playbook catalog to entries an
+// operator can start a session against: locked entries are the
+// launcher's own metas (the guided entrypoint, closing offer, and
+// sub-flows the walker delegates to), and disabled / broken entries
+// can't be walked. Investigation-typed playbooks sort first, then
+// other types, each group by id.
+export function selectablePlaybooks(items: PlaybookListItem[]): PlaybookListItem[] {
+  const typeOf = (p: PlaybookListItem) => p.type || DEFAULT_PLAYBOOK_TYPE;
+  const rank = (p: PlaybookListItem) => (typeOf(p) === DEFAULT_PLAYBOOK_TYPE ? 0 : 1);
+  return items
+    .filter((p) => !p.locked && !p.disabled && p.source !== "broken")
+    .sort(
+      (a, b) =>
+        rank(a) - rank(b) ||
+        typeOf(a).localeCompare(typeOf(b)) ||
+        a.id.localeCompare(b.id),
+    );
+}
diff --git a/internal/server/handlers.go b/internal/server/handlers.go
index cb22e2de..b4f8d66b 100644
--- a/internal/server/handlers.go
+++ b/internal/server/handlers.go
@@ -343,6 +343,12 @@ func (a *apiHandlers) handlePreflight(w http.ResponseWriter, r *http.Request) {
 			return
 		}
 	}
+	if body.Playbook != "" {
+		if err := a.validateSelectedPlaybook(body.Playbook); err != nil {
+			writeError(w, http.StatusBadRequest, err.Error())
+			return
+		}
+	}
 
 	// Extract typed values from the generic inputs map.
 	// Canonical input IDs (same for any profile that
@@ -472,6 +478,7 @@ func (a *apiHandlers) handlePreflight(w http.ResponseWriter, r *http.Request) {
 		IncidentioMCPEnabled: ioMCPToken != "",
 		LinkedRepos:          linked,
 		Profile:              a.prof,
+		Playbook:             body.Playbook,
 		PromTarget:           promTarget,
 		PromDisabled:         promDisabled,
 		ActiveContext:        activeContext,
@@ -1030,6 +1037,25 @@ type preflightRequest struct {
 	// turn — EnableAuto runs in a goroutine. Operator-side failures are
 	// logged to stderr and the investigation continues in manual mode.
 	Auto bool `json:"auto,omitempty"`
+	// Playbook is an optional playbook id the session should walk
+	// instead of the profile's guided investigation flow. Must name a
+	// loadable, non-disabled playbook from GET /api/playbooks.
+	Playbook string `json:"playbook,omitempty"`
+}
+
+// validateSelectedPlaybook checks that id names a playbook the session
+// can actually walk: present in the catalog and not disabled.
+func (a *apiHandlers) validateSelectedPlaybook(id string) error {
+	for _, pb := range a.collectPlaybooks() {
+		if pb.ID != id {
+			continue
+		}
+		if pb.Disabled {
+			return fmt.Errorf("playbook %q is disabled", id)
+		}
+		return nil
+	}
+	return fmt.Errorf("playbook %q not found", id)
 }
 
 // promOverrideBody is the per-investigation Prometheus override received
diff --git a/internal/server/handlers_start_test.go b/internal/server/handlers_start_test.go
index 923b32a6..730be448 100644
--- a/internal/server/handlers_start_test.go
+++ b/internal/server/handlers_start_test.go
@@ -2,6 +2,7 @@ package server
 
 import (
 	"context"
+	"encoding/json"
 	"net/http"
 	"net/http/httptest"
 	"strings"
@@ -10,6 +11,8 @@ import (
 	"github.com/sourcehawk/triagent/internal/connections"
 	"github.com/sourcehawk/triagent/internal/preflight"
 	"github.com/sourcehawk/triagent/internal/profile"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 // newPreflightAPIWithInputsProfile returns an apiHandlers whose prof field is
@@ -124,3 +127,71 @@ func TestPreflight_InputsMap_EmptyIsOK(t *testing.T) {
 		t.Fatalf("status=%d, body=%s", rr.Code, rr.Body.String())
 	}
 }
+
+// seedPlaybooks populates the handler's meta cache with the given
+// playbooks so preflight's playbook validation has a catalog to check.
+func seedPlaybooks(a *apiHandlers, pbs map[string]MetaPlaybook) {
+	a.metaCache = &metaCache{}
+	a.metaCache.set(&Meta{Playbooks: pbs})
+}
+
+func postPreflight(t *testing.T, a *apiHandlers, body string) *httptest.ResponseRecorder {
+	t.Helper()
+	req := httptest.NewRequest(http.MethodPost, "/api/preflight", strings.NewReader(body))
+	rr := httptest.NewRecorder()
+	a.handlePreflight(rr, req)
+	return rr
+}
+
+func TestPreflight_SelectedPlaybookIsRecordedOnInvestigation(t *testing.T) {
+	t.Parallel()
+	a := newPreflightAPIWithInputsProfile(t)
+	seedPlaybooks(a, map[string]MetaPlaybook{
+		"release_verification": {Source: "plugin", Type: "general", YAML: "id: release_verification\nsymptom: x\nentrypoint: n\nnodes:\n  n: {description: d}\n"},
+	})
+
+	rr := postPreflight(t, a, `{"inputs": {}, "playbook": "release_verification"}`)
+	require.Equal(t, http.StatusOK, rr.Code, rr.Body.String())
+
+	var dto InvestigationDTO
+	require.NoError(t, json.Unmarshal(rr.Body.Bytes(), &dto))
+	assert.Equal(t, "release_verification", dto.Playbook)
+	inv := a.manager.Get(dto.ID)
+	require.NotNil(t, inv)
+	assert.Equal(t, "release_verification", inv.Playbook)
+}
+
+func TestPreflight_UnknownPlaybookRejected(t *testing.T) {
+	t.Parallel()
+	a := newPreflightAPIWithInputsProfile(t)
+	seedPlaybooks(a, map[string]MetaPlaybook{})
+
+	rr := postPreflight(t, a, `{"inputs": {}, "playbook": "nope"}`)
+	assert.Equal(t, http.StatusBadRequest, rr.Code)
+	assert.Contains(t, rr.Body.String(), "nope", "error must name the offending playbook")
+}
+
+func TestPreflight_DisabledPlaybookRejected(t *testing.T) {
+	t.Parallel()
+	a := newPreflightAPIWithInputsProfile(t)
+	seedPlaybooks(a, map[string]MetaPlaybook{
+		"off": {Source: "plugin", Type: "general", YAML: "id: off\nactive: false\nsymptom: x\nentrypoint: n\nnodes:\n  n: {description: d}\n"},
+	})
+
+	rr := postPreflight(t, a, `{"inputs": {}, "playbook": "off"}`)
+	assert.Equal(t, http.StatusBadRequest, rr.Code)
+	assert.Contains(t, rr.Body.String(), "off")
+}
+
+func TestPreflight_NoPlaybookLeavesInvestigationUnset(t *testing.T) {
+	t.Parallel()
+	a := newPreflightAPIWithInputsProfile(t)
+	// No meta cache seeded: the default path must not consult the catalog.
+
+	rr := postPreflight(t, a, `{"inputs": {}}`)
+	require.Equal(t, http.StatusOK, rr.Code, rr.Body.String())
+	var dto InvestigationDTO
+	require.NoError(t, json.Unmarshal(rr.Body.Bytes(), &dto))
+	assert.Empty(t, dto.Playbook)
+	assert.NotContains(t, rr.Body.String(), `"playbook"`, "unset playbook must be omitted from the wire DTO")
+}
diff --git a/internal/server/manager.go b/internal/server/manager.go
index 45ac851a..7c5697aa 100644
--- a/internal/server/manager.go
+++ b/internal/server/manager.go
@@ -81,6 +81,11 @@ type Investigation struct {
 	IncidentioMCPEnabled bool
 	LinkedRepos          []repos.LinkedRepo
 	Profile              *profile.Profile // investigation profile (prompt content + playbook IDs)
+	// Playbook is the playbook id the operator selected at preflight.
+	// When set, the session walks that playbook instead of the
+	// profile's guided investigation flow. Empty for the default flow
+	// and for signal-watch spawns.
+	Playbook string
 	// PromTarget is the per-investigation Prometheus port-forward target,
 	// resolved from the profile defaults overlaid with any per-investigation
 	// override supplied at preflight time. Nil means no prom target was
@@ -299,6 +304,7 @@ type InvestigationDTO struct {
 	SlackMCPEnabled      bool               `json:"slackMCPEnabled,omitempty"`
 	IncidentioMCPEnabled bool               `json:"incidentioMCPEnabled,omitempty"`
 	LinkedRepos          []repos.LinkedRepo `json:"linkedRepos,omitempty"`
+	Playbook             string             `json:"playbook,omitempty"`
 	// CloudMCPs are the cloud-context MCP servers wired into this session,
 	// derived from the profile's cloud sources. Empty when no cloud sources are
 	// configured, or when the session carries no profile (e.g. an import).
@@ -398,6 +404,7 @@ func (i *Investigation) Snapshot() InvestigationDTO {
 		SlackMCPEnabled:      i.SlackMCPEnabled,
 		IncidentioMCPEnabled: i.IncidentioMCPEnabled,
 		LinkedRepos:          i.LinkedRepos,
+		Playbook:             i.Playbook,
 		CloudMCPs:            cloudMCPsForProfile(i.Profile),
 		CreatedAt:            i.CreatedAt,
 		Started:              i.started,
@@ -542,6 +549,7 @@ func (i *Investigation) Start() error {
 		LaunchCwd:              i.LaunchCwd,
 		KubeconfigPath:         i.KubeconfigPath,
 		Profile:                i.Profile,
+		Playbook:               i.Playbook,
 	})
 	if err != nil {
 		i.mu.Unlock()
diff --git a/internal/server/manager_test.go b/internal/server/manager_test.go
index 38bd7b14..fb5a3f23 100644
--- a/internal/server/manager_test.go
+++ b/internal/server/manager_test.go
@@ -714,3 +714,20 @@ func TestPersistOriginatingSignalRoundtrips(t *testing.T) {
 		t.Fatalf("unexpected restore: %+v", got.OriginatingSignal)
 	}
 }
+
+func TestLoadInvestigation_RestoresSelectedPlaybook(t *testing.T) {
+	dir := t.TempDir()
+	st := newStore(dir)
+	t.Cleanup(st.close)
+	require.NoError(t, st.writeMetadata(InvestigationDTO{
+		ID:         "rid",
+		SessionDir: dir,
+		CreatedAt:  time.Now().UTC(),
+		Playbook:   "release_verification",
+	}))
+
+	loaded, err := loadInvestigation(dir)
+	require.NoError(t, err)
+	assert.Equal(t, "release_verification", loaded.Playbook)
+	assert.Equal(t, "release_verification", loaded.Snapshot().Playbook)
+}
diff --git a/internal/server/persist.go b/internal/server/persist.go
index a4a4bfeb..adfc4f5d 100644
--- a/internal/server/persist.go
+++ b/internal/server/persist.go
@@ -44,6 +44,7 @@ type persistedMetadata struct {
 	SlackChannelName string `json:"slackChannelName,omitempty"`
 	Notes            string `json:"notes,omitempty"`
 	Label            string `json:"label,omitempty"`
+	Playbook         string `json:"playbook,omitempty"`
 	MCPConfigPath   string `json:"mcpConfigPath"`
 	DocsPrefix      string `json:"docsPrefix,omitempty"`
 	SessionDir      string `json:"sessionDir"`
@@ -196,6 +197,7 @@ func (s *store) writeMetadata(dto InvestigationDTO) error {
 		SlackChannelName: dto.SlackChannelName,
 		Notes:            dto.Notes,
 		Label:            dto.Label,
+		Playbook:         dto.Playbook,
 		MCPConfigPath:   dto.MCPConfigPath,
 		DocsPrefix:      dto.DocsPrefix,
 		SessionDir:      dto.SessionDir,
@@ -335,6 +337,7 @@ func loadInvestigation(dir string) (*Investigation, error) {
 		SlackChannelName: meta.SlackChannelName,
 		Notes:            meta.Notes,
 		Label:            meta.Label,
+		Playbook:         meta.Playbook,
 		MCPConfigPath:   meta.MCPConfigPath,
 		DocsPrefix:      meta.DocsPrefix,
 		SessionDir:      meta.SessionDir,
diff --git a/internal/sessions/session.go b/internal/sessions/session.go
index 8d9e5925..e2b826e4 100644
--- a/internal/sessions/session.go
+++ b/internal/sessions/session.go
@@ -53,6 +53,30 @@ type Options struct {
 	ProjectID string
 	// Cluster is the kube-context / cluster name (when known).
 	Cluster string
+
+	// Playbook is the playbook id the operator selected at session
+	// start. When set, the session walks that playbook instead of the
+	// profile's guided investigation flow. Empty = profile defaults.
+	Playbook string
+}
+
+// promptEnv projects the options into the prompt environment Build
+// renders into the opening system prompt.
+func (o Options) promptEnv() prompts.Env {
+	clusterID := clusterIDFromNamespace(o.Namespace)
+	return prompts.Env{
+		UserNotes: o.UserNotes,
+		InputValues: map[string]map[string]any{
+			"cluster_id":    {"value": clusterID},
+			"incident_url":  {"value": o.IncidentURL},
+			"slack_channel": {"id": o.SlackChannelID, "name": o.SlackChannelName, "url": o.SlackChannelURL},
+			"notes":         {"value": o.UserNotes},
+		},
+		SlackMCPAvailable:      o.SlackMCPAvailable,
+		IncidentioMCPAvailable: o.IncidentioMCPAvailable,
+		LinkedRepos:            o.LinkedRepos,
+		Playbook:               o.Playbook,
+	}
 }
 
 // Session is a thin wrapper around claude.Session with prompt + allowed-tools
@@ -184,19 +208,7 @@ func clusterIDFromNamespace(ns string) string {
 // from Options. Events are delivered on the returned channel; the channel
 // closes when claude exits or ctx is cancelled.
 func (s *Session) Start(ctx context.Context) (<-chan claude.Event, error) {
-	clusterID := clusterIDFromNamespace(s.opts.Namespace)
-	prompt := prompts.Build(prompts.Env{
-		UserNotes:              s.opts.UserNotes,
-		InputValues: map[string]map[string]any{
-			"cluster_id":    {"value": clusterID},
-			"incident_url":  {"value": s.opts.IncidentURL},
-			"slack_channel": {"id": s.opts.SlackChannelID, "name": s.opts.SlackChannelName, "url": s.opts.SlackChannelURL},
-			"notes":         {"value": s.opts.UserNotes},
-		},
-		SlackMCPAvailable:      s.opts.SlackMCPAvailable,
-		IncidentioMCPAvailable: s.opts.IncidentioMCPAvailable,
-		LinkedRepos:            s.opts.LinkedRepos,
-	}, s.opts.Profile)
+	prompt := prompts.Build(s.opts.promptEnv(), s.opts.Profile)
 	return s.inner.Start(ctx, prompt)
 }
 
diff --git a/internal/sessions/session_test.go b/internal/sessions/session_test.go
index 7fab1f2b..0a996f00 100644
--- a/internal/sessions/session_test.go
+++ b/internal/sessions/session_test.go
@@ -139,3 +139,10 @@ func TestNew_ForwardsProfileInvestigationModel(t *testing.T) {
 	require.NoError(t, err)
 	assert.Equal(t, "claude-opus-4-7", sess.inner.Model())
 }
+
+func TestPromptEnv_ForwardsSelectedPlaybook(t *testing.T) {
+	t.Parallel()
+	env := Options{Namespace: "abc-zeebe", Playbook: "release_verification"}.promptEnv()
+	assert.Equal(t, "release_verification", env.Playbook)
+	assert.Equal(t, "abc", env.InputValues["cluster_id"]["value"])
+}
diff --git a/prompts/prompts.go b/prompts/prompts.go
index 25071ff7..d95e4461 100644
--- a/prompts/prompts.go
+++ b/prompts/prompts.go
@@ -37,6 +37,12 @@ type Env struct {
 	// known-noop outcomes so the ingestion agent can dismiss similar
 	// signals on the next poll.
 	OriginatingSignalSet bool
+	// Playbook, when non-empty, is the playbook id the operator picked
+	// at session start. It replaces the profile's entrypoint playbook
+	// and suppresses the closing playbook: the session walks only the
+	// selected playbook, without the guided investigation flow around
+	// it. Empty means the profile defaults apply.
+	Playbook string
 }
 
 // incidentioRefFromURL extracts the trailing path segment of an
@@ -103,9 +109,13 @@ func Build(env Env, prof *profile.Profile) string {
 	b.WriteString("kubernetes-context: ")
 	b.WriteString(orUnset(env.Context))
 	b.WriteString("\nsuggested-entrypoint-playbook: ")
-	b.WriteString(prof.Playbooks.Entrypoint)
-	b.WriteString("\nsuggested-closing-playbook: ")
-	b.WriteString(prof.Playbooks.Closing)
+	if env.Playbook != "" {
+		b.WriteString(env.Playbook)
+	} else {
+		b.WriteString(prof.Playbooks.Entrypoint)
+		b.WriteString("\nsuggested-closing-playbook: ")
+		b.WriteString(prof.Playbooks.Closing)
+	}
 	b.WriteString("\n")
 
 	// Dynamic section: walk profile inputs in declaration order.
@@ -146,7 +156,11 @@ func Build(env Env, prof *profile.Profile) string {
 		b.WriteString("Author the wiki entry with `status: wontfix` and include enough ")
 		b.WriteString("symptom keywords for `wiki_correlate` to find it.\n")
 	}
-	b.WriteString("- Investigation playbooks: mcp__triagent-strategies__*   (start with `walk_playbook` against the `suggested-entrypoint-playbook` from the parameter block; walk `suggested-closing-playbook` after every `summarize`)")
+	if env.Playbook != "" {
+		b.WriteString("- Investigation playbooks: mcp__triagent-strategies__*   (the operator selected this playbook for the session: start with `walk_playbook` against the `suggested-entrypoint-playbook` from the parameter block and follow it to completion; there is no closing playbook to walk afterwards)")
+	} else {
+		b.WriteString("- Investigation playbooks: mcp__triagent-strategies__*   (start with `walk_playbook` against the `suggested-entrypoint-playbook` from the parameter block; walk `suggested-closing-playbook` after every `summarize`)")
+	}
 	b.WriteString("\n- Cluster-inspection tools: mcp__triagent-k8s__*   (read-only: list_resource_kinds, list_resources, get_resource, get_logs, list_events, list_namespaces, trace_crossplane). Pass `namespace` per call; default to `cluster-resource-namespace` from the parameter block, or call `list_namespaces` if it is `<unset>`.")
 	if env.IncidentioMCPAvailable {
 		b.WriteString("\n- incident.io tools: mcp__triagent-incidentio__*   (incidentio_get_incident, incidentio_get_timeline, incidentio_get_postmortem, incidentio_search_related). Pass `incident_id` on every call.")
diff --git a/prompts/prompts_test.go b/prompts/prompts_test.go
index 992505f9..fee95ec1 100644
--- a/prompts/prompts_test.go
+++ b/prompts/prompts_test.go
@@ -365,3 +365,24 @@ func TestBuildIncludesAutoTriggerHintWhenSet(t *testing.T) {
 		t.Fatal("hinted prompt should nudge toward wiki capture decision")
 	}
 }
+
+func TestBuild_SelectedPlaybookReplacesEntrypointAndDropsClosing(t *testing.T) {
+	t.Parallel()
+	out := Build(Env{Context: "ctx-A", Playbook: "release_verification"}, testProf())
+
+	assert.Contains(t, out, "suggested-entrypoint-playbook: release_verification")
+	assert.NotContains(t, out, "suggested-entrypoint-playbook: investigation")
+	assert.NotContains(t, out, "suggested-closing-playbook")
+	assert.NotContains(t, out, "capture_offer")
+	assert.Contains(t, out, "operator selected this playbook",
+		"the tool bullet must tell the agent the playbook was chosen by the operator and no closing playbook follows")
+}
+
+func TestBuild_NoSelectedPlaybookKeepsProfileDefaults(t *testing.T) {
+	t.Parallel()
+	out := Build(Env{Context: "ctx-A"}, testProf())
+
+	assert.Contains(t, out, "suggested-entrypoint-playbook: investigation")
+	assert.Contains(t, out, "suggested-closing-playbook: capture_offer")
+	assert.NotContains(t, out, "operator selected this playbook")
+}

From 0c9a7699c2fef2a640192eb86e74ca514a51ff1b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=86gir=20M=C3=A1ni=20Hauksson?=
 <54936225+sourcehawk@users.noreply.github.com>
Date: Wed, 26 Aug 2026 01:21:46 +0200
Subject: [PATCH 2/2] fix(server): reject locked playbook ids at preflight
 (#83)

The UI already hides launcher metas from the picker, but the server accepted them, so a crafted request could start a session on capture_offer or select investigation with the closing playbook suppressed. Enforce the same contract server-side.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Sh4mHX8JUzvrdpWg56iZth
---
 internal/server/handlers.go            |  8 +++++++-
 internal/server/handlers_start_test.go | 12 ++++++++++++
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/internal/server/handlers.go b/internal/server/handlers.go
index b4f8d66b..6acffa63 100644
--- a/internal/server/handlers.go
+++ b/internal/server/handlers.go
@@ -1044,7 +1044,10 @@ type preflightRequest struct {
 }
 
 // validateSelectedPlaybook checks that id names a playbook the session
-// can actually walk: present in the catalog and not disabled.
+// can start on: present in the catalog, not disabled, and not one of
+// the launcher's locked metas (the guided entrypoint, the closing
+// offer, and the sub-flows the walker delegates to are internal, not
+// standalone session entrypoints).
 func (a *apiHandlers) validateSelectedPlaybook(id string) error {
 	for _, pb := range a.collectPlaybooks() {
 		if pb.ID != id {
@@ -1053,6 +1056,9 @@ func (a *apiHandlers) validateSelectedPlaybook(id string) error {
 		if pb.Disabled {
 			return fmt.Errorf("playbook %q is disabled", id)
 		}
+		if pb.Locked {
+			return fmt.Errorf("playbook %q is a launcher meta and cannot be selected", id)
+		}
 		return nil
 	}
 	return fmt.Errorf("playbook %q not found", id)
diff --git a/internal/server/handlers_start_test.go b/internal/server/handlers_start_test.go
index 730be448..a9caaa75 100644
--- a/internal/server/handlers_start_test.go
+++ b/internal/server/handlers_start_test.go
@@ -183,6 +183,18 @@ func TestPreflight_DisabledPlaybookRejected(t *testing.T) {
 	assert.Contains(t, rr.Body.String(), "off")
 }
 
+func TestPreflight_LockedPlaybookRejected(t *testing.T) {
+	t.Parallel()
+	a := newPreflightAPIWithInputsProfile(t)
+	seedPlaybooks(a, map[string]MetaPlaybook{
+		"investigation": {Source: "system", Locked: true, Type: "general", YAML: "id: investigation\nsymptom: x\nentrypoint: n\nnodes:\n  n: {description: d}\n"},
+	})
+
+	rr := postPreflight(t, a, `{"inputs": {}, "playbook": "investigation"}`)
+	assert.Equal(t, http.StatusBadRequest, rr.Code)
+	assert.Contains(t, rr.Body.String(), "investigation")
+}
+
 func TestPreflight_NoPlaybookLeavesInvestigationUnset(t *testing.T) {
 	t.Parallel()
 	a := newPreflightAPIWithInputsProfile(t)