feat(tools): the P2 toggle bridge — toolToggles first-class, definitive vocabulary

Reconciliation of the diverged tool-toggles seam (2026-09-19, master's
P2): Platform injected the resolved delta as an ad-hoc intersection on
AgentBuildOptions while the factories' enabled? param sat unread — the
seam was inert on both sides.

- teacher-agent: AgentBuildOptions gains toolToggles?: EnabledTools;
  both constructors thread it to the factories (createTeacherTools /
  createProberTools). An explicitly injected opts.tools registry is
  never filtered — the caller owns it.
- Vocabulary ADJUDICATED with the user (2026-09-19): TOGGLEABLE_TOOLS is
  the definitive list — the job tools only (research/demo/visual/pdf).
  quiz/ask_user_question stay always-on forever (the prober's flow is
  graded-quiz brackets -> probe_done; quiz-off collapses assessment and
  teaching doctrine is built on graded verification — the wedge danger);
  the learner-fs set, plan tools, and probe_done also always-on.
- settings-body (write side): unknown tool keys reject with 400 + the
  supported list, mirroring the prompt-switch validation; the read-side
  sanitizer stays lenient for forward-compat.
- chat-handler: the intersection is gone (field now first-class) and the
  seam comment states the adjudicated vocabulary.

Gates: typecheck, 28 new/updated tests green (tool-toggles-bridge,
question-tools, settings-body), chat-flow + settings suites green.

src/agent/teacher-agent.ts

@@ -15,7 +15,7 @@ import {
 } from "./tools.ts";
 import { toPiTools, type LhTool } from "./lh-tool.ts";
 import { quizInputObject, quizInputProblems } from "../core/question-core.ts";
-import { QUESTION_TOOLS } from "../core/pending.ts";
+import { QUESTION_TOOLS, type EnabledTools } from "../core/pending.ts";
 
 /**
  * The two teaching-side agents (docs/probe-teach-split.md): the PROBER and
@@ -88,8 +88,15 @@ export interface AgentBuildOptions {
 	onUsage?: StepUsageCollector;
 	/** Safety net (the old stepCountIs). Default 20 turns. */
 	maxTurns?: number;
-	/** Tests may pass a bare tool registry to drive deterministic flows. */
+	/** Tests may pass a bare tool registry to drive deterministic flows.
+	 *  An explicit registry is NEVER toggle-filtered — the caller owns it. */
 	tools?: Record<string, LhTool<any, any>>;
+	/** The resolved per-user tool toggles (core/pending EnabledTools — the
+	 *  2026-09-19 P2 bridge: Platform's chat-handler passes
+	 *  effective.agent.tools; the factories drop any tool explicitly false.
+	 *  THE DEFINITIVE toggleable set is TOGGLEABLE_TOOLS (job tools only);
+	 *  the filtering is generic, but writes validate against the list). */
+	toolToggles?: EnabledTools;
 }
 
 /**
@@ -159,7 +166,7 @@ function baseAgentOptions(kind: AgentKind, opts: AgentBuildOptions, tools: Agent
  * handler keys teacher construction on.
  */
 export function createProberAgent(ctx: ProbeDoneContext, opts: AgentBuildOptions = {}) {
-	return baseAgentOptions("prober", opts, toPiTools(createProberTools(ctx)));
+	return baseAgentOptions("prober", opts, toPiTools(createProberTools(ctx, opts.toolToggles)));
 }
 
 /**
@@ -175,7 +182,8 @@ export function createTeacherAgent(
 	ctx?: TeacherToolContext,
 	opts: AgentBuildOptions = {},
 ) {
-	const tools = opts.tools ?? (ctx ? createTeacherTools(ctx) : bareQuestionTools());
+	const tools =
+		opts.tools ?? (ctx ? createTeacherTools(ctx, opts.toolToggles) : bareQuestionTools());
 	return baseAgentOptions("teacher", opts, toPiTools(tools));
 }
 

src/core/pending.ts

@@ -32,15 +32,20 @@ export const JOB_TOOLS = ["research", "demo", "visual"] as const;
 
 // ─── Tool availability (2026-09 settings seam) ─────────────────────────────
 
-/** The tools a user may toggle off in settings (Wave 2 T2a, user-decided
- *  2026-09-15): for now only the SUB-AGENT dispatch tools — quiz,
- *  ask_user_question and the read tool are always on;
- *  the long-term vision is that everything becomes toggleable as new
- *  tool variants (e.g. alternative question tools) ship, so the factory
- *  seam below is GENERIC: it honors any tool name it receives. New
- *  toggleables join this list when settings exposes them.
- *  The names are the MODEL-FACING tool names (research, not researcher;
- *  pdf is the PDF-reader dispatch, sources v0 2026-09). */
+/** The tools a user may toggle off in settings — THE DEFINITIVE LIST
+ *  (adjudicated 2026-09-19, P2 reconciliation: the sub-agent JOB tools
+ *  only — research/demo/visual/pdf). Deliberately NOT toggleable, ever:
+ *  quiz + ask_user_question (the prober's flow is graded-quiz brackets →
+ *  probe_done; quiz-off would collapse the assessment and teaching
+ *  doctrine is built on graded verification — the wedge danger), the
+ *  learner-filesystem set (user-decided 2026-09, sources v1: always-on),
+ *  plan tools, and probe_done (it is how the phase ENDS — a prober that
+ *  can never conclude is a lockout).
+ *  The write side validates against this list (settings-body.ts: unknown
+ *  key = 400 with the supported list); the read-side sanitizer stays
+ *  lenient for forward-compat. The names are the MODEL-FACING tool names
+ *  (research, not researcher; pdf is the PDF-reader dispatch, sources v0
+ *  2026-09). */
 export const TOGGLEABLE_TOOLS = ["research", "demo", "visual", "pdf"] as const;
 
 /** The resolved settings → factory seam shape (Platform wires chat-handler

src/server/chat-handler.ts

@@ -210,13 +210,14 @@ export async function handleChatRequest(
 	// Tests inject a factory: the agent is stateless per turn (docs/
 	// pi-engine-swap.md §2), so each request builds a fresh one off the
 	// transcript — the factory mirrors that seam exactly.
-	// CROSS-STREAM SEAM (agreed 2026-09-19, settings wave): `toolToggles`
+	// CROSS-STREAM SEAM (P2 reconciliation, 2026-09-19): `toolToggles`
 	// rides the build opts as the user-level DELTA map (absent key =
-	// enabled — quiz, ask_user_question, research, demo, visual). The
-	// Teacher stream adds the field to AgentBuildOptions + the filtering in
-	// createTeacherTools / the prober's registry this same wave; until that
-	// merge, the extra property is structurally ignored (a harmless no-op).
-	const agentOpts: AgentBuildOptions & { toolToggles?: Record<string, boolean> } = {
+	// enabled). The definitive toggleable set is TOGGLEABLE_TOOLS — the
+	// sub-agent JOB tools (research/demo/visual/pdf; adjudicated with the
+	// user: quiz/ask/fs/plan/probe_done are always-on). First-class on
+	// AgentBuildOptions; the factories drop anything explicitly false and
+	// the settings write side rejects unknown keys.
+	const agentOpts: AgentBuildOptions = {
 		engine,
 		messages: recordToPiMessages(outgoing),
 		onUsage: collectUsage,

src/server/settings-body.ts

@@ -22,6 +22,7 @@ import type {
 	RoleModelOverride,
 } from "../core/settings.ts";
 import { BACKGROUND_MODEL_ROLES } from "../core/settings.ts";
+import { TOGGLEABLE_TOOLS } from "../core/pending.ts";
 
 /** Parsed-or-rejected — `ok: false` carries the 400's error message. */
 export type SettingsBodyResult<T> =
@@ -166,7 +167,20 @@ export function parseAgentSettingsBody(body: unknown): SettingsBodyResult<AgentS
 	}
 	const tools = parseBooleanMap(raw.tools, "tools");
 	if (tools.error) return { ok: false, error: tools.error };
-	if (tools.map) settings.tools = tools.map;
+	if (tools.map) {
+		// Unknown tool keys are rejected at WRITE time (user decision
+		// 2026-09-19): the delta is inert while unread, but once the bridge
+		// honors it a persisted `quiz: false` would genuinely drop the quiz —
+		// and the definitive list is the adjudicated job-tools-only set.
+		// The read-side sanitizer stays lenient for forward-compat.
+		const supported = TOGGLEABLE_TOOLS as readonly string[];
+		for (const key of Object.keys(tools.map)) {
+			if (!supported.includes(key)) {
+				return { ok: false, error: `unknown tool "${key}" (supported: ${supported.join(", ")})` };
+			}
+		}
+		settings.tools = tools.map;
+	}
 	const prompts = parseBooleanMap(raw.prompts, "prompts");
 	if (prompts.error) return { ok: false, error: prompts.error };
 	if (prompts.map) settings.prompts = prompts.map;

tests/question-tools.test.ts

@@ -155,10 +155,12 @@ describe("the prober's quiz: no nodeId field at all", () => {
 
 describe("tool toggles (core/pending.ts + factories)", () => {
 	it("TOGGLEABLE_TOOLS: the sub-agent dispatch tools; quiz/ask/read stay off the list", () => {
-		// The user-toggleable vocabulary Platform's settings validates against.
-		// quiz/ask_user_question/read are always-on FOR NOW (user-decided
-		// 2026-09-15, sources v0); they join when settings exposes them — the
-		// factory seam is generic.
+		// THE DEFINITIVE vocabulary (adjudicated with the user 2026-09-19, P2
+		// reconciliation): the job tools only. quiz/ask_user_question are
+		// permanently always-on (the prober's assessment + teaching doctrine
+		// are built on graded questions — the wedge danger), as are the
+		// learner-fs set, plan tools, and probe_done. The settings WRITE side
+		// validates against this list (settings-body).
 		assert.deepEqual(TOGGLEABLE_TOOLS, ["research", "demo", "visual", "pdf"]);
 	});
 

tests/tool-toggles-bridge.test.ts

@@ -0,0 +1,78 @@
+/**
+ * The P2 tool-toggle bridge (2026-09-19): AgentBuildOptions.toolToggles is
+ * first-class — the agent constructors thread it to the factories' enabled?
+ * param (an explicit opts.tools registry is never filtered), and the
+ * settings write side rejects unknown tool keys against TOGGLEABLE_TOOLS
+ * (the definitive adjudicated list — a persisted `quiz: false` would
+ * genuinely drop the quiz once the bridge honors the delta).
+ *
+ * Parser tests are PURE (no fs — parallel-test discipline); the agent
+ * construction tests use an in-memory chat fixture like
+ * question-tools.test.ts.
+ */
+import assert from "node:assert/strict";
+import { z } from "zod";
+import { describe, it } from "node:test";
+import { createProberAgent, createTeacherAgent } from "../src/agent/teacher-agent.ts";
+import type { ProbeDoneContext } from "../src/agent/tools.ts";
+import { parseAgentSettingsBody } from "../src/server/settings-body.ts";
+import { chatStore } from "../src/store/chats.ts";
+import type { AgentSettings } from "../src/core/settings.ts";
+
+describe("AgentBuildOptions.toolToggles (the P2 bridge)", () => {
+	const toolNames = (agent: { state: { tools: Array<{ name: string }> } }) =>
+		agent.state.tools.map((t) => t.name).sort();
+
+	it("flows into the teacher's registry: a job-tool delta is a no-op on the bare set", () => {
+		// No ctx → bare agent: quiz/ask only. A job-tool delta names tools
+		// that don't exist there — the bridge must not crash on it.
+		const bare = createTeacherAgent(undefined, { toolToggles: { research: false } });
+		assert.deepEqual(toolNames(bare), ["ask_user_question", "quiz"]);
+	});
+
+	it("flows into the prober's registry; probe_done survives everything", () => {
+		const chatId = chatStore.createChat("Toggle bridge test").id;
+		const ctx: ProbeDoneContext = { chatId, chatStore, deliver: () => {} };
+		const prober = createProberAgent(ctx, { toolToggles: { ask_user_question: false } });
+		const names = toolNames(prober);
+		assert.ok(!names.includes("ask_user_question"), "the delta dropped the tool");
+		assert.ok(names.includes("probe_done"), "probe_done always-on");
+	});
+
+	it("an explicitly injected opts.tools registry is NEVER toggle-filtered", () => {
+		const teacher = createTeacherAgent(undefined, {
+			tools: {
+				quiz: { name: "quiz", description: "test", clientQuestion: true, schema: z.object({}) },
+			},
+			toolToggles: { quiz: false },
+		});
+		assert.deepEqual(toolNames(teacher), ["quiz"]);
+	});
+});
+
+describe("parseAgentSettingsBody: tool keys validate at write time", () => {
+	const parse = (tools: Record<string, boolean>) =>
+		parseAgentSettingsBody({ tools }) as
+			| { ok: true; settings: AgentSettings }
+			| { ok: false; error: string };
+
+	it("a valid job-tool delta parses", () => {
+		const r = parse({ research: false, pdf: false });
+		assert.equal(r.ok, true);
+		assert.deepEqual(r.ok && r.settings.tools, { research: false, pdf: false });
+	});
+
+	it("unknown keys are rejected with the supported list (the quiz wedge never persists)", () => {
+		const r = parse({ quiz: false });
+		assert.equal(r.ok, false);
+		assert.match(!r.ok && r.error, /unknown tool "quiz" \(supported: research, demo, visual, pdf\)/);
+		const typo = parse({ reasearch: false });
+		assert.equal(typo.ok, false);
+		assert.match(!typo.ok && typo.error, /unknown tool "reasearch"/);
+	});
+
+	it("absent tools field is fine (absent = enabled everywhere)", () => {
+		const r = parseAgentSettingsBody({}) as { ok: boolean };
+		assert.equal(r.ok, true);
+	});
+});