// The warm `/objective-review-browser` door: the summonable streaming objective-draft review —
// from an objective-authoring session the human summons a plannotator PLAN-REVIEW browser on
// the RENDERED working objective draft (prose + roadmap table), a draft-reviewer wave streams
// phrase-anchored findings into that browser via `push_annotations`, and the browser decision
// routes through the shared objective seams: APPROVE → the decision ladder → the shared
// objective completion (`completeObjectiveReviewV1`: `objectiveApprovalSave`, the D1a gate exit
// riding the seam); DENY → a model-mediated `objective_draft` revision round. Plannotator
// always, no provider dispatch (the surface-named command IS the selection — the
// `/plan-review-browser` precedent); only the plannotator PRESENCE probe gates it.
//
// THE OBJECTIVE DIFFERENCE — Direct Edits NEVER auto-apply/auto-save (structural): the browser
// patches the RENDERED markdown, but the save seam re-reads the STRUCTURED `{prose, roadmap}`
// artifact — rendered-markdown edits (roadmap-table rows included) cannot be mechanically
// folded back, so an approval whose feedback opens a Direct Edits section saves NOTHING and
// returns one model-mediated revise round (fold the diff in via `objective_draft`, re-review
// to confirm). The plan arm's mechanical Direct-Edits apply writes `plan-draft.md` and must never
// run on this path.
//
// THE GUARDS (`draftReview.ts`, contracts.md §8.23): the door opens the activation's
// current-review slot at entry with the RAW artifact bytes as the reviewed bytes (the
// save-authoritative surface — it catches render-invisible changes like `base` or a node
// `slug`/`pr`/`comment`) and runs every completed browser decision through the decision ladder:
// a superseded review's decision is ignored loudly; an APPROVE over a moved draft, a moved save
// destination, or a latched unconfirmed save saves nothing and tells the model why; a DENY over
// a moved draft proceeds with a one-line note. Nothing is persisted — a browser decision does
// not survive a Pi restart (the human re-runs the door).
//
// ARTIFACT-FIRST, DRAFTS ONLY: the reviewed bytes are the RENDERED validated
// `objective-draft.json` artifact (one seam read + `decodeObjectiveDraft` + `renderObjectiveDraft`) — no param
// tier, no transcript tier, never raw JSON (the review-surface law; JSON is storage only).
// Stage-gated to the two registry stages whose STAGE_TOOLS carry `objective_draft`
// ({objective-author, objective-save}); anything else refuses loudly.
//
// THE BACKGROUND OPEN mirrors `planReviewBrowser.ts` byte-for-byte in shape: the plan server's
// URL is deterministic the moment the port is picked, so the handler starts
// `startPlannotatorPlanReview` (the `plan-review` bridge carries the rendered objective as
// `planContent` — arbitrary markdown bytes), primes BOTH companion surfaces
// (`mode: "plan"` annotations + the `draftType: "objective"` wave context), injects the
// guidance IMMEDIATELY, and ends its turn. Readiness is observed in a background task (ready →
// info; never-ready → a loud degrade clearing both surfaces); the human DECISION is awaited in
// a second background task and routes the outcome. The door registers no tools of its own —
// the companions (`start_draft_review_wave`/`collect_draft_review_wave`/`push_annotations`)
// are global.
//
// Accepted edges (the /pr-review-browser posture — noted, not engineered around):
//  - concurrent double-open: a second open re-primes both surfaces and takes the slot (a new
//    review supersedes everything); the FIRST bridge's later decision is ignored loudly by the
//    ladder, its `finally` leaves the second session's surfaces alone, and its readiness
//    observer is fenced too (a superseded review's observer neither announces nor degrades —
//    it can never clear the second session's surfaces or flip its door session).
//  - an early human decision mid-wave is authoritative — the save proceeds; the cleared
//    surface makes any late `push_annotations` refuse `no_surface`; a still-pending wave stays
//    collectable (the wave module's timeout is the orphan insurance).

import type { ExtensionAPI, ExtensionContext } from "@earendil-works/pi-coding-agent";
import {
  decodeObjectiveDraft,
  OBJECTIVE_DRAFT_ARTIFACT,
  renderObjectiveDraft,
} from "../../authoring/objective/draft.ts";
import {
  clearDraftReviewContext,
  type DraftReviewWaveState,
  primeDraftReviewContext,
} from "../../authoring/review/draftContext.ts";
import { openBranchWorkflowSession } from "../../session/branchWorkflowSession.ts";
import { bindingSuffix } from "../../substrate/bindingDelivery.ts";
import { registerPerkCommand } from "../../substrate/command.ts";
import { interceptConsoleError } from "../../substrate/consoleCapture.ts";
import { render } from "../../substrate/prompts.ts";
import type { ToolGating } from "../../substrate/toolGating.ts";
import { branchOf, rebuildWorkflowState } from "../../substrate/workflowState.ts";
import { type ReportTarget, report } from "../../surfaces/report.ts";
import type { ActivityHandle } from "../../surfaces/surfaces.ts";
import {
  checkDraftReviewDecision,
  type DraftReviewSlot,
  injectDraftReviewResult,
  type OpenDraftReview,
  SUPERSEDED_DECISION_WARNING,
  withDraftChangedNote,
} from "./draftReview.ts";
import {
  completeObjectiveReviewV1,
  objectiveEffectOf,
  objectiveGuardResult,
} from "./objectiveReview.ts";
import {
  type AnnotationState,
  clearAnnotationSurface,
  primeAnnotationSurface,
  resumeAnnotationDelivery,
} from "./providers/annotations.ts";
import {
  plannotatorPresent,
  type RespondSink,
  type StartBrowserDeps,
  type StartedSurface,
  startPlannotatorPlanReview,
} from "./providers/plannotatorHandoff.ts";
import { type ReviewOutcome, type ToolResult, untrustedReviewFeedback } from "./review.ts";

/** The door's report scope — also the `command:<id>` binding trigger id. */
const SCOPE = "objective-review-browser";

/**
 * The stage gate: the two registry stages whose STAGE_TOOLS carry `objective_draft` — every
 * session where the objective draft is the working draft. Other/absent stage → loud refusal.
 */
const DRAFT_STAGES: ReadonlySet<string> = new Set(["objective-author", "objective-save"]);

// ------------------------------------------------------------------------ guidance

/**
 * The seed guidance the door injects (the perk-objective-review-browser skill pointer rides
 * the skill-binding suffix — command:objective-review-browser — not hardcoded here). Pure +
 * exported for offline tests. One arm (no foreign/active split): `custom` renders the primed
 * custom-lane note when the human supplied a custom-angle definition.
 */
export function objectiveReviewBrowserGuidance(opts: { custom?: string }): string {
  return render("stages/objective-review-browser.md", { custom: opts.custom ?? "" });
}

// ------------------------------------------------------------------------ the background open

/**
 * The degrade notice injected when the browser never comes up — the model surfaces the wave's
 * findings in-session for the human, and the human falls back to `plan_review` (the in-session
 * review door) or `/objective-save` (the manual failsafe).
 */
const DEGRADE_NOTICE =
  "The plannotator plan-review browser is unavailable (the review server never became ready) — " +
  "degrade in-session: surface the draft-review wave's findings in your reply for the human. " +
  "Both door surfaces are cleared — `push_annotations` now refuses (`no_surface`) and the " +
  "draft-review context is gone. The human decides the next step: `plan_review` (the in-session " +
  "review door) or `/objective-save` (the manual failsafe).";

/**
 * One door open's shared token carrying its liveness AND its currency. Liveness: the degrade
 * arm flips `degraded` and the decision task refuses to route a later bridge decision through
 * the save path — without it, a readiness false-negative (endpoint/version drift while the
 * browser is actually open) could let a post-degrade approval auto-save and exit the gate AFTER
 * the human already followed the fallback path. Currency: `current` is the review's
 * `isCurrent` — the observer consults it before announcing readiness and before degrading, so a
 * review superseded by a newer open never disturbs the newer one's surfaces. A local twin of
 * the plan door's token on purpose — importing `PlanReviewDoorSession` here would mislead.
 */
export interface ObjectiveReviewDoorSession {
  degraded: boolean;
  readonly current: () => boolean;
}

/**
 * Observe the readiness poll in the background (the objective flavor of
 * `observePlanReviewReadiness`; the handler has already injected the guidance and ended):
 * `ready` → an info note plus one annotation-delivery continuation if the still-current
 * surface has held or in-flight work; `aborted` → no-op; `bridge_settled` → await the
 * bridge — a completed/aborted outcome returns silently (the decision task routes them) while
 * `unavailable` falls through to the degrade; `timeout` → degrade. Degrade = a loud error
 * report PLUS the degrade notice injected to the model (idle → immediate, streaming →
 * followUp), both door surfaces cleared (idempotent beside the decision task's clears), AND the
 * door session marked `degraded` so the still-live decision task ignores any later bridge
 * decision (loudly — never a silent late save). A superseded review's observer is inert — it
 * neither announces readiness nor degrades, so a still-starting review A can never clear the
 * surfaces or flip the session of the review B that replaced it (`session.current` is
 * consulted after every await; `session` is required so a forgotten token can never silently
 * unfence). Structural param slices keep it offline-testable; exported for the door tests.
 */
export async function observeObjectiveReviewReadiness(
  pi: RespondSink,
  ctx: ReportTarget & Pick<ExtensionContext, "isIdle">,
  started: StartedSurface<ReviewOutcome>,
  draftReview: DraftReviewWaveState,
  annotations: AnnotationState,
  session: ObjectiveReviewDoorSession,
): Promise<void> {
  const surface = annotations.surface;
  const state = await started.readiness;
  // A superseded review's observer is inert: no announce, no delivery resume, no degrade.
  if (!session.current()) return;
  if (state === "ready") {
    report(ctx, SCOPE, "info", `plannotator is up at ${started.url} — browser opening`);
    resumeAnnotationDelivery(annotations, surface, pi, ctx);
    return;
  }
  if (state === "aborted") return; // the turn was interrupted — no-op
  if (state === "bridge_settled") {
    const out = await started.bridgePromise;
    // The decision task routes a settled outcome; the bridge wait can outlast a superseding
    // open, so re-check currency before degrading.
    if (out.status !== "unavailable" || !session.current()) return;
  }
  report(
    ctx,
    SCOPE,
    "error",
    `the plannotator plan-review server did not become ready at ${started.url} — the browser ` +
      "review is unavailable",
    { alsoLog: true },
  );
  if (ctx.isIdle()) {
    pi.sendUserMessage(DEGRADE_NOTICE);
  } else {
    pi.sendUserMessage(DEGRADE_NOTICE, { deliverAs: "followUp" });
  }
  // Consistent with "surface findings in-session": a post-degrade push_annotations refuses
  // loudly (`no_surface`) and a post-degrade start_draft_review_wave refuses
  // `no_draft_context`. Idempotent beside the decision task's clears. The session flag makes
  // the degrade authoritative for the decision task too — a later bridge decision is ignored.
  clearAnnotationSurface(annotations);
  clearDraftReviewContext(draftReview);
  session.degraded = true;
}

/** The model-facing DENY revision result (the feedback delimited as untrusted DATA). */
function objectiveRevisionResult(out: Extract<ReviewOutcome, { status: "completed" }>): ToolResult {
  const feedback = out.feedback
    ? `\n\nReviewer feedback:\n${untrustedReviewFeedback(out.feedback)}`
    : "";
  return {
    content: [
      {
        type: "text",
        text:
          "The human DENIED the objective in the browser review — revise the working draft with " +
          "objective_draft per this feedback; the human re-runs /objective-review-browser (or you " +
          `call plan_review) for the next round.${feedback}`,
      },
    ],
    details: { ok: true, status: "denied", subject: "objective" },
  };
}

/**
 * Route the settled browser decision back into the session (the decision task's core; exported
 * for the door tests — pure over the injected pi/ctx/gating/slot slices):
 *
 * - `aborted` → no-op (the turn was interrupted);
 * - `unavailable` → a loud error report (the readiness observer's degrade arm owns the model
 *   notice — never inject it twice);
 * - `completed` → the decision ladder (`checkDraftReviewDecision`; the effect is `save` only for
 *   an APPROVE WITHOUT a Direct-Edits heading — rendered-markdown edits cannot be folded back
 *   into the structured `{prose, roadmap}` artifact mechanically, so that approval is a
 *   no-save revise round, `revision`): `superseded` → one TUI warning, nothing injected,
 *   nothing saved; `save-unconfirmed` / `stale-approval` / `destination-changed` → an error
 *   report AND the matching fixed model text injected (nothing saved, gate untouched);
 *   `proceed` → the shared objective completion (`completeObjectiveReviewV1`: an approval
 *   re-reads the STRUCTURED artifact → `saveObjective` → D1a gate exit → the latch record;
 *   Direct Edits → the revise-round text) with its text reported (info on saved / revise, error
 *   on save-failed) AND injected; on DENY the model-mediated revision round (the feedback
 *   delimited as untrusted DATA) — each prefixed with `DRAFT_CHANGED_NOTE` when the draft moved;
 * - `dismissed`/`implement-here` → defensively unreachable (the plannotator bridge never
 *   produces them) — no-op.
 */
export async function routeObjectiveReviewDecision(
  pi: ExtensionAPI,
  ctx: ExtensionContext,
  gating: ToolGating,
  slot: DraftReviewSlot,
  out: ReviewOutcome,
  review: OpenDraftReview,
): Promise<void> {
  if (out.status === "unavailable") {
    report(ctx, SCOPE, "error", out.warning, { alsoLog: true });
    return;
  }
  if (out.status !== "completed") return; // aborted (+ the bridge-unreachable arms) — no-op

  const effect = objectiveEffectOf(out);
  const check = checkDraftReviewDecision(slot, ctx, review, effect);
  if (check.kind === "superseded") {
    report(ctx, SCOPE, "warning", SUPERSEDED_DECISION_WARNING);
    return;
  }
  if (check.kind !== "proceed") {
    const result = objectiveGuardResult(check, review, out.feedback);
    report(ctx, SCOPE, "error", result.content[0]?.text.split("\n")[0] ?? check.kind, {
      alsoLog: true,
    });
    injectDraftReviewResult(pi, ctx, result);
    return;
  }

  if (out.approved) {
    // APPROVE: the shared completion (byte-identical to plan_review's objective arm) — Direct
    // Edits is its no-save revise round; a plain approval re-reads the STRUCTURED artifact.
    const result = await completeObjectiveReviewV1(pi, ctx, gating, slot, out);
    if (effect === "revision") {
      report(
        ctx,
        SCOPE,
        "info",
        "objective APPROVED with direct browser edits — routed as a revise round (never " +
          "auto-saved)",
      );
    } else if (result.details.ok === true && result.details.saved === true) {
      report(ctx, SCOPE, "info", "objective APPROVED in the browser — saved");
    } else if (result.details.status === "refused-draft") {
      // Defensively unreachable behind the reviewed-bytes guard (identical raw bytes decode
      // deterministically), but rendered truthfully: rewrite + a FRESH review — never the
      // /objective-save failsafe (the composed text carries the same guidance).
      report(
        ctx,
        SCOPE,
        "error",
        "objective APPROVED in the browser but the working draft was invalid at save time — " +
          "NOTHING was saved; rewrite it with objective_draft and request a fresh review",
        { alsoLog: true },
      );
    } else {
      // save-failed (+ the defensively-unreachable no-draft arm): loud, gate left on; the
      // composed text names the check-the-backend step and the /objective-save deliberate retry.
      report(
        ctx,
        SCOPE,
        "error",
        "objective APPROVED in the browser but the auto-save did not confirm — the session " +
          "stays read-only and automatic saves are paused; check the backend for this run id, " +
          "then run /objective-save (the deliberate retry)",
        { alsoLog: true },
      );
    }
    injectDraftReviewResult(pi, ctx, withDraftChangedNote(result, check.draftChanged));
    return;
  }

  // DENY: model-mediated revise round (contracts.md §8.23) — no auto re-open. The feedback is
  // passed through verbatim (Direct Edits diff included) but DELIMITED as untrusted DATA.
  report(
    ctx,
    SCOPE,
    "info",
    "objective DENIED in the browser — feedback routed for a revision round",
  );
  injectDraftReviewResult(
    pi,
    ctx,
    withDraftChangedNote(objectiveRevisionResult(out), check.draftChanged),
  );
}

/**
 * The guidance-returning open core: start the plan-review browser on the RENDERED objective
 * draft, prime BOTH companion surfaces the moment the port is picked (the URL is deterministic
 * — see the header note), observe readiness and the human decision in background tasks, and
 * RETURN the composed guidance string (template + the `command:objective-review-browser`
 * binding suffix) — the caller decides how to deliver it (the door wrapper injects it via
 * `sendUserMessage`; `plan_review`'s wave arm returns it as a non-terminating tool result,
 * contracts.md §8.23). Returns `null` on the synchronous port-pick failure arm — loudly
 * reported here, then CALLER-handled: the door wrapper simply injects nothing (the report
 * already spoke), while `plan_review`'s wave arm — the one fallback caller — falls open to the
 * plain blocking review. While plannotator sets up, its in-process `console.error`
 * chatter re-routes through the TUI-safe report() seam (the debounce restores once setup goes
 * quiet, with the `finally` as a backstop). `deps` is the injectable browser-open seam (tests
 * drive a fake port picker/probe/clock). `rendered` is the reviewed markdown; `artifactRaw` is
 * the raw structured `objective-draft.json` bytes captured at open — the reviewed bytes the
 * slot digests and the ladder compares. The slot opens FIRST: no browser launches for a review
 * that could never be routed (a refusal is reported and returns `null`).
 */
export async function openObjectiveReviewSurface(
  pi: ExtensionAPI,
  ctx: ExtensionContext,
  gating: ToolGating,
  opts: { rendered: string; artifactRaw: string; custom?: string },
  draftReview: DraftReviewWaveState,
  annotations: AnnotationState,
  slot: DraftReviewSlot,
  status: ActivityHandle,
  deps: StartBrowserDeps = {},
): Promise<string | null> {
  const opened = slot.open(ctx, {
    subject: "objective",
    source: "artifact",
    raw: opts.artifactRaw,
    markdown: opts.rendered,
  });
  if (!opened.ok) {
    report(ctx, SCOPE, "error", `cannot open the browser review: ${opened.detail}`, {
      alsoLog: true,
    });
    return null;
  }
  const review = opened.review;

  let started: StartedSurface<ReviewOutcome>;
  try {
    // The plan-review bridge sends arbitrary string bytes as `planContent` — the rendered
    // objective rides it unchanged (no plan-specific validation).
    started = await startPlannotatorPlanReview(
      pi.events,
      {
        plan: opts.rendered,
        signal: ctx.signal,
        activity: (text) => status.beginActivity(ctx, text),
      },
      deps,
    );
  } catch (error) {
    const detail = error instanceof Error ? error.message : String(error);
    report(
      ctx,
      SCOPE,
      "error",
      `could not pick a free local port for the plannotator plan-review server: ${detail}`,
      { alsoLog: true },
    );
    return null;
  }

  // Prime BOTH companion surfaces the moment the port is picked: push_annotations serves this
  // browser session in plan mode (phrase-anchored — the rendered-objective findings reuse it
  // as-is), and the draft-review wave reviews exactly the browsed bytes (reviewed bytes ==
  // browsed bytes == wave bytes — all the RENDERED markdown). Priming resets any pending wave —
  // a new browser session supersedes everything (the accepted double-open edge in the header).
  primeAnnotationSurface(annotations, { mode: "plan", url: started.url });
  primeDraftReviewContext(draftReview, {
    draftType: "objective",
    draft: opts.rendered,
    ...(opts.custom !== undefined ? { custom: opts.custom } : {}),
  });

  // The shared door-session token: the observer's degrade arm flips `degraded` so the decision
  // task never routes a post-degrade decision through the save path (a readiness false-negative
  // must not let a late approval auto-save after the human followed the fallback), and
  // `current` fences the observer itself to this review (a superseding open must not be
  // degraded by this one's late timeout).
  const session: ObjectiveReviewDoorSession = { degraded: false, current: review.isCurrent };
  void observeObjectiveReviewReadiness(pi, ctx, started, draftReview, annotations, session);

  // The decision task: the wait is open-ended (exactly the model-called `plan_review` bridge
  // semantics — a turn abort settles `aborted` via the bridge's abort handling).
  void (async () => {
    const interceptor = interceptConsoleError((line) => report(ctx, SCOPE, "info", line), {
      // plannotator can pause up to ~4s between setup lines — keep the quiet window above that.
      quietMs: 6000,
    });
    try {
      const out = await started.bridgePromise;
      if (session.degraded) {
        // The review already degraded (surfaces cleared, the fallback announced) — a late
        // decision is ignored LOUDLY, never routed into a stale/duplicate save.
        if (out.status === "completed") {
          report(
            ctx,
            SCOPE,
            "warning",
            "a browser decision arrived after the review degraded — ignored (nothing saved); " +
              "re-run /objective-review-browser to review the current draft",
          );
        }
        return;
      }
      await routeObjectiveReviewDecision(pi, ctx, gating, slot, out, review);
    } finally {
      // The browser session is over — drop both surfaces so a late push refuses (`no_surface`)
      // and a late wave start refuses (`no_draft_context`), but ONLY while this review is still
      // the current one: a superseding open re-primed the surfaces for ITS session. Idempotent
      // beside the degrade-arm clears; an early decision mid-wave leaves a still-pending wave
      // collectable.
      if (review.isCurrent()) {
        clearAnnotationSurface(annotations);
        clearDraftReviewContext(draftReview);
      }
      interceptor.restore();
    }
  })();

  report(
    ctx,
    SCOPE,
    "info",
    opts.custom !== undefined
      ? `working objective draft → plannotator browser review + draft reviewers (custom lane: ${opts.custom}) → APPROVE auto-saves / DENY returns feedback`
      : "working objective draft → plannotator browser review + draft reviewers → APPROVE auto-saves / DENY returns feedback",
  );
  return (
    objectiveReviewBrowserGuidance({
      ...(opts.custom !== undefined ? { custom: opts.custom } : {}),
    }) + bindingSuffix(ctx.cwd, `command:${SCOPE}`)
  );
}

/**
 * The door-facing open: the thin `sendUserMessage` wrapper over `openObjectiveReviewSurface` —
 * the command handler's delivery is the guidance injection; a `null` core return (slot refusal
 * or port-pick failure, already loudly reported) injects nothing.
 */
export async function openObjectiveReviewAndGuide(
  pi: ExtensionAPI,
  ctx: ExtensionContext,
  gating: ToolGating,
  opts: { rendered: string; artifactRaw: string; custom?: string },
  draftReview: DraftReviewWaveState,
  annotations: AnnotationState,
  slot: DraftReviewSlot,
  status: ActivityHandle,
  deps: StartBrowserDeps = {},
): Promise<void> {
  const guidance = await openObjectiveReviewSurface(
    pi,
    ctx,
    gating,
    opts,
    draftReview,
    annotations,
    slot,
    status,
    deps,
  );
  if (guidance !== null) pi.sendUserMessage(guidance);
}

// ------------------------------------------------------------------------ registration

/** Register the warm `/objective-review-browser` command (no tools — the companions are global). */
export function registerObjectiveReviewBrowser(
  pi: ExtensionAPI,
  gating: ToolGating,
  draftReview: DraftReviewWaveState,
  annotations: AnnotationState,
  slot: DraftReviewSlot,
  status: ActivityHandle,
): void {
  registerPerkCommand(pi, SCOPE, {
    description:
      "Review the working objective draft (prose + roadmap) human-in-the-loop in the " +
      "plannotator browser UI: draft reviewers stream findings into the browser; APPROVE " +
      "auto-saves the objective, DENY returns feedback for revision. Any argument text defines " +
      "an extra custom review angle.",
    handler: async (args, ctx: ExtensionContext) => {
      // Entry gates, in order — nothing executed on refusal, each a loud error.
      if (!ctx.hasUI) {
        report(
          ctx,
          SCOPE,
          "error",
          "/objective-review-browser requires an interactive session — the plannotator browser " +
            "surface and the human are constitutive",
        );
        return;
      }
      if (!plannotatorPresent(pi)) {
        report(
          ctx,
          SCOPE,
          "error",
          "the plannotator extension is not loaded (its /plannotator-review command was not " +
            "found) — select the plannotator plan provider (`[providers] plan = " +
            '"plannotator-plan"`), run `perk init`, then restart pi',
        );
        return;
      }
      const stage = rebuildWorkflowState(branchOf(ctx)).stage;
      if (stage === undefined || !DRAFT_STAGES.has(stage)) {
        report(
          ctx,
          SCOPE,
          "error",
          "/objective-review-browser only runs inside an objective-authoring session (stage " +
            "objective-author or objective-save) — the door reviews the working objective draft",
        );
        return;
      }
      // The draft resolve, artifact ONLY: no param tier, no transcript tier (the review-surface
      // law tightened to drafts-only — an approval auto-saves the reviewed bytes). ONE
      // seam-validated read (digest-checked): its bytes are BOTH the decode input and the
      // reviewed bytes the slot digests (the save-authoritative surface), so there is no
      // check-to-open window between what was validated and what the approval compares against.
      const artifact = openBranchWorkflowSession(pi, ctx).readArtifact(OBJECTIVE_DRAFT_ARTIFACT);
      if (artifact.status === "invalid") {
        // Seam-level corruption (pointer-without-file, digest mismatch) is NOT absence — the
        // classified problem + rewrite guidance surface here, mirroring the decode arm below.
        report(
          ctx,
          SCOPE,
          "error",
          `the working objective draft is invalid: ${artifact.problem} — rewrite it with ` +
            "objective_draft, then re-run /objective-review-browser",
        );
        return;
      }
      if (artifact.status !== "found" || artifact.content.trim().length === 0) {
        report(
          ctx,
          SCOPE,
          "error",
          "no working objective draft — write it with objective_draft (prose + the structured " +
            "roadmap), then re-run /objective-review-browser",
        );
        return;
      }
      // Decode the SAME bytes (schema-checked), classified: `refused` carries the problem.
      const resumed = decodeObjectiveDraft(artifact.content);
      if (resumed.kind === "refused") {
        report(
          ctx,
          SCOPE,
          "error",
          `the working objective draft is invalid: ${resumed.problem} — rewrite it with ` +
            "objective_draft, then re-run /objective-review-browser",
        );
        return;
      }
      const rendered = renderObjectiveDraft(resumed.draft);
      // The entire trimmed arg string is the optional custom-angle definition (no parse-failure
      // arm — any text is a valid lens definition).
      const custom = (args ?? "").trim();
      await openObjectiveReviewAndGuide(
        pi,
        ctx,
        gating,
        {
          rendered,
          artifactRaw: artifact.content,
          ...(custom.length > 0 ? { custom } : {}),
        },
        draftReview,
        annotations,
        slot,
        status,
      );
    },
  });
}