feat: add /gsd fast command and gate service tier icon to supported models (#1848) (#1862)

Add `/gsd fast [on|off|flex|status]` command for toggling OpenAI service
tiers, with `supportsServiceTier()` gating so the status bar icon only
appears on models that actually support service tiers (gpt-5.4 variants).

Fixes #1848

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/resources/extensions/gsd/auto-dashboard.ts

@@ -24,6 +24,7 @@ import { GLYPH, INDENT } from "../shared/mod.js";
 import { computeProgressScore } from "./progress-score.js";
 import { getActiveWorktreeName } from "./worktree-command.js";
 import { loadEffectiveGSDPreferences, getGlobalGSDPreferencesPath } from "./preferences.js";
+import { resolveServiceTierIcon, getEffectiveServiceTier } from "./service-tier.js";
 
 // ─── UAT Slice Extraction ─────────────────────────────────────────────────────
 
@@ -460,6 +461,9 @@ export function updateProgressWidget(
   // Pre-fetch last commit for display
   refreshLastCommit(accessors.getBasePath());
 
+  // Cache the effective service tier at widget creation time (reads preferences)
+  const effectiveServiceTier = getEffectiveServiceTier();
+
   ctx.ui.setWidget("gsd-progress", (tui, theme) => {
     let pulseBright = true;
     let cachedLines: string[] | undefined;
@@ -572,9 +576,10 @@ export function updateProgressWidget(
         // Model display — shown in context section, not stats
         const modelId = cmdCtx?.model?.id ?? "";
         const modelProvider = cmdCtx?.model?.provider ?? "";
-        const modelDisplay = modelProvider && modelId
+        const tierIcon = resolveServiceTierIcon(effectiveServiceTier, modelId);
+        const modelDisplay = (modelProvider && modelId
           ? `${modelProvider}/${modelId}`
-          : modelId;
+          : modelId) + (tierIcon ? ` ${tierIcon}` : "");
 
         // ── Mode: off — return empty ──────────────────────────────────
         if (widgetMode === "off") {

src/resources/extensions/gsd/bootstrap/register-hooks.ts

@@ -191,5 +191,18 @@ export function registerHooks(pi: ExtensionAPI): void {
   pi.on("tool_execution_end", async (event) => {
     markToolEnd(event.toolCallId);
   });
+
+  pi.on("before_provider_request", async (event) => {
+    if (!isAutoActive()) return;
+    const modelId = event.model?.id;
+    if (!modelId) return;
+    const { getEffectiveServiceTier, supportsServiceTier } = await import("../service-tier.js");
+    const tier = getEffectiveServiceTier();
+    if (!tier || !supportsServiceTier(modelId)) return;
+    const payload = event.payload as Record<string, unknown> | null;
+    if (!payload || typeof payload !== "object") return;
+    payload.service_tier = tier;
+    return payload;
+  });
 }
 

src/resources/extensions/gsd/commands/catalog.ts

@@ -14,7 +14,7 @@ export interface GsdCommandDefinition {
 type CompletionMap = Record<string, readonly GsdCommandDefinition[]>;
 
 export const GSD_COMMAND_DESCRIPTION =
-  "GSD — Get Shit Done: /gsd help|start|templates|next|auto|stop|pause|status|widget|visualize|queue|quick|discuss|capture|triage|dispatch|history|undo|rate|skip|export|cleanup|mode|prefs|config|keys|hooks|run-hook|skill-health|doctor|logs|forensics|changelog|migrate|remote|steer|knowledge|new-milestone|parallel|cmux|park|unpark|init|setup|inspect|extensions|update";
+  "GSD — Get Shit Done: /gsd help|start|templates|next|auto|stop|pause|status|widget|visualize|queue|quick|discuss|capture|triage|dispatch|history|undo|rate|skip|export|cleanup|mode|prefs|config|keys|hooks|run-hook|skill-health|doctor|logs|forensics|changelog|migrate|remote|steer|knowledge|new-milestone|parallel|cmux|park|unpark|init|setup|inspect|extensions|update|fast";
 
 export const TOP_LEVEL_SUBCOMMANDS: readonly GsdCommandDefinition[] = [
   { cmd: "help", desc: "Categorized command reference with descriptions" },
@@ -64,6 +64,7 @@ export const TOP_LEVEL_SUBCOMMANDS: readonly GsdCommandDefinition[] = [
   { cmd: "start", desc: "Start a workflow template (bugfix, spike, feature, etc.)" },
   { cmd: "templates", desc: "List available workflow templates" },
   { cmd: "extensions", desc: "Manage extensions (list, enable, disable, info)" },
+  { cmd: "fast", desc: "Toggle OpenAI service tier (on/off/flex/status)" },
 ];
 
 const NESTED_COMPLETIONS: CompletionMap = {
@@ -176,6 +177,12 @@ const NESTED_COMPLETIONS: CompletionMap = {
     { cmd: "disable", desc: "Disable an extension" },
     { cmd: "info", desc: "Show extension details" },
   ],
+  fast: [
+    { cmd: "on", desc: "Priority tier (2x cost, faster)" },
+    { cmd: "off", desc: "Disable service tier" },
+    { cmd: "flex", desc: "Flex tier (0.5x cost, slower)" },
+    { cmd: "status", desc: "Show current service tier setting" },
+  ],
   doctor: [
     { cmd: "fix", desc: "Auto-fix detected issues" },
     { cmd: "heal", desc: "AI-driven deep healing" },

src/resources/extensions/gsd/commands/handlers/core.ts

@@ -52,6 +52,7 @@ export function showHelp(ctx: ExtensionCommandContext): void {
     "  /gsd keys           API key manager  [list|add|remove|test|rotate|doctor]",
     "  /gsd hooks          Show post-unit hook configuration",
     "  /gsd extensions     Manage extensions  [list|enable|disable|info]",
+    "  /gsd fast           Toggle OpenAI service tier  [on|off|flex|status]",
     "",
     "MAINTENANCE",
     "  /gsd doctor         Diagnose and repair .gsd/ state  [audit|fix|heal] [scope]",

src/resources/extensions/gsd/commands/handlers/ops.ts

@@ -172,6 +172,11 @@ Examples:
     await handleUpdate(ctx);
     return true;
   }
+  if (trimmed === "fast" || trimmed.startsWith("fast ")) {
+    const { handleFast } = await import("../../service-tier.js");
+    await handleFast(trimmed.replace(/^fast\s*/, "").trim(), ctx);
+    return true;
+  }
   if (trimmed === "extensions" || trimmed.startsWith("extensions ")) {
     const { handleExtensions } = await import("../../commands-extensions.js");
     await handleExtensions(trimmed.replace(/^extensions\s*/, "").trim(), ctx);

src/resources/extensions/gsd/preferences-types.ts

@@ -88,6 +88,7 @@ export const KNOWN_PREFERENCE_KEYS = new Set<string>([
   "widget_mode",
   "reactive_execution",
   "github",
+  "service_tier",
 ]);
 
 /** Canonical list of all dispatch unit types. */
@@ -220,6 +221,8 @@ export interface GSDPreferences {
   reactive_execution?: ReactiveExecutionConfig;
   /** GitHub sync configuration. Opt-in: syncs GSD events to GitHub Issues, Milestones, and PRs. */
   github?: GitHubSyncConfig;
+  /** OpenAI service tier preference. "priority" = 2x cost, faster. "flex" = 0.5x cost, slower. Only affects gpt-5.4 models. */
+  service_tier?: "priority" | "flex";
 }
 
 export interface LoadedGSDPreferences {

src/resources/extensions/gsd/preferences.ts

@@ -285,6 +285,7 @@ function mergePreferences(base: GSDPreferences, override: GSDPreferences): GSDPr
     github: (base.github || override.github)
       ? { ...(base.github ?? {}), ...(override.github ?? {}) } as import("../github-sync/types.js").GitHubSyncConfig
       : undefined,
+    service_tier: override.service_tier ?? base.service_tier,
   };
 }
 

src/resources/extensions/gsd/service-tier.ts

@@ -0,0 +1,171 @@
+/**
+ * Service Tier — gating, status formatting, icon resolution, and
+ * the /gsd fast command handler.
+ *
+ * Service tiers (priority/flex) are an OpenAI feature that only applies
+ * to gpt-5.4 variants. This module centralizes the model-gating logic
+ * so that icons, preferences, and the before_provider_request hook all
+ * use a single source of truth.
+ */
+
+import type { ExtensionCommandContext } from "@gsd/pi-coding-agent";
+
+import { existsSync, readFileSync } from "node:fs";
+import { saveFile } from "./files.js";
+import {
+  getGlobalGSDPreferencesPath,
+  loadEffectiveGSDPreferences,
+  loadGlobalGSDPreferences,
+} from "./preferences.js";
+import { ensurePreferencesFile, serializePreferencesToFrontmatter } from "./commands-prefs-wizard.js";
+
+// ─── Types ───────────────────────────────────────────────────────────────────
+
+export type ServiceTierSetting = "priority" | "flex" | undefined;
+
+// ─── Gating ──────────────────────────────────────────────────────────────────
+
+/**
+ * Returns true when the given model ID supports OpenAI service tiers.
+ * Currently only gpt-5.4 variants qualify.
+ */
+export function supportsServiceTier(modelId: string): boolean {
+  if (!modelId) return false;
+  // Strip provider prefix if present (e.g. "openai/gpt-5.4" → "gpt-5.4")
+  const bare = modelId.includes("/") ? modelId.split("/").pop()! : modelId;
+  return bare.startsWith("gpt-5.4");
+}
+
+// ─── Status Formatting ───────────────────────────────────────────────────────
+
+/**
+ * Human-readable description of the current service tier setting.
+ */
+export function formatServiceTierStatus(tier: ServiceTierSetting): string {
+  if (!tier) {
+    return [
+      "Service tier: disabled",
+      "",
+      "Usage:",
+      "  /gsd fast on     Set to priority (2x cost, faster)",
+      "  /gsd fast flex   Set to flex (0.5x cost, slower)",
+      "  /gsd fast off    Disable service tier",
+      "",
+      "Only affects gpt-5.4 models.",
+    ].join("\n");
+  }
+
+  const label = tier === "priority" ? "priority (2x cost, faster)" : "flex (0.5x cost, slower)";
+  return [
+    `Service tier: ${label}`,
+    "",
+    "Usage:",
+    "  /gsd fast on     Set to priority (2x cost, faster)",
+    "  /gsd fast flex   Set to flex (0.5x cost, slower)",
+    "  /gsd fast off    Disable service tier",
+    "",
+    "Only affects gpt-5.4 models.",
+  ].join("\n");
+}
+
+// ─── Icon Resolution ─────────────────────────────────────────────────────────
+
+/**
+ * Returns the appropriate icon for the active service tier and model.
+ * Returns empty string when the tier is inactive or the model doesn't
+ * support service tiers.
+ */
+export function resolveServiceTierIcon(tier: ServiceTierSetting, modelId: string): string {
+  if (!tier || !supportsServiceTier(modelId)) return "";
+  return tier === "priority" ? "⚡" : "💰";
+}
+
+// ─── Preference Read ─────────────────────────────────────────────────────────
+
+/**
+ * Read the effective service_tier setting from preferences.
+ */
+export function getEffectiveServiceTier(): ServiceTierSetting {
+  const prefs = loadEffectiveGSDPreferences()?.preferences;
+  const raw = prefs?.service_tier;
+  if (raw === "priority" || raw === "flex") return raw;
+  return undefined;
+}
+
+// ─── Preference Write ────────────────────────────────────────────────────────
+
+function extractBodyAfterFrontmatter(content: string): string | null {
+  const start = content.startsWith("---\n") ? 4 : content.startsWith("---\r\n") ? 5 : -1;
+  if (start === -1) return null;
+  const closingIdx = content.indexOf("\n---", start);
+  if (closingIdx === -1) return null;
+  const after = content.slice(closingIdx + 4);
+  return after.trim() ? after : null;
+}
+
+async function writeGlobalServiceTier(
+  ctx: ExtensionCommandContext,
+  tier: ServiceTierSetting,
+): Promise<void> {
+  const path = getGlobalGSDPreferencesPath();
+  await ensurePreferencesFile(path, ctx, "global");
+
+  const existing = loadGlobalGSDPreferences();
+  const prefs: Record<string, unknown> = existing?.preferences ? { ...existing.preferences } : {};
+  prefs.version = prefs.version || 1;
+
+  if (tier) {
+    prefs.service_tier = tier;
+  } else {
+    delete prefs.service_tier;
+  }
+
+  const frontmatter = serializePreferencesToFrontmatter(prefs);
+  let body = "\n# GSD Skill Preferences\n\nSee `~/.gsd/agent/extensions/gsd/docs/preferences-reference.md` for full field documentation and examples.\n";
+  if (existsSync(path)) {
+    const preserved = extractBodyAfterFrontmatter(readFileSync(path, "utf-8"));
+    if (preserved) body = preserved;
+  }
+
+  await saveFile(path, `---\n${frontmatter}---${body}`);
+  await ctx.waitForIdle();
+  await ctx.reload();
+}
+
+// ─── Command Handler ─────────────────────────────────────────────────────────
+
+/**
+ * Handle `/gsd fast [on|off|flex|status]`.
+ */
+export async function handleFast(args: string, ctx: ExtensionCommandContext): Promise<void> {
+  const trimmed = args.trim().toLowerCase();
+
+  if (!trimmed || trimmed === "status") {
+    const tier = getEffectiveServiceTier();
+    ctx.ui.notify(formatServiceTierStatus(tier), "info");
+    return;
+  }
+
+  if (trimmed === "on") {
+    await writeGlobalServiceTier(ctx, "priority");
+    ctx.ui.notify("Service tier set to priority (2x cost, faster responses). Only affects gpt-5.4 models.", "info");
+    return;
+  }
+
+  if (trimmed === "off") {
+    await writeGlobalServiceTier(ctx, undefined);
+    ctx.ui.notify("Service tier disabled.", "info");
+    return;
+  }
+
+  if (trimmed === "flex") {
+    await writeGlobalServiceTier(ctx, "flex");
+    ctx.ui.notify("Service tier set to flex (0.5x cost, slower responses). Only affects gpt-5.4 models.", "info");
+    return;
+  }
+
+  ctx.ui.notify(
+    "Usage: /gsd fast [on|off|flex|status]\n\n  on    Priority tier (2x cost, faster)\n  off   Disable service tier\n  flex  Flex tier (0.5x cost, slower)\n  status Show current setting",
+    "warning",
+  );
+}

src/resources/extensions/gsd/tests/service-tier.test.ts

@@ -0,0 +1,98 @@
+import test, { describe } from "node:test";
+import assert from "node:assert/strict";
+
+import {
+  supportsServiceTier,
+  formatServiceTierStatus,
+  resolveServiceTierIcon,
+  type ServiceTierSetting,
+} from "../service-tier.ts";
+
+// ─── supportsServiceTier ─────────────────────────────────────────────────────
+
+describe("supportsServiceTier", () => {
+  test("returns true for gpt-5.4", () => {
+    assert.equal(supportsServiceTier("gpt-5.4"), true);
+  });
+
+  test("returns true for gpt-5.4-pro", () => {
+    assert.equal(supportsServiceTier("gpt-5.4-pro"), true);
+  });
+
+  test("returns true for gpt-5.4-mini", () => {
+    assert.equal(supportsServiceTier("gpt-5.4-mini"), true);
+  });
+
+  test("returns true for openai/gpt-5.4 (provider-prefixed)", () => {
+    assert.equal(supportsServiceTier("openai/gpt-5.4"), true);
+  });
+
+  test("returns false for claude-opus-4-6", () => {
+    assert.equal(supportsServiceTier("claude-opus-4-6"), false);
+  });
+
+  test("returns false for gemini-2.5-pro", () => {
+    assert.equal(supportsServiceTier("gemini-2.5-pro"), false);
+  });
+
+  test("returns false for gpt-4o", () => {
+    assert.equal(supportsServiceTier("gpt-4o"), false);
+  });
+
+  test("returns false for empty string", () => {
+    assert.equal(supportsServiceTier(""), false);
+  });
+});
+
+// ─── formatServiceTierStatus ─────────────────────────────────────────────────
+
+describe("formatServiceTierStatus", () => {
+  test("shows disabled when service_tier is undefined", () => {
+    const output = formatServiceTierStatus(undefined);
+    assert.ok(output.includes("disabled"), `Expected 'disabled' in: ${output}`);
+  });
+
+  test("shows priority when set to priority", () => {
+    const output = formatServiceTierStatus("priority");
+    assert.ok(output.includes("priority"), `Expected 'priority' in: ${output}`);
+  });
+
+  test("shows flex when set to flex", () => {
+    const output = formatServiceTierStatus("flex");
+    assert.ok(output.includes("flex"), `Expected 'flex' in: ${output}`);
+  });
+});
+
+// ─── resolveServiceTierIcon ──────────────────────────────────────────────────
+
+describe("resolveServiceTierIcon", () => {
+  test("returns lightning bolt for priority tier on supported model", () => {
+    const icon = resolveServiceTierIcon("priority", "gpt-5.4");
+    assert.equal(icon, "⚡");
+  });
+
+  test("returns money icon for flex tier on supported model", () => {
+    const icon = resolveServiceTierIcon("flex", "gpt-5.4");
+    assert.equal(icon, "💰");
+  });
+
+  test("returns empty string when tier is set but model does not support it", () => {
+    const icon = resolveServiceTierIcon("priority", "claude-opus-4-6");
+    assert.equal(icon, "");
+  });
+
+  test("returns empty string when tier is undefined", () => {
+    const icon = resolveServiceTierIcon(undefined, "gpt-5.4");
+    assert.equal(icon, "");
+  });
+
+  test("returns empty string when both tier and model are unsupported", () => {
+    const icon = resolveServiceTierIcon(undefined, "claude-opus-4-6");
+    assert.equal(icon, "");
+  });
+
+  test("returns empty string when model is empty", () => {
+    const icon = resolveServiceTierIcon("priority", "");
+    assert.equal(icon, "");
+  });
+});