feat(export): serve client configs from the management API

Phase 030 of devlog/_plan/260731_client_config_export.

GET /api/client-config?client=<opencode|pi> returns the same bytes the
CLI prints, wrapped in an envelope carrying the destination path, the env
var name, and the model counts the GUI needs to render its states.

The /api/models row logic moved into listManagementModelRows() and both
branches now call it. Copying it would have created a second definition
of which models exist, free to drift from the first; disabled/dedupe
precedence is ~40 lines and only correct in one place.

modelsWithoutLimits is counted from the serialized document rather than
re-derived from input rows, so the number cannot disagree with the bytes
the caller receives. A catalog failure is 503, never a partial 200.

Author: lidge-jun

devlog/_plan/260731_client_config_export/030_management_api.md

@@ -32,7 +32,7 @@ fetch path for no isolation benefit.
 {
   "client": "opencode",
   "filename": "opencode.json",
-  "destination": "/Users/you/.config/opencode/opencode.json",
+  "destination": "~/.config/opencode/opencode.json",
   "apiKeyEnv": "OPENCODEX_OPENCODE_API_KEY",
   "exportHint": "export OPENCODEX_OPENCODE_API_KEY=<your key>",
   "modelCount": 19,

src/server/management/model-routes.ts

@@ -31,6 +31,7 @@ function readInputModalities(raw: unknown): { values?: string[]; error?: string
 }
 import type { CatalogModel } from "../../codex/catalog";
 import { catalogModelSlug, disabledNativeSlugs, invalidateCodexModelsCache, nativeModelRows, uniqueCatalogModelsForPublicList } from "../../codex/catalog";
+import { CatalogGatherBusyError } from "../../codex/catalog/provider-fetch";
 import { getProviderLiveModelCount } from "../../codex/model-cache";
 import {
   DEFAULT_SUBAGENT_MODELS,
@@ -85,12 +86,127 @@ import { estimateComboCost, estimateRequestCost, normalizeCostTokens, tokensPerS
 import type { PersistedUsageAttempt } from "../../usage/log";
 import { isAllowedRequestOrigin, jsonResponse, providerManagementConfigError, publicProviderBaseUrl, safeConfigDTO, corsHeaders } from "../auth-cors";
 import { applySystemEnvToggle } from "../system-env";
+import {
+  EXPORT_CLIENTS,
+  EXPORT_CLIENT_IDS,
+  OPENCODE_PROVIDER_ID,
+  buildClientConfig,
+  isExportClientId,
+  opencodeProxyBaseUrl,
+} from "../../clients/config-export";
+import type {
+  ExportClientId,
+  ExportModel,
+  OpencodeGeneratedConfig,
+  PiGeneratedConfig,
+} from "../../clients/config-export";
 
 import { isPlainRecord, parseDebugLogQuery, tokPerSecondResult, unavailableCostReason, costResult, requestLogDto, stripRegistryOnlyStaticHeaders, fetchAllModels } from "./shared";
 import type { MetricUnavailableReason, TokPerSecondResult, CostEstimateReason, CostResult, MetricSource } from "./shared";
 import type { ManagementContext } from "./context";
 import { readManagementJsonBody, rethrowManagementBodyTooLarge } from "./body";
 
+/**
+ * One row of the `/api/models` list. Routed rows spread a `CatalogModel`, so the shape is
+ * that model plus the identity/visibility fields this boundary computes for every row
+ * regardless of source. `disabled` is always present; the rest vary by row origin.
+ */
+type ManagementModelRow = Partial<CatalogModel> & {
+  provider: string;
+  id: string;
+  namespaced: string;
+  disabled: boolean;
+  native?: boolean;
+  custom?: boolean;
+  customId?: string;
+};
+
+/**
+ * The exact row list `/api/models` returns. Extracted so `/api/client-config` exports the
+ * models the GUI's Models tab shows — including this function's `disabled` computation,
+ * which the export core (src/clients/config-export.ts) deliberately does not perform.
+ */
+async function listManagementModelRows(config: OcxConfig): Promise<ManagementModelRow[]> {
+  const models = await fetchAllModels(config);
+  const disabled = new Set(config.disabledModels ?? []);
+  // Native GPT passthrough rows lead (provider "openai", bare-slug namespaced ids): sourced
+  // from the static supported set so a disabled model stays listed and re-enableable.
+  const native: ManagementModelRow[] = nativeModelRows(config).map(row => ({
+    provider: "openai",
+    id: row.slug,
+    namespaced: row.slug,
+    disabled: row.disabled,
+    native: true,
+    ...(row.contextWindow !== undefined ? { contextWindow: row.contextWindow } : {}),
+  }));
+  const customModels: ManagementModelRow[] = (config.customModels ?? []).map(cm => {
+    const namespaced = routedSlug(cm.provider, cm.modelId);
+    return {
+      provider: cm.provider,
+      id: cm.modelId,
+      namespaced,
+      disabled: [...disabled].some(stored => slugEquals(stored, cm.provider, cm.modelId)),
+      custom: true,
+      customId: cm.id,
+      displayName: cm.displayName,
+      ...(cm.contextWindow ? { contextWindow: cm.contextWindow } : {}),
+      ...(cm.inputModalities ? { inputModalities: cm.inputModalities } : {}),
+    };
+  });
+  const publicModels = uniqueCatalogModelsForPublicList(models);
+  const comboNamespaced = new Set(
+    publicModels.filter(model => model.provider === "combo").map(catalogModelSlug),
+  );
+  const visibleCustomModels = customModels.filter(model => !comboNamespaced.has(model.namespaced));
+  // Custom metadata wins when a physical live/static row resolves to the same Codex-facing
+  // slug, while a combo keeps the same precedence it has in routing and /v1/models.
+  const customNamespaced = new Set(visibleCustomModels.map(c => c.namespaced));
+  const dedupedRouted = publicModels.map((m): ManagementModelRow | null => {
+    // Codex-facing slug (one "/", slug-codec); disabledModels compares tolerate both forms.
+    const namespaced = catalogModelSlug(m);
+    if (m.provider !== "combo" && customNamespaced.has(namespaced)) return null;
+    const contextCap = providerContextCap(config, m.provider);
+    return {
+      ...m,
+      namespaced,
+      disabled: [...disabled].some(stored => (
+        stored === namespaced || slugEquals(stored, m.provider, m.id)
+      )),
+      ...(contextCap !== undefined ? { contextCap, contextCapped: m.contextCapped === true } : {}),
+    };
+  }).filter((row): row is ManagementModelRow => row !== null);
+  return [...native, ...dedupedRouted, ...visibleCustomModels];
+}
+
+/** `/api/models` row → the narrower input the client-config serializers accept. */
+function toExportModel(row: ManagementModelRow): ExportModel {
+  return {
+    namespaced: row.namespaced,
+    provider: row.provider,
+    id: row.id,
+    ...(row.native ? { native: true } : {}),
+    ...(row.displayName ? { displayName: row.displayName } : {}),
+    ...(row.contextWindow !== undefined ? { contextWindow: row.contextWindow } : {}),
+    ...(row.inputModalities ? { inputModalities: row.inputModalities } : {}),
+  };
+}
+
+/**
+ * Counts read back off the SERIALIZED document rather than recomputed from the input rows.
+ * `modelsWithoutLimits` drives a GUI line claiming "these models ship without limits", so it
+ * has to describe the bytes the user actually receives — a parallel reimplementation of the
+ * core's "authoritative context window" rule would be free to drift from it silently.
+ */
+function summarizeExportedModels(client: ExportClientId, document: unknown): { modelCount: number; modelsWithoutLimits: number } {
+  if (client === "opencode") {
+    const models = (document as OpencodeGeneratedConfig).provider[OPENCODE_PROVIDER_ID].models;
+    const entries = Object.values(models);
+    return { modelCount: entries.length, modelsWithoutLimits: entries.filter(entry => entry.limit === undefined).length };
+  }
+  const models = (document as PiGeneratedConfig).providers[OPENCODE_PROVIDER_ID].models;
+  return { modelCount: models.length, modelsWithoutLimits: models.filter(entry => entry.contextWindow === undefined).length };
+}
+
 export async function handleModelRoutes(ctx: ManagementContext): Promise<Response | null> {
   const { req, url, config, deps, refreshCodexCatalogBestEffort, syncClaudeAgentDefsBestEffort } = ctx;
   // A handler persists the exact config object passed in. Production defaults to
@@ -114,55 +230,58 @@ export async function handleModelRoutes(ctx: ManagementContext): Promise<Respons
   }
 
   if (url.pathname === "/api/models" && req.method === "GET") {
-    const models = await fetchAllModels(config);
-    const disabled = new Set(config.disabledModels ?? []);
-    // Native GPT passthrough rows lead (provider "openai", bare-slug namespaced ids): sourced
-    // from the static supported set so a disabled model stays listed and re-enableable.
-    const native = nativeModelRows(config).map(row => ({
-      provider: "openai",
-      id: row.slug,
-      namespaced: row.slug,
-      disabled: row.disabled,
-      native: true,
-      ...(row.contextWindow !== undefined ? { contextWindow: row.contextWindow } : {}),
-    }));
-    const customModels = (config.customModels ?? []).map(cm => {
-      const namespaced = routedSlug(cm.provider, cm.modelId);
-      return {
-        provider: cm.provider,
-        id: cm.modelId,
-        namespaced,
-        disabled: [...disabled].some(stored => slugEquals(stored, cm.provider, cm.modelId)),
-        custom: true,
-        customId: cm.id,
-        displayName: cm.displayName,
-        ...(cm.contextWindow ? { contextWindow: cm.contextWindow } : {}),
-        ...(cm.inputModalities ? { inputModalities: cm.inputModalities } : {}),
-      };
+    return jsonResponse(await listManagementModelRows(config));
+  }
+
+  /**
+   * Client config document for OpenCode / Pi, built from the SAME function `ocx export`
+   * calls, so the bytes a user downloads here and the bytes they pipe from the CLI cannot
+   * disagree. Read-only: this route never writes the user's client config.
+   */
+  if (url.pathname === "/api/client-config" && req.method === "GET") {
+    const requested = url.searchParams.get("client")?.trim() ?? "";
+    if (!isExportClientId(requested)) {
+      return jsonResponse(
+        { error: `client must be one of: ${EXPORT_CLIENT_IDS.join(", ")}` },
+        400,
+        req,
+        config,
+      );
+    }
+    const spec = EXPORT_CLIENTS[requested];
+    let rows: ManagementModelRow[];
+    try {
+      rows = await listManagementModelRows(config);
+    } catch (error) {
+      // A partial or empty `models` block reads as a valid config while offering nothing,
+      // so a catalog failure is surfaced as unavailable rather than serialized. The
+      // catalog-busy error keeps its own 503 from handleManagementAPI.
+      if (error instanceof CatalogGatherBusyError) throw error;
+      return jsonResponse(
+        { error: `model catalog unavailable: ${error instanceof Error ? error.message : String(error)}` },
+        503,
+        req,
+        config,
+      );
+    }
+    // The export core does not filter visibility — it serializes what it is given. A model the
+    // user disabled in the Models tab is absent from /v1/models, so exporting it would hand the
+    // client a selector the proxy refuses to route.
+    const models = rows.filter(row => !row.disabled).map(toExportModel);
+    const document = buildClientConfig(requested, {
+      baseUrl: opencodeProxyBaseUrl(Number(url.port) || config.port, config.hostname),
+      models,
+      config,
     });
-    const publicModels = uniqueCatalogModelsForPublicList(models);
-    const comboNamespaced = new Set(
-      publicModels.filter(model => model.provider === "combo").map(catalogModelSlug),
-    );
-    const visibleCustomModels = customModels.filter(model => !comboNamespaced.has(model.namespaced));
-    // Custom metadata wins when a physical live/static row resolves to the same Codex-facing
-    // slug, while a combo keeps the same precedence it has in routing and /v1/models.
-    const customNamespaced = new Set(visibleCustomModels.map(c => c.namespaced));
-    const dedupedRouted = publicModels.map(m => {
-      // Codex-facing slug (one "/", slug-codec); disabledModels compares tolerate both forms.
-      const namespaced = catalogModelSlug(m);
-      if (m.provider !== "combo" && customNamespaced.has(namespaced)) return null;
-      const contextCap = providerContextCap(config, m.provider);
-      return {
-        ...m,
-        namespaced,
-        disabled: [...disabled].some(stored => (
-          stored === namespaced || slugEquals(stored, m.provider, m.id)
-        )),
-        ...(contextCap !== undefined ? { contextCap, contextCapped: m.contextCapped === true } : {}),
-      };
-    }).filter(Boolean);
-    return jsonResponse([...native, ...dedupedRouted, ...visibleCustomModels]);
+    return jsonResponse({
+      client: spec.id,
+      filename: spec.filename,
+      destination: spec.destination(process.env),
+      apiKeyEnv: spec.apiKeyEnv,
+      exportHint: spec.exportHint,
+      ...summarizeExportedModels(requested, document),
+      config: document,
+    }, 200, req, config);
   }
 
   // Enable/disable models: which routed models Codex sees. PUT hides them from the catalog +