diff --git a/src/config.test.ts b/src/config.test.ts
index 607e2c908..404210799 100644
--- a/src/config.test.ts
+++ b/src/config.test.ts
@@ -3,9 +3,10 @@ import { mkdtemp, mkdir, writeFile, rm } from "node:fs/promises";
 import { tmpdir } from "node:os";
 import { join } from "node:path";
 
-import { buildBifrostSource, buildOpenAISource, buildProviderCatalog, KEYLESS_API_KEY, loadConfig, providerCatalogToSettings, runtimeSettingsWithCatalog, SOURCE_MAX_TOKENS } from "./config/index.js";
+import { buildBifrostSource, buildOpenAISource, buildProviderCatalog, catalogEntryAsProviderSettings, KEYLESS_API_KEY, loadConfig, providerCatalogToSettings, runtimeSettingsWithCatalog, SOURCE_MAX_TOKENS } from "./config/index.js";
 import type { Config, UnconfiguredConfig } from "./config/index.js";
 import { mergeProviderIntoSettings, type ResolvedProvider, type Settings } from "./config/settings.js";
+import { OPENCODE_GO_BASE_URL } from "../packages/opencode-go/src/index.js";
 
 function assertConfigured(config: Config | UnconfiguredConfig): asserts config is Config {
   if (config.configured === false) {
@@ -648,6 +649,74 @@ describe("buildProviderCatalog", () => {
     });
     expect(restOut).toEqual(restExisting);
   });
+
+  test("round-trips every ProviderSettings field a catalog entry can carry through buildProviderCatalog and back", () => {
+    // ProviderCatalogEntry is defined as Omit<ProviderSettings, "name" | "contextWindow">.
+    // This exercises every field that relationship carries over, so a field
+    // added to ProviderSettings and forgotten in the two conversion sites
+    // below fails here instead of being silently dropped at runtime.
+    // `anthropic` and `opencodeGo` are exercised separately below: both are
+    // protocol markers that also normalize `baseURL` in buildProviderCatalog,
+    // so a provider combining them with an arbitrary baseURL isn't a real
+    // round trip (the healing logic rewrites baseURL by design).
+    const provider: Settings["providers"][string] = {
+      baseURL: "https://fp/v1",
+      apiKey: "fp-key",
+      models: ["fp-large"],
+      defaultModel: "fp-large",
+      free: true,
+      keyless: true,
+      bifrostVirtualKey: true,
+    };
+    const settings: Settings = { providers: { fp: provider } };
+    const catalog = buildProviderCatalog(settings, {
+      providerName: "fp",
+      baseURL: provider.baseURL,
+      apiKey: "fp-key",
+      model: "fp-large",
+    } as ResolvedProvider);
+    const entry = catalog.find((c) => c.name === "fp")!;
+    const roundTripped = { fp: catalogEntryAsProviderSettings(entry) };
+    expect(roundTripped).toEqual({ fp: provider });
+  });
+
+  test("round-trips the anthropic protocol marker", () => {
+    const provider: Settings["providers"][string] = {
+      baseURL: "https://api.anthropic.com/v1",
+      apiKey: "an-key",
+      models: ["claude"],
+      anthropic: true,
+    };
+    const settings: Settings = { providers: { an: provider } };
+    const catalog = buildProviderCatalog(settings, {
+      providerName: "an",
+      baseURL: provider.baseURL,
+      apiKey: "an-key",
+      model: "claude",
+    } as ResolvedProvider);
+    const entry = catalog.find((c) => c.name === "an")!;
+    const roundTripped = { an: catalogEntryAsProviderSettings(entry) };
+    expect(roundTripped).toEqual({ an: provider });
+  });
+
+  test("round-trips the opencodeGo protocol marker", () => {
+    const provider: Settings["providers"][string] = {
+      baseURL: OPENCODE_GO_BASE_URL,
+      apiKey: "go-key",
+      models: ["go-model"],
+      opencodeGo: true,
+    };
+    const settings: Settings = { providers: { go: provider } };
+    const catalog = buildProviderCatalog(settings, {
+      providerName: "go",
+      baseURL: provider.baseURL,
+      apiKey: "go-key",
+      model: "go-model",
+    } as ResolvedProvider);
+    const entry = catalog.find((c) => c.name === "go")!;
+    const roundTripped = { go: catalogEntryAsProviderSettings(entry) };
+    expect(roundTripped).toEqual({ go: provider });
+  });
 });
 
 describe("mergeProviderIntoSettings", () => {
diff --git a/src/config/index.ts b/src/config/index.ts
index 3310d189f..ee4cd78d7 100644
--- a/src/config/index.ts
+++ b/src/config/index.ts
@@ -91,24 +91,23 @@ export function buildOpenAISource(fields: {
 
 // One configured provider the /agent modal can switch to. Carries credentials
 // because live switching builds an InferenceSource from it; the modal only ever
-// receives fields needed for provider management, never the key.
-export type ProviderCatalogEntry = {
+// receives fields needed for provider management, never the key. Derived from
+// ProviderSettings (the persisted record) so the field *set* stays tied to it:
+// a newly required ProviderSettings field forces every catalog-entry literal
+// to supply it. `name` becomes required (every catalog entry is resolved to a
+// concrete provider id) and `contextWindow` is dropped (it is a settings-only
+// override, never surfaced to the /agent modal). The OAuth-profile markers
+// below have no ProviderSettings counterpart because such entries are never
+// written to settings.json (their credentials live in the Codex/xAI auth
+// stores). Optional fields still need the round-trip test in config.test.ts —
+// TS does not flag a missing optional property against an explicitly-typed
+// object literal, so forwarding of an optional field can only be caught at
+// runtime.
+export type ProviderCatalogEntry = Omit<ProviderSettings, "name" | "contextWindow"> & {
   name: string;
-  baseURL: string;
-  // Absent for keyless providers (see `keyless`). When present, carries the
-  // secret key the harness injects as a Bearer credential.
-  apiKey?: string;
-  models: string[];
-  defaultModel?: string;
-  // True for local providers that require no authentication (e.g. Ollama).
-  // When set, `apiKey` is omitted and resolution skips the key check.
-  keyless?: boolean;
-  // Manual override suppressing the status-bar dollar cost for this provider.
-  free?: boolean;
   // Set when this entry is a Codex OAuth profile rather than an API-key
   // provider. Holds the profile name; the send path uses it to refresh the
-  // access token before each turn. Such entries are never written to
-  // settings.json (their credentials live in the Codex auth store).
+  // access token before each turn.
   codexProfile?: string;
   // ChatGPT account id for a Codex profile, sent as the chatgpt-account-id
   // header by the Responses adapter. Present only on Codex entries.
@@ -116,17 +115,6 @@ export type ProviderCatalogEntry = {
   // Set when this entry is an xAI/Grok OAuth profile. It still routes through
   // openai-compatible; the marker only controls token refresh and persistence.
   xaiProfile?: string;
-  // When true this provider is backed by a Bifrost virtual key. Inference
-  // sources for it are built with provider "bifrost" so the adapter can
-  // inject the x-bf-vk header (in addition to Authorization). The flag is
-  // also used to enable /models auto-discovery scoped to the key.
-  bifrostVirtualKey?: boolean;
-  // Anthropic Messages API (x-api-key). Used by first-class Anthropic and by
-  // OpenCode Go models that speak the messages protocol.
-  anthropic?: boolean;
-  // OpenCode Go multi-protocol provider. Per-model routing picks
-  // openai-compatible, openai-responses, or anthropic at source-build time.
-  opencodeGo?: boolean;
 };
 
 // Build the InferenceSource for a Codex OAuth profile. Routes to the