diff --git a/apps/cli/src/shared/cli/invalid-value-message.ts b/apps/cli/src/shared/cli/invalid-value-message.ts
new file mode 100644
index 0000000000..8bf079581d
--- /dev/null
+++ b/apps/cli/src/shared/cli/invalid-value-message.ts
@@ -0,0 +1,54 @@
+// Workaround for a doubled "Expected: Expected ..." prefix in
+// effect@4.0.0-beta.93's own primitive parsers. Several `Primitive`s under
+// `effect/unstable/cli` (`choice` — used by `Flag.choice`/
+// `Flag.choiceWithValue` — plus the schema-backed `integer`, `float`,
+// `boolean`, and `date`) fail with a raw message that already starts with
+// the word "Expected" (e.g. `Expected "micro" | "small", got "nano"` or
+// `Expected a valid date, got Invalid Date`), and `CliError.InvalidValue`'s
+// own `message` getter independently prepends its own `"Expected: "` label
+// on top of that — so any flag or argument backed by one of these
+// primitives renders "Expected: Expected ...". Detect this from
+// `error.expected` (the field the buggy primitives actually populate)
+// rather than searching the fully composed `error.message`: `error.value`
+// is user-controlled and interpolated into that same message (including a
+// second time inside `expected` itself, via `choice`'s "got <value>"
+// suffix), so a message-wide, first-occurrence string replace can target
+// the wrong spot if the value itself happens to contain the literal text
+// "Expected: Expected ". Anchoring on `error.expected` and rebuilding the
+// message from the same template `CliError.InvalidValue` uses avoids ever
+// scanning `error.value`. Remove once upstream `effect` fixes this (see
+// CLI-1898).
+//
+// Shared by two call sites that each see `InvalidValue` failures at a
+// different point in `effect`'s CLI runtime:
+// - `subcommand-flag-suggestions.ts` formats errors that reach the
+//   `CliOutput.Formatter` via the `ShowHelp` envelope — i.e. ordinary
+//   subcommand/argument flags, validated while `Command.runWith` parses the
+//   command tree.
+// - `normalize-error.ts` formats errors from `GlobalFlag.setting` flags
+//   (`--output-format`, and the legacy `--output`/`-o`, `--dns-resolver`,
+//   `--agent`), which `Command.runWith` validates in a later step that runs
+//   *outside* the `ShowHelp` path and therefore never reaches the
+//   formatter — it surfaces as a raw failure through `runCli`'s catch-all
+//   instead.
+const EXPECTED_PREFIX = "Expected ";
+
+export interface InvalidValueMessageFields {
+  readonly option: string;
+  readonly value: string;
+  readonly expected: string;
+  readonly kind: "flag" | "argument";
+}
+
+/**
+ * Rebuilds a `CliError.InvalidValue` message from its own template when
+ * `expected` carries the doubled "Expected" prefix. Returns `undefined` when
+ * `expected` is unaffected, so callers can fall back to the error's own
+ * untouched `message`.
+ */
+export function formatInvalidValueMessage(error: InvalidValueMessageFields): string | undefined {
+  if (!error.expected.startsWith(EXPECTED_PREFIX)) return undefined;
+  return error.kind === "argument"
+    ? `Invalid value for argument <${error.option}>: "${error.value}". ${error.expected}`
+    : `Invalid value for flag --${error.option}: "${error.value}". ${error.expected}`;
+}
diff --git a/apps/cli/src/shared/cli/subcommand-flag-suggestions.ts b/apps/cli/src/shared/cli/subcommand-flag-suggestions.ts
index 1cc5124f98..c6da39c2e1 100644
--- a/apps/cli/src/shared/cli/subcommand-flag-suggestions.ts
+++ b/apps/cli/src/shared/cli/subcommand-flag-suggestions.ts
@@ -1,4 +1,5 @@
 import type { CliError, Command, HelpDoc } from "effect/unstable/cli";
+import { formatInvalidValueMessage } from "./invalid-value-message.ts";
 
 export interface CliErrorSuggestionContext {
   readonly rootCommand: Command.Command.Any;
@@ -228,6 +229,20 @@ export function formatCliErrorsForDisplay(
       continue;
     }
 
+    if (error._tag === "InvalidValue") {
+      const message = formatInvalidValueMessage(error);
+      if (message !== undefined) {
+        changed = true;
+        formatted.push({
+          _tag: error._tag,
+          message,
+          source: error,
+          changed: true,
+        });
+        continue;
+      }
+    }
+
     formatted.push({ _tag: error._tag, message: error.message, source: error, changed: false });
   }
 
diff --git a/apps/cli/src/shared/cli/subcommand-flag-suggestions.unit.test.ts b/apps/cli/src/shared/cli/subcommand-flag-suggestions.unit.test.ts
index 079256d354..595b0969c6 100644
--- a/apps/cli/src/shared/cli/subcommand-flag-suggestions.unit.test.ts
+++ b/apps/cli/src/shared/cli/subcommand-flag-suggestions.unit.test.ts
@@ -122,4 +122,101 @@ describe("subcommand flag placement suggestions", () => {
     );
     expect(errors.errors[0]?.message).not.toContain("--project-ref=jacraenyzrorgjhsdvvf <value>");
   });
+
+  it("collapses the doubled 'Expected: Expected' prefix for an invalid choice flag value", () => {
+    const errors = formatCliErrorsForDisplay([
+      new CliError.InvalidValue({
+        option: "size",
+        value: "nano",
+        expected: 'Expected "micro" | "small" | "medium", got "nano"',
+        kind: "flag",
+      }),
+    ]);
+
+    expect(errors.changed).toBe(true);
+    expect(errors.errors).toHaveLength(1);
+    expect(errors.errors[0]?.message).toBe(
+      'Invalid value for flag --size: "nano". Expected "micro" | "small" | "medium", got "nano"',
+    );
+    expect(errors.errors[0]?.message).not.toMatch(/Expected:\s*Expected/);
+  });
+
+  it("collapses the doubled 'Expected: Expected' prefix for an invalid choice argument value", () => {
+    const errors = formatCliErrorsForDisplay([
+      new CliError.InvalidValue({
+        option: "level",
+        value: "bogus",
+        expected: 'Expected "debug" | "info", got "bogus"',
+        kind: "argument",
+      }),
+    ]);
+
+    expect(errors.changed).toBe(true);
+    expect(errors.errors[0]?.message).toBe(
+      'Invalid value for argument <level>: "bogus". Expected "debug" | "info", got "bogus"',
+    );
+    expect(errors.errors[0]?.message).not.toMatch(/Expected:\s*Expected/);
+  });
+
+  it("also collapses the doubled prefix for a non-choice primitive whose failure text starts with 'Expected' (e.g. an invalid integer flag value)", () => {
+    // Real failure text from effect@4.0.0-beta.93's schema-backed `Primitive.integer`
+    // (also affects `float`, `boolean`, and `date` — every primitive whose parse
+    // failure happens to start with the word "Expected" hits the same doubling).
+    const errors = formatCliErrorsForDisplay([
+      new CliError.InvalidValue({
+        option: "port",
+        value: "abc",
+        expected: 'Expected a string representing a finite number, got "abc"',
+        kind: "flag",
+      }),
+    ]);
+
+    expect(errors.changed).toBe(true);
+    expect(errors.errors[0]?.message).toBe(
+      'Invalid value for flag --port: "abc". Expected a string representing a finite number, got "abc"',
+    );
+    expect(errors.errors[0]?.message).not.toMatch(/Expected:\s*Expected/);
+  });
+
+  it("leaves invalid-value errors whose expected text does not start with 'Expected' unchanged", () => {
+    // Real failure text from effect@4.0.0-beta.93's `Primitive.keyValuePair` —
+    // it never starts with the word "Expected", so it isn't doubled by
+    // `CliError.InvalidValue`'s own "Expected: " prefix and needs no rewriting.
+    const errors = formatCliErrorsForDisplay([
+      new CliError.InvalidValue({
+        option: "define",
+        value: "bogus",
+        expected: "Invalid key=value format. Expected format: key=value, got: bogus",
+        kind: "flag",
+      }),
+    ]);
+
+    expect(errors.changed).toBe(false);
+    expect(errors.errors[0]?.changed).toBe(false);
+    expect(errors.errors[0]?.message).toBe(
+      'Invalid value for flag --define: "bogus". Expected: Invalid key=value format. Expected format: key=value, got: bogus',
+    );
+  });
+
+  it("does not corrupt a value that itself contains the literal 'Expected: Expected' text", () => {
+    // Regression test: the fix must anchor on `error.expected` (the field the
+    // buggy primitive actually populates) rather than searching the fully
+    // composed `error.message`, since `error.value` is user-controlled and is
+    // interpolated into that same message twice (once directly, once again
+    // inside `expected`'s "got <value>" suffix). A value that happens to
+    // contain the literal doubled-prefix text must be left untouched.
+    const errors = formatCliErrorsForDisplay([
+      new CliError.InvalidValue({
+        option: "env",
+        value: "Expected: Expected nano",
+        expected: 'Expected "dev" | "staging" | "prod", got "Expected: Expected nano"',
+        kind: "flag",
+      }),
+    ]);
+
+    expect(errors.changed).toBe(true);
+    expect(errors.errors[0]?.message).toBe(
+      'Invalid value for flag --env: "Expected: Expected nano". Expected "dev" | "staging" | "prod", got "Expected: Expected nano"',
+    );
+  });
 });
diff --git a/apps/cli/src/shared/output/normalize-error.ts b/apps/cli/src/shared/output/normalize-error.ts
index a143b414b3..19cc375913 100644
--- a/apps/cli/src/shared/output/normalize-error.ts
+++ b/apps/cli/src/shared/output/normalize-error.ts
@@ -1,4 +1,5 @@
 import { Cause, Option } from "effect";
+import { formatInvalidValueMessage } from "../cli/invalid-value-message.ts";
 
 type NormalizedCliError = {
   readonly code: string;
@@ -17,6 +18,16 @@ const readString = (value: ErrorRecord, key: string): string | undefined => {
   return typeof field === "string" && field.trim().length > 0 ? field.trim() : undefined;
 };
 
+// Unlike `readString`, does not trim or reject empty strings. Use this for
+// fields that carry raw user input (e.g. `CliError.InvalidValue#value`),
+// where an empty string or meaningful surrounding whitespace is a legitimate
+// value the user typed (`supabase --output-format ''`) and must be preserved
+// and reported verbatim rather than normalized away.
+const readRawString = (value: ErrorRecord, key: string): string | undefined => {
+  const field = value[key];
+  return typeof field === "string" ? field : undefined;
+};
+
 const mappedError = (error: ErrorRecord): NormalizedCliError | undefined => {
   const tag = readString(error, "_tag");
   switch (tag) {
@@ -75,6 +86,35 @@ const mappedError = (error: ErrorRecord): NormalizedCliError | undefined => {
           : "Error: required flag(s) not set",
       };
     }
+    case "InvalidValue": {
+      // `CliError.InvalidValue` for a `GlobalFlag.setting` flag (e.g.
+      // `--output-format`, or the legacy `--output`/`-o`, `--dns-resolver`,
+      // `--agent`) never reaches `CliOutput.Formatter` — `Command.runWith`
+      // validates those flags in a step that runs outside the `ShowHelp`
+      // path, so the failure lands here instead. Apply the same
+      // doubled-"Expected"-prefix workaround `subcommand-flag-suggestions.ts`
+      // applies for the `ShowHelp`-formatted case (see CLI-1898), so every
+      // `InvalidValue` failure — whichever path it takes — renders the same
+      // way.
+      const option = readString(error, "option");
+      // Raw read: `value` is the exact argv token the user typed and can
+      // legitimately be `""` or carry surrounding whitespace — `readString`
+      // would trim it or drop it entirely, either masking the bug this case
+      // exists to fix or misreporting what the user actually typed.
+      const value = readRawString(error, "value");
+      const expected = readString(error, "expected");
+      const kind = readString(error, "kind");
+      if (
+        option !== undefined &&
+        value !== undefined &&
+        expected !== undefined &&
+        (kind === "flag" || kind === "argument")
+      ) {
+        const message = formatInvalidValueMessage({ option, value, expected, kind });
+        if (message !== undefined) return { code: tag, message };
+      }
+      return undefined;
+    }
     case "ShowHelp": {
       // Effect CLI wraps parse errors in a ShowHelp envelope (`CliError.ts`)
       // whose `errors` array holds the underlying causes. If exactly one of
diff --git a/apps/cli/src/shared/output/normalize-error.unit.test.ts b/apps/cli/src/shared/output/normalize-error.unit.test.ts
index 1eba0f07f6..107600ac13 100644
--- a/apps/cli/src/shared/output/normalize-error.unit.test.ts
+++ b/apps/cli/src/shared/output/normalize-error.unit.test.ts
@@ -1,5 +1,6 @@
 import { describe, expect, test } from "vitest";
 import { Cause } from "effect";
+import { CliError } from "effect/unstable/cli";
 import { formatCliError, normalizeCause, normalizeCliError } from "./normalize-error.ts";
 
 describe("normalizeCliError", () => {
@@ -50,6 +51,98 @@ describe("normalizeCliError", () => {
     });
   });
 
+  test("InvalidValue collapses the doubled 'Expected: Expected' prefix (e.g. a bad GlobalFlag.setting value)", () => {
+    // Regression test for CLI-1898: `--output-format`/`--dns-resolver`/`--agent`/
+    // legacy `--output` are `GlobalFlag.setting` flags backed by `Flag.choice`.
+    // `Command.runWith` validates their values in a step that runs outside the
+    // `ShowHelp` path, so a bad value never reaches `CliOutput.Formatter` (and
+    // `subcommand-flag-suggestions.ts`'s fix) — it surfaces here instead.
+    const error = new CliError.InvalidValue({
+      option: "output-format",
+      value: "bogus",
+      expected: 'Expected "text" | "json" | "stream-json", got "bogus"',
+      kind: "flag",
+    });
+
+    expect(normalizeCliError(error)).toEqual({
+      code: "InvalidValue",
+      message:
+        'Invalid value for flag --output-format: "bogus". Expected "text" | "json" | "stream-json", got "bogus"',
+    });
+  });
+
+  test("InvalidValue preserves an empty invalid value (e.g. `--output-format ''`)", () => {
+    // Regression test for a Codex review finding on CLI-1898: `value` is raw
+    // user input read straight off argv, so `''` is a legitimate way to
+    // trigger this failure. Reading it through the trim-and-reject-empty
+    // `readString` helper would fail the guard and leak the original
+    // doubled "Expected: Expected" message instead of fixing it.
+    const error = new CliError.InvalidValue({
+      option: "output-format",
+      value: "",
+      expected: 'Expected "text" | "json" | "stream-json", got ""',
+      kind: "flag",
+    });
+
+    expect(normalizeCliError(error)).toEqual({
+      code: "InvalidValue",
+      message:
+        'Invalid value for flag --output-format: "". Expected "text" | "json" | "stream-json", got ""',
+    });
+  });
+
+  test("InvalidValue preserves surrounding whitespace in the invalid value (e.g. `--output-format ' json'`)", () => {
+    // Regression test for the same Codex finding: trimming `value` would
+    // report a different string than what the user actually typed.
+    const error = new CliError.InvalidValue({
+      option: "output-format",
+      value: " json",
+      expected: 'Expected "text" | "json" | "stream-json", got " json"',
+      kind: "flag",
+    });
+
+    expect(normalizeCliError(error)).toEqual({
+      code: "InvalidValue",
+      message:
+        'Invalid value for flag --output-format: " json". Expected "text" | "json" | "stream-json", got " json"',
+    });
+  });
+
+  test("InvalidValue leaves an already-clean 'expected' message untouched", () => {
+    const error = new CliError.InvalidValue({
+      option: "define",
+      value: "bogus",
+      expected: "Invalid key=value format. Expected format: key=value, got: bogus",
+      kind: "flag",
+    });
+
+    expect(normalizeCliError(error)).toEqual({
+      code: "InvalidValue",
+      message:
+        'Invalid value for flag --define: "bogus". Expected: Invalid key=value format. Expected format: key=value, got: bogus',
+    });
+  });
+
+  test("ShowHelp envelope unwraps a single InvalidValue with the same doubled-prefix fix", () => {
+    const error = {
+      _tag: "ShowHelp",
+      commandPath: ["db", "lint"],
+      errors: [
+        new CliError.InvalidValue({
+          option: "level",
+          value: "bogus",
+          expected: 'Expected "warning" | "error", got "bogus"',
+          kind: "flag",
+        }),
+      ],
+    };
+
+    expect(normalizeCliError(error)).toEqual({
+      code: "InvalidValue",
+      message: 'Invalid value for flag --level: "bogus". Expected "warning" | "error", got "bogus"',
+    });
+  });
+
   test("ShowHelp envelope unwraps a single MissingOption to Cobra wording", () => {
     // Effect CLI raises `ShowHelp` containing the parse error in its `errors`
     // array. We unwrap to surface the actionable message instead of "Help requested".
diff --git a/apps/cli/src/shared/output/text-formatter.unit.test.ts b/apps/cli/src/shared/output/text-formatter.unit.test.ts
index f49cf597ea..fff1a4a17b 100644
--- a/apps/cli/src/shared/output/text-formatter.unit.test.ts
+++ b/apps/cli/src/shared/output/text-formatter.unit.test.ts
@@ -53,4 +53,22 @@ describe("textCliOutputFormatter", () => {
     expect(text).toContain("Did you mean this?");
     expect(text).toContain("--plan");
   });
+
+  it("does not double the 'Expected' prefix for an invalid choice flag value", () => {
+    const formatter = textCliOutputFormatter();
+
+    const text = formatter.formatErrors([
+      new CliError.InvalidValue({
+        option: "size",
+        value: "nano",
+        expected: 'Expected "micro" | "small" | "medium", got "nano"',
+        kind: "flag",
+      }),
+    ]);
+
+    expect(text).toContain(
+      'Invalid value for flag --size: "nano". Expected "micro" | "small" | "medium", got "nano"',
+    );
+    expect(text).not.toMatch(/Expected:\s*Expected/);
+  });
 });