diff --git a/packages/client/src/promise/generated/types.ts b/packages/client/src/promise/generated/types.ts
index b74f223006e..17d21221a70 100644
--- a/packages/client/src/promise/generated/types.ts
+++ b/packages/client/src/promise/generated/types.ts
@@ -2510,7 +2510,7 @@ export type FormRequestListOutput = {
             custom?: boolean
             default?: Array<string>
           }
-        | { type: "external"; url: string; title?: string; description?: string }
+        | { key: string; type: "external"; url: string; title?: string; description?: string }
       ),
       ...Array<
         | {
@@ -2593,7 +2593,7 @@ export type FormRequestListOutput = {
             custom?: boolean
             default?: Array<string>
           }
-        | { type: "external"; url: string; title?: string; description?: string }
+        | { key: string; type: "external"; url: string; title?: string; description?: string }
       >,
     ]
   }>
@@ -2689,7 +2689,7 @@ export type FormListOutput = {
             custom?: boolean
             default?: Array<string>
           }
-        | { type: "external"; url: string; title?: string; description?: string }
+        | { key: string; type: "external"; url: string; title?: string; description?: string }
       ),
       ...Array<
         | {
@@ -2772,7 +2772,7 @@ export type FormListOutput = {
             custom?: boolean
             default?: Array<string>
           }
-        | { type: "external"; url: string; title?: string; description?: string }
+        | { key: string; type: "external"; url: string; title?: string; description?: string }
       >,
     ]
   }>
@@ -2874,7 +2874,13 @@ export type FormCreateInput = {
             readonly custom?: boolean
             readonly default?: ReadonlyArray<string>
           }
-        | { readonly type: "external"; readonly url: string; readonly title?: string; readonly description?: string }
+        | {
+            readonly key: string
+            readonly type: "external"
+            readonly url: string
+            readonly title?: string
+            readonly description?: string
+          }
       ),
       ...Array<
         | {
@@ -2965,7 +2971,13 @@ export type FormCreateInput = {
             readonly custom?: boolean
             readonly default?: ReadonlyArray<string>
           }
-        | { readonly type: "external"; readonly url: string; readonly title?: string; readonly description?: string }
+        | {
+            readonly key: string
+            readonly type: "external"
+            readonly url: string
+            readonly title?: string
+            readonly description?: string
+          }
       >,
     ]
   }["id"]
@@ -3063,7 +3075,13 @@ export type FormCreateInput = {
             readonly custom?: boolean
             readonly default?: ReadonlyArray<string>
           }
-        | { readonly type: "external"; readonly url: string; readonly title?: string; readonly description?: string }
+        | {
+            readonly key: string
+            readonly type: "external"
+            readonly url: string
+            readonly title?: string
+            readonly description?: string
+          }
       ),
       ...Array<
         | {
@@ -3154,7 +3172,13 @@ export type FormCreateInput = {
             readonly custom?: boolean
             readonly default?: ReadonlyArray<string>
           }
-        | { readonly type: "external"; readonly url: string; readonly title?: string; readonly description?: string }
+        | {
+            readonly key: string
+            readonly type: "external"
+            readonly url: string
+            readonly title?: string
+            readonly description?: string
+          }
       >,
     ]
   }["title"]
@@ -3252,7 +3276,13 @@ export type FormCreateInput = {
             readonly custom?: boolean
             readonly default?: ReadonlyArray<string>
           }
-        | { readonly type: "external"; readonly url: string; readonly title?: string; readonly description?: string }
+        | {
+            readonly key: string
+            readonly type: "external"
+            readonly url: string
+            readonly title?: string
+            readonly description?: string
+          }
       ),
       ...Array<
         | {
@@ -3343,7 +3373,13 @@ export type FormCreateInput = {
             readonly custom?: boolean
             readonly default?: ReadonlyArray<string>
           }
-        | { readonly type: "external"; readonly url: string; readonly title?: string; readonly description?: string }
+        | {
+            readonly key: string
+            readonly type: "external"
+            readonly url: string
+            readonly title?: string
+            readonly description?: string
+          }
       >,
     ]
   }["metadata"]
@@ -3441,7 +3477,13 @@ export type FormCreateInput = {
             readonly custom?: boolean
             readonly default?: ReadonlyArray<string>
           }
-        | { readonly type: "external"; readonly url: string; readonly title?: string; readonly description?: string }
+        | {
+            readonly key: string
+            readonly type: "external"
+            readonly url: string
+            readonly title?: string
+            readonly description?: string
+          }
       ),
       ...Array<
         | {
@@ -3532,7 +3574,13 @@ export type FormCreateInput = {
             readonly custom?: boolean
             readonly default?: ReadonlyArray<string>
           }
-        | { readonly type: "external"; readonly url: string; readonly title?: string; readonly description?: string }
+        | {
+            readonly key: string
+            readonly type: "external"
+            readonly url: string
+            readonly title?: string
+            readonly description?: string
+          }
       >,
     ]
   }["fields"]
@@ -3626,7 +3674,7 @@ export type FormCreateOutput = {
             custom?: boolean
             default?: Array<string>
           }
-        | { type: "external"; url: string; title?: string; description?: string }
+        | { key: string; type: "external"; url: string; title?: string; description?: string }
       ),
       ...Array<
         | {
@@ -3709,7 +3757,7 @@ export type FormCreateOutput = {
             custom?: boolean
             default?: Array<string>
           }
-        | { type: "external"; url: string; title?: string; description?: string }
+        | { key: string; type: "external"; url: string; title?: string; description?: string }
       >,
     ]
   }
@@ -3808,7 +3856,7 @@ export type FormGetOutput = {
             custom?: boolean
             default?: Array<string>
           }
-        | { type: "external"; url: string; title?: string; description?: string }
+        | { key: string; type: "external"; url: string; title?: string; description?: string }
       ),
       ...Array<
         | {
@@ -3891,7 +3939,7 @@ export type FormGetOutput = {
             custom?: boolean
             default?: Array<string>
           }
-        | { type: "external"; url: string; title?: string; description?: string }
+        | { key: string; type: "external"; url: string; title?: string; description?: string }
       >,
     ]
   }
@@ -5429,7 +5477,7 @@ export type EventSubscribeOutput =
                   custom?: boolean
                   default?: Array<string>
                 }
-              | { type: "external"; url: string; title?: string; description?: string }
+              | { key: string; type: "external"; url: string; title?: string; description?: string }
             ),
             ...Array<
               | {
@@ -5492,7 +5540,7 @@ export type EventSubscribeOutput =
                   custom?: boolean
                   default?: Array<string>
                 }
-              | { type: "external"; url: string; title?: string; description?: string }
+              | { key: string; type: "external"; url: string; title?: string; description?: string }
             >,
           ]
         }
diff --git a/packages/core/src/form.ts b/packages/core/src/form.ts
index 8c810e6c8ae..30ae70e16c2 100644
--- a/packages/core/src/form.ts
+++ b/packages/core/src/form.ts
@@ -224,15 +224,16 @@ export const locationLayer = layer
 export const node = makeLocationNode({ service: Service, layer, deps: [EventV2.node] })
 
 function validateAnswer(form: Info, answer: Answer) {
-  const fields = new Map(
-    form.fields.flatMap((field) => (field.type === "external" ? [] : [[field.key, field] as const])),
-  )
+  const fields = new Map(form.fields.map((field) => [field.key, field] as const))
   for (const key of Object.keys(answer)) {
     if (!fields.has(key)) return `Unknown form field: ${key}`
   }
   for (const field of form.fields) {
-    if (field.type === "external") continue
     const value = answer[field.key]
+    if (field.type === "external") {
+      if (value !== true) return `External form field must be acknowledged: ${field.key}`
+      continue
+    }
     const active = isActive(field, answer)
     if (value === undefined) {
       if (field.required && active) return `Missing required form field: ${field.key}`
@@ -266,9 +267,11 @@ function matches(when: Form.When, value: Form.Value | undefined) {
 function validateFields(fields: ReadonlyArray<Form.Field>) {
   if (fields.length === 0) return "Form must have at least one field"
   const earlier = new Map<string, InputField>()
+  const keys = new Set<string>()
   for (const field of fields) {
+    if (keys.has(field.key)) return `Duplicate form field key: ${field.key}`
+    keys.add(field.key)
     if (field.type === "external") continue
-    if (earlier.has(field.key)) return `Duplicate form field key: ${field.key}`
     for (const when of field.when ?? []) {
       const target = earlier.get(when.key)
       if (!target) return `Form field condition must reference an earlier field: ${field.key} -> ${when.key}`
diff --git a/packages/core/src/mcp/index.ts b/packages/core/src/mcp/index.ts
index 0da4ed01eeb..731e4a08adb 100644
--- a/packages/core/src/mcp/index.ts
+++ b/packages/core/src/mcp/index.ts
@@ -311,7 +311,7 @@ export const layer = Layer.effect(
                   elicitationID: input.params.elicitationId,
                   message: input.params.message,
                 },
-                fields: [{ type: "external", url: input.params.url }],
+                fields: [{ key: "elicitation", type: "external", url: input.params.url }],
               })
               .pipe(
                 Effect.raceFirst(waitForAbort(input.signal)),
@@ -355,7 +355,7 @@ export const layer = Layer.effect(
         Effect.gen(function* () {
           const formID = urlElicitations.get(input.server + "\u0000" + input.elicitationID)
           if (!formID) return
-          yield* forms.reply({ id: formID, answer: {} }).pipe(Effect.ignore)
+          yield* forms.reply({ id: formID, answer: { elicitation: true } }).pipe(Effect.ignore)
         }),
     } satisfies MCPClient.ElicitationHandler
 
diff --git a/packages/core/test/form.test.ts b/packages/core/test/form.test.ts
index 44893d3b826..33283722032 100644
--- a/packages/core/test/form.test.ts
+++ b/packages/core/test/form.test.ts
@@ -61,10 +61,10 @@ describe("Form", () => {
       const externalOnly = yield* service.create({
         sessionID: "global",
         title: "External setup",
-        fields: [{ type: "external", url: "https://example.com/setup" }],
+        fields: [{ key: "setup", type: "external", url: "https://example.com/setup" }],
       })
-      yield* service.reply({ id: externalOnly.id, answer: {} })
-      expect(yield* service.state(externalOnly.id)).toEqual({ status: "answered", answer: {} })
+      yield* service.reply({ id: externalOnly.id, answer: { setup: true } })
+      expect(yield* service.state(externalOnly.id)).toEqual({ status: "answered", answer: { setup: true } })
     }),
   )
 
@@ -247,6 +247,13 @@ describe("Form", () => {
         ]),
       ).toEqual(new Form.InvalidFormError({ message: "Duplicate form field key: a" }))
 
+      expect(
+        yield* flipCreate([
+          { key: "a", type: "external", url: "https://example.com" },
+          { key: "a", type: "string" },
+        ]),
+      ).toEqual(new Form.InvalidFormError({ message: "Duplicate form field key: a" }))
+
       expect(
         yield* flipCreate([
           { key: "a", type: "boolean" },
@@ -267,25 +274,37 @@ describe("Form", () => {
     }),
   )
 
-  it.effect("treats external fields as non-answerable", () =>
+  it.effect("requires external field acknowledgements", () =>
     Effect.gen(function* () {
       const service = yield* Form.Service
       const created = yield* service.create({
         sessionID: "global",
         title: "External setup",
         fields: [
-          { type: "external", url: "https://example.com/setup", title: "Open setup" },
+          { key: "authorization", type: "external", url: "https://example.com/setup", title: "Open setup" },
           { key: "name", type: "string", required: true },
         ],
       })
 
-      const invalid = yield* service
-        .reply({ id: created.id, answer: { link: "opened", name: "Ava" } })
-        .pipe(Effect.flip)
-      expect(invalid).toEqual(new Form.InvalidAnswerError({ id: created.id, message: "Unknown form field: link" }))
+      const invalidAnswers: ReadonlyArray<Form.Answer> = [
+        { name: "Ava" },
+        { authorization: false, name: "Ava" },
+        { authorization: "yes", name: "Ava" },
+      ]
+      for (const answer of invalidAnswers) {
+        expect(yield* service.reply({ id: created.id, answer }).pipe(Effect.flip)).toEqual(
+          new Form.InvalidAnswerError({
+            id: created.id,
+            message: "External form field must be acknowledged: authorization",
+          }),
+        )
+      }
 
-      yield* service.reply({ id: created.id, answer: { name: "Ava" } })
-      expect(yield* service.state(created.id)).toEqual({ status: "answered", answer: { name: "Ava" } })
+      yield* service.reply({ id: created.id, answer: { authorization: true, name: "Ava" } })
+      expect(yield* service.state(created.id)).toEqual({
+        status: "answered",
+        answer: { authorization: true, name: "Ava" },
+      })
     }),
   )
 
diff --git a/packages/core/test/mcp.test.ts b/packages/core/test/mcp.test.ts
index 727247ba5c1..68ee1eb0ac0 100644
--- a/packages/core/test/mcp.test.ts
+++ b/packages/core/test/mcp.test.ts
@@ -47,7 +47,9 @@ type ResourceTemplatePage = {
   nextCursor?: string
 }
 
-function resourceServer(input: { resources?: boolean; listChanged?: boolean; emptyElicitation?: boolean } = {}) {
+function resourceServer(
+  input: { resources?: boolean; listChanged?: boolean; emptyElicitation?: boolean; urlElicitation?: boolean } = {},
+) {
   return Effect.acquireRelease(
     Effect.promise(async () => {
       const state = {
@@ -75,7 +77,9 @@ function resourceServer(input: { resources?: boolean; listChanged?: boolean; emp
         Promise.resolve({
           tools: input.emptyElicitation
             ? [{ name: "empty-elicitation", inputSchema: { type: "object" as const, properties: {} } }]
-            : [],
+            : input.urlElicitation
+              ? [{ name: "url-elicitation", inputSchema: { type: "object" as const, properties: {} } }]
+              : [],
         }),
       )
       if (input.emptyElicitation) {
@@ -91,6 +95,20 @@ function resourceServer(input: { resources?: boolean; listChanged?: boolean; emp
           }
         })
       }
+      if (input.urlElicitation) {
+        protocol.setRequestHandler(CallToolRequestSchema, async () => {
+          const result = await protocol.elicitInput({
+            mode: "url",
+            message: "Authorize access",
+            url: "https://example.com/authorize",
+            elicitationId: "elicitation-test",
+          })
+          return {
+            content: [{ type: "text", text: JSON.stringify(result) }],
+            structuredContent: result,
+          }
+        })
+      }
       if (input.resources !== false) {
         protocol.setRequestHandler(ListResourcesRequestSchema, (request) => {
           state.resourceLists += 1
@@ -117,6 +135,7 @@ function resourceServer(input: { resources?: boolean; listChanged?: boolean; emp
         state,
         url: http.url.toString(),
         sendResourceListChanged: () => protocol.sendResourceListChanged(),
+        completeElicitation: () => protocol.createElicitationCompletionNotifier("elicitation-test")(),
         close: async () => {
           await protocol.close().catch(() => {})
           await http.stop(true)
@@ -127,7 +146,10 @@ function resourceServer(input: { resources?: boolean; listChanged?: boolean; emp
   )
 }
 
-function resourceMcpLayer(url: string) {
+function resourceMcpLayer(
+  url: string,
+  form: Partial<Form.Interface> = { ask: () => Effect.die("Empty MCP elicitation must not create a form") },
+) {
   const directory = AbsolutePath.make(import.meta.dir)
   const unusedIntegration = () => Effect.die("unused integration service")
   return MCP.layer.pipe(
@@ -159,9 +181,7 @@ function resourceMcpLayer(url: string) {
               data,
             } as EventV2.Payload<typeof definition>),
         }),
-        Layer.mock(Form.Service, {
-          ask: () => Effect.die("Empty MCP elicitation must not create a form"),
-        }),
+        Layer.mock(Form.Service, form),
         Layer.mock(Integration.Service, {
           connection: {
             active: unusedIntegration,
@@ -527,6 +547,42 @@ test("accepts empty MCP elicitations without creating forms", async () => {
   )
 })
 
+test("acknowledges completed MCP URL elicitations without returning internal content", async () => {
+  await Effect.runPromise(
+    Effect.scoped(
+      Effect.gen(function* () {
+        const server = yield* resourceServer({ resources: false, urlElicitation: true })
+        const asked = yield* Deferred.make<Form.CreateInput>()
+        const terminal = yield* Deferred.make<Form.TerminalState>()
+        const replied = yield* Deferred.make<Form.ReplyInput>()
+        const call = yield* Effect.gen(function* () {
+          const service = yield* MCP.Service
+          return yield* service.callTool({ server: "resources", name: "url-elicitation" })
+        }).pipe(
+          Effect.provide(
+            resourceMcpLayer(server.url, {
+              ask: (input) => Deferred.succeed(asked, input).pipe(Effect.andThen(Deferred.await(terminal))),
+              reply: (input) =>
+                Effect.gen(function* () {
+                  yield* Deferred.succeed(replied, input)
+                  yield* Deferred.succeed(terminal, { status: "answered", answer: input.answer })
+                }),
+            }),
+          ),
+          Effect.forkScoped,
+        )
+
+        const form = yield* Deferred.await(asked)
+        expect(form.fields).toEqual([{ key: "elicitation", type: "external", url: "https://example.com/authorize" }])
+
+        yield* Effect.promise(server.completeElicitation)
+        expect((yield* Deferred.await(replied)).answer).toEqual({ elicitation: true })
+        expect((yield* Fiber.join(call)).structured).toEqual({ action: "accept" })
+      }),
+    ),
+  )
+})
+
 test("loads and reads MCP resources", async () => {
   await Effect.runPromise(
     Effect.scoped(
diff --git a/packages/opencode/test/cli/run/noninteractive.test.ts b/packages/opencode/test/cli/run/noninteractive.test.ts
index 043dcde413c..2b13155403d 100644
--- a/packages/opencode/test/cli/run/noninteractive.test.ts
+++ b/packages/opencode/test/cli/run/noninteractive.test.ts
@@ -14,7 +14,7 @@ function form(id: string, sessionID: string): FormInfo {
     id,
     sessionID,
     title: "Input requested",
-    fields: [{ type: "external", url: "https://example.com/form" }],
+    fields: [{ key: "authorization", type: "external", url: "https://example.com/form" }],
   }
 }
 
diff --git a/packages/opencode/test/server/httpapi-exercise/index.ts b/packages/opencode/test/server/httpapi-exercise/index.ts
index 71a0bea3bd6..88617f46ab5 100644
--- a/packages/opencode/test/server/httpapi-exercise/index.ts
+++ b/packages/opencode/test/server/httpapi-exercise/index.ts
@@ -840,7 +840,7 @@ const scenarios: Scenario[] = [
       headers: ctx.headers(),
       body: {
         title: "External form",
-        fields: [{ type: "external", url: "https://example.com/form" }],
+        fields: [{ key: "authorization", type: "external", url: "https://example.com/form" }],
       },
     }))
     .json(200, (body) => {
diff --git a/packages/schema/src/form.ts b/packages/schema/src/form.ts
index c12620b0274..6c2fdc29e80 100644
--- a/packages/schema/src/form.ts
+++ b/packages/schema/src/form.ts
@@ -95,6 +95,7 @@ export const MultiselectField = Schema.Struct({
 export interface MultiselectField extends Schema.Schema.Type<typeof MultiselectField> {}
 
 export const ExternalField = Schema.Struct({
+  key: Schema.String,
   type: Schema.Literal("external"),
   url: Schema.String,
   title: Schema.String.pipe(optional),
diff --git a/packages/schema/test/contract-hygiene.test.ts b/packages/schema/test/contract-hygiene.test.ts
index 8a0484f692c..c441ad88c38 100644
--- a/packages/schema/test/contract-hygiene.test.ts
+++ b/packages/schema/test/contract-hygiene.test.ts
@@ -62,9 +62,17 @@ describe("contract hygiene", () => {
         id: Form.ID.create(),
         sessionID: "global",
         title: "External form",
-        fields: [{ type: "external", url: "https://example.com" }],
+        fields: [{ key: "authorization", type: "external", url: "https://example.com" }],
       }).fields,
     ).toHaveLength(1)
+    expect(() =>
+      Schema.decodeUnknownSync(Form.Info)({
+        id: Form.ID.create(),
+        sessionID: "global",
+        title: "External form",
+        fields: [{ type: "external", url: "https://example.com" }],
+      }),
+    ).toThrow()
   })
 
   test("model defaults and provider overlays preserve public invariants", () => {
diff --git a/packages/sdk/js/src/v2/gen/types.gen.ts b/packages/sdk/js/src/v2/gen/types.gen.ts
index 64c1297d873..56a9bff6b66 100644
--- a/packages/sdk/js/src/v2/gen/types.gen.ts
+++ b/packages/sdk/js/src/v2/gen/types.gen.ts
@@ -3546,6 +3546,7 @@ export type FormMultiselectField = {
 }
 
 export type FormExternalField = {
+  key: string
   type: "external"
   url: string
   title?: string
diff --git a/packages/tui/src/routes/session/form.tsx b/packages/tui/src/routes/session/form.tsx
index 4620a4ee695..e3ec51c48d4 100644
--- a/packages/tui/src/routes/session/form.tsx
+++ b/packages/tui/src/routes/session/form.tsx
@@ -178,6 +178,7 @@ function FieldsPrompt(props: { form: FormInfo }) {
         return value === undefined ? [] : [[field.key, value]]
       }),
     ) as Record<string, string>,
+    externalReady: {} as Record<string, boolean>,
     selected: selectedRow(configuredFields()[0], configuredFields()[0]?.default),
     editing: false,
     error: "",
@@ -219,7 +220,7 @@ function FieldsPrompt(props: { form: FormInfo }) {
   })
   const answered = createMemo(
     () =>
-      answerable().filter((item) => {
+      fields().filter((item) => {
         const value = store.answers[item.key]
         return value !== undefined
       }).length,
@@ -262,8 +263,12 @@ function FieldsPrompt(props: { form: FormInfo }) {
   })
   const multi = createMemo(() => answerField()?.type === "multiselect")
   const actionLabel = createMemo(() => {
-    if (confirm()) return answerable().length === 0 ? "I finished" : "submit"
-    if (externalField()) return "open link"
+    if (confirm()) return "submit"
+    const external = externalField()
+    if (external) {
+      if (store.answers[external.key] === true) return "continue"
+      return store.externalReady[external.key] ? "I finished" : "open link"
+    }
     if (multi()) return "toggle"
     if (single()) return "submit"
     return "confirm"
@@ -490,10 +495,9 @@ function FieldsPrompt(props: { form: FormInfo }) {
   function openExternal() {
     const current = externalField()
     if (!current) return
-    const index = store.tab
     setStore("error", "")
     void open(current.url)
-      .then(() => selectTab(index + 1))
+      .then(() => setStore("externalReady", { ...store.externalReady, [current.key]: true }))
       .catch(() => setStore("error", "Could not open the browser. Copy the URL and continue manually."))
   }
 
@@ -502,11 +506,34 @@ function FieldsPrompt(props: { form: FormInfo }) {
     if (!current || !clipboard.write) return
     void clipboard
       .write(current.url)
-      .then(() => toast.show({ message: "Copied URL to clipboard", variant: "info" }))
+      .then(() => {
+        setStore("externalReady", { ...store.externalReady, [current.key]: true })
+        toast.show({ message: "Copied URL to clipboard", variant: "info" })
+      })
       .catch(toast.error)
   }
 
+  function acknowledgeExternal() {
+    const current = externalField()
+    if (!current) return
+    if (store.answers[current.key] === true) {
+      selectTab(store.tab + 1)
+      return
+    }
+    if (!store.externalReady[current.key]) {
+      openExternal()
+      return
+    }
+    answer(current.key, true)
+    selectTab(store.tab + 1)
+  }
+
   function submit() {
+    const unacknowledged = fields().find((field) => field.type === "external" && store.answers[field.key] !== true)
+    if (unacknowledged) {
+      setStore("error", `External action must be acknowledged: ${fieldLabel(unacknowledged)}`)
+      return
+    }
     const invalid = answerable().find((field) => validateValue(field, store.answers[field.key]))
     if (invalid) {
       setStore("error", validateValue(invalid, store.answers[invalid.key]) ?? "Invalid answer")
@@ -518,7 +545,7 @@ function FieldsPrompt(props: { form: FormInfo }) {
           sessionID: props.form.sessionID,
           formID: props.form.id,
           answer: Object.fromEntries(
-            answerable().flatMap((field) => {
+            fields().flatMap((field) => {
               const value = store.answers[field.key]
               return value === undefined ? [] : [[field.key, value] as const]
             }),
@@ -618,6 +645,7 @@ function FieldsPrompt(props: { form: FormInfo }) {
   useBindings(() => {
     const total = rows().length + (custom() ? 1 : 0)
     const max = Math.min(total, 9)
+    const external = externalField()
 
     return {
       mode: FORM_MODE,
@@ -657,9 +685,19 @@ function FieldsPrompt(props: { form: FormInfo }) {
           group: "Form",
           cmd: () => selectTab((store.tab - 1 + tabs()) % tabs()),
         },
-        ...(externalField()
+        ...(external
           ? [
-              { key: "return", desc: "Open link", group: "Form", cmd: openExternal },
+              {
+                key: "return",
+                desc:
+                  store.answers[external.key] === true
+                    ? "Continue"
+                    : store.externalReady[external.key]
+                      ? "Confirm completion"
+                      : "Open link",
+                group: "Form",
+                cmd: acknowledgeExternal,
+              },
               { key: "c", desc: "Copy link", group: "Form", cmd: copyExternal },
               { key: "escape", desc: "Dismiss form", group: "Form", cmd: cancel },
               ...tuiConfig.keybinds.get("app.exit"),
@@ -668,7 +706,7 @@ function FieldsPrompt(props: { form: FormInfo }) {
             ? [
                 {
                   key: "return",
-                  desc: answerable().length === 0 ? "Finish" : "Submit form",
+                  desc: "Submit form",
                   group: "Form",
                   cmd: submit,
                 },
@@ -752,9 +790,9 @@ function FieldsPrompt(props: { form: FormInfo }) {
             <text fg={theme.textMuted}>
               {confirm() ? "Review" : `Field ${Math.min(store.tab, fields().length - 1) + 1} of ${fields().length}`}
             </text>
-            <Show when={answerable().length > 0}>
+            <Show when={fields().length > 0}>
               <text fg={theme.textMuted}>
-                · {answered()}/{answerable().length} answered
+                · {answered()}/{fields().length} completed
               </text>
             </Show>
           </box>
@@ -764,7 +802,7 @@ function FieldsPrompt(props: { form: FormInfo }) {
             <For each={fields()}>
               {(item, index) => {
                 const isTab = () => index() === store.tab
-                const isAnswered = () => item.type !== "external" && store.answers[item.key] !== undefined
+                const isAnswered = () => store.answers[item.key] !== undefined
                 return (
                   <box
                     paddingLeft={1}
@@ -826,6 +864,13 @@ function FieldsPrompt(props: { form: FormInfo }) {
               >
                 {external().url}
               </text>
+              <text fg={store.answers[external().key] === true ? theme.success : theme.textMuted}>
+                {store.answers[external().key] === true
+                  ? "✓ Acknowledged"
+                  : store.externalReady[external().key]
+                    ? "Complete the external action, then press enter to confirm."
+                    : "Open or copy the URL, complete the external action, then confirm."}
+              </text>
             </box>
           )}
         </Show>
@@ -963,51 +1008,52 @@ function FieldsPrompt(props: { form: FormInfo }) {
         </Show>
 
         <Show when={confirm()}>
-          <Show when={tabbed() && answerable().length > 0}>
+          <Show when={tabbed()}>
             <box paddingLeft={1}>
               <text fg={theme.text}>Review</text>
             </box>
           </Show>
-          <Show
-            when={answerable().length > 0}
-            fallback={
-              <box paddingLeft={1}>
-                <text fg={theme.textMuted}>Complete the browser flow before continuing.</text>
-              </box>
-            }
+          <scrollbox
+            maxHeight={Math.min(fields().length, Math.max(3, dimensions().height - 14))}
+            scrollbarOptions={{ visible: false }}
+            ref={(r: ScrollBoxRenderable) => (review = r)}
           >
-            <scrollbox
-              maxHeight={Math.min(answerable().length, Math.max(3, dimensions().height - 14))}
-              scrollbarOptions={{ visible: false }}
-              ref={(r: ScrollBoxRenderable) => (review = r)}
-            >
-              <For each={answerable()}>
-                {(item) => {
-                  const value = () => display(item, store.answers[item.key])
-                  const answered = () => {
-                    const value = store.answers[item.key]
-                    return value !== undefined
-                  }
-                  const missing = () => !answered() && item.required === true
-                  const invalid = () => validateValue(item, store.answers[item.key])
+            <For each={fields()}>
+              {(item) => {
+                if (item.type === "external") {
+                  const acknowledged = () => store.answers[item.key] === true
                   return (
                     <box paddingLeft={1}>
                       <text>
                         <span style={{ fg: theme.textMuted }}>{truncate(fieldLabel(item), 40)}:</span>{" "}
-                        <span
-                          style={{
-                            fg: invalid() || missing() ? theme.error : answered() ? theme.text : theme.textMuted,
-                          }}
-                        >
-                          {invalid() ?? (answered() ? value() : missing() ? "(required)" : "(not answered)")}
+                        <span style={{ fg: acknowledged() ? theme.success : theme.error }}>
+                          {acknowledged() ? "Acknowledged" : "(acknowledgement required)"}
                         </span>
                       </text>
                     </box>
                   )
-                }}
-              </For>
-            </scrollbox>
-          </Show>
+                }
+                const value = () => display(item, store.answers[item.key])
+                const answered = () => store.answers[item.key] !== undefined
+                const missing = () => !answered() && item.required === true
+                const invalid = () => validateValue(item, store.answers[item.key])
+                return (
+                  <box paddingLeft={1}>
+                    <text>
+                      <span style={{ fg: theme.textMuted }}>{truncate(fieldLabel(item), 40)}:</span>{" "}
+                      <span
+                        style={{
+                          fg: invalid() || missing() ? theme.error : answered() ? theme.text : theme.textMuted,
+                        }}
+                      >
+                        {invalid() ?? (answered() ? value() : missing() ? "(required)" : "(not answered)")}
+                      </span>
+                    </text>
+                  </box>
+                )
+              }}
+            </For>
+          </scrollbox>
         </Show>
       </box>
       <box
@@ -1030,7 +1076,7 @@ function FieldsPrompt(props: { form: FormInfo }) {
               {"↑↓"} <span style={{ fg: theme.textMuted }}>select</span>
             </text>
           </Show>
-          <Show when={confirm() && answerable().length > 0}>
+          <Show when={confirm() && fields().length > 0}>
             <text fg={theme.text}>
               {"↑↓"} <span style={{ fg: theme.textMuted }}>scroll</span>
             </text>
@@ -1040,7 +1086,7 @@ function FieldsPrompt(props: { form: FormInfo }) {
             onMouseUp={() => {
               if (renderer.getSelection()?.getSelectedText()) return
               if (confirm()) submit()
-              if (externalField()) openExternal()
+              if (externalField()) acknowledgeExternal()
             }}
           >
             enter <span style={{ fg: theme.textMuted }}>{actionLabel()}</span>
diff --git a/packages/tui/test/cli/cmd/tui/notifications.test.ts b/packages/tui/test/cli/cmd/tui/notifications.test.ts
index efd46c38e8f..a5931c4481a 100644
--- a/packages/tui/test/cli/cmd/tui/notifications.test.ts
+++ b/packages/tui/test/cli/cmd/tui/notifications.test.ts
@@ -82,7 +82,7 @@ function form(id: string, sessionID = "session"): Extract<OpenCodeEvent, { type:
     id,
     sessionID,
     title: "Input requested",
-    fields: [{ type: "external", url: "https://example.com" }],
+    fields: [{ key: "authorization", type: "external", url: "https://example.com" }],
   }
 }
 
diff --git a/packages/tui/test/cli/tui/data.test.tsx b/packages/tui/test/cli/tui/data.test.tsx
index 8360b952923..f2f996bf5e4 100644
--- a/packages/tui/test/cli/tui/data.test.tsx
+++ b/packages/tui/test/cli/tui/data.test.tsx
@@ -12,8 +12,9 @@ import { createSessionRows, type SessionRow } from "../../../src/routes/session/
 import { createApi, createClient, createEventStream, createFetch, directory, json } from "../../fixture/tui-sdk"
 import { TestTuiContexts } from "../../fixture/tui-environment"
 
-const formFields = [{ type: "external", url: "https://example.com" }] satisfies [
+const formFields = [{ key: "authorization", type: "external", url: "https://example.com" }] satisfies [
   {
+    key: string
     type: "external"
     url: string
   },
@@ -1813,7 +1814,7 @@ test("reconciles all pending form requests when the event stream reconnects", as
       id: "frm_keep",
       sessionID: "ses_keep",
       title: "Input requested",
-      fields: [{ type: "external" as const, url: "https://example.com" }],
+      fields: [{ key: "authorization", type: "external" as const, url: "https://example.com" }],
     },
   ]
   let calls = 0
diff --git a/packages/tui/test/cli/tui/form.test.tsx b/packages/tui/test/cli/tui/form.test.tsx
new file mode 100644
index 00000000000..debb312beec
--- /dev/null
+++ b/packages/tui/test/cli/tui/form.test.tsx
@@ -0,0 +1,199 @@
+/** @jsxImportSource @opentui/solid */
+import { createDefaultOpenTuiKeymap } from "@opentui/keymap/opentui"
+import { testRender, useRenderer } from "@opentui/solid"
+import { beforeEach, expect, mock, test } from "bun:test"
+import { mkdir } from "node:fs/promises"
+import path from "node:path"
+import { onCleanup } from "solid-js"
+import { ClipboardProvider } from "../../../src/context/clipboard"
+import type { FormInfo } from "../../../src/context/data"
+import { KVProvider } from "../../../src/context/kv"
+import { SDKProvider } from "../../../src/context/sdk"
+import { ThemeProvider } from "../../../src/context/theme"
+import { TuiConfigProvider } from "../../../src/config"
+import { OpencodeKeymapProvider, registerOpencodeKeymap } from "../../../src/keymap"
+import { ToastProvider } from "../../../src/ui/toast"
+import { tmpdir } from "../../fixture/fixture"
+import { TestTuiContexts } from "../../fixture/tui-environment"
+import { createTuiResolvedConfig } from "../../fixture/tui-runtime"
+import { createApi, createClient, createEventStream, createFetch } from "../../fixture/tui-sdk"
+
+const opened: string[] = []
+let failOpen = false
+
+await mock.module("open", () => ({
+  default: (url: string) => {
+    opened.push(url)
+    return failOpen ? Promise.reject(new Error("open failed")) : Promise.resolve()
+  },
+}))
+
+beforeEach(() => {
+  opened.length = 0
+  failOpen = false
+})
+
+async function wait(fn: () => boolean, timeout = 2000) {
+  const start = Date.now()
+  while (!fn()) {
+    if (Date.now() - start > timeout) throw new Error("timed out waiting for condition")
+    await Bun.sleep(10)
+  }
+}
+
+async function mountForm(width = 80) {
+  const tmp = await tmpdir()
+  const state = path.join(tmp.path, "state")
+  await mkdir(state, { recursive: true })
+  await Bun.write(path.join(state, "kv.json"), "{}")
+
+  const events = createEventStream()
+  const replies: unknown[] = []
+  const copied: string[] = []
+  const transport = createFetch(undefined, events)
+  const fetch = Object.assign(
+    async (input: RequestInfo | URL, init?: RequestInit) => {
+      const request = input instanceof Request ? input : new Request(input, init)
+      if (new URL(request.url).pathname === "/api/session/ses_test/form/frm_test/reply") {
+        replies.push(await request.clone().json())
+        return new Response(null, { status: 204 })
+      }
+      return transport.fetch(request)
+    },
+    { preconnect: globalThis.fetch.preconnect },
+  )
+  const config = createTuiResolvedConfig()
+  const form = {
+    id: "frm_test",
+    sessionID: "ses_test",
+    title: "Authorization required",
+    fields: [
+      {
+        key: "authorization",
+        type: "external",
+        url: "https://example.com/authorize",
+        title: "Authorize access",
+      },
+    ],
+  } satisfies FormInfo
+  const { FormPrompt } = await import("../../../src/routes/session/form")
+
+  function Harness() {
+    const renderer = useRenderer()
+    const keymap = createDefaultOpenTuiKeymap(renderer)
+    const off = registerOpencodeKeymap(keymap, renderer, config)
+    onCleanup(off)
+
+    return (
+      <TestTuiContexts
+        directory={tmp.path}
+        paths={{
+          home: tmp.path,
+          state,
+          worktree: tmp.path,
+        }}
+      >
+        <ClipboardProvider
+          value={{
+            write(text) {
+              copied.push(text)
+              return Promise.resolve()
+            },
+          }}
+        >
+          <OpencodeKeymapProvider keymap={keymap}>
+            <TuiConfigProvider config={config}>
+              <SDKProvider client={createClient(fetch)} api={createApi(fetch)}>
+                <KVProvider>
+                  <ThemeProvider mode="dark" source={{ discover: () => Promise.resolve({}) }}>
+                    <ToastProvider>
+                      <FormPrompt form={form} />
+                    </ToastProvider>
+                  </ThemeProvider>
+                </KVProvider>
+              </SDKProvider>
+            </TuiConfigProvider>
+          </OpencodeKeymapProvider>
+        </ClipboardProvider>
+      </TestTuiContexts>
+    )
+  }
+
+  const app = await testRender(() => <Harness />, { width, height: 20, kittyKeyboard: true })
+  await wait(() => app.captureCharFrame().includes("Authorization required"))
+  return {
+    app,
+    copied,
+    replies,
+    async cleanup() {
+      app.renderer.destroy()
+      await tmp[Symbol.asyncDispose]()
+    },
+  }
+}
+
+test("requires explicit acknowledgement after a successful browser launch", async () => {
+  const prompt = await mountForm()
+  try {
+    prompt.app.mockInput.pressKey("right")
+    await wait(() => prompt.app.captureCharFrame().includes("(acknowledgement required)"))
+    prompt.app.mockInput.pressEnter()
+    await wait(() => prompt.app.captureCharFrame().includes("External action must be acknowledged"))
+    expect(prompt.replies).toEqual([])
+    expect(prompt.app.captureCharFrame()).toContain("External action must be acknowledged")
+
+    prompt.app.mockInput.pressKey("left")
+    failOpen = true
+    prompt.app.mockInput.pressEnter()
+    await wait(() => prompt.app.captureCharFrame().includes("Could not open the browser"))
+    expect(prompt.app.captureCharFrame()).not.toContain("press enter to confirm")
+
+    failOpen = false
+    prompt.app.mockInput.pressEnter()
+    await wait(() => prompt.app.captureCharFrame().includes("press enter to confirm"))
+    expect(opened).toEqual(["https://example.com/authorize", "https://example.com/authorize"])
+    expect(prompt.replies).toEqual([])
+
+    prompt.app.mockInput.pressEnter()
+    await wait(() => prompt.app.captureCharFrame().includes("Acknowledged"))
+    expect(prompt.replies).toEqual([])
+
+    prompt.app.mockInput.pressEnter()
+    await wait(() => prompt.replies.length === 1)
+    expect(prompt.replies).toEqual([{ answer: { authorization: true } }])
+  } finally {
+    await prompt.cleanup()
+  }
+})
+
+test("includes external acknowledgements in progress", async () => {
+  const prompt = await mountForm(32)
+  try {
+    expect(prompt.app.captureCharFrame()).toContain("0/1")
+    expect(prompt.replies).toEqual([])
+  } finally {
+    await prompt.cleanup()
+  }
+})
+
+test("requires explicit acknowledgement after copying an external URL", async () => {
+  const prompt = await mountForm()
+  try {
+    prompt.app.mockInput.pressKey("c")
+    await wait(() => prompt.copied.length === 1 && prompt.app.captureCharFrame().includes("press enter to confirm"))
+    expect(prompt.copied).toEqual(["https://example.com/authorize"])
+    expect(opened).toEqual([])
+    expect(prompt.app.captureCharFrame()).toContain("press enter to confirm")
+    expect(prompt.replies).toEqual([])
+
+    prompt.app.mockInput.pressEnter()
+    await wait(() => prompt.app.captureCharFrame().includes("Acknowledged"))
+    expect(prompt.replies).toEqual([])
+
+    prompt.app.mockInput.pressEnter()
+    await wait(() => prompt.replies.length === 1)
+    expect(prompt.replies).toEqual([{ answer: { authorization: true } }])
+  } finally {
+    await prompt.cleanup()
+  }
+})