diff --git a/src/client/http.ts b/src/client/http.ts
index 1394bc4..978841a 100644
--- a/src/client/http.ts
+++ b/src/client/http.ts
@@ -71,11 +71,15 @@ export async function request(config: Config, opts: RequestOpts): Promise<Respon
     Object.assign(headers, getAuthHeader(cred));
   }
 
-  if (opts.body !== undefined) {
+  // The API edge answers a mutating request without a JSON content type with a
+  // 403 HTML page before it reaches a worker, so a body-less POST, PUT, PATCH or
+  // DELETE goes out as an empty object.
+  const payload = opts.body !== undefined ? opts.body : method === 'GET' ? undefined : {};
+  if (payload !== undefined) {
     headers['Content-Type'] = 'application/json';
   }
 
-  const body = opts.body !== undefined ? JSON.stringify(opts.body) : undefined;
+  const body = payload !== undefined ? JSON.stringify(payload) : undefined;
 
   logVerbose(config, '>', `${method} ${fullUrl}`);
   if (headers['x-api-key']) {
diff --git a/src/commands/auth/bind-run.ts b/src/commands/auth/bind-run.ts
index 83a7326..731de3f 100644
--- a/src/commands/auth/bind-run.ts
+++ b/src/commands/auth/bind-run.ts
@@ -40,13 +40,9 @@ export async function bindOnboardingRun(
     process.stderr.write(`Not signed in; onboarding run ${runId} left unbound.\n`);
     return { bound: false, runId };
   }
-  // The route takes no input, but the API edge answers a body-less POST without
-  // a JSON content type with a bare 403 before the worker sees it (nominal#1575).
-  // `request` sets Content-Type only when a body is present, so send `{}`.
   const result = await requestJson<{ bound: boolean }>(config, {
     method: 'POST',
     url: `/v1/auth/onboarding_runs/${runId}/bind`,
-    body: {},
     ...(apiKey ? { headers: { 'x-api-key': apiKey }, noAuth: true } : {}),
   });
   const bound = result.bound === true;
diff --git a/test/client-http-body.test.ts b/test/client-http-body.test.ts
new file mode 100644
index 0000000..dfd5c2a
--- /dev/null
+++ b/test/client-http-body.test.ts
@@ -0,0 +1,47 @@
+import { describe, it, before, after, beforeEach } from 'node:test';
+import assert from 'node:assert/strict';
+
+const { request } = await import('../src/client/http');
+const { mockConfig } = await import('./helpers/config');
+
+type Call = { method: string; contentType: string | null; body: string | undefined };
+
+// The Polylane API edge answers a mutating request without a JSON content type
+// with a 403 HTML page before it reaches a worker (nominal#1575). The client
+// must therefore send the header and an empty object on every POST, PUT, PATCH
+// and DELETE that has no body of its own; GET stays body-less.
+describe('request body and content type', () => {
+  const originalFetch = globalThis.fetch;
+  let calls: Call[] = [];
+
+  before(() => {
+    globalThis.fetch = (async (_url: string | URL | Request, init?: RequestInit): Promise<Response> => {
+      const headers = new Headers(init?.headers as HeadersInit);
+      calls.push({ method: String(init?.method), contentType: headers.get('content-type'), body: init?.body === undefined ? undefined : String(init.body) });
+      return new Response(JSON.stringify({ message: null, success: true, error: null, result: {} }), { status: 200, headers: { 'content-type': 'application/json' } });
+    }) as typeof fetch;
+  });
+  after(() => {
+    globalThis.fetch = originalFetch;
+  });
+  beforeEach(() => {
+    calls = [];
+  });
+
+  for (const method of ['POST', 'PUT', 'PATCH', 'DELETE'] as const) {
+    it(`${method} without a body sends a JSON content type and an empty object`, async () => {
+      await request(mockConfig(), { url: '/v1/things/x', method, noAuth: true });
+      assert.deepEqual(calls, [{ method, contentType: 'application/json', body: '{}' }]);
+    });
+  }
+
+  it('a body given by the caller is sent as is', async () => {
+    await request(mockConfig(), { url: '/v1/things', method: 'POST', body: { a: 1 }, noAuth: true });
+    assert.deepEqual(calls, [{ method: 'POST', contentType: 'application/json', body: '{"a":1}' }]);
+  });
+
+  it('GET stays body-less with no content type', async () => {
+    await request(mockConfig(), { url: '/v1/things', noAuth: true });
+    assert.deepEqual(calls, [{ method: 'GET', contentType: null, body: undefined }]);
+  });
+});