diff --git a/README.md b/README.md
index 5f553ba..3a17e19 100644
--- a/README.md
+++ b/README.md
@@ -181,6 +181,8 @@ flowchart TD
 - Reuse session state with `--session-name` for continuity.
 - Keep locale/timezone consistent with target market.
 - Use `--risk-mode block` in strict pipelines that require explicit operator intervention on verification pages.
+- For `cookies set`, use either `--url <url>`, or `--domain <domain> --path <path>` together.
+- If `--url`, `--domain`, and `--path` are all omitted, the cookie is scoped from the current page URL.
 
 ## Validation Scripts
 
diff --git a/cli/src/commands.rs b/cli/src/commands.rs
index 57554f4..820d44d 100644
--- a/cli/src/commands.rs
+++ b/cli/src/commands.rs
@@ -828,6 +828,17 @@ pub fn parse_command(args: &[String], flags: &Flags) -> Result<Value, ParseError
                         }
                     }
 
+                    // Playwright requires either `url` or a complete `domain`+`path` pair.
+                    let has_url = cookie.get("url").is_some();
+                    let has_domain = cookie.get("domain").is_some();
+                    let has_path = cookie.get("path").is_some();
+                    if !has_url && (has_domain != has_path) {
+                        return Err(ParseError::MissingArguments {
+                            context: "cookies set".to_string(),
+                            usage: "When not using --url, you must provide both --domain <domain> and --path <path>",
+                        });
+                    }
+
                     Ok(json!({ "id": id, "action": "cookies_set", "cookies": [cookie] }))
                 }
                 "clear" => Ok(json!({ "id": id, "action": "cookies_clear" })),
@@ -2097,28 +2108,34 @@ mod tests {
     }
 
     #[test]
-    fn test_cookies_set_with_domain() {
-        let cmd = parse_command(
+    fn test_cookies_set_with_domain_requires_path() {
+        let result = parse_command(
             &args("cookies set mycookie myvalue --domain example.com"),
             &default_flags(),
+        );
+        assert!(result.is_err());
+    }
+
+    #[test]
+    fn test_cookies_set_with_path_requires_domain() {
+        let result = parse_command(
+            &args("cookies set mycookie myvalue --path /api"),
+            &default_flags(),
+        );
+        assert!(result.is_err());
+    }
+
+    #[test]
+    fn test_cookies_set_with_domain_and_path() {
+        let cmd = parse_command(
+            &args("cookies set mycookie myvalue --domain example.com --path /api"),
+            &default_flags(),
         )
         .unwrap();
         assert_eq!(cmd["action"], "cookies_set");
         assert_eq!(cmd["cookies"][0]["name"], "mycookie");
         assert_eq!(cmd["cookies"][0]["value"], "myvalue");
         assert_eq!(cmd["cookies"][0]["domain"], "example.com");
-    }
-
-    #[test]
-    fn test_cookies_set_with_path() {
-        let cmd = parse_command(
-            &args("cookies set mycookie myvalue --path /api"),
-            &default_flags(),
-        )
-        .unwrap();
-        assert_eq!(cmd["action"], "cookies_set");
-        assert_eq!(cmd["cookies"][0]["name"], "mycookie");
-        assert_eq!(cmd["cookies"][0]["value"], "myvalue");
         assert_eq!(cmd["cookies"][0]["path"], "/api");
     }
 
diff --git a/cli/src/output.rs b/cli/src/output.rs
index 834942b..0f3ae46 100644
--- a/cli/src/output.rs
+++ b/cli/src/output.rs
@@ -1486,8 +1486,8 @@ Operations:
 
 Cookie Set Options:
   --url <url>                        URL for the cookie (allows setting before page load)
-  --domain <domain>                  Cookie domain (e.g., ".example.com")
-  --path <path>                      Cookie path (e.g., "/api")
+  --domain <domain>                  Cookie domain (use with --path, e.g., ".example.com")
+  --path <path>                      Cookie path (use with --domain, e.g., "/api")
   --httpOnly                         Set HttpOnly flag (prevents JavaScript access)
   --secure                           Set Secure flag (HTTPS only)
   --sameSite <Strict|Lax|None>       SameSite policy
@@ -1495,6 +1495,7 @@ Cookie Set Options:
 
 Note: If --url, --domain, and --path are all omitted, the cookie will be set
 for the current page URL.
+When --url is omitted, --domain and --path must be provided together.
 
 Global Options:
   --json               Output as JSON
diff --git a/docs/src/app/commands/page.mdx b/docs/src/app/commands/page.mdx
index 6be0158..63477c3 100644
--- a/docs/src/app/commands/page.mdx
+++ b/docs/src/app/commands/page.mdx
@@ -172,6 +172,14 @@ agent-browser storage local clear     # Clear all
 agent-browser storage session         # Same for sessionStorage
 ```
 
+For `cookies set`, use one of these patterns:
+
+- `--url <url>`
+- `--domain <domain> --path <path>`
+- omit all three to scope from the current page URL
+
+When `--url` is omitted, `--domain` and `--path` must be provided together.
+
 ## Network
 
 ```bash
diff --git a/skills/agent-browser/SKILL.md b/skills/agent-browser/SKILL.md
index c2d5dd9..a7a341a 100644
--- a/skills/agent-browser/SKILL.md
+++ b/skills/agent-browser/SKILL.md
@@ -137,6 +137,20 @@ agent-browser state load auth.json
 agent-browser open https://app.example.com/dashboard
 ```
 
+### Cookie Injection for Auth Callbacks
+
+```bash
+# Before navigation: set by URL
+agent-browser cookies set session_id "abc123" --url https://app.example.com/api/auth/sso/callback
+
+# Explicit domain/path pair (must be provided together)
+agent-browser cookies set auth_token "xyz789" --domain .example.com --path /api
+
+# Or navigate first and rely on current URL
+agent-browser open https://app.example.com/api/auth/sso/callback
+agent-browser cookies set callback_token "token123"
+```
+
 ### Session Persistence
 
 ```bash
diff --git a/src/actions.ts b/src/actions.ts
index 9860ef8..4c11d40 100644
--- a/src/actions.ts
+++ b/src/actions.ts
@@ -1378,9 +1378,20 @@ async function handleCookiesSet(
 ): Promise<Response> {
   const page = browser.getPage();
   const context = page.context();
-  // Auto-fill URL for cookies that don't have domain/path/url set
+  // Playwright requires either `url` or a complete `domain` + `path` pair.
+  // If none are provided, we default to the current page URL.
   const pageUrl = page.url();
   const cookies = command.cookies.map((cookie) => {
+    const hasUrl = Boolean(cookie.url);
+    const hasDomain = Boolean(cookie.domain);
+    const hasPath = Boolean(cookie.path);
+
+    if (!hasUrl && hasDomain !== hasPath) {
+      throw new Error(
+        `Invalid cookie "${cookie.name}": provide either url, or both domain and path`
+      );
+    }
+
     if (!cookie.url && !cookie.domain && !cookie.path) {
       return { ...cookie, url: pageUrl };
     }