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Published: July 15, 2026
While passkeys are straightforward to implement, capabilities and best practices
continue to evolve. Learning why they are needed and how to use them takes time.
To simplify this process, the Chrome team introduces the Modern Web Guidance
passkey skills to help you and your agents build secure, modern sign-in
experiences using passkeys.
## Why use the passkey skills?
[Modern Web Guidance](https://developer.chrome.com/docs/modern-web-guidance.md.txt) is a set of skills designed to
guide AI coding agents, such as Anti Gravity or Claude Code. With the passkey
skills, you can implement registration, authentication, management, and
reauthentication using the latest APIs and best practices. The coding agent
autonomously generates the implementation for both frontend UI and backend
logic.
An evaluation shows that an implementation using passkey skills outperforms one
without them on Claude Code Opus 4.8. This evaluation uses the demo application
and prompts described in this document.
| | Without passkey skills | With passkey skills |
|---|---|---|
| PASS | 47 | 80 |
| FAIL | 32 | 0 |
| N/A | 12 | 11 |
| Total | 91 | 91 |
The most visible difference is the passkey management screen, which displays a
list of created passkeys based on a community-curated passkey provider list,
following the [passkey management best
practices](https://web.dev/articles/passkey-management#display_a_list_of_registered_passkeys).
 Notice how the passkey provider name and icon are recognized.
The passkey skills also empower your coding agent with powerful, less visible
capabilities:
- **`getClientCapabilities`:** Perform modern feature detection.
- **JSON Serialization:** Serialize encoded payload with one JavaScript call.
- **Error handling:** Display a message or dismiss depending on the error type.
- **Conditional mediation:** Allow users to sign in directly from browser autofill suggestions.
- **Signal API:** Keep the list of credentials in sync between the provider and your server.
- **Conditional create:** Automatically create a passkey for users who have recently signed in with a password.
## Step 1: Clone the demo repository
Try passkey skills with the [passkey skills
demo](https://github.com/GoogleChromeLabs/passkey-skills-demo) project. Clone
the repository:
```bash
git clone git@github.com:GoogleChromeLabs/passkey-skills-demo.git
```
## Step 2: Install Modern Web Guidance
Run the interactive setup wizard in your project directory to install Modern Web
Guidance:
```bash
npx modern-web-guidance@latest install
```
This wizard adds the necessary files to your project layout, letting your AI
agent understand the passkey requirements.
> [!NOTE]
> **Note:** Due to a [Claude Code Skills directory
> issue](https://github.com/vercel-labs/skills/issues/744), make sure you have a `.claude` directory.
## Step 3: Use prompts
Once installed, use these prompts to build your features. These examples cover
the four use cases that the passkeys skill covers and are specifically designed
for the sandbox project.
### Registration
Allow users to register a passkey for their account. To implement, try the
following prompt:
```text
Implement passkey registration at /settings page under start directory
```
**Example agent execution**: The agent autonomously generates or modifies the
frontend UI and backend logic to register a new passkey.
### Authentication
Enable returning users to sign in quickly using discoverable credentials,
through either explicit button triggers or browser autofill suggestions. To
implement, try the following prompt:
```text
Implement passkey authentication at the top page under start directory
```
**Example agent execution**: The agent handles the login and verification loop
autonomously on the main landing or sign-in route.
### Management
Let users view, rename, and delete their registered passkeys while keeping
credentials synchronized between the server and the browser's password managers.
To implement, try the following prompt:
```text
Implement passkey management at /settings page under start directory
```
**Example agent execution**: The agent creates structural choices for users to
view, add, or revoke existing passkeys.
### Reauthentication
Verify a signed-in user's identity using their existing passkeys before allowing
sensitive actions like security changes or financial transfers. To implement,
try the following prompt:
```text
Implement passkey reauthentication at /reauth under start directory
```
**Example agent execution**: The agent sets up step-up security for sensitive
user actions.
> [!NOTE]
> **Note:** If the passkey skills aren't picked up, [try the following
> command](https://developer.chrome.com/docs/modern-web-guidance/troubleshoot#diagnose_modern_web_guidance_not_being_used_by_your_agent) for Claude Code and Anti Gravity:
```text
/modern-web-guidance
```
Or the following command for Codex:
```text
$modern-web-guidance
```
Refer to your agent's documentation, or ask your agent how to directly invoke
the `modern-web-guidance` skill if you are unsure.
## Integrate the server side
While coding agents can generate server-side passkey code, they might not use
the latest library versions. The passkey skills demo repository includes the
`simplewebauthn` skill, which is a skill for the recommended server-side library
for JavaScript and TypeScript---[SimpleWebAuthn](https://simplewebauthn.dev/).
This skill complements the coding agent's behavior.
For other server-side programming languages, Google recommends integrating
passkeys with a language-specific passkey, FIDO2, or WebAuthn library, along
with a skill to use its latest APIs. Library authors write their own skills so
that coding agents can always use the latest APIs.
## Disclaimer and feedback
Modern Web Guidance and the passkey skills are in preview. These skills were
developed and tested using the [passkey skills
demo](https://github.com/GoogleChromeLabs/passkey-skills-demo) project with
agents such as Antigravity and Claude Code. Although tested against other
codebases, the skills might require adjustments beyond the provided example
prompts. Review the generated code to ensure it meets your expectations, and
provide additional prompts as needed.
The Chrome team updates these skills and adds other identity and authentication
features to Modern Web Guidance over time. If you have feedback or feature
requests, submit them to the
[modern-web-guidance-src](https://github.com/GoogleChrome/modern-web-guidance-src/issues)
repository.
Try it today to simplify passkey adoption.