Cerbos agent skills

Build authorization with your coding agent

Cerbos keeps access rules in policies instead of your application code, and your app asks it for each decision. Our skills teach your coding agent to write, test and enforce those policies, and ship them through Cerbos Hub.

Paste this into your coding agent

Set up Cerbos using cerbos.dev/agents.md

Works in Claude Code, Codex, Cursor, Copilot, Gemini CLI, Grok and most other agents. The agent asks before it installs anything.

View on GitHub

Install it in your agent

Each agent installs the same plugin from the cerbos/skills repository, and updates from it with one command.

claude plugin marketplace add cerbos/skillsclaude plugin install cerbos-skills@cerbos-skills

Update with claude plugin marketplace update cerbos-skills.

What the plugin runs

The plugin contains skills only. It has no hooks, no MCP servers and no background processes, and it sends no data anywhere itself. Your agent asks before running commands the skills don't pre-approve, and the README lists what each skill runs. Policy uploads and decision logs go to your own Cerbos Hub workspace, and only once you set them up. See what each skill runs

claude · expenses-api

Managers can approve expenses for their own team, up to $5,000. Add that.. Skill cerbos. Skill cerbos-policy. Writing a Cerbos policy for the manager approval rule, then I'll wire the check into the Express route.. Write cerbos/policies/resource_policies/finance/expense.yaml. Write cerbos/policies/resource_policies/finance/expense_test.yaml. Bash cerbos compile cerbos/policies. 5 tests executed [5 OK]. Bash npm install @cerbos/http. Edit src/server.js. Added 17 lines, removed 2 lines. Bash cerbos server, then curl the approve route. $1,200 → 200 · $7,500 → 403 · other team → 403. Managers can now approve expenses for their own team, up to and including $5,000. Everyone else gets a 403.

A recorded Claude Code session with the Cerbos skills on a sample Express app, condensed to its main steps.

From prompt to policy

Tell your agent who should be able to do what, in your own words. You usually don't need to name Cerbos. The starter skill, cerbos, recognizes an access-control problem, works out which parts of Cerbos it needs and hands off to the skill that builds them.

  1. Step 1

    Describe the rule

    Tell your agent who can do what, in plain words. The session above started from this one sentence.

  2. Step 2

    Get policies with tests

    Your agent writes the Cerbos policy and its test suite, then compiles both until every test passes.

  3. Step 3

    Enforce it in your code

    It adds a Cerbos SDK check to your code. The SDK asks a policy decision point (PDP), a Cerbos service beside your app.

  4. Step 4

    Ship it through Cerbos Hub

    Create a free Hub account and approve the sign-in. Your agent connects your PDP, so rule changes ship without a release.

    Sign up for Cerbos Hub

What the agent produced

The policy, tests and code change from the session above, as the agent wrote them.

cerbos/policies/resource_policies/finance/expense.yaml

apiVersion: api.cerbos.dev/v1
resourcePolicy:
  version: "default"
  resource: "expense"
  schemas:
    principalSchema:
      ref: "cerbos:///principal.json"
    resourceSchema:
      ref: "cerbos:///resources/expense.json"
  rules:
    # Managers sign off their own team's expenses; anything over $5,000 needs someone else.
    - name: manager-approves-own-team-up-to-5000
      actions: ["approve"]
      roles: ["manager"]
      effect: EFFECT_ALLOW
      condition:
        match:
          all:
            of:
              - expr: R.attr.team == P.attr.team
              - expr: R.attr.amount <= 5000

Try prompting your agent

Copy a prompt into Claude Code, Codex, Cursor, Copilot, Gemini CLI, Grok or any agent with the skills installed. Each one names the skill it uses.

  • Only managers should see salary fields in the employee API. Set that up.

    Follow the cerbos skill.

  • Turn this access-control spec into Cerbos policies with tests.

    Follow the cerbos-policy skill.

  • Filter the documents list so people only see records they're allowed to view.

    Follow the cerbos-pep-integration skill.

  • Hide the delete button for users who can't delete this project.

    Follow the cerbos-embedded-pdp skill.

What your agent learns

Eight skills cover authorization from the first design question to the audit trail. Your agent reads a skill's full instructions only when your request calls for it.

cerbos

Starts here, and picks the parts of Cerbos your request needs.

Cerbos PDP

  • cerbos-policy

    Resource and role policies, conditions and test suites.

  • cerbos-pep-integration

    SDK checks in eight languages, list filtering and agent tool calls.

  • cerbos-authz-migration

    Moves checks out of code or off OPA, Casbin, OpenFGA and others.

Cerbos Hub

  • cerbos-hub-setup

    Policy stores, deployments, PDP connections and rollback.

  • cerbos-embedded-pdp

    Checks in the browser, at the edge and in serverless, in WebAssembly.

  • cerbos-audit-insights

    Decision logs, masking, and why a request was denied.

Cerbos Synapse

  • cerbos-synapse-extension

    Adds data to requests and enforces policy at gateways.

When the rule changes

Raise the limit from $5,000 to $10,000. Hard-coded, the rule lives in every service that checks it, so each one changes and ships on its own. In Cerbos, it lives in one policy.

Hard-coded in each service

expenses-apiJavaScript

EditPull requestReviewBuildDeploy

approvals-workerGo

EditPull requestReviewBuildDeploy

finance-reportsPython

EditPull requestReviewBuildDeploy

In one Cerbos policy

Edit the policyReview the changeCerbos Hub tests it and updates every PDP

expenses-api

✓ Updated

approvals-worker

✓ Updated

finance-reports

✓ Updated

Same request, different answers

A sales manager approves a $7,500 sales expense on Tuesday, mid-rollout.

Hard-codedWith Cerbos
expenses-apiShipped Monday
Allowed
Allowed
approvals-workerShips Wednesday
Denied
Allowed
finance-reportsShips Friday
Denied
Allowed

Until the last service ships, the answer depends on which service the request reaches. With Cerbos, every PDP has the new limit within seconds.

Example services. The same holds for however many services check the rule.

Give your agent a place to ship

Cerbos Hub tests the policies your agent writes, rolls them out to every PDP and keeps an audit trail of decisions. Start on the free Proof of Concept plan.

The Cerbos platform handles more than 2 billion authorization checks a month.

Further reading