read_after_login_success

Response predicate + output-field filter: permit a Read only if the same user had a Login that succeeded (output.result: true) within the last hour. A response predicate reads output.* fields and matches the result event, not the request — so it can gate on the login’s outcome.

The trace shows both verdicts:

• @100 — alice reads doc1, 100s after a Login::response with output.result: true for alice → ALLOW (a matching successful login is within the window).
• @300 — bob reads doc2, after a Login::response with output.result: false for bob → DENY (the login failed, so the output.result: true filter rejects it).

Referenced by guide/04-temporal-expressions.md.

Policy

// A response predicate reads output.* fields. Permit a Read only if the
// same user's Login SUCCEEDED (output.result: true) within the last hour --
// a response predicate matches the result event, not the request event.
@id("read_after_login_success")
permit (
    principal,
    action == Drupe::Action::"Read",
    resource
)
when temporal {
    formerly within 1h Drupe::Action::"Login"::response{
        input.user: context.input.user,
        output.result: true
    }
};

Schema

namespace Drupe {
  type ContentFilterFinding = {
    severityScore: decimal
  };

  type LoginInput = {
    server: String,
    user: String
  };

  type LoginOutput = {
    result: Bool
  };

  type PromptAttackFinding = {
    severityScore: decimal
  };

  type ReadInput = {
    document: String,
    user: String
  };

  type ReadOutput = {  };

  type SensitiveInfoFinding = {
    confidenceScore: decimal
  };

  type SystemContext = {
    now: datetime
  };

  entity Gateway;

  entity IamEntity = {
    id: String
  };

  entity OAuthUser = {
    id: String
  } tags String;

  entity UnauthenticatedUser;

  action "CallTool" in [Action::"Mcp"] appliesTo {
    principal: [OAuthUser, IamEntity, UnauthenticatedUser],
    resource: [Gateway],
    context: {
      system: SystemContext
    }
  };

  action "Http" appliesTo {
    principal: [OAuthUser, IamEntity, UnauthenticatedUser],
    resource: [Gateway],
    context: {
      system: SystemContext
    }
  };

  action "InvokeAgent" in [Action::"Http"] appliesTo {
    principal: [OAuthUser, IamEntity, UnauthenticatedUser],
    resource: [Gateway],
    context: {
      input?: {      },
      system: SystemContext
    }
  };

  action "InvokeLLM" in [Action::"Http"] appliesTo {
    principal: [OAuthUser, IamEntity, UnauthenticatedUser],
    resource: [Gateway],
    context: {
      input?: {      },
      system: SystemContext
    }
  };

  action "Login" in [Action::"CallTool"] appliesTo {
    principal: [IamEntity, OAuthUser, UnauthenticatedUser],
    resource: [Gateway],
    context: {
      input: LoginInput,
      output?: LoginOutput,
      system: SystemContext
    }
  };

  action "Mcp" appliesTo {
    principal: [OAuthUser, IamEntity, UnauthenticatedUser],
    resource: [Gateway],
    context: {
      system: SystemContext
    }
  };

  action "Read" in [Action::"CallTool"] appliesTo {
    principal: [IamEntity, OAuthUser, UnauthenticatedUser],
    resource: [Gateway],
    context: {
      input: ReadInput,
      output?: ReadOutput,
      system: SystemContext
    }
  };

  action "UnknownTool" in [Action::"CallTool"] appliesTo {
    principal: [OAuthUser, IamEntity, UnauthenticatedUser],
    resource: [Gateway],
    context: {
      system: SystemContext
    }
  };
}

Trace

@0 scope(principal: Drupe::OAuthUser::"alice", resource: Drupe::Gateway::"gw1") Drupe::Action::"Login"::response(input: { server: "s1", user: "alice" }, output: { result: true }, callerPrincipal: Drupe::OAuthUser::"alice", callerResource: Drupe::Gateway::"gw1", requestId: "u1")
@100 scope(principal: Drupe::OAuthUser::"alice", resource: Drupe::Gateway::"gw1") request_context(input: { document: "doc1", user: "alice" }) Drupe::Action::"Read"::request(input: { document: "doc1", user: "alice" }, callerPrincipal: Drupe::OAuthUser::"alice", callerResource: Drupe::Gateway::"gw1", requestId: "u2")
@200 scope(principal: Drupe::OAuthUser::"bob", resource: Drupe::Gateway::"gw1") Drupe::Action::"Login"::response(input: { server: "s1", user: "bob" }, output: { result: false }, callerPrincipal: Drupe::OAuthUser::"bob", callerResource: Drupe::Gateway::"gw1", requestId: "u3")
@300 scope(principal: Drupe::OAuthUser::"bob", resource: Drupe::Gateway::"gw1") request_context(input: { document: "doc2", user: "bob" }) Drupe::Action::"Read"::request(input: { document: "doc2", user: "bob" }, callerPrincipal: Drupe::OAuthUser::"bob", callerResource: Drupe::Gateway::"gw1", requestId: "u4")

Expected Output

@100 (time point 0): ALLOW  [rules: 0]
@300 (time point 1): DENY