MCP Tools Reference: iam.googleapis.com

Tool: update_deny_policy

Updates an existing deny policy attached to a Google Cloud project. Organizations and folders are not supported.

Use this tool to modify deny rules, denied principals, exceptions, or display names. Perform a read-modify-write pattern by fetching the latest policy via get_deny_policy and providing the current etag to prevent concurrency conflicts. Updating a deny policy is asynchronous and returns a long-running operation. Use the get_deny_policy_status tool to check for operation completion.

This tool requires the policy parameter, which is the updated deny policy containing name, display_name, rules, and the current etag.

This tool returns a long-running operation resource whose resolution status can be tracked with get_deny_policy_status.

The following code sample shows how to use curl to call the update_deny_policy MCP tool.

Curl Request 
curl --location 'https://iam.googleapis.com/mcp' \
--header 'content-type: application/json' \
--header 'accept: application/json, text/event-stream' \
--data '{
  "method": "tools/call",
  "params": {
    "name": "update_deny_policy",
    "arguments": {
      // Provide these details according to the MCP tool specification.
    }
  },
  "jsonrpc": "2.0",
  "id": 1
}'

Input Schema

Request message for UpdatePolicy.

UpdatePolicyRequest

JSON representation 
{
  "policy": {
    object (Policy)
  }
}
Fields
policy

object (Policy)

Required. The policy to update.

To prevent conflicting updates, the etag value must match the value that is stored in IAM. If the etag values do not match, the request fails with a 409 error code and ABORTED status.

Policy

JSON representation 
{
  "name": string,
  "uid": string,
  "kind": string,
  "displayName": string,
  "annotations": {
    string: string,
    ...
  },
  "etag": string,
  "createTime": string,
  "updateTime": string,
  "deleteTime": string,
  "rules": [
    {
      object (PolicyRule)
    }
  ]
}
Fields
name

string

Immutable. The resource name of the Policy, which must be unique. Format: policies/{attachment_point}/denypolicies/{policy_id}

The attachment point is identified by its URL-encoded full resource name, which means that the forward-slash character, /, must be written as %2F. For example, policies/cloudresourcemanager.googleapis.com%2Fprojects%2Fmy-project/denypolicies/my-deny-policy.

For organizations and folders, use the numeric ID in the full resource name. For projects, requests can use the alphanumeric or the numeric ID. Responses always contain the numeric ID.
uid

string

Immutable. The globally unique ID of the Policy. Assigned automatically when the Policy is created.
kind

string

Output only. The kind of the Policy. Always contains the value DenyPolicy.
displayName

string

A user-specified description of the Policy. This value can be up to 63 characters.
annotations

map (key: string, value: string)

A key-value map to store arbitrary metadata for the Policy. Keys can be up to 63 characters. Values can be up to 255 characters.

An object containing a list of "key": value pairs. Example: { "name": "wrench", "mass": "1.3kg", "count": "3" }.
etag

string

An opaque tag that identifies the current version of the Policy. IAM uses this value to help manage concurrent updates, so they do not cause one update to be overwritten by another.

If this field is present in a CreatePolicyRequest, the value is ignored.
createTime

string (Timestamp format)

Output only. The time when the Policy was created.

Uses RFC 3339, where generated output will always be Z-normalized and use 0, 3, 6 or 9 fractional digits. Offsets other than "Z" are also accepted. Examples: "2014-10-02T15:01:23Z", "2014-10-02T15:01:23.045123456Z" or "2014-10-02T15:01:23+05:30".
updateTime

string (Timestamp format)

Output only. The time when the Policy was last updated.

Uses RFC 3339, where generated output will always be Z-normalized and use 0, 3, 6 or 9 fractional digits. Offsets other than "Z" are also accepted. Examples: "2014-10-02T15:01:23Z", "2014-10-02T15:01:23.045123456Z" or "2014-10-02T15:01:23+05:30".
deleteTime

string (Timestamp format)

Output only. The time when the Policy was deleted. Empty if the policy is not deleted.

Uses RFC 3339, where generated output will always be Z-normalized and use 0, 3, 6 or 9 fractional digits. Offsets other than "Z" are also accepted. Examples: "2014-10-02T15:01:23Z", "2014-10-02T15:01:23.045123456Z" or "2014-10-02T15:01:23+05:30".
rules[]

object (PolicyRule)

A list of rules that specify the behavior of the Policy. All of the rules should be of the kind specified in the Policy.

AnnotationsEntry

JSON representation 
{
  "key": string,
  "value": string
}
Fields
key

string
value

string

Timestamp

JSON representation 
{
  "seconds": string,
  "nanos": integer
}
Fields
seconds

string (int64 format)

Represents seconds of UTC time since Unix epoch 1970-01-01T00:00:00Z. Must be between -62135596800 and 253402300799 inclusive (which corresponds to 0001-01-01T00:00:00Z to 9999-12-31T23:59:59Z).
nanos

integer

Non-negative fractions of a second at nanosecond resolution. This field is the nanosecond portion of the duration, not an alternative to seconds. Negative second values with fractions must still have non-negative nanos values that count forward in time. Must be between 0 and 999,999,999 inclusive.

PolicyRule

JSON representation 
{
  "description": string,

  // Union field kind can be only one of the following:
  "denyRule": {
    object (DenyRule)
  }
  // End of list of possible types for union field kind.
}
Fields
description

string

A user-specified description of the rule. This value can be up to 256 characters.

Union field kind.

kind can be only one of the following:
denyRule

object (DenyRule)

A rule for a deny policy.

DenyRule

JSON representation 
{
  "deniedPrincipals": [
    string
  ],
  "exceptionPrincipals": [
    string
  ],
  "deniedPermissions": [
    string
  ],
  "exceptionPermissions": [
    string
  ],
  "denialCondition": {
    object (Expr)
  }
}
Fields
deniedPrincipals[]

string

The identities that are prevented from using one or more permissions on Google Cloud resources. This field can contain the following values:

  • principal://goog/subject/{email_id}: A specific Google Account. Includes Gmail, Cloud Identity, and Google Workspace user accounts. For example, principal://goog/subject/alice@example.com.

  • principal://iam.googleapis.com/projects/-/serviceAccounts/{service_account_id}: A Google Cloud service account. For example, principal://iam.googleapis.com/projects/-/serviceAccounts/my-service-account@iam.gserviceaccount.com.

  • principalSet://goog/group/{group_id}: A Google group. For example, principalSet://goog/group/admins@example.com.

  • principalSet://goog/public:all: A special identifier that represents any principal that is on the internet, even if they do not have a Google Account or are not logged in.

  • principalSet://goog/cloudIdentityCustomerId/{customer_id}: All of the principals associated with the specified Google Workspace or Cloud Identity customer ID. For example, principalSet://goog/cloudIdentityCustomerId/C01Abc35.

  • principal://iam.googleapis.com/locations/global/workforcePools/{pool_id}/subject/{subject_attribute_value}: A single identity in a workforce identity pool.

  • principalSet://iam.googleapis.com/locations/global/workforcePools/{pool_id}/group/{group_id}: All workforce identities in a group.

  • principalSet://iam.googleapis.com/locations/global/workforcePools/{pool_id}/attribute.{attribute_name}/{attribute_value}: All workforce identities with a specific attribute value.

  • principalSet://iam.googleapis.com/locations/global/workforcePools/{pool_id}/*: All identities in a workforce identity pool.

  • principal://iam.googleapis.com/projects/{project_number}/locations/global/workloadIdentityPools/{pool_id}/subject/{subject_attribute_value}: A single identity in a workload identity pool.

  • principalSet://iam.googleapis.com/projects/{project_number}/locations/global/workloadIdentityPools/{pool_id}/group/{group_id}: A workload identity pool group.

  • principalSet://iam.googleapis.com/projects/{project_number}/locations/global/workloadIdentityPools/{pool_id}/attribute.{attribute_name}/{attribute_value}: All identities in a workload identity pool with a certain attribute.

  • principalSet://iam.googleapis.com/projects/{project_number}/locations/global/workloadIdentityPools/{pool_id}/*: All identities in a workload identity pool.

  • principalSet://cloudresourcemanager.googleapis.com/[projects|folders|organizations]/{project_number|folder_number|org_number}/type/ServiceAccount: All service accounts grouped under a resource (project, folder, or organization).

  • principalSet://cloudresourcemanager.googleapis.com/[projects|folders|organizations]/{project_number|folder_number|org_number}/type/ServiceAgent: All service agents grouped under a resource (project, folder, or organization).

  • deleted:principal://goog/subject/{email_id}?uid={uid}: A specific Google Account that was deleted recently. For example, deleted:principal://goog/subject/alice@example.com?uid=1234567890. If the Google Account is recovered, this identifier reverts to the standard identifier for a Google Account.

  • deleted:principalSet://goog/group/{group_id}?uid={uid}: A Google group that was deleted recently. For example, deleted:principalSet://goog/group/admins@example.com?uid=1234567890. If the Google group is restored, this identifier reverts to the standard identifier for a Google group.

  • deleted:principal://iam.googleapis.com/projects/-/serviceAccounts/{service_account_id}?uid={uid}: A Google Cloud service account that was deleted recently. For example, deleted:principal://iam.googleapis.com/projects/-/serviceAccounts/my-service-account@iam.gserviceaccount.com?uid=1234567890. If the service account is undeleted, this identifier reverts to the standard identifier for a service account.

  • deleted:principal://iam.googleapis.com/locations/global/workforcePools/{pool_id}/subject/{subject_attribute_value}: Deleted single identity in a workforce identity pool. For example, deleted:principal://iam.googleapis.com/locations/global/workforcePools/my-pool-id/subject/my-subject-attribute-value.
exceptionPrincipals[]

string

The identities that are excluded from the deny rule, even if they are listed in the denied_principals. For example, you could add a Google group to the denied_principals, then exclude specific users who belong to that group.

This field can contain the same values as the denied_principals field, excluding principalSet://goog/public:all, which represents all users on the internet.
deniedPermissions[]

string

The permissions that are explicitly denied by this rule. Each permission uses the format {service_fqdn}/{resource}.{verb}, where {service_fqdn} is the fully qualified domain name for the service. For example, iam.googleapis.com/roles.list.
exceptionPermissions[]

string

Specifies the permissions that this rule excludes from the set of denied permissions given by denied_permissions. If a permission appears in denied_permissions and in exception_permissions then it will not be denied.

The excluded permissions can be specified using the same syntax as denied_permissions.
denialCondition

object (Expr)

The condition that determines whether this deny rule applies to a request. If the condition expression evaluates to true, then the deny rule is applied; otherwise, the deny rule is not applied.

Each deny rule is evaluated independently. If this deny rule does not apply to a request, other deny rules might still apply.

The condition can use CEL functions that evaluate resource tags. Other functions and operators are not supported.

Expr

JSON representation 
{
  "expression": string,
  "title": string,
  "description": string,
  "location": string
}
Fields
expression

string

Textual representation of an expression in Common Expression Language syntax.
title

string

Optional. Title for the expression, i.e. a short string describing its purpose. This can be used e.g. in UIs which allow to enter the expression.
description

string

Optional. Description of the expression. This is a longer text which describes the expression, e.g. when hovered over it in a UI.
location

string

Optional. String indicating the location of the expression for error reporting, e.g. a file name and a position in the file.

Output Schema

This resource represents a long-running operation that is the result of a network API call.

Operation

JSON representation 
{
  "name": string,
  "metadata": {
    "@type": string,
    field1: ...,
    ...
  },
  "done": boolean,

  // Union field result can be only one of the following:
  "error": {
    object (Status)
  },
  "response": {
    "@type": string,
    field1: ...,
    ...
  }
  // End of list of possible types for union field result.
}
Fields
name

string

The server-assigned name, which is only unique within the same service that originally returns it. If you use the default HTTP mapping, the name should be a resource name ending with operations/{unique_id}.
metadata

object

Service-specific metadata associated with the operation. It typically contains progress information and common metadata such as create time. Some services might not provide such metadata. Any method that returns a long-running operation should document the metadata type, if any.

An object containing fields of an arbitrary type. An additional field "@type" contains a URI identifying the type. Example: { "id": 1234, "@type": "types.example.com/standard/id" }.
done

boolean

If the value is false, it means the operation is still in progress. If true, the operation is completed, and either error or response is available.
Union field result. The operation result, which can be either an error or a valid response. If done == false, neither error nor response is set. If done == true, exactly one of error or response can be set. Some services might not provide the result. result can be only one of the following:
error

object (Status)

The error result of the operation in case of failure or cancellation.
response

object

The normal, successful response of the operation. If the original method returns no data on success, such as Delete, the response is google.protobuf.Empty. If the original method is standard Get/Create/Update, the response should be the resource. For other methods, the response should have the type XxxResponse, where Xxx is the original method name. For example, if the original method name is TakeSnapshot(), the inferred response type is TakeSnapshotResponse.

An object containing fields of an arbitrary type. An additional field "@type" contains a URI identifying the type. Example: { "id": 1234, "@type": "types.example.com/standard/id" }.

Any

JSON representation 
{
  "typeUrl": string,
  "value": string
}
Fields
typeUrl

string

Identifies the type of the serialized Protobuf message with a URI reference consisting of a prefix ending in a slash and the fully-qualified type name.

Example: type.googleapis.com/google.protobuf.StringValue

This string must contain at least one / character, and the content after the last / must be the fully-qualified name of the type in canonical form, without a leading dot. Do not write a scheme on these URI references so that clients do not attempt to contact them.

The prefix is arbitrary and Protobuf implementations are expected to simply strip off everything up to and including the last / to identify the type. type.googleapis.com/ is a common default prefix that some legacy implementations require. This prefix does not indicate the origin of the type, and URIs containing it are not expected to respond to any requests.

All type URL strings must be legal URI references with the additional restriction (for the text format) that the content of the reference must consist only of alphanumeric characters, percent-encoded escapes, and characters in the following set (not including the outer backticks): /-.~_!$&()*+,;=. Despite our allowing percent encodings, implementations should not unescape them to prevent confusion with existing parsers. For example, type.googleapis.com%2FFoo should be rejected.

In the original design of Any, the possibility of launching a type resolution service at these type URLs was considered but Protobuf never implemented one and considers contacting these URLs to be problematic and a potential security issue. Do not attempt to contact type URLs.
value

string (bytes format)

Holds a Protobuf serialization of the type described by type_url.

A base64-encoded string.

Status

JSON representation 
{
  "code": integer,
  "message": string,
  "details": [
    {
      "@type": string,
      field1: ...,
      ...
    }
  ]
}
Fields
code

integer

The status code, which should be an enum value of google.rpc.Code.
message

string

A developer-facing error message, which should be in English. Any user-facing error message should be localized and sent in the google.rpc.Status.details field, or localized by the client.
details[]

object

A list of messages that carry the error details. There is a common set of message types for APIs to use.

An object containing fields of an arbitrary type. An additional field "@type" contains a URI identifying the type. Example: { "id": 1234, "@type": "types.example.com/standard/id" }.

Tool Annotations

Tool annotations are sent to MCP clients to describe the basic risk of a given tool. Most clients treat these hints as untrusted, but they can be used to decide when a confirmation prompt might be sent to a user.

Along with the title string, the following boolean hints are defined as follows:

  • readOnlyHint: If true, the tool doesn't modify its environment. Default: false.
  • destructiveHint: If true, then the tool can perform destructive actions. If false, then the tool can only perform additive actions. Default: true.
  • idempotentHint: If true, then calling the tool repeatedly with the same arguments will have no additional effect on its environment. Default: false.
  • openWorldHint: If true, then the tool can interact with an 'open world' of external entities. If false, then the tool can only interact with internal entities. For example, a web search tool would be open world, while a memory tool would not be open world.

Destructive Hint: ❌ | Idempotent Hint: ✅ | Read Only Hint: ❌ | Open World Hint: ❌