Guards

Overview

Guards sit on Dome’s content path and decide what of an authorized call’s body may leave a backend or reach the agent. They attach to a model or tool connection and to a direction (request or response). When an assigned Guard cannot be evaluated, the gateway blocks that connection and direction. Filters are a Guard type. Model connections accept only text Filters. Tool connections accept only json Filters. The typical workflow is:

Create a Filter for the connection kind you need.
Assign ordered Filter chains on the connection and direction.
Configure the streaming window when model response Filters need more context.

Requirements

Before you begin:

Authenticate to Dome and select a workspace
Have at least one model or tool connection to assign

Permissions

Guard Filter operations require platform permissions. Each operation restates its permission inline.

Default roles	Permission	Grants
All workspace roles	`filters.view`	List Filters and assignments
`admin`, `operator`	`filters.manage`	Create, update, roll back, or delete Filters and set assignment chains
`admin`, `operator`	`gateway.manage`	Set a per-model filter window
`admin`, `operator`	`config.manage`	Set the workspace streaming filter window floor

Filters

Filters are a Guard type. Create and version Filters here, assign them to connections, and tune the streaming window used when response Filters inspect model output.

Create a Filter

Create a Filter to define its first active version. Text Filters use convenience flags. JSON Filters use a config file.

Requires filters.manage.

When more than one JSON action targets the same path, precedence is BLOCK > OMIT > REDACT. REDACT rewrites the matched span or value, OMIT removes a JSON field, and BLOCK withholds the whole message and stops the chain.

CLI
MCP
Agent

Text Filter

dome guards filters create pii-redact \
  --description "Redact PII in model responses" \
  --redact-ssn \
  --redact-substring "internal-only" \
  --block-substring "TOP-SECRET"

JSON Filter

dome guards filters create tool-scrub \
  --config-from ./tool-scrub.json

tool-scrub.json

{
  "json": {
    "components": [
      {
        "field_actions": [
          {"matcher": {"path": "ssn"}, "action": "FILTER_ACTION_OMIT"},
          {"matcher": {"path": "email"}, "action": "FILTER_ACTION_REDACT"},
          {"matcher": {"path": "card"}, "action": "FILTER_ACTION_BLOCK"}
        ]
      }
    ]
  }
}

Convenience flags build at most two text components. Redact runs first, then block. Use --config-from for a JSON Filter or a multi-component text chain.

Reference: dome guards filters create

Tool: dome_guards_create_filter

{
  "name": "pii-redact",
  "description": "Redact PII in model responses",
  "redact_ssn": true,
  "redact_substrings": ["internal-only"],
  "block_substrings": ["TOP-SECRET"]
}

Pass config_json with a protojson dome.guards.v1.FilterConfig to author a JSON Filter or a multi-component text chain. Convenience params only produce text Filters.

Reference: dome_guards_create_filter

Create a Filter

Create a text Filter named "pii-redact" that redacts SSNs and the substring "internal-only", and blocks on "TOP-SECRET".

Update a Filter

Update Filter metadata in place, or pass any config flag to deploy a new active version. The previous version remains in history. Assigned connections follow the active version on the next gateway sync.

Requires filters.manage.

dome guards filters update pii-redact \
  --description "Redact PII and secrets in model responses" \
  --redact-ssn \
  --block-substring "TOP-SECRET"

Reference: dome guards filters update

Tool: dome_guards_update_filter

{
  "filter": "pii-redact",
  "description": "Redact PII and secrets in model responses",
  "redact_ssn": true,
  "block_substrings": ["TOP-SECRET"]
}

Reference: dome_guards_update_filter

Roll back a Filter

Roll a Filter back to an earlier version. The target version’s config is copied forward into a new active version. History is never mutated.

Requires filters.manage.

dome guards filters rollback pii-redact --to-version 1

Reference: dome guards filters rollback

Tool: dome_guards_rollback_filter

{
  "filter": "pii-redact",
  "to_version": 1
}

Reference: dome_guards_rollback_filter

Delete a Filter

Delete a Filter and its connection assignments. Corrupt Filters can still be addressed by UUID when their config fails to render.

Requires filters.manage.

Delete removes the Filter and every assignment that references it.

dome guards filters delete pii-redact

Reference: dome guards filters delete

Tool: dome_guards_delete_filter

{
  "filter": "pii-redact"
}

Reference: dome_guards_delete_filter

Assign ordered Filter chains

Each assignment binds Filters to a (connection, direction) slot. Setting a chain replaces the complete ordered list for that slot. Clear a chain with an empty filter list.

Requires filters.manage.

Model connections accept only text Filters. Tool connections accept only json Filters.

CLI
MCP
Agent

Model connection

dome model guards filters set claude-prod \
  --direction response \
  --filters pii-redact,secrets-block

Tool connection

dome tool guards filters set github-mcp \
  --direction request \
  --filters tool-scrub

Clear a chain

dome model guards filters set claude-prod \
  --direction request \
  --filters ""

Inspect assignments with:

dome model guards filters list <connection>
dome tool guards filters list <connection>

Reference: dome model guards filters set · dome tool guards filters set

Tool: dome_model_guards_filters_set

{
  "connection": "claude-prod",
  "direction": "response",
  "filters": ["pii-redact", "secrets-block"]
}

Tool: dome_tool_guards_filters_set

{
  "connection": "github-mcp",
  "direction": "request",
  "filters": ["tool-scrub"]
}

Reference: dome_model_guards_filters_set · dome_tool_guards_filters_set

Assign Filter chains

Assign Filters "pii-redact" and "secrets-block" in that order to the response direction on model connection "claude-prod".

Configure the streaming window

Configure how much streamed model output the gateway buffers before applying response Filters. Layering rules are on the Guards concept and streaming window reference.

Requires config.manage for the workspace floor. Per-connection windows require gateway.manage. Per-request overrides are set by the calling agent in the request body.

In the dashboard, set the workspace floor under Settings → Config. From the API:

POST /dome.mgmt.v1.Management/UpdateWorkspaceLLMFilterWindow
Content-Type: application/json

{
  "tenant_id": "<tenant-uuid>",
  "workspace_id": "<workspace-uuid>",
  "llm_filter_window_bytes": 4096,
  "llm_filter_window_tokens": 1024
}

Reference: UpdateWorkspaceLLMFilterWindow

Agents can request a wider buffer for a single call by adding a _dome block to the OpenAI- or Anthropic-shaped body:

{
  "model": "production",
  "messages": [{"role": "user", "content": "Summarize the notes."}],
  "_dome": {"filter_window_bytes": 8192, "filter_window_tokens": 64}
}

The override is validated against the same bounds the workspace floor uses and is invisible to the upstream provider. Refer to Models for the per-connection flags.

Next steps

Guards concept for how content inspection works
Guards reference for Filter kinds, actions, path syntax, and streaming layers
Connect Tools to add tool connections
Models to set per-connection filter windows
Authorize Access when a call should be allowed or denied before Guards run
Architecture concept for where Guards sit in the request path

Get started

Core concepts

Connect

Govern

Operate

Manage

Develop

Reference

Overview

Requirements

Permissions

Filters

Create a Filter

Update a Filter

Roll back a Filter

Delete a Filter

Assign ordered Filter chains

Configure the streaming window

Next steps

​Overview

​Requirements

​Permissions

​Filters

​Create a Filter

​Update a Filter

​Roll back a Filter

​Delete a Filter

​Assign ordered Filter chains

​Configure the streaming window

​Next steps

Overview

Requirements

Permissions

Filters

Create a Filter

Update a Filter

Roll back a Filter

Delete a Filter

Assign ordered Filter chains

Configure the streaming window

Next steps