MCP servers

walkerOS provides Model Context Protocol servers for AI assistant integration.

Package	Purpose
`@walkeros/mcp`	Flow development: tools, reference resources, guided prompts, cloud API
`@walkeros/mcp-source-browser`	HTML tagging: generate, parse, and validate `data-elb` attributes

Claude Code plugin

The recommended way to get started in Claude Code. One plugin installs both MCP servers and 18 skills that teach Claude how to build sources, destinations, transformers, and flows.

Step 1: add the marketplace:

/plugin marketplace add elbwalker/walkerOS

Step 2: install the plugin:

/plugin install walkeros@elbwalker-walkerOS

That's it. Claude Code will reload with the MCP tools and skills active.

Quick start

For Claude Desktop or other MCP clients, add servers to your configuration manually:

Each server starts on STDIO and registers its tools automatically.

Environment variables

Variable	Used by	Required	Default	Purpose
`WALKEROS_TOKEN`	mcp	No	none	Bearer token fallback (alternative to `auth` tool login)
`WALKEROS_PROJECT_ID`	mcp	No	none	Active project ID (`proj_...`)
`WALKEROS_APP_URL`	mcp	No	`https://app.walkeros.io`	Base URL override

@walkeros/mcp-source-browser works without any environment variables. All tools are always registered. To authenticate with the walkerOS cloud, use the auth tool (device code flow) or set WALKEROS_TOKEN as a fallback.

@walkeros/mcp (flow development)

Unified server for flow development, package discovery, reference resources, guided prompts, and cloud API. Replaces the previous separate @walkeros/mcp-cli and @walkeros/mcp-api packages.

Installation

Programmatic usage

@walkeros/mcp exports a transport-agnostic server factory so host applications can mount the MCP protocol over HTTP (e.g., from a Next.js Route Handler) instead of running the stdio binary:

To use the raw tool registry without the MCP protocol (e.g., with the Vercel AI SDK), import `TOOL_DEFINITIONS` and provide your own `ToolClient` implementation. The stdio binary stays available via `@walkeros/mcp/stdio` and the `walkeros-mcp` bin entry, unchanged for end users.

Tools

`flow_load`

Load an existing flow configuration from a local file path, URL, inline JSON, or the walkerOS API, or create a new empty flow by specifying a platform.

Parameter	Type	Required	Description
`source`	string	No	Flow source: file path, URL, inline JSON, or API flow/config ID (`flow_...` / `cfg_...`). Omit to create new.
`platform`	`"web"` \| `"server"`	No	Platform for new flows. Required when source is omitted.

Passing a flow_... or cfg_... ID loads that flow from the API (the same source flow_manage reads from). Returned configs are round-trip safe: structural values such as package names, platform, and IDs come back literally, so a loaded config can be edited and sent straight back to flow_manage({ action: "update" }) without altering anything you did not change.

`flow_validate`

Validate walkerOS events, flow configurations, mapping rules, or data contracts.

Parameter	Type	Required	Description
`type`	`"event"` \| `"flow"` \| `"mapping"` \| `"contract"`	Yes	Validation type
`input`	string	Yes	JSON string, file path, or URL to validate
`flow`	string	No	Flow name for multi-flow configs
`path`	string	No	Entry path for package schema validation

`flow_bundle`

Bundle a walkerOS flow configuration into deployable JavaScript.

Parameter	Type	Required	Description
`configPath`	string	Yes	Path to flow configuration file
`flow`	string	No	Flow name for multi-flow configs
`stats`	boolean	No	Return bundle statistics (default: `true`)
`output`	string	No	Output file path

`flow_simulate`

Simulate events through a walkerOS flow without making real API calls. Returns summarized per-destination results.

Parameter	Type	Required	Description
`configPath`	string	Yes	Path to flow configuration file
`event`	string \| object	Yes	Event input (see shapes below). JSON string, file path, or URL also accepted.
`step`	string	Yes	Target step as `"type.name"` (e.g. `"source.demo"`, `"destination.gtag"`, `"transformer.router"`)
`flow`	string	No	Flow name for multi-flow configs
`platform`	`"web"` \| `"server"`	No	Override platform detection
`verbose`	boolean	No	Include full payload per destination (default: `false`)

The event shape depends on the step type:

Destinations / transformers: a walkerOS event, { name: "entity action", data: {...} }. Add consent (e.g. { marketing: true }) when the destination requires it.
Sources: { content, trigger? }, where content is the walkerOS event { name, data } and the optional trigger is { type?, options? }. There is no env field in the source-step event.

Sources can be simulated as a step, including the @walkeros/source-demo demo source.

`flow_push`

Push a real event through a walkerOS flow to actual destinations. This makes real API calls. Best for server-side flows. Web destinations require browser globals not available in Node.js.

Parameter	Type	Required	Description
`configPath`	string	Yes	Path to flow configuration file
`event`	string	Yes	Event as JSON string, file path, or URL
`flow`	string	No	Flow name for multi-flow configs
`platform`	`"web"` \| `"server"`	No	Override platform detection

`flow_examples`

List all step examples in a walkerOS flow configuration.

Parameter	Type	Required	Description
`configPath`	string	Yes	Path to flow configuration file
`flow`	string	No	Flow name for multi-flow configs
`step`	string	No	Filter to a specific step (e.g., `"destination.gtag"`)
`full`	boolean	No	Return full in/out/mapping data (default: `false`, metadata only)

`package_search`

Browse walkerOS packages or look up a specific one. Without package name: returns catalog filtered by type/platform. With package name: returns metadata.

Parameter	Type	Required	Description
`package`	string	No	Exact npm package name for lookup
`type`	`"source"` \| `"destination"` \| `"transformer"` \| `"store"`	No	Filter by type (browse)
`platform`	`"web"` \| `"server"`	No	Filter by platform (browse)
`version`	string	No	Package version (default: latest)

In browse mode the tool returns the complete catalog. If it has to fall back to a partial source or omit packages, the response includes a warnings array explaining what is incomplete rather than silently returning a partial list.

`package_get`

Fetch walkerOS package details from npm. By default returns schemas + hint texts + example summaries. Use section parameter for full content.

Parameter	Type	Required	Description
`package`	string	Yes	Exact npm package name
`version`	string	No	Package version (default: latest)
`section`	`"hints"` \| `"examples"` \| `"all"`	No	Section to expand with full content

`diagnostics`

Report the MCP runtime surface. Read-only, takes no parameters, and works even when logged out. Reach for it when a request fails, to see which versions and backend you are on. The response includes the MCP version, the CLI version, the resolved app URL and whether it came from WALKEROS_APP_URL or the default, app /api/health reachability, the bundled OpenAPI contract version, and which source served the last package catalog lookup.

This tool has no parameters.

`auth`

Authenticate with the walkerOS cloud. Uses device code flow — the user receives a URL to open in a browser to complete login.

Parameter	Type	Required	Description
`action`	`"status"` \| `"login"` \| `"logout"`	Yes	Auth action
`deviceCode`	string	No	Device code from a previous pending login. Provide with `action: "login"` to resume polling without requesting a new code.

`project_manage`

Manage walkerOS projects in the cloud.

Parameter	Type	Required	Description
`action`	`"list"` \| `"get"` \| `"create"` \| `"update"` \| `"delete"` \| `"set_default"`	Yes	Project action
`projectId`	string	No	Project ID (`proj_...`). Required for: get, update, delete, set_default. Falls back to `WALKEROS_PROJECT_ID` env.
`name`	string	No	Name for create/update operations

`flow_manage`

Manage walkerOS flow configurations and previews in the cloud.

Parameter	Type	Required	Description
`action`	`"list"` \| `"get"` \| `"create"` \| `"update"` \| `"delete"` \| `"duplicate"` \| `"preview_list"` \| `"preview_get"` \| `"preview_create"` \| `"preview_delete"`	Yes	Flow action
`projectId`	string	No	Project ID (`proj_...`). Optional filter for list. Required for create if no default project set. Falls back to `WALKEROS_PROJECT_ID` env.
`flowId`	string	No	Flow ID (`flow_...`) or config ID (`cfg_...`). Required for: get, update, delete, duplicate, preview_list, preview_get, preview_create, preview_delete.
`name`	string	No	Flow name. Required for create. Optional for update (to rename) and duplicate.
`content`	object	No	Flow.Json content. Used for create and update.
`patch`	boolean	No	Merge-patch for update (default: `true`). When true, only provided fields are updated.
`fields`	string[]	No	Dot-path selectors for get to return only specific fields.
`sort`	`"name"` \| `"updated_at"` \| `"created_at"`	No	Sort field for list.
`order`	`"asc"` \| `"desc"`	No	Sort order for list.
`includeDeleted`	boolean	No	Include soft-deleted flows in list results.
`previewId`	string	No	Preview ID (`prv_...`). Required for: preview_get, preview_delete.
`flowName`	string	No	Flow settings name. Used by preview_create as an alternative to `flowSettingsId`.
`flowSettingsId`	string	No	Flow settings ID. Used by preview_create as an alternative to `flowName`.
`source`	object	No	What preview_create should run: `{ "kind": "draft" }` (default) or `{ "kind": "deployment-version", "deploymentVersionId": "..." }` to preview a deployed version's stored config ("preview what's live").
`siteUrl`	string	No	Optional site URL for preview_create. When provided, the response includes full `activationUrl` and `deactivationUrl` the user can click.

Configs returned by get are round-trip safe: structural values (package names, platform, IDs) are returned literally, so a returned config can be edited and sent back to update unchanged.

`deploy_manage`

Deploy walkerOS flows and manage deployments.

Parameter	Type	Required	Description
`action`	`"deploy"` \| `"list"` \| `"get"` \| `"delete"`	Yes	Deployment action
`flowId`	string	Conditional	Flow ID. Required for: `deploy`, `get`, `delete`. Optional filter for `list`.
`slug`	string	No	Deployment slug. Optional disambiguator for `get`/`delete` when the flow has multiple active deployments.
`projectId`	string	No	Project ID. Optional; falls back to the default project.
`type`	`"web"` \| `"server"`	No	Deployment type filter for `list`.
`status`	string	No	Status filter for `list`.
`wait`	boolean	No	Wait for deploy to complete (default: `true`). Only used with `deploy`.
`flowName`	string	No	Flow name for multi-settings flows. Only used with `deploy`.

When a flow has more than one active deployment and no slug is supplied, get and delete return a MULTIPLE_DEPLOYMENTS error with a details[] list so the caller can pick a specific deployment. Soft-deleted deployments are always excluded.

{
  "error": "Flow flow_abc has 2 active deployments; pass slug to disambiguate",
  "code": "MULTIPLE_DEPLOYMENTS",
  "details": [
    { "slug": "abc123456789", "type": "web", "status": "active", "updatedAt": "2026-04-20T00:00:00.000Z" },
    { "slug": "def987654321", "type": "web", "status": "active", "updatedAt": "2026-04-21T00:00:00.000Z" }
  ]
}

Resources

URI	Description
`walkeros://reference/flow-schema`	Flow.Json structure and connection rules
`walkeros://reference/event-model`	Event naming, properties, auto-populated fields
`walkeros://reference/mapping`	Mapping syntax (data/map/loop/set/condition/consent/policy)
`walkeros://reference/consent`	Consent model (destination/rule/field level)
`walkeros://reference/variables`	Variable patterns ($var/$env/$code/$store)
`walkeros://reference/contract`	Event schemas, wildcards, inheritance
`walkeros://reference/openapi`	OpenAPI 3.1 specification
`walkeros://reference/packages`	Full package catalog
`walkeros://schema/{packageName}`	Per-package JSON schemas

Prompts

Prompt	Description
`add-step`	Add a source, destination, transformer, or store to a flow
`setup-mapping`	Configure event mapping for a step
`manage-contract`	Create/update event contracts (bidirectional with mappings)

@walkeros/mcp-source-browser (HTML tagging tools)

Generate, parse, and validate walkerOS data-elb HTML attributes using real DOM parsing (JSDOM). No API token or CLI dependency required.

Installation

Tools (3)

`generate_tagging`

Generate walkerOS data-elb HTML attributes from structured input. Returns attribute key-value pairs and an example HTML snippet.

Parameter	Type	Required	Description
`entity`	string	No	Entity name (creates `data-elb="entity"`)
`data`	object	No	Entity properties as key:value pairs
`action`	object	No	Trigger:action pairs for `data-elbaction` (nearest entity)
`actions`	object	No	Trigger:action pairs for `data-elbactions` (all entities)
`context`	object	No	Context properties for `data-elbcontext`
`globals`	object	No	Global properties for `data-elbglobals`
`link`	object	No	Link relationships for `data-elblink`
`prefix`	string	No	Custom prefix (default: `data-elb`)

At least one parameter must be provided.

`parse_tagging`

Parse HTML with data-elb attributes using real DOM parsing (JSDOM). Extracts all walkerOS events and globals.

Parameter	Type	Required	Description
`html`	string	Yes	HTML snippet with `data-elb` attributes
`prefix`	string	No	Custom prefix (default: `data-elb`)

`validate_tagging`

Validate HTML data-elb tagging for common mistakes. Checks for orphan actions, missing entities, unknown triggers, orphan properties, and entities without actions.

Parameter	Type	Required	Description
`html`	string	Yes	HTML snippet to validate
`prefix`	string	No	Custom prefix (default: `data-elb`)

Resources

URI	Description
`walkeros://docs/tagging/html-attributes`	Complete guide to `data-elb` HTML attribute tagging
`walkeros://docs/tagging/tagger`	`createTagger()` fluent API reference

Example workflows

Create and validate a flow

Ask your AI assistant:

"Create a new web flow, add a GA4 destination, then validate it."

The assistant uses flow_load to create a skeleton, the add-step prompt to add GA4, and flow_validate to check the result.

Simulate events

"Simulate a page view event through my flow at ./flow.json."

The assistant calls flow_simulate and returns per-destination results showing which destinations received the event.

Deploy a flow

"Deploy flow cfg_abc123 and wait for it to finish."

The assistant calls deploy_manage({ action: "deploy", flowId: "cfg_abc123" }) and streams progress updates through bundling, publishing, and activation.

Preview a flow on a live site

"Create a preview of my demo settings on flow_abc123 and give me the link to open on https://example.com."

The assistant calls flow_manage({ action: "preview_create", flowId: "flow_abc123", flowName: "demo", siteUrl: "https://example.com" }) and returns the activationUrl the user clicks to activate preview mode on their site. Running flow_manage({ action: "preview_delete", … }) later removes the bundle; the production walker self-heals on visitors' next page load.

Set up event mapping

"Help me set up mapping for the gtag destination in my flow."

The assistant uses the setup-mapping prompt, reads the mapping reference resource, fetches package examples, and generates mapping rules.

Generate HTML tagging

"Generate data-elb attributes for a promotion entity with name 'Summer Sale' and a click action."

The assistant calls generate_tagging with entity: "promotion", data: { name: "Summer Sale" }, and action: { click: "click" }, returning ready-to-use HTML attributes.

Discover a package

"What configuration does the Snowplow destination need?"

The assistant calls package_search for @walkeros/web-destination-snowplow, then package_get to fetch schemas, hints, and examples.

Next steps

CLI: Learn about the underlying CLI commands
Flow configuration: Understand flow structure
HTML attributes: Learn about data-elb tagging
MCP specification: Learn about the Model Context Protocol

💡 Need implementation support?

elbwalker offers hands-on support: setup review, measurement planning, destination mapping, and live troubleshooting. Book a 2-hour session (€399)

Claude Code plugin​

Quick start​

Environment variables​

@walkeros/mcp (flow development)​

Installation​

Programmatic usage​

Tools​

flow_load​

flow_validate​

flow_bundle​

flow_simulate​

flow_push​

flow_examples​

package_search​

package_get​

diagnostics​

auth​

project_manage​

flow_manage​

deploy_manage​

Resources​

Prompts​

@walkeros/mcp-source-browser (HTML tagging tools)​

Installation​

Tools (3)​

generate_tagging​

parse_tagging​

validate_tagging​

Resources​

Example workflows​

Create and validate a flow​

Simulate events​

Deploy a flow​

Preview a flow on a live site​

Set up event mapping​

Generate HTML tagging​

Discover a package​

Next steps​

Claude Code plugin

Quick start

Environment variables

@walkeros/mcp (flow development)

Installation

Programmatic usage

Tools

`flow_load`

`flow_validate`

`flow_bundle`

`flow_simulate`

`flow_push`

`flow_examples`

`package_search`

`package_get`

`diagnostics`

`auth`

`project_manage`

`flow_manage`

`deploy_manage`

Resources

Prompts

@walkeros/mcp-source-browser (HTML tagging tools)

Installation

Tools (3)

`generate_tagging`

`parse_tagging`

`validate_tagging`

Resources

Example workflows

Create and validate a flow

Simulate events

Deploy a flow

Preview a flow on a live site

Set up event mapping

Generate HTML tagging

Discover a package

Next steps