Validation and versions

Yukta refuses a broken graph before any plugin runs, with an error that names the node and the option at fault. It also keeps each workflow’s recent versions so you can compare and restore them.

Validate a definition

Validate without applying:

POST /api/sessions/validate
Content-Type: application/json

Send one workflow definition (the object you would put under workflows in a session). The server checks it with the same rules as execution and stores nothing. The answer is always 200:

{
  "valid": false,
  "message": "Workflow must contain at least one TERMINAL node",
  "ports": { "fetch": ["success", "failure"], "trigger": ["default"] }
}

valid says whether the draft would be accepted, message names the first problem found (it is null when valid), and ports lists the output ports of each node for its configuration, so an editor can offer the right sourcePort values. Applying a session runs the same checks, so an invalid definition is never stored. The web UI validates before it saves.

What is checked

Check	Rejected when
Structure	The graph has a cycle, a duplicate node id or a duplicate edge; an edge references a node that does not exist
Roles	There is no trigger or no terminal, or an entry point that is not a trigger
Ports	An edge names a `sourcePort` that the source plugin does not declare. `error` is allowed on nodes with `onError: ROUTE`
Size	More than 500 nodes or 2000 edges
Failure policy	Unknown `engine` keys, `maxBackoffMs` not below the node timeout, `retryOn` and `noRetryOn` sharing an entry, `deadlineMs` not above `elementTimeoutMs`
Plugin options	A required option is missing or has the wrong type, as reported by the plugin
Identifiers	A session, workflow or node id is blank, too long or contains a path separator

Versions

Each workflow keeps its newest 20 versions per session.

Saving an identical definition adds no version.
Every execution records a content hash of the graph it used, carried by progress, history and the log.
A version can carry a short note that explains the change.

Diff two versions

GET /api/sessions/{sessionId}/workflows/{workflowId}/versions/diff?from={version}&to={version}

Omit to to compare with the current definition. The result lists a changed description, nodes added, removed or changed, and edges added or removed.

Annotate a version

POST /api/sessions/{sessionId}/workflows/{workflowId}/versions/note?version={version}&note={text}

List versions

GET /api/sessions/{sessionId}/workflows/{workflowId}/versions

Roll back

POST /api/sessions/{sessionId}/workflows/{workflowId}/rollback?version={version}

restores an earlier version as the current definition. Rollback is also available as an MCP tool and in the web UI’s versions panel.

Run a specific version

Put yukta.version in the start payload to run a saved version without changing the current one. Such a run bypasses the prepared-workflow cache.

{
  "sessionId": "demo",
  "workflowId": "greet",
  "payload": { "name": "Ada", "yukta.version": "a1b2c3" }
}

Get started

Concepts

Building workflows

Plugin reference

Running and controlling

Interfaces

Operations

Reference

Validation and versions

Validate a definition

What is checked

Versions

Diff two versions

Annotate a version

List versions

Roll back

Run a specific version

​Validate a definition

​What is checked

​Versions

​Diff two versions

​Annotate a version

​List versions

​Roll back

​Run a specific version

​Related

Validate a definition

What is checked

Versions

Diff two versions

Annotate a version

List versions

Roll back

Run a specific version

Related