Workflows ship two expression languages in adjacent fields. Agent
`prompt_template` and end `output_template` are Jinja2, so `{{query}}` is
correct there. State and condition `expression` fields are bare CEL,
where the same string is a parse error.
Nothing told users this. docs/content/Agents/nodes.mdx documented the
pre-CEL Set State node with `{{variable_name}}` examples and Set /
Increment / Append operations that no longer exist — "CEL" appeared
nowhere in the docs. The builder's own placeholder was `input.foo + 1`,
referencing an `input` namespace that is not in workflow state, while the
panel beside it advertised `{{ agent.variable }}`.
There was also no validation anywhere: neither validateWorkflow nor
validate_workflow_structure looked at state nodes at all, and conditions
were only checked for a non-empty string. A workflow containing
`{{query}}` saved and published clean, then aborted on the first message
with a bare caret dump that sanitize_api_error collapsed into "An error
occurred … please try again later" — advice that sends the user round the
same loop, which is what the 2026-08-01 report shows.
Adds validate_cel_expression (compile-only, since state is built at run
time and unresolved names are not knowable when saving) and wires it into
the workflow save path for both node types, plus the half-configured
state operations the engine silently skips. `{{ }}` gets a targeted hint,
raised only after compilation has already failed so valid CEL that
contains braces — `x == "{{y}}"`, or a nested map literal — is not
rejected.
celpy errors are now summarized: undeclared-reference messages embed a
repr of the entire activation, thousands of characters including the
user's own query, and others interpolate the offending state value.
Quoted fragments that are not bare identifiers are redacted, since
config errors now bypass sanitize_api_error to reach the user, and a
shared agent's runner is not its owner.
Docs rewritten with a table of which field takes which syntax, CEL
examples for Set State, and the Condition node section that basics.mdx
has been linking to all along.
Add a code workflow node that runs code in the run-scoped sandbox session and
writes produced files as artifact references into workflow state, passing them
by reference (only id and metadata, never bytes) so downstream nodes and CEL
conditions can branch on them. Add an artifacts.* templating namespace that
resolves those references to metadata via a run-scoped lookup, available to
both the workflow engine and the prompt renderer. Extract the sandbox-to-
artifact persistence into a shared helper reused by the code node and the
code_executor tool.
* feat: add condition node functionality with CEL evaluation
- Introduced ConditionNode to support conditional branching in workflows.
- Implemented CEL evaluation for state updates and condition expressions.
- Updated WorkflowEngine to handle condition nodes and their execution logic.
- Enhanced validation for workflows to ensure condition nodes have at least two outgoing edges and valid expressions.
- Modified frontend components to support new condition node type and its configuration.
- Added necessary types and interfaces for condition cases and state operations.
- Updated requirements to include cel-python for expression evaluation.
* mini-fixes
* feat(workflow): improve UX
---------
Co-authored-by: Alex <a@tushynski.me>
* feat: implement WorkflowAgent and GraphExecutor for workflow management and execution
* refactor: workflow schemas and introduce WorkflowEngine
- Updated schemas in `schemas.py` to include new agent types and configurations.
- Created `WorkflowEngine` class in `workflow_engine.py` to manage workflow execution.
- Enhanced `StreamProcessor` to handle workflow-related data.
- Added new routes and utilities for managing workflows in the user API.
- Implemented validation and serialization functions for workflows.
- Established MongoDB collections and indexes for workflows and related entities.
* refactor: improve WorkflowAgent documentation and update type hints in WorkflowEngine
* feat: workflow builder and managing in frontend
- Added new endpoints for workflows in `endpoints.ts`.
- Implemented `getWorkflow`, `createWorkflow`, and `updateWorkflow` methods in `userService.ts`.
- Introduced new UI components for alerts, buttons, commands, dialogs, multi-select, popovers, and selects.
- Enhanced styling in `index.css` with new theme variables and animations.
- Refactored modal components for better layout and styling.
- Configured TypeScript paths and Vite aliases for cleaner imports.
* feat: add workflow preview component and related state management
- Implemented WorkflowPreview component for displaying workflow execution.
- Created WorkflowPreviewSlice for managing workflow preview state, including queries and execution steps.
- Added WorkflowMiniMap for visual representation of workflow nodes and their statuses.
- Integrated conversation handling with the ability to fetch answers and manage query states.
- Introduced reusable Sheet component for UI overlays.
- Updated Redux store to include workflowPreview reducer.
* feat: enhance workflow execution details and state management in WorkflowEngine and WorkflowPreview
* feat: enhance workflow components with improved UI and functionality
- Updated WorkflowPreview to allow text truncation for better display of long names.
- Enhanced BaseNode with connectable handles and improved styling for better visibility.
- Added MobileBlocker component to inform users about desktop requirements for the Workflow Builder.
- Introduced PromptTextArea component for improved variable insertion and search functionality, including upstream variable extraction and context addition.
* feat(workflow): add owner validation and graph version support
* fix: ruff lint
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Co-authored-by: Alex <a@tushynski.me>
Alex