* Validate flow CEL expressions at definition load time
Promote CEL expression handling to a public Expression API and validate expressions when a FlowDefinition is built instead of when it executes.
Invalid CEL syntax or unknown roots now raise ValidationError from FlowDefinition.from_yaml() and FlowDefinition.from_dict(). Expressions may reference state and outputs, plus item inside each.do; bare identifiers are rejected as unknown roots.
For with values, the CEL contract is intentionally simple: after trimming whitespace, a string is evaluated as CEL only if it starts with ${ and ends with }. Anything else is treated as a literal value, so partial interpolation is not supported. If the content inside the wrapper is not valid CEL, validation fails.
Examples:
```text
"${state.topic}" -> evaluated, returns state.topic
"topic is ${state.topic}" -> literal string
"${state.topic} suffix" -> literal string
"${'a'}${'b'}" -> invalid CEL
```
* Honor explicit empty-context overrides in evaluate() / render_template()
* Add script/code blocks to FlowDefinition
Let a Flow method run trusted inline Python with `call: script`. The code
is compiled once into a generated function and receives the runtime
values as arguments.
```yaml
methods:
normalize:
start: true
do:
call: script
code: |
import math
state["rounded"] = math.ceil(state["raw_score"])
return f"rounded:{state['rounded']}"
```
Even though this shares the same surface of tools (custom code), I
decided to make it opt-in for now, using
`CREWAI_ALLOW_FLOW_SCRIPT_EXECUTION=1`.
* Address code review comments
A custom BaseLLM subclass serializes with the inherited llm_type "base",
which the registry maps to the abstract BaseLLM. Restore then crashed on
cls(**value). Rebuild a concrete LLM from the saved config when the
resolved class is abstract.
Checkpoint serialization stamps checkpoint_completed_methods onto every live
Flow in RuntimeState.root, including the agent executor reused across a crew's
tasks. kickoff_async read that stamp as a restore signal, so the second task
replayed the first task's completed methods and never reached a final answer.
Gate is_restoring on _restored_from_checkpoint, set only by
_restore_from_checkpoint, and consume it single-shot.
Add fork classmethod, _restore_runtime, and _restore_event_scope
to BaseAgent. Fix from_checkpoint to set runtime state on the
event bus and restore event scopes. Store kickoff event ID across
checkpoints to skip re-emission on resume. Handle agent entity
type in checkpoint CLI and TUI.
- Rewrite TUI with Tree widget showing branch/fork lineage
- Add Resume and Fork buttons in detail panel with Collapsible entities
- Show branch and parent_id in detail panel and CLI info output
- Auto-detect .checkpoints.db when default dir missing
- Append .db to location for SqliteProvider when no extension set
- Fix RuntimeState.from_checkpoint not setting provider/location
- Fork now writes initial checkpoint on new branch
- Add from_checkpoint, fork, and CLI docs to checkpointing.mdx
Accept CheckpointConfig on Crew and Flow kickoff/kickoff_async/akickoff.
When restore_from is set, the entity resumes from that checkpoint.
When only config fields are set, checkpointing is enabled for the run.
Adds restore_from field (Path | str | None) to CheckpointConfig.
Write the crewAI package version into every checkpoint blob. On restore,
run version-based migrations so older checkpoints can be transformed
forward to the current format. Adds crewai.utilities.version module.
