* Require explicit CrewAI project definitions
JSON crews and declarative flows now resolve from `[tool.crewai]`
metadata instead of implicit filename discovery. This makes project type
selection deterministic, prevents stray `crew.json(c)` files from changing
CLI behavior, and centralizes definition path validation for run, install,
deploy validation, plotting, and memory reset paths.
`[tool.crewai].definition` must be a project-local file path. Absolute
paths, `~`, missing files, directories, and paths escaping the project root
are rejected so deploy and runtime commands use the same contract.
Breaking changes and migration paths:
* JSON crew projects are no longer discovered from `crew.json` or
`crew.jsonc` alone. Add explicit metadata:
```toml
[tool.crewai]
type = "crew"
definition = "crew.jsonc"
```
* Declarative flow projects must use a valid project-local definition path:
```toml
[tool.crewai]
type = "flow"
definition = "flows/research.yaml"
```
* `Flow.from_definition(definition)` is removed. Use:
```python
Flow.from_declaration(contents=definition)
```
* `FlowDefinition.to_json()` and `FlowDefinition.to_yaml()` are removed.
Use `FlowDefinition.to_dict()` and serialize with the caller's JSON or
YAML library.
* `FlowDefinition.from_dict()` is removed. Use:
```python
FlowDefinition.from_declaration(contents=data)
```
* `FlowDefinition.json_schema()` is removed. Use Pydantic's schema API only
where schema generation is intentionally needed:
```python
FlowDefinition.model_json_schema(by_alias=True)
```
* `crewai_cli.run_crew.find_crew_json_file()` and `_has_json_crew()` are
removed. Use `configured_project_json_crew()` or the shared
`crewai_core.project.configured_project_definition("crew")` helper.
* `crewai reset-memories` now only loads JSON crews declared through
`[tool.crewai].definition`, and invalid declared JSON crew definitions
fail instead of silently falling back to classic crew discovery.
* Address code review comments
`StateProxy` looked like a thread-safety boundary, but it only protected
a small slice of state operations. Some examples of operations that were
not covered:
- `self.state.counter += 1`, `self.state["counter"] += 1` (increments)
- `self.state.user.profile.score += 1` (nested object mutations)
- `self.state.config["limits"]["max"] = 10` (mutation through model fields)
- `self.state.items[0].status = "done"` (list/container mutations)
This commit decided to remove it completely for simplicity and
performance:
- Simpler runtime code
- attr read: 24x faster, attr write: 27x faster, list append: 19x faster (local benchmark)
- Clearer concurrency contract (lifecycle locks remain, but arbitrary
shared state mutation is not presented as thread-safe)
Allow required JSON schema state fields to be supplied by kickoff inputs
instead of requiring every field to exist in state.default before
runtime.
Example: a flow with required lead_name and no state.default can now run
with kickoff inputs={"lead_name": "Ada Lovelace"}.
Add a single declaration loader shared by API and CLI callers.
- Add FlowDefinition.from_declaration for FlowDefinition instances, dictionaries, YAML/JSON strings, and file paths
- Add Flow.from_declaration to build runnable flows directly from the same inputs
- Route declarative flow CLI loading through Flow.from_declaration so path handling and validation stay centralized
```
# Load just the serializable definition when you do not need to run it yet.
definition = FlowDefinition.from_declaration(path="flows/research.crewai")
definition = FlowDefinition.from_declaration(contents=flow_yaml)
definition = FlowDefinition.from_declaration(contents=flow_dict)
# Build a runnable flow directly from the same declaration inputs.
flow = Flow.from_declaration(path="flows/research.crewai")
flow = Flow.from_declaration(contents=flow_yaml)
flow = Flow.from_declaration(contents=flow_dict)
flow = Flow.from_declaration(contents=definition)
# Run it like any other flow.
result = flow.kickoff(inputs={"topic": "AI agents"})
# The CLI now goes through the same path-based loader.
# crewai run --definition flows/research.crewai
```
* Add declarative Flow CLI support
Currently, declarative flows can be loaded by the runtime, but the CLI
still treats them as an experimental definition file instead of a
first-class Flow project shape.
With this PR, `crewai create flow --declarative` scaffolds a YAML-backed
Flow project, and `crewai run`, `crewai flow kickoff`, and `crewai flow
plot` can run against the configured definition.
This also lets crew actions reference reusable crew definition files or
folders and override their inputs from the Flow definition, so
declarative flows can compose existing declarative crews without
inlining everything.
* Address code review comments
* Add single agent action to Flow definitions
Lets a flow method build and run a single CrewAI agent directly, without
wrapping it in a crew. Same idea as the existing `crew` action, but for
one agent.
methods:
answer:
do:
call: agent
with:
role: Analyst
goal: Answer questions
backstory: Knows things.
input: "${state.question}"
start: true
* `input` is required and interpolated from flow state, like
`${state.question}` or `${item}` inside an `each` loop
* optional `response_format` points at a Pydantic model (`{"python":
"models.AnswerModel"}`) to get structured output
* `input` must be a string and its CEL is validated at load time, so bad
expressions like `${state.}` fail early
* Simplify test code
* 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()
* Use explicit name/action shape for each.do steps
* Add optional `if` expression to `each.do` steps
Lets a step inside an `each` action run conditionally based on a CEL
expression evaluated against `item` and prior step `outputs`.
* 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 `do:` step can now say `call: tool` and name a CrewAI tool to run,
passing its inputs under `with:`. Before this, a definition could only
point at Python code to run.
```yaml
methods:
search:
start: true
do:
call: tool
ref: crewai_tools:ExaSearchTool
with:
search_query: ai agents
```
* Drive human feedback from the flow definition
@human_feedback previously wrapped methods with the full HITL runtime (feedback
request, outcome collapse, learn loop), so flows built from a YAML definition —
which carry no decorated callables — could not pause for or route on human
feedback.
# Conflicts:
# lib/crewai/src/crewai/flow/persistence/decorators.py
# lib/crewai/src/crewai/flow/runtime/__init__.py
* Address code review comments
* Wire config and persistence from FlowDefinition into the runtime
`from_definition` was silently dropping all config fields; it now passes
`config.model_dump()` so suppress_flow_events, max_method_calls, etc.
actually apply.
Persistence is now engine-driven: `_persist_method_completion` fires
after every method using the definition's persist metadata, so
`@persist` no longer needs to wrap methods — it just stamps them.
* Address code review comments
* Read flow dispatch from FlowDefinition
Store the definition in a `_definition` PrivateAttr at post-init and
convert the dispatch helpers (`_start_method_names`, `_listener_methods`,
`_start_condition`, `_listen_condition`, `_is_router`) from classmethods
to instance methods that read it. Event names now fall back to
`self._definition.name` instead of `self.__class__.__name__`.
Behavior is identical for decorator subclasses, but the engine no longer
assumes the definition comes from the class. This is the seam for
`Flow.from_definition`, where an instance runs a definition that was
loaded rather than built from a Python subclass.
* Add Flow.from_definition to run flows without a subclass
A FlowDefinition (e.g. loaded from YAML) was only usable for dispatch on
decorator-authored subclasses. Now each method definition records an
importable `module:qualname` handler ref, and `Flow.from_definition`
resolves and binds those handlers to build a runnable flow directly.
* Build flow state from FlowDefinition
Definition-driven flows previously always started with a bare dict
state.
* Replace handler string with structured FlowActionDefinition
`handler: str | None` was optional and opaque — missing handlers only
surfaced at kickoff time. `do: FlowActionDefinition` is required, so
Pydantic rejects invalid definitions at parse time.
The `call: "code"` discriminator prepares the schema for future
non-Python action types (e.g. MCP tool, crew) without touching
`FlowMethodDefinition`. Resolution logic is extracted to
`runtime/_action_resolvers.py` to keep the dispatch point isolated.
* Fix conversational start router missing required do field
FlowMethodDefinition.do became required when the handler string was
replaced with FlowActionDefinition, but _conversation_start_router still
built its fragment without it, breaking crewai import entirely.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
* Add event scoping to flow test
* Change lib/crewai/tests/test_flow_from_definition.py
---------
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
