fix: support async callables in akickoff before/after callbacks

[ashusnapx]

Summary

Fixes silent discarding of async callables in Crew.akickoff().

Closes #6481

Problem

Crew.akickoff() is a native async execution path, but before_kickoff_callbacks and after_kickoff_callbacks were invoked synchronously with no inspect.isawaitable check. Async callables were silently discarded — their coroutine objects were never awaited.

async def my_callback(result):
    await some_async_operation()  # never awaited
    return result

crew = Crew(..., after_kickoff_callbacks=[my_callback])
await crew.akickoff()  # callback silently discarded

Fix

Component	Change
after_kickoff_callbacks in akickoff()	Added inspect.isawaitable check + await
before_kickoff_callbacks in akickoff()	Created aprepare_kickoff() async variant that awaits async callbacks

Follows the same pattern used by task_callback and step_callback throughout the codebase:

cb_result = callback(result)
if inspect.isawaitable(cb_result):
    await cb_result

Files Changed

File	Change
crew.py	Added import inspect, fixed after_callback loop, imports aprepare_kickoff
crews/utils.py	Added aprepare_kickoff() async variant with inspect.isawaitable for before_callbacks
tests/crew/test_async_crew.py	3 new tests: async before, async after, mixed sync+async

Tests

# Run async crew tests
pytest lib/crewai/tests/crew/test_async_crew.py -v

# Run all crew tests
pytest lib/crewai/tests/test_crew.py lib/crewai/tests/crew/ -v

• 14 async crew tests pass (3 new)
• ruff: all checks passed
• mypy: no issues found

[coderabbitai]

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📒 Files selected for processing (3)

• lib/crewai/src/crewai/crew.py
• lib/crewai/src/crewai/crews/utils.py
• lib/crewai/tests/crew/test_async_crew.py

🚧 Files skipped from review as they are similar to previous changes (2)

• lib/crewai/src/crewai/crew.py
• lib/crewai/tests/crew/test_async_crew.py

---

📝 Walkthrough

Walkthrough

Adds asynchronous kickoff preparation in crews/utils.py, updates Crew.akickoff to await before and after callback results, and extends async kickoff tests for callback completion and ordering.

Changes

Async before/after kickoff callback support

Layer / File(s)	Summary
Shared and asynchronous kickoff preparation lib/crewai/src/crewai/crews/utils.py	Extracts shared kickoff setup helpers, preserves synchronous preparation, and adds aprepare_kickoff with awaitable before_kickoff_callbacks support.
Native async kickoff integration lib/crewai/src/crewai/crew.py	Uses awaited asynchronous preparation in akickoff and awaits awaitable after_kickoff_callbacks results.
Async callback validation lib/crewai/tests/crew/test_async_crew.py	Adds tests verifying async before/after callbacks are awaited and mixed callback types execute in the expected order.

Sequence Diagram(s)

sequenceDiagram
  participant Caller
  participant Crew as Crew.akickoff
  participant Utils as aprepare_kickoff
  participant BeforeCB as before_kickoff_callbacks
  participant AfterCB as after_kickoff_callbacks

  Caller->>Crew: await akickoff(inputs)
  Crew->>Utils: await aprepare_kickoff(crew, inputs)
  Utils->>BeforeCB: invoke callback chain
  BeforeCB-->>Utils: result or awaitable
  Utils->>Utils: await awaitable result
  Utils-->>Crew: normalized inputs
  Crew->>AfterCB: invoke callback chain
  AfterCB-->>Crew: result or awaitable
  Crew->>Crew: await awaitable result
  Crew-->>Caller: CrewOutput

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🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly summarizes the main change: async support for before/after kickoff callbacks in akickoff.
Description check	✅ Passed	The description is directly related to the code changes and accurately describes the async callback fix.
Linked Issues check	✅ Passed	The changes satisfy #6481 by awaiting async after callbacks and adding an async kickoff prep path for before callbacks.
Out of Scope Changes check	✅ Passed	The refactor into shared kickoff helpers supports the async callback fix and does not introduce unrelated changes.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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---

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[coderabbitai]

Actionable comments posted: 2

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@lib/crewai/src/crewai/crews/utils.py`:
- Around line 362-474: The kickoff preparation logic is duplicated between
prepare_kickoff and aprepare_kickoff, creating drift risk as shared behavior
changes over time. Extract the common control flow into a shared internal helper
used by both functions, and keep only the before_kickoff_callbacks execution
different by injecting a callback runner that either returns directly or awaits
awaitable results. Preserve the existing behavior around crewai_event_bus
emission, store_files, _set_tasks_callbacks, setup_agents, and planning in the
shared helper.
- Around line 423-431: The kickoff planning path is still blocking the event
loop because `aprepare_kickoff` ultimately calls `crew._handle_crew_planning()`
synchronously via `CrewPlanner._handle_crew_planning()` and `execute_sync()`.
Update the async kickoff flow in `utils.py` so planning is offloaded to a thread
or handled through a non-blocking async path before returning from `akickoff()`,
using the existing `aprepare_kickoff`, `crew._handle_crew_planning`, and
`CrewPlanner` hooks to locate the change.

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Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 460ccfbf-0675-415f-a37f-8ca756db70d3

📥 Commits

Reviewing files that changed from the base of the PR and between 289686a and eb92e41.

📒 Files selected for processing (3)

• lib/crewai/src/crewai/crew.py
• lib/crewai/src/crewai/crews/utils.py
• lib/crewai/tests/crew/test_async_crew.py

[ErenAta16]

Same underlying fix as #6500 and #6482 (also open) — the crew.py change here is identical to both. Where this one differs is crews/utils.py: it copy-pastes the full body of prepare_kickoff into a new aprepare_kickoff rather than factoring out the shared setup/teardown logic, which #6500 and #6482 both do via extracted helpers. Functionally correct either way and the test coverage here (including the test_akickoff_mixed_sync_async_callbacks ordering check) is solid, but the duplication means a future change to the shared kickoff-preparation logic would need to be applied in two places instead of one — worth weighing against the other two when picking which of the three to merge.

[ashusnapx]

Refactored - extracted shared logic into _prepare_kickoff_common and _run_before_callbacks. Both prepare_kickoff and aprepare_kickoff now call the shared helpers. No more duplication.

[ErenAta16]

Confirmed - prepare_kickoff and aprepare_kickoff now both go through _normalize_inputs and _prepare_kickoff_common, with _run_before_callbacks handling the sync path and the async version inlining its own inspect.isawaitable loop (needed since it has to await mid-loop, so it can't reuse the sync helper as-is). Ran the full test_async_crew.py - 14 passed, including the mixed sync/async callback case. No more full-body duplication between the two entry points. Good refactor.

[ashusnapx]

Thanks for confirming. Ready for maintainer review.