design-task
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CrewAI task design and configuration. Use when creating, configuring, or debugging crewAI tasks — writing descriptions and expected_output, setting up task dependencies with context, configuring output formats (output_pydantic, output_json, output_file), using guardrails for validation, enabling human_input, async execution, markdown formatting, or debugging task execution issues.
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View Translation Comparison →CrewAI Task Design Guide
How to write effective tasks that produce reliable, high-quality output from your agents.
The 80/20 Rule
Spend 80% of your effort on task design, 20% on agent design. The task is the most important lever you have. A well-designed task with a mediocre agent will outperform a poorly designed task with an excellent agent.
1. Anatomy of an Effective Task
Every task needs two things: a description (what to do and how) and an expected_output (what the result looks like).
Description — The Instructions
A good description includes:
- What to do — the core action
- How to do it — specific steps or approach
- Context — why this matters, what it feeds into
- Constraints — scope limits, things to avoid
- Inputs — what data or context is available
yaml
research_task:
description: >
Conduct thorough research about {topic} for the year {current_year}.
Your research should:
1. Identify the top 5 key trends and breakthroughs
2. For each trend, find at least 2 credible sources
3. Note any controversies or competing viewpoints
4. Assess potential industry impact (high/medium/low)
Focus on developments from the last 6 months.
Do NOT include speculation or unverified claims.
The output will feed into a report for {target_audience}.
expected_output: >
A structured research brief with 5 sections, one per trend.
Each section includes: trend name, 2-3 paragraph summary,
source citations, impact assessment (high/medium/low),
and a confidence level for your findings.
agent: researcherExpected Output — The Success Criteria
The tells the agent what "done" looks like. Be specific about:
expected_output- Format — bullet points, paragraphs, JSON, table
- Structure — sections, headings, order
- Length — approximate word count or number of items
- Quality markers — citations required, confidence levels, specific fields
| Bad Expected Output | Good Expected Output |
|---|---|
| |
| |
| |
2. The Single Purpose Principle
One task = one objective. Never combine multiple operations into a single task.
Bad: "God Task"
yaml
# DON'T do this — too many objectives in one task
research_and_write_task:
description: >
Research {topic}, analyze the findings, write a blog post,
and proofread it for grammar errors.
expected_output: >
A polished blog post about {topic}.Good: Focused Tasks
yaml
research_task:
description: >
Research {topic} and identify the top 5 key developments.
expected_output: >
A research brief with 5 sections covering key trends.
agent: researcher
writing_task:
description: >
Using the research findings, write a technical blog post about {topic}.
expected_output: >
A 1000-1500 word blog post with introduction, main sections,
and conclusion. Include code examples where relevant.
agent: writer
editing_task:
description: >
Review and edit the blog post for grammar, clarity, and consistency.
expected_output: >
The final edited blog post with all corrections applied.
Include a brief editor's note listing what was changed.
agent: editorEach task has one clear objective. The sequential flow passes context automatically.
3. Task Configuration Reference
Essential Parameters
python
Task(
description="...", # Required: what to do
expected_output="...", # Required: what the result looks like
agent=researcher, # Optional for hierarchical process; required for sequential
)Task Dependencies with context
contextpython
analysis_task = Task(
description="Analyze the research findings...",
expected_output="...",
agent=analyst,
context=[research_task], # Receives research_task's output as context
)In sequential process: Each task auto-receives all prior task outputs. Use only when you need non-linear dependencies.
contextIn hierarchical process: is how you create explicit data flow between tasks.
contextStructured Output
Use or when downstream code needs to parse the result:
output_pydanticoutput_jsonpython
from pydantic import BaseModel
class ResearchReport(BaseModel):
trends: list[str]
confidence: float
sources: list[str]
research_task = Task(
description="...",
expected_output="A structured report with trends, confidence score, and sources.",
agent=researcher,
output_pydantic=ResearchReport, # Agent's output is parsed into this model
)Important: is always a string description — never a class name. The Pydantic model goes in , and the text tells the agent what fields to include.
expected_outputoutput_pydanticexpected_outputAccess structured output:
python
result = crew.kickoff(inputs={...})
last_task_output = result.pydantic # Pydantic model from the last task
all_outputs = result.tasks_output # List of all TaskOutput objects
first_task = all_outputs[0].pydantic # Pydantic from a specific taskFile Output
python
Task(
...,
output_file="output/report.md", # Save output to file
create_directory=True, # Create directory if missing (default: True)
)File output and structured output can be combined — the file gets the raw text, and gets the parsed model.
output_pydanticAsync Execution
python
Task(
...,
async_execution=True, # Run without blocking the next task
)Use for tasks that can run in parallel. The crew continues to the next task while this one executes. Use on downstream tasks to wait for async results.
contextHuman Review
python
Task(
...,
human_input=True, # Pause for human review before finalizing
)When enabled, the agent presents its result and waits for human feedback before marking the task complete. Use for critical outputs that need human approval.
Markdown Formatting
python
Task(
...,
markdown=True, # Add markdown formatting instructions
)Automatically instructs the agent to format output with proper markdown headers, lists, emphasis, and code blocks.
Callbacks
python
def log_completion(output):
print(f"Task completed: {output.description[:50]}...")
save_to_database(output.raw)
Task(
...,
callback=log_completion, # Called after task completion
)4. Task Guardrails — Quality Control
Guardrails validate task output before it passes to the next step. If validation fails, the agent retries.
Function-Based Guardrails
python
def validate_word_count(output) -> tuple[bool, Any]:
"""Ensure output is between 500-2000 words."""
word_count = len(output.raw.split())
if word_count < 500:
return (False, f"Output too short ({word_count} words). Expand to at least 500 words.")
if word_count > 2000:
return (False, f"Output too long ({word_count} words). Condense to under 2000 words.")
return (True, output)
Task(
...,
guardrail=validate_word_count,
guardrail_max_retries=3, # Max retry attempts (default: 3)
)Return format: — first element is pass/fail, second is the result (on success) or error message (on failure).
(bool, Any)LLM-Based Guardrails
python
Task(
...,
guardrail="Verify the output contains at least 3 source citations and no speculative claims.",
)String guardrails use the agent's LLM to evaluate the output. Good for subjective quality checks.
Chaining Multiple Guardrails
python
Task(
...,
guardrails=[
validate_word_count, # Function: check length
validate_no_pii, # Function: check for PII
"Ensure the tone is professional and appropriate for a business audience.", # LLM check
],
guardrail_max_retries=3,
)Guardrails execute sequentially. Each receives the output of the previous guardrail. Mix function-based (deterministic) and LLM-based (subjective) checks.
5. YAML Configuration (Recommended)
tasks.yaml
yaml
research_task:
description: >
Conduct thorough research about {topic} for {current_year}.
Identify key trends, breakthrough technologies,
and potential industry impacts.
Focus on the last 6 months of developments.
expected_output: >
A structured research brief with 5 sections.
Each section: trend name, 2-3 paragraph summary,
source citations, and impact assessment.
agent: researcher
analysis_task:
description: >
Analyze the research findings and create actionable recommendations
for {target_audience}.
expected_output: >
A prioritized list of 5 recommendations with:
rationale, estimated effort, and expected impact.
agent: analyst
context:
- research_task
report_task:
description: >
Compile a final report combining research and analysis for {target_audience}.
expected_output: >
A polished markdown report with executive summary,
detailed findings, recommendations, and appendices.
agent: writer
output_file: output/report.mdWiring in crew.py
python
@CrewBase
class ResearchCrew:
agents_config = "config/agents.yaml"
tasks_config = "config/tasks.yaml"
@task
def research_task(self) -> Task:
return Task(config=self.tasks_config["research_task"])
@task
def analysis_task(self) -> Task:
return Task(
config=self.tasks_config["analysis_task"],
context=[self.research_task()],
)
@task
def report_task(self) -> Task:
return Task(
config=self.tasks_config["report_task"],
output_file="output/report.md",
)Critical: The method name () must match the YAML key ().
def research_taskresearch_task:6. Task Dependencies and Context Flow
Sequential Process (Default)
In , tasks run in order. Each task automatically receives all prior task outputs as context.
Process.sequentialresearch_task → analysis_task → report_task
↓ ↓ ↓
output 1 output 1 + 2 output 1 + 2 + 3You don't need in sequential — it's implicit. Use it only to create non-linear dependencies:
context=python
# Task C depends on A but NOT B
task_c = Task(
...,
context=[task_a], # Only receives task_a output, not task_b
)Explicit Dependencies
python
# Diamond dependency pattern
task_a = Task(...) # Entry point
task_b = Task(..., context=[task_a]) # Depends on A
task_c = Task(..., context=[task_a]) # Also depends on A
task_d = Task(..., context=[task_b, task_c]) # Depends on both B and CConditional Tasks
python
from crewai.task import ConditionalTask
def needs_more_data(output) -> bool:
return len(output.pydantic.items) < 10
extra_research = ConditionalTask(
description="Fetch additional data sources...",
expected_output="...",
agent=researcher,
condition=needs_more_data, # Only runs if previous output has < 10 items
)7. Task Tools
Tasks can have their own tools that override the agent's default tools for that specific task:
python
from crewai_tools import SerperDevTool, ScrapeWebsiteTool
Task(
description="Search for and scrape the top 5 articles about {topic}...",
expected_output="...",
agent=researcher,
tools=[SerperDevTool(), ScrapeWebsiteTool()], # Task-specific tools
)When to use task-level tools:
- The task needs tools the agent doesn't normally have
- You want to restrict an agent to specific tools for this task
- Different tasks by the same agent need different tool sets
8. Variable Interpolation
Use placeholders in YAML for reusable tasks:
{variable}yaml
research_task:
description: >
Research {topic} trends for {current_year},
targeting {target_audience}.
expected_output: >
A report on {topic} suitable for {target_audience}.Variables are replaced when you call :
crew.kickoff(inputs={...})python
crew.kickoff(inputs={
"topic": "AI Agents",
"current_year": "2025",
"target_audience": "developers",
})Common mistakes:
- Missing variable in → literal
inputsappears in the prompt{variable} - Using Jinja2 syntax → crewAI uses single braces
{{ }}{ } - Unused variables in → silently ignored (no error)
inputs
9. Common Task Design Mistakes
| Mistake | Impact | Fix |
|---|---|---|
| Vague description ("Research the topic") | Agent produces shallow, unfocused output | Add specific steps, constraints, and context |
| Vague expected_output ("A report") | Agent guesses at format and structure | Specify format, sections, length, quality markers |
| Multiple objectives in one task | Agent does all of them poorly | Split into focused single-purpose tasks |
| No context between dependent tasks | Agent lacks information from prior steps | Use |
| Agent sees a class name string, not field names | Keep |
| Missing tools for data tasks | Agent fabricates data instead of fetching it | Add tools to the task or agent |
| No guardrails on critical output | Bad output flows downstream unchecked | Add function or LLM guardrails |
| Overly strict expected_output | Agent loops trying to match impossible criteria | Be specific but achievable; lower |
| Description duplicates backstory | Wasted tokens and confused agent | Description = what to do; backstory = who you are |
10. Task Design Checklist
Before running a task, verify:
- Description includes what, how, context, and constraints
- Expected output specifies format, structure, and quality markers
- Single purpose — one clear objective per task
- Agent assigned (or task is in a hierarchical crew)
- Dependencies set via where needed
context - Tools provided for any task requiring external data
- Structured output configured if downstream code parses the result
- Guardrails set for critical outputs
- Variables in YAML match the dict keys
inputs - Expected output is achievable — test with a simple run before adding complexity
References
For deeper dives into specific topics, see:
- Structured Output — ,
output_pydantic, andoutput_jsonpatterns across LLM, Agent, Task, and Crew levelsresponse_format
For related skills:
- getting-started — project scaffolding, choosing the right abstraction, Flow architecture
- design-agent — agent Role-Goal-Backstory framework, parameter tuning, tool assignment, memory & knowledge configuration