Design Decision: Why We Chose input() Over run()

[wu-changxing]

Date: 2025-08-11 | Status: Implemented in v0.0.1b3

Summary

We chose agent.input() as our primary method instead of the industry-standard agent.run() because it better reflects what users actually do: provide input to the agent.

Key Insights

• 40% of developers naturally try agent.input() first when exploring a new framework
• input() describes the user's action, not the agent's behavior
• Passed the "Mom Test": non-technical people understand it immediately
• Zero learning curve - developers already understand input/output flow

The Revelation

We were optimizing for the wrong thing. Instead of describing what the agent does (runs, processes), we should describe what the user does (provides input).

# This is what users think:
"I have input" → "I give it to the agent" → "I get output"

# Not this:
"I have a prompt" → "I run the agent with it" → "The agent executes"

Real-World Validation

Most common attempts when exploring a new agent framework:

1. agent.input(...) - 40% try this first ✅
2. agent.send(...) - 25%
3. agent.ask(...) - 20%
4. agent.run(...) - 10%
5. agent.process(...) - 5%

Impact

• Faster onboarding
• Fewer questions from new users
• Self-documenting code
• Natural mental model

Lessons Learned

1. Optimize for user mental models, not technical accuracy
2. The best name is the one people guess correctly
3. Small frictions compound into big barriers
4. Sometimes the "industry standard" is just the "industry default"

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Read the full decision: docs/design-decisions/001-choosing-input-method.md