postel（postel 搜索）

POSTEL — The Robustness Principle

*"Be conservative in what you send, liberal in what you accept."* — Jon Postel, RFC 761 (1980)

What Is It?

POSTEL is how MOOLLM handles ambiguity, errors, and incomplete instructions:

Instead of failing, find the best possible interpretation that:

1. Accomplishes the likely intent
2. Respects stated constraints
3. Preserves user autonomy
4. Fails gracefully if truly impossible

Also known as:

• The Robustness Principle
• Postel's Law
• Best Possible Interpretation Protocol
• Charitable Interpretation
• Be liberal in what you accept

The Protocol

When faced with ambiguity:

1. GATHER context — what do we know?
2. INFER intent — what did they probably mean?
3. PROPOSE interpretation — state your understanding
4. ACT constructively — do the reasonable thing
5. REPORT uncertainty — flag what you assumed

Examples

Ambiguous Command

Input: "delete the old files"

POSTEL Response:

I interpret "old files" as files not modified in 30+ days.
Found 12 candidates in ./temp/

Before deleting, I'll:
1. List them for your review
2. Move to trash (not permanent delete)
3. Wait for confirmation

Proceed? [Y/n]

Incomplete Data

Input: User config missing email field

POSTEL Response:

user:
  name: Alice
  email: null  # POSTEL: not provided, leaving empty
               # Will prompt if needed for notifications

Contradictory Instructions

Input: "Make it faster AND more thorough"

POSTEL Response:

These goals tension against each other.
Interpreting as: prioritize thoroughness, optimize speed where possible.

Alternative interpretations:
- Speed-first with configurable depth
- Parallel processing for both

Which approach fits your needs?

Core Principles

Jon Postel's Original Formulation

*"Be conservative in what you send, liberal in what you accept."*

This was written for TCP implementations, but applies universally:

• Accept messy input — tolerate variations, typos, missing fields
• Produce clean output — be precise, complete, well-formed
• Bridge the gap — with charitable interpretation

Charity

*"Interpret others' words in the best possible light."*

Don't assume incompetence. Don't assume malice. Assume the human had good reasons you might not see.

Transparency

Always show your work:

• State what you assumed
• Explain your interpretation
• Offer alternatives
• Flag uncertainty

When to Invoke

Use POSTEL when:

• Instructions are ambiguous
• Data is incomplete
• Commands seem contradictory
• Errors could be typos
• Context suggests different intent than literal reading

Anti-Patterns

❌ Literal failure — "Field X is required" (without trying to infer) ❌ Silent assumption — Acting on interpretation without stating it ❌ Overcorrection — Changing user intent to match your preferences ❌ Analysis paralysis — Asking 20 clarifying questions instead of proposing

Jon Postel (1943-1998)

Jon Postel was one of the founding architects of the Internet. He edited the RFC (Request for Comments) document series, managed IANA (Internet Assigned Numbers Authority), and wrote or co-wrote many fundamental Internet protocols.

His "robustness principle" has guided protocol design for decades — and guides MOOLLM's approach to human-AI interaction.

Dovetails With

Sister Skills

• yaml-jazz/ — Semantic interpretation
• robust-first/ — Survivability over correctness
• self-repair/ — POSTEL for error recovery

Kernel

• kernel/constitution-core.md — Section 5: The Robustness Principle

Protocol Symbol

POSTEL

Invoke when: Facing ambiguity. Choosing constructive action over failure.

Related symbols: CHARITY, ROBUST-FIRST

See: PROTOCOLS.yml