external-precondition-audit

name	external-precondition-audit
description	Trigger Pattern Any external contract interaction detected in attack_surface.md - Inject Into Breadth agents (merged via M7 hierarchy)

EXTERNAL_PRECONDITION_AUDIT Skill

Trigger Pattern: Any external contract interaction detected in attack_surface.md Inject Into: Breadth agents (merged via M7 hierarchy) Constraint: Interface-level inference only -- no production fetch required

For every external contract the protocol interacts with:

1. Interface-Level Requirement Inference

From the interface/import used by the protocol, infer what the external contract requires:

External Function Called	Parameters Passed	Likely Preconditions (from interface)	Our Protocol Validates?

Inference method: Read the function signature, parameter names, NatSpec comments (if any), and common patterns for that function type. Example: IVault.swap(FundManagement memory funds) -> infer that funds.sender must be authorized, funds.recipient determines where output goes.

2. Return Value Consumption

External Call	Return Type	How Protocol Uses Return	Failure Mode if Return Unexpected

For each return value: what happens if it returns 0? What happens if it returns MAX? What happens if the external call reverts?

• For each external data structure received (Vec, array, Map, list): (a) What ordering/uniqueness does the consuming code assume? (b) Does the external contract's spec guarantee that ordering? (c) What happens if the assumption is violated (unsorted, duplicates, gaps)?

3. State Dependency Mapping

Protocol State	Depends on External State	External State Can Change Without Our Knowledge?

For each dependency: model what happens when the external state changes between our protocol's read and use.

Step Execution Checklist

Section	Required	Completed?
1. Interface-Level Requirement Inference	YES	Y/N/?
2. Return Value Consumption	YES	Y/N/?
3. State Dependency Mapping	YES	Y/N/?