Substantial Performance vs Perfect Tender
Contracts & Sales · Lesson 10
Substantial Performance vs Perfect Tender
這一課問的是：履行上的小偏差是否解除對方的義務？CL 採 substantial performance；UCC 採 perfect tender。
Actor
Act
Object
Standard
Consequence
Issue · what this lesson is really about
Does a minor deviation in performance discharge the other party's duty — or merely give rise to damages?
這一課問的是：履行上的小偏差是否解除對方的義務？CL 採 substantial performance；UCC 採 perfect tender。
Trigger words & phrases that should flag this issue:
minor deviationsubstantially performedwrong colornon-conformingcure
Core Terminology · 7 must-know
Tap a card to flip and reveal the meaning.
substantial performance
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CL: performance fulfilling the essential purpose with only minor deviations.
實質履行（CL）。
perfect tender
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UCC §2-601: goods that fail to conform in any respect may be rejected.
完美交付（UCC §2-601）。
cure
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UCC §2-508: seller may cure non-conforming tender.
補正（§2-508）。
installment contract
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UCC §2-612: separate-lot deliveries — uses materiality standard.
分期合約。
damages for minor breach
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Minor breach gives damages but no excuse.
輕微違約之損害。
Rule Sentence · the workhorse
Under the Common Law, substantial performance discharges the performing party's duty (with damages for the deviation); under UCC §2-601, goods that fail to conform to the contract in any respect may be rejected.
Sentence Anatomy · 5 roles, 5 colors
Every rule sentence breaks into five visual roles.
Actor 行為人the performing party履行方
Act 行為tendering performance交付履行
Object 對象CL service or UCC goodsCL 服務 / UCC 貨物
Standard 法律標準substantial perf. (CL) · perfect tender (UCC)實質履行 / 完美交付
Consequence 後果duty discharged or rejection right義務解除 或 拒收權
Casebook Snapshot · a real American case
Jacob & Youngs, Inc. v. Kent
Holding. Where a builder substantially performs a construction contract but uses a different brand of pipe than specified, that minor deviation does not entitle the owner to refuse the price; the owner is limited to damages — measured by diminished value, not cost of tearing down and rebuilding.
Why it matters. Minor breach = collectible loss, not license to walk away. Remedy fits the breach.
小違約只能索差額，不可拒付全價。
Common Mistakes · what trips students
✗ UCC 與 CL 在「履行不完美」上規則一致。
✓ UCC perfect tender vs CL substantial performance — different standards.
UCC 完美交付；CL 實質履行。
✗ 「reject」就無法回頭。
✓ UCC §2-508 cure allowed.
UCC §2-508 容許補正。
Mini IRAC · build the Application
Issue. Where a seller of goods ships a slightly wrong color (the contract specified blue, the seller shipped navy), may the buyer reject?
Rule. Under UCC §2-601, a buyer may reject any tender that fails to conform to the contract in any respect.
Application (model). The contract called for blue widgets; the seller shipped navy. Because UCC §2-601 applies the perfect-tender rule to single-lot goods contracts, the fact that the goods deviated from the contract's color specification — even minimally — means the tender failed to conform in some respect.
Pick the right element for each blank:
g1.
g2.
g3.
Conclusion. Therefore, the buyer may reject the tender, subject to the seller's right to cure under §2-508.
MBE Check · multiple choice
Builder substantially completes a $300,000 house but installs the wrong brand of identical-quality pipe (no functional difference). Owner withholds the entire final payment of $20,000. What can owner recover?
Practice Drill · tap to build the rule
Drop the chips here in correct order:
Tap chips to add → tap chips in the target to remove: