Align swap widget fee naming and signed fee display

[ted-palmer]

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Project	Deployment	Actions	Updated (UTC)
relay-sdk-demo	Ready	Preview	Aug 28, 2026 6:35pm

[github-actions]

Claude finished @ted-palmer's task in 1m 42s —— View job

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Code Review

• Gather context (PR diff, commit history)
• Read changed files in full
• Review for correctness, security, error handling, repo guidelines

Code Review — No issues found.

Reviewed 4 files (quote.ts, PriceImpactTooltip.tsx, FeeBreakdown.tsx, and the changeset), ~46 lines changed. Checked correctness, sign/precision handling, and repo guidelines compliance.

Notes from the review (all clear, no action needed):

• formatUsdFee sign/precision logic (utils/quote.ts:23-41) is consistent with the codebase's convention that negative USD = cost and positive = benefit/reward. Zero → $0.00, sub-cent → < $0.01, and the + prefix only applies to positive values, so costs still render -$X.XX. finalValue === 0 correctly handles -0 (JS treats -0 === 0 as true), so a flipped-sign zero gas fee doesn't slip into the sub-cent branch.
• Reward path is coherent end-to-end. parseFees now always labels the relayer fee Platform Fee, and PriceImpactTooltip.tsx:63 derives isReward = fee.id === 'relayer-fee' && fee.usd.value > 0. That lines up with getFeeColor (green for value > 0) and the + prefix, so a positive platform fee renders green +$X.XX with a green (Reward) note — matching the changeset.
• Deposit gas collapsed summary (FeeBreakdown.tsx:66-68) still uses formatDollar(Math.abs(...)) independently of formatUsdFee, so the sign-flip changes don't double-apply there.
• The changeset follows the repo guidelines: leads with the reader-facing outcome, names the exact strings changed, and stays customer-facing.

One thing worth being aware of (not a defect, and it matches the documented behavior in the changeset): a sub-cent cost renders as < $0.01 with no leading minus, so it reads the same as a sub-cent credit apart from color. Since color already differentiates reward (green) from cost (plain), this is fine — just flagging the intentional trade-off.
• ted/int2-1322-align-swap-widget-fee-naming

[github-actions]

Claude finished @ted-palmer's task in 46s —— View job

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📝 Docs Drift Check — No docs impact

This PR does not touch surfaces that require a relayprotocol/relay-docs update.

The change renames swap-widget fee display labels (e.g. "Swap Impact" → "Swap Cost", "Relay Fee" → "Platform Fee", "Network cost" → "Deposit gas") and adjusts signed/zero/sub-cent fee formatting inside FeeBreakdown / PriceImpactTooltip and the internal parseFees util. No public props, types, exports, or hooks changed. The reference docs (references/relay-kit/ui/swap-widget.mdx) document widget props, not these row labels, and the fee concepts page already uses the aligned naming ("Execution Cost", "Swap Cost", "Platform Fees").

[greptile-apps]

Greptile Summary

Updates swap fee terminology and makes small fee credits and charges distinguishable. The fee formatter now preserves the sign for values below one cent.

Confidence Score: 5/5

No blocking failure remains.

No accepted blocking findings remain.

T-Rex Logs

What T-Rex did

• The harness source was uploaded and wired to invoke parseFees.
• The harness was executed against the parseFees implementation with +0.005 and -0.005 execution fees, revealing the parent behavior as < $0.01 for both inputs and the current behavior as +< $0.01 for +0.005 and -< $0.01 for -0.005.
• The UI package TypeScript typecheck completed successfully.

_{Ran code and verified through T-Rex}

_{Reviews (2): Last reviewed commit: "Keep the sign on sub-cent fee amounts" | Re-trigger Greptile}

[github-actions]

Claude finished @ted-palmer's task in 1m 2s —— View job

---

Code Review

• Gather context (PR diff, commit history)
• Read changed files in full
• Review for correctness, sign/precision handling, and repo guidelines

Code Review — No issues found.

Reviewed the 4 PR files (.changeset/fee-naming-signed-display.md, FeeBreakdown.tsx, PriceImpactTooltip.tsx, utils/quote.ts), ~46 lines changed. Checked correctness, sign/zero/precision handling, and repo guidelines.

The Greptile P1 (sub-cent discards sign) is resolved. Commit fa9be960 updated formatUsdFee (utils/quote.ts:27-37) so sub-cent amounts now render signed — +< $0.01 for a credit and -< $0.01 for a charge — instead of a direction-less < $0.01. The changeset was updated to match.

Verified end-to-end:

• formatUsdFee branches (quote.ts:28-37) are exhaustive and correct: finalValue === 0 → $0.00 (also catches -0, since -0 === 0); Math.abs < 0.01 (and non-zero) → signed ±< $0.01, where finalValue > 0 ? '+' : '-' is unambiguous because the zero case is already handled; otherwise formatDollar with a + prefix only for positive values, so costs keep their native -$X.XX.
• Reward path is coherent. parseFees now always labels the relayer fee Platform Fee, and PriceImpactTooltip.tsx:63 derives isReward = fee.id === 'relayer-fee' && fee.usd.value > 0, rendering a green (Reward) note next to a green +$X.XX. Gas-sponsored relayer fees resolve to { value: 0 }, so isReward is correctly false there.
• Deposit gas collapsed summary (FeeBreakdown.tsx) still uses formatDollar(Math.abs(...)) independently, so the sign-formatting changes don't double-apply.
• Labels ("Swap Impact" → "Swap Cost", "Relay Fee" → "Platform Fee", "Execution Fee" → "Execution Cost", "Network cost"/"Deposit Gas" → "Deposit gas") are consistent across parseFees, FeeBreakdown, and PriceImpactTooltip, and the changeset names the exact strings — compliant with the repo's changeset guidelines.

Note: the two-dot origin/main...HEAD diff surfaces unrelated drift (svm-wallet-adapter, TransactionModal polling, walletCompatibility, etc.) because this branch predates those merges on main; those are not changes introduced by this PR and were excluded from the review.
• ted/int2-1322-align-swap-widget-fee-naming

[github-actions]

Claude finished @ted-palmer's task in 47s —— View job

---

📝 Docs Drift Check — No docs impact

This PR does not touch surfaces that require a relayprotocol/relay-docs update.

The change renames swap-widget fee display labels ("Swap Impact" → "Swap Cost", "Relay Fee" → "Platform Fee", "Execution Fee" → "Execution Cost", "Network cost" → "Deposit gas") and adjusts signed/zero/sub-cent USD fee formatting inside FeeBreakdown / PriceImpactTooltip and the internal parseFees util. No public props, types, exports, or hooks changed, so the reference docs (which document widget props, not these row labels) remain accurate.

• ted/int2-1322-align-swap-widget-fee-naming