Fix generic error for oversized MCP file uploads by ved015 · Pull Request #1193 · supermemoryai/supermemory

ved015 · 2026-07-03T15:11:23Z

Summary

The MCP transport (agents SDK) rejects JSON-RPC bodies over 4 MiB with a bare HTTP 413 before the tool ever runs, so uploading a large file showed a generic "Something went wrong / Upload failed" in the widget.
The upload widget now rejects oversized files at selection time with an inline error stating the file's size and the maximum (~3.0 MB raw, accounting for base64 inflation and the JSON-RPC envelope inside the 4 MiB transport limit), advertises the limit in the dropzone copy, and maps any transport 413 / "payload too large" error that still reaches the error path to the same friendly message.

claude · 2026-07-03T15:11:42Z

Claude finished @ishaanxgupta's task in 1m 24s —— View job

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Summary: Reviewed the oversized file upload error handling changes. No bugs, security issues, or logic errors found. The file size calculation correctly accounts for base64 inflation and the JSON-RPC envelope. The Graphite style comments about function declarations have been addressed in the latest commit.

Score: 10/10 — Clean fix, ready to ship.

cloudflare-workers-and-pages · 2026-07-03T15:12:54Z

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Status	Name	Latest Commit	Updated (UTC)
❌ Deployment failed View logs	supermemory-mcp	`521db2b`	Jul 04 2026, 02:49 PM

claude

Overview: This PR fixes two UX issues in the MCP widget: showing friendly errors for oversized file uploads (instead of generic "something went wrong"), and returning a properly typed ViewMessage from fetch-graph-data so the widget renders the graph view instead of "unrecognized response."

Issues found: None — this looks good to ship.

Details:

fetch-graph-data.ts:

Correctly returns a ViewMessage with view: "graph" discriminant instead of raw API response
The containerTag is optional in the type (containerTag?: string), so passing effectiveTag (which could be undefined) is type-safe
Text content now provides a human-readable summary instead of raw JSON

Upload.tsx:

File size limit calculation is conservative and correct: ((4 MiB - 64 KiB) * 3/4) ≈ 2.95 MB, properly accounting for base64 inflation (~4/3) and the JSON-RPC envelope
Client-side validation prevents oversized uploads before they're attempted
The regex /413|too large|payload/i for detecting transport errors is broad but safe — worst case it shows a size-related error for a non-size issue, which is better than a generic "Upload failed"
The file reference in the catch block is captured in the useCallback closure after the null check, so accessing file.size is safe

Score: 10/10

Clean fix for real UX issues with proper typing and defensive error handling.

cloudflare-workers-and-pages · 2026-07-03T15:13:45Z

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Status	Name	Latest Commit	Preview URL	Updated (UTC)
✅ Deployment successful! View logs	supermemory-app	`521db2b`	Commit Preview URL Branch Preview URL	Jul 04 2026, 02:49 PM

ved015 · 2026-07-03T15:16:12Z

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This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
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Fix generic error for oversized MCP file uploads #1193 : 2 dependent PRs (#1194 , #1195 ) 👈 (View in Graphite)
Fix nonexistent container tag handling in MCP tools #1192
Fix MCP widgets according to consumer app #1189
MCP Revamp #1120
main

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claude

Overview: This PR fixes two UX issues in the MCP widget: showing friendly errors for oversized file uploads (instead of generic "something went wrong"), and returning a properly typed ViewMessage from fetch-graph-data so the widget renders the graph view instead of "unrecognized response."

Issues found: None — this looks good to ship.

Details:

fetch-graph-data.ts:

Correctly returns a ViewMessage with view: "graph" discriminant instead of raw API response
The containerTag is optional in the type (containerTag?: string), so passing effectiveTag (which could be undefined) is type-safe
Text content now provides a human-readable summary instead of raw JSON

Upload.tsx:

File size limit calculation is conservative and correct: ((4 MiB - 64 KiB) * 3/4) ≈ 2.95 MB, properly accounting for base64 inflation (~4/3) and the JSON-RPC envelope
Client-side validation prevents oversized uploads before they're attempted
The regex /413|too large|payload/i for detecting transport errors is broad but safe — worst case it shows a size-related error for a non-size issue, which is better than a generic "Upload failed"
The file reference in the catch block is captured in the useCallback closure after the null check, so accessing file.size is safe

Score: 10/10

Clean fix for real UX issues with proper typing and defensive error handling.

claude

Overview: This PR fixes UX issues in the Upload widget by showing friendly errors for oversized file uploads and properly handling transport-level 413 errors.

Issues found: None — this looks good to ship.

Details:

File size limit calculation is correct: ((4 MiB - 64 KiB) * 3/4) ≈ 2.95 MB, properly accounting for base64 inflation (~4/3) and the JSON-RPC envelope
Client-side validation in handleFileSelect prevents oversized uploads before they're attempted
The file reference in the catch block is safe — it's captured in the closure after the null check at line 86, so file.size access is guaranteed valid
The regex /413|too large|payload/i for detecting transport errors is broad but safe — worst case it shows a size-related error for a non-size issue, which is better than a generic "Upload failed"
Error display includes role="alert" for accessibility

Score: 10/10

Clean fix for real UX issues with proper typing and defensive error handling.

graphite-app · 2026-07-03T15:23:47Z

+const FILE_TOO_LARGE_MESSAGE = (size: number) =>
+	`This file is ${formatFileSize(size)}. The maximum upload size is ${formatFileSize(MAX_UPLOAD_BYTES)} — please choose a smaller file.`


The rule 'Use function declarations over function expressions' is violated here. FILE_TOO_LARGE_MESSAGE is defined as a const arrow function expression:

const FILE_TOO_LARGE_MESSAGE = (size: number) => `This file is ...`

This should be rewritten as a function declaration:

function fileTooLargeMessage(size: number): string { return `This file is ${formatFileSize(size)}. The maximum upload size is ${formatFileSize(MAX_UPLOAD_BYTES)} — please choose a smaller file.` }

Suggested change

const FILE_TOO_LARGE_MESSAGE = (size: number) =>

`This file is ${formatFileSize(size)}. The maximum upload size is ${formatFileSize(MAX_UPLOAD_BYTES)} — please choose a smaller file.`

function fileTooLargeMessage(size: number): string {

return `This file is ${formatFileSize(size)}. The maximum upload size is ${formatFileSize(MAX_UPLOAD_BYTES)} — please choose a smaller file.`

}

Spotted by Graphite (based on custom rule: TypeScript style guide (Google))

Is this helpful? React 👍 or 👎 to let us know.

graphite-app · 2026-07-03T15:23:48Z

+	const handleFileSelect = (selected: File) => {
+		if (selected.size > MAX_UPLOAD_BYTES) {
+			log(
+				"warning",
+				`[upload] rejected oversized file: ${selected.name} (${selected.size}B > ${MAX_UPLOAD_BYTES}B)`,
+			)
+			setFileError(FILE_TOO_LARGE_MESSAGE(selected.size))
+			setFile(null)
+			return
+		}
+		setFileError(null)
+		setFile(selected)
+	}


The rule 'Use function declarations over function expressions' is violated here. handleFileSelect is defined as a const arrow function expression:

const handleFileSelect = (selected: File) => { ... }

Since this is a named function (not a concise callback), it should be rewritten as a function declaration:

function handleFileSelect(selected: File) { ... }

Suggested change

const handleFileSelect = (selected: File) => {

if (selected.size > MAX_UPLOAD_BYTES) {

log(

"warning",

`[upload] rejected oversized file: ${selected.name} (${selected.size}B > ${MAX_UPLOAD_BYTES}B)`,

)

setFileError(FILE_TOO_LARGE_MESSAGE(selected.size))

setFile(null)

return

}

setFileError(null)

setFile(selected)

}

function handleFileSelect(selected: File) {

if (selected.size > MAX_UPLOAD_BYTES) {

log(

"warning",

`[upload] rejected oversized file: ${selected.name} (${selected.size}B > ${MAX_UPLOAD_BYTES}B)`,

)

setFileError(FILE_TOO_LARGE_MESSAGE(selected.size))

setFile(null)

return

}

setFileError(null)

setFile(selected)

}

Spotted by Graphite (based on custom rule: TypeScript style guide (Google))

Is this helpful? React 👍 or 👎 to let us know.

vorflux · 2026-07-03T15:43:48Z

Summary

Reviewed the live PR diff for apps/mcp/src/widget/views/Upload.tsx, including the oversized upload validation and friendly payload-too-large error handling. The current GitHub PR diff contains only this upload widget change, and I found no actionable correctness, security, data loss, race condition, or breaking-change issues.

Verdict

✅ Reviewed — no issues found. The implementation is scoped and handles the reviewed oversized-file states appropriately.

vorflux · 2026-07-03T15:43:48Z

Testing

Validated the live PR diff for apps/mcp/src/widget/views/Upload.tsx. Browser/UI validation passed for oversized file pre-validation, friendly size-limit messaging, disabled upload state, clearing the error after selecting a valid file, and friendly mapping for mocked 413 Payload Too Large and thrown Payload Too Large errors. Static formatting for Upload.tsx passed; full apps/mcp typecheck still fails in unrelated existing widget hook files.

Commands run:

cd /code/supermemoryai/supermemory/apps/mcp
bun run dev:widget --host 0.0.0.0
__VITE_ADDITIONAL_SERVER_ALLOWED_HOSTS=gfs7r8i3m2jf.preview.us1.vorflux.com bun run dev:widget --host 0.0.0.0
npx agent-browser upload "input[accept=\".txt,.pdf,.png,.jpg,.jpeg,.mp4\"]" /var/tmp/testing_upload_pr1193/oversized-3_1mb.txt --args "--no-sandbox"
npx agent-browser upload "input[accept=\".txt,.pdf,.png,.jpg,.jpeg,.mp4\"]" /var/tmp/testing_upload_pr1193/small-valid.txt --args "--no-sandbox"
bunx biome ci apps/mcp/src/widget/views/Upload.tsx
cd apps/mcp && bun run check-types

Result:

final_public_preview status=200 type=text/html bytes=827

Oversized upload observed:
This file is 3.0 MB. The maximum upload size is 3.0 MB — please choose a smaller file.

Valid file observed:
small-valid.txt
39 B
Upload file enabled
oversized error cleared

Mocked 413 response observed:
Upload: onError → This file is 39 B. The maximum upload size is 3.0 MB — please choose a smaller file.

Mocked thrown payload error observed:
Upload: onError → This file is 2.0 KB. The maximum upload size is 3.0 MB — please choose a smaller file.

bunx biome ci apps/mcp/src/widget/views/Upload.tsx: passed
cd apps/mcp && bun run check-types: failed only in unrelated existing files:
src/widget/hooks/useHostContext.ts(19,5)
src/widget/hooks/useViewState.ts(78,4)
src/widget/hooks/useViewState.ts(79,4)
src/widget/hooks/useViewState.ts(80,4)
src/widget/hooks/useViewState.ts(81,4)
Filtered for Upload.tsx: no errors

Verdict

⚠️ Issues found. The live upload widget behavior passed targeted validation, but full apps/mcp typecheck is not green due to unrelated existing hook errors.

Attached Images and Videos

🎥 View recording: pr1193_upload_widget_verified.webm

The MCP transport rejects JSON-RPC bodies over 4 MiB with a bare 413, so large file uploads died with a generic "Upload failed" widget error. The upload widget now rejects oversized files at selection time with the size limit spelled out, advertises the limit in the dropzone copy, and maps any transport 413 that still occurs to the same friendly message. Co-authored-by: Cursor <cursoragent@cursor.com>

Address Graphite style review on Upload.tsx. Co-authored-by: Cursor <cursoragent@cursor.com>

claude

Overview: This PR improves UX by showing friendly error messages for oversized file uploads instead of generic "Upload failed" errors.

Issues found: None — this looks good to ship.

Details:

File size limit calculation is correct: ((4 MiB - 64 KiB) * 3/4) ≈ 2.95 MB, properly accounting for base64 inflation and JSON-RPC envelope
Client-side validation in handleFileSelect prevents oversized uploads before network requests
The file reference in error handlers is safe — captured after the null check at line 87
The regex /413|too large|payload/i for transport errors is intentionally broad — worst case shows a size-related message for a non-size issue, better than a generic failure
Error display includes role="alert" for accessibility
The Graphite style comments about function declarations have been addressed in the latest commit

Score: 10/10

Clean fix for a real UX issue with correct math and defensive error handling.

graphite-app Bot assigned ved015 Jul 3, 2026

claude Bot reviewed Jul 3, 2026

View reviewed changes

ved015 force-pushed the fix/mcp-widget-error-display branch from 31f77a7 to 3a02393 Compare July 3, 2026 15:15

ved015 force-pushed the fix/mcp-invalid-container-tag branch from 500a4b5 to df671c6 Compare July 3, 2026 15:15

ved015 mentioned this pull request Jul 3, 2026

MCP Revamp #1120

Open

This was referenced Jul 3, 2026

Fix MCP widgets according to consumer app #1189

Open

Fix nonexistent container tag handling in MCP tools #1192

Open

claude Bot reviewed Jul 3, 2026

View reviewed changes

ved015 force-pushed the fix/mcp-widget-error-display branch from 3a02393 to f7fc662 Compare July 3, 2026 15:21

ved015 mentioned this pull request Jul 3, 2026

DONT merge #1194

Closed

ved015 changed the title ~~Fix MCP widget error display for large uploads and fetch-graph-data~~ Fix generic error for oversized MCP file uploads Jul 3, 2026

claude Bot reviewed Jul 3, 2026

View reviewed changes

graphite-app Bot reviewed Jul 3, 2026

View reviewed changes

ishaanxgupta changed the base branch from fix/mcp-invalid-container-tag to graphite-base/1193 July 3, 2026 15:46

ishaanxgupta force-pushed the graphite-base/1193 branch from df671c6 to e706a13 Compare July 3, 2026 15:46

ishaanxgupta changed the base branch from graphite-base/1193 to main July 3, 2026 15:46

ishaanxgupta mentioned this pull request Jul 3, 2026

fix(mcp): return graph view message from fetch-graph-data #1195

Open

2 tasks

ishaanxgupta changed the base branch from main to graphite-base/1193 July 3, 2026 16:00

ishaanxgupta force-pushed the graphite-base/1193 branch from acd2fea to df671c6 Compare July 3, 2026 16:00

ishaanxgupta changed the base branch from graphite-base/1193 to fix/mcp-invalid-container-tag July 3, 2026 16:00

ishaanxgupta mentioned this pull request Jul 3, 2026

mcp: relocate enterprise-mcp as the public mcp revamp (apps/mcp) #1196

Closed

ved015 and others added 2 commits July 4, 2026 20:14

fix(mcp): use function declarations in upload widget

521db2b

Address Graphite style review on Upload.tsx. Co-authored-by: Cursor <cursoragent@cursor.com>

ishaanxgupta force-pushed the fix/mcp-widget-error-display branch from f7fc662 to 521db2b Compare July 4, 2026 14:47

claude Bot reviewed Jul 4, 2026

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Fix generic error for oversized MCP file uploads#1193

Fix generic error for oversized MCP file uploads#1193
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		const FILE_TOO_LARGE_MESSAGE = (size: number) =>
		`This file is ${formatFileSize(size)}. The maximum upload size is ${formatFileSize(MAX_UPLOAD_BYTES)} — please choose a smaller file.`

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