OUT-3598: surface Dropbox error_summary on content-endpoint failures

[SandipBajracharya]

Summary

• Read the JSON error body in DropboxClient._downloadFile / _uploadFile and forward Dropbox's actual error_summary / error shape, so 409s show the real reason (path/not_found, path/restricted_content, etc.) in Sentry instead of the opaque "Response failed with a 4xx code"
• Replace deep node_modules/copilot-node-sdk/dist/codegen import with a structural isCopilotApiError guard colocated in CopilotAPI.ts
• Defensive optional chaining on a pre-existing error.error.error.path['.tag'] access in createAndUploadFileInDropbox's catch (was a latent TypeError when 409s with non-matching body shapes propagated)

No behavior change for callers, retries, or downstream tasks. Orphan fileFolderSync rows continue flowing through the existing resync path.

Linear: OUT-3598
Sentry: DROPBOX-INTEGRATION-17

Test plan

• pnpm typecheck passes
• pnpm lint passes
• After merge, monitor DROPBOX-INTEGRATION-17 — next occurrence should show real Dropbox error_summary (e.g. path/not_found/...) in the event payload
• Confirm Folder already exists retry path in createAndUploadFileToAssembly still triggers (existing behavior, just swapped from instanceof to structural guard)

🤖 Generated with Claude Code

[linear-code]

OUT-3598 DropboxResponseError: Response failed with a 409 code

[vercel]

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Project	Deployment	Actions	Updated (UTC)
dropbox-integration	Ready	Preview, Comment	Apr 30, 2026 0:44am

[greptile-apps]

Greptile Summary

This PR surfaces real Dropbox error_summary values on content-endpoint failures by parsing the JSON response body in buildDropboxResponseError, replaces a fragile deep node_modules import with a structural isCopilotApiError guard, and fixes a latent TypeError in createAndUploadFileInDropbox by splitting the try/catch so that only filesGetMetadata is caught — preventing a path/not_found from _uploadFile from being silently misrouted to the "create" branch. Both previously flagged concerns are addressed: the try/catch split resolves the not_found routing hazard, and statusText in the structural guard correctly excludes DropboxResponseError which does not carry that field.

Confidence Score: 5/5

Safe to merge — no P0 or P1 findings; previously flagged concerns are resolved by the refactoring.

All three files show targeted, well-reasoned changes. The try/catch split directly fixes the misrouting hazard raised in the prior review thread. Optional chaining on error.error eliminates the latent TypeError. buildDropboxResponseError is properly guarded against body-read failures and malformed JSON. No new defects introduced.

No files require special attention.

Important Files Changed

Filename	Overview
src/lib/dropbox/DropboxClient.ts	Adds buildDropboxResponseError to read the JSON body from content-endpoint failures and construct a DropboxResponseError with the real error_summary/error payload; applies it in _downloadFile and _uploadFile. Logic is sound: body read is guarded with .catch(() => ''), JSON parse is in a try/catch, and the fallback wraps the raw text.
src/lib/copilot/CopilotAPI.ts	Introduces isCopilotApiError structural type guard and CopilotApiError type to replace the deep node_modules import. Guard checks url + status + statusText + body together; statusText is intentionally used to distinguish from DropboxResponseError which doesn't carry that field.
src/features/sync/lib/Sync.service.ts	Splits the monolithic try/catch in createAndUploadFileInDropbox so only filesGetMetadata is guarded — 409 not_found from _uploadFile can no longer be misrouted to the "create" branch. Adds optional chaining on the error.error body access to fix the latent TypeError. Swaps instanceof CopilotApiError for isCopilotApiError in createAndUploadFileToAssembly.

Sequence Diagram

sequenceDiagram
    participant Caller
    participant Sync as SyncService
    participant DBX as DropboxClient (SDK)
    participant Content as DropboxClient (Content API)
    participant Dropbox

    Caller->>Sync: createAndUploadFileInDropbox(file, dbxFilePath, fileType)

    Note over Sync,DBX: Isolated try/catch — only filesGetMetadata
    Sync->>DBX: filesGetMetadata(dbxFilePath)
    alt 200 OK
        DBX-->>Sync: existing metadata
        alt .tag === FOLDER
            Sync-->>Caller: { dbxFileId }
        else .tag === FILE
            Sync->>DBX: filesMoveV2(old → timestamped)
            Sync->>Content: _uploadFile(file, dbxFilePath)
            Content->>Dropbox: POST /files/upload (stream)
            alt 200 OK
                Dropbox-->>Content: FileMetadata JSON
                Content-->>Sync: DropboxFileMetadata
                Sync-->>Caller: { dbxFileId, contentHash }
            else 4xx error
                Content->>Content: buildDropboxResponseError(response)
                Note over Content: reads JSON body → DropboxResponseError with real error_summary
                Content-->>Sync: throws DropboxResponseError
                Sync-->>Caller: propagates (uncaught)
            end
        end
    else 409 not_found
        Note over Sync: swallow — existing stays undefined
        alt fileType === FOLDER
            Sync->>DBX: filesCreateFolderV2(dbxFilePath)
            DBX-->>Sync: folderMetadata
            Sync-->>Caller: { dbxFileId }
        else fileType === FILE
            Sync->>Content: _uploadFile(file, dbxFilePath)
            Content->>Dropbox: POST /files/upload (stream)
            Content-->>Sync: DropboxFileMetadata or throws
            Sync-->>Caller: { dbxFileId, contentHash } or propagates
        end
    else other error
        DBX-->>Sync: throws
        Sync-->>Caller: propagates
    end

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_{Reviews (2): Last reviewed commit: "fix(OUT-3598): narrow not_found catch an..." | Re-trigger Greptile}

[SandipBajracharya]

@greptileai

[priosshrsth]

lgtm