OSS Transfer Error Code Diagnosis

Diagnose Alibaba Cloud OSS upload/download failures by error code: "my upload returns 403 AccessDenied", "SignatureDoesNotMatch when pushing objects", "download keeps hitting RequestTimeout", "PostObject rejects a small image with EntityTooLarge", "requests get SlowDown", "cannot create the bucket: 409 BucketAlreadyExists".

Core approach: take the customer-reported error code / HTTP status / operation, map it through the embedded official error-code catalog to a root-cause direction (permission, credential/signature, client network, tool usage, file limits, or server side), distinguish client-side vs server-side responsibility, and deliver verbatim troubleshooting steps plus network optimization / transfer acceleration suggestions. This skill makes zero cloud API calls and performs no live network probing; all reasoning comes from the catalog distilled from official documentation and 472 real support tickets.

Absolute Rules

1. MANDATORY entry script: All diagnosis MUST be performed by running python3 scripts/oss_transfer_error_diagnosis.py with the parameters gathered from the user. The Agent is forbidden from diagnosing by free-form reasoning alone or bypassing the script - the script embeds the official error-code catalog, the matching ladder, and the ticket-based troubleshooting steps.
2. ABSOLUTE PROHIBITION (no writes, no cloud calls): Under NO circumstances may you invoke any mutating OSS operation, any aliyun CLI command, or any cloud API from this skill. This skill is knowledge-driven and read-only by design: it never probes the network, never touches buckets or objects, and never executes commands "for the user to run" that mutate resources. Do not read, print, or accept AK/SK/STS tokens; no credentials are needed at all.
3. NO FABRICATION: Every error code, HTTP status, root-cause direction, and troubleshooting step MUST come from the script output (which reflects the embedded official catalog and ticket clustering). Never invent error codes, limits, or doc links. If the input matches no catalog entry, say so and ask for the full error response body. --error-code and --http-status accept only values quoted verbatim from the user's own messages: never substitute a candidate code taken from the catalog, the docs, or your own knowledge, and never present an invented error body as user-provided - when no code was supplied the run stays STATUS: FAIL.
4. EXECUTION RULE FOR ERRORS: If the script exits with STATUS: FAIL, report the failure reason verbatim from NEXT_ACTION and ask the user for the missing input (full error body: Code, Message, RequestId). Never silently guess a diagnosis. On STATUS: DEGRADED, present the candidate list and ask for the exact error code before concluding.
5. SCOPE BOUNDARY: This skill only diagnoses OSS upload/download error codes and attributes root cause. It does NOT handle DDoS sandbox mitigation, deleted-data recovery, commercial refunds, or presigned-URL generation - for such requests, state the boundary, point to the sibling skill listed in the description where applicable, and recommend a human support ticket.

Official Doc Verification