Competition File Parser Chain

Use this skill only as a downstream specialization after $ctf-sandbox-orchestrator is already active and has established sandbox assumptions, node ownership, and evidence priorities. If that has not happened yet, return to $ctf-sandbox-orchestrator first.

Use this skill when the hard part is following a file from ingress through every parser, extractor, converter, or deserializer boundary that matters.

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Quick Start

1. Preserve the original upload and every derived artifact separately.
2. Map the chain in order: ingress, temp storage, archive extraction, format conversion, parser call, deserialization, and final consumer.
3. Record filenames, MIME guesses, extensions, temp paths, and parser choices before mutating anything.
4. Separate client-visible validation from backend parser behavior.
5. Reproduce the smallest file-processing chain that yields the decisive branch or artifact.

Workflow

1. Map File Ingress And Derivation

• Record request shape, multipart names, content type, filename, temp paths, upload staging, and storage keys.
• Note every derived artifact: extracted archive member, converted preview, generated thumbnail, temp document, or deserialized object.
• Keep original file and each derivative labeled separately.

2. Trace Parser And Conversion Boundaries

• Show which parser, converter, extractor, or deserializer runs at each step.
• Record parser-specific decisions driven by extension, MIME, magic bytes, schema, archive member names, or embedded metadata.
• Distinguish parsing success, preview success, conversion success, and business-logic acceptance.

3. Reduce To The Decisive File Chain

• Compress the result to the smallest sequence: upload -> derived artifact -> parser boundary -> resulting effect.
• State clearly whether the decisive weakness lives in archive handling, MIME inference, file conversion, path resolution, or deserialization.
• If the chain becomes mostly a generic async worker problem after enqueue, hand off to the tighter queue or worker skill.

Read This Reference

• Load references/file-parser-chain.md for the ingress checklist, parser checklist, and evidence packaging.

What To Preserve

• Original uploads, derived files, temp paths, storage keys, parser names, and conversion steps
• The exact boundary where backend behavior diverges from user-visible validation
• One minimal replayable file-processing sequence that reaches the decisive effect