encoding-formats_skill

Overview

This skill encodes, decodes, and converts between common data formats used in APIs, files, and wire protocols. It handles Base64 (including URL-safe), URL encoding, hex, Unicode and character-set conversions, JWT inspection, hashing/checksums, and serialization formats like JSON, MessagePack, and protobuf. Use it to inspect opaque blobs, verify integrity, or translate data between ecosystems. The goal is fast, reliable transformations and safe inspection of encoded content.

How this skill works

The skill detects or accepts a specified format and runs the appropriate transformation or decoder—Base64/URL-safe Base64, URL encoding/decoding, hex ↔ binary, Unicode code-point inspection and iconv conversions, JWT header/payload decoding, and common hash/checksum computation. For binary serialization it can unpack MessagePack, CBOR, or decode protobuf wire data without a schema (showing field numbers). It provides command-line examples and code snippets in Python and JavaScript for automation and integration.

When to use it

• Decoding Base64 or Base64url from API responses or config values
• URL-encoding query parameters or decoding percent-encoded strings
• Inspecting hex dumps or converting hex to binary/text
• Decoding JWTs to view claims and check expiry
• Computing or verifying file checksums (SHA-256, MD5 for non-security)
• Converting between JSON, YAML, CSV, MessagePack, CBOR, or protobuf for inspection or tooling integration

Best practices

• Prefer URL-safe Base64 for tokens and URLs; avoid manual character replacements
• Use SHA-256 for integrity checks; reserve MD5 only for non-security deduplication
• Never store secrets in JWT claims; JWTs are readable even if signed
• Use library functions for encoding/decoding (urllib.parse, base64, crypto) to avoid edge-case bugs
• Handle text encodings explicitly (declare UTF-8) and normalize Unicode (NFC/NFD) when comparing strings
• When decoding protobuf without a schema, treat output as inspection only—use schema for reliable parsing

Example use cases

• Quickly decode an API response containing a Base64 payload and inspect the JSON inside
• URL-encode complex query values before sending them with curl or fetch
• Convert a hex dump to a binary image or view a file as hex for debugging
• Decode a JWT to extract claims and check expiration during troubleshooting
• Generate a sha256 checksum for release artifacts and verify checksums on CI
• Convert MessagePack/CBOR logs into pretty JSON for human review