contract-decode SKILL.md skillA
contract-decode from sd0xdev/sd0x-harness is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add sd0xdev/sd0x-harness/contract-decode@git:20260309.0aecf29Pins git:20260309.0aecf29 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- sd0xdev/sd0x-harness
- Path
skills/contract-decode/SKILL.md- Versions recorded
- 2
- Latest version
- git:20260309.0aecf29, committed Mar 9, 2026
- First version recorded
- Mar 5, 2026
- Size
- 5,310 bytes
- Repository stars
- 194
- License
- MIT
EVM contract error and calldata decoder. Use when: user pastes hex revert data, calldata, function selector, or mentions custom error, execution reverted, 4byte, decode. Input contains 0x + 8+ hex chars.
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# Contract Decode — EVM Error & Calldata Decoder Decode EVM contract function selectors, custom errors, calldata, and revert data. ## Trigger - Keywords: revert, selector, 4byte, calldata, decode, custom error, execution reverted, abi decode - Message contains `0x` + 8+ hex chars (selector or revert data) ## When NOT to Use - Standard `Error(string)` revert already handled by your codebase - Non-EVM chain errors - Only need error code definitions (not hex decoding) ## Input Parsing Extract from user input: | Field | Source | Example | |-------|--------|---------| | `revertData` | Error data or user-pasted hex | `0xaca553e4` | | `calldata` | Transaction data | `0x5e15c749000...1c05` | | `contractAddr` | Contract address | `0x5874...f064` | | `chainId` | Chain identifier | `1` (Ethereum mainnet) | ## Workflow ``` Step 1: Classify input → Step 2: Local fast decode → Step 3: ABI query → Step 4: Precise decode → Report ``` ### Step 1: Classify Input | Length | Classification | Next Step | |--------|---------------|-----------| | 4 bytes (`0x` + 8 hex) | Pure selector | Step 2 | | > 4 bytes, with selector prefix | Calldata or revert data | Step 2 + Step 3 | …
Read the whole file at its exact version.
How to install
mdr add sd0xdev/sd0x-harness/contract-decode@sha256:0515628660da0095The line at the top of this page pins the label git:20260309.0aecf29, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_rbongael5ba5ctwn)
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Versions
The registry has recorded 2 versions of this file, between Mar 5, 2026 and Mar 9, 2026, about one every 4 days.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| git:20260309.0aecf29 latest | 2026-03-09 | 0aecf29 | 5,310 B | A | view · diff |
| git:20260305.25a32f6 | 2026-03-05 | 25a32f6 | 5,309 B | A | view |
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (5310 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
sd0xdev/sd0x-harness · 194 stars · license MIT · pushed 2026-10-08 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_rbongael5ba5ctwn GET https://markdownregistry.com/api/v1/resolve?ref=sd0xdev/sd0x-harness/contract-decode GET https://markdownregistry.com/api/v1/blob/0515628660da0095c4dd53891e3ce2059f9831b2a1f415dcf32611cf219e768b
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.