Agent skill

Abi Encoding

by Nethereum in Nethereum/Nethereum

Encode and decode Ethereum ABI data with Nethereum. An agent skill from Nethereum/Nethereum.

MITAuto-check passedBackend & APIs

Install Abi Encoding

skills CLI
$ npx skills add Nethereum/Nethereum --skill abi-encoding -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI
$ gh skill install Nethereum/Nethereum abi-encoding --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy
$ git clone --depth 1 https://github.com/Nethereum/Nethereum.git skills-src && mkdir -p .claude/skills && cp -r skills-src/plugins/nethereum-skills/skills/abi-encoding .claude/skills/abi-encoding && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Facts

Skill name
abi-encoding
GitHub stars
2.3k
Token cost
~1.3k tokens
SKILL.md length
49 words
Files
1
Skills in repo
71
Repo updated
First seen
Licence
MIT

At a glance

Encode and decode Ethereum ABI data with Nethereum. An agent skill from Nethereum/Nethereum.

  • The user needs to encode function calls
  • SKILL.md covers Function selector calculation, Function encoding with…, Parameter attribute encoding and Output decoding, plus 5 more sections
  • Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
  • Decode contract output

What it does

Abi Encoding is an agent skill from Nethereum/Nethereum. Encode and decode Ethereum ABI data with Nethereum. Use when the user needs to encode function calls, decode contract output, work with event topics, parse ABI JSON, handle custom errors, or calculate function selectors.

Its SKILL.md is about 1.3k tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.

It sits in Backend & APIs. It works with Ethereum. The repository describes itself as: Ethereum .Net cross platform integration library. The licence is MIT.

When your agent uses it

  • The user needs to encode function calls
  • Decode contract output
  • Work with event topics
  • Handle custom errors

Example prompts

  • “/abi-encoding”

What it can do on your machine

Read from SKILL.md and the folder at commit 229f278. It shows what the files ask for, not the result of running them.

  • Tool permissions

    Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

    From allowed-tools in the SKILL.md frontmatter.

  • Runs code

    No scripts in the folder and no shell commands in SKILL.md (its code samples are csharp).

    From the folder's file list and the shell code blocks in SKILL.md.

  • Network

    No URLs in SKILL.md.

    From URLs in SKILL.md, links to its own repository left out.

  • Credentials

    Names no API keys, tokens, secrets or passwords.

    From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Abi Encoding loads about 1.3k tokens when it runs. Until then it costs about 58 tokens; SKILL.md has 49 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it
~58
When it runs · the whole SKILL.md, loaded when a task matches
~1.3k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from Nethereum/Nethereum at commit 229f278, republished under its MIT licence (© Nethereum). 49 words, ~1,279 tokens.

Download SKILL.mdSave it as .claude/skills/abi-encoding/SKILL.md (or your agent's skills folder).
name
abi-encoding
description
Encode and decode Ethereum ABI data with Nethereum. Use when the user needs to encode function calls, decode contract output, work with event topics, parse ABI JSON, handle custom errors, or calculate function selectors.
user-invocable
true

ABI Encoding with Nethereum

NuGet: Nethereum.ABI

Function selector calculation

csharp
var keccak = Sha3Keccack.Current;

var selector = keccak.CalculateHash("transfer(address,uint256)").Substring(0, 8);
// "a9059cbb"

var balanceOf = keccak.CalculateHash("balanceOf(address)").Substring(0, 8);
// "70a08231"

var approve = keccak.CalculateHash("approve(address,uint256)").Substring(0, 8);
// "095ea7b3"

Source: AbiEncodingDocExampleTests.ShouldCalculateFunctionSelector

Function encoding with Parameter array

csharp
var functionCallEncoder = new FunctionCallEncoder();
var sha3Signature = "a9059cbb";
var inputsParameters = new[]
{
    new Parameter("address", "to") { DecodedType = typeof(string) },
    new Parameter("uint256", "value") { DecodedType = typeof(BigInteger) }
};

var result = functionCallEncoder.EncodeRequest(sha3Signature, inputsParameters,
    "1234567890abcdef1234567890abcdef12345678", new BigInteger(1000));

Source: AbiEncodingDocExampleTests.ShouldEncodeBasicFunctionCall

Parameter attribute encoding

csharp
[Function("transfer")]
public class TransferFunction
{
    [Parameter("address", "to", 1)]
    public string To { get; set; }

    [Parameter("uint256", "amount", 2)]
    public BigInteger Amount { get; set; }
}

var input = new TransferFunction
{
    To = "1234567890abcdef1234567890abcdef12345678",
    Amount = new BigInteger(5000)
};

var result = new FunctionCallEncoder().EncodeRequest(input, "a9059cbb");

Source: AbiEncodingDocExampleTests.ShouldEncodeUsingParameterAttributes

Output decoding

csharp
var functionCallDecoder = new FunctionCallDecoder();
var outputParameters = new[]
{
    new ParameterOutput
    {
        Parameter = new Parameter("uint256", "balance") { DecodedType = typeof(BigInteger) }
    }
};

var encodedOutput = "0x" +
    "0000000000000000000000000000000000000000000000000000000000000045";

var result = functionCallDecoder.DecodeOutput(encodedOutput, outputParameters);
var balance = (BigInteger)result[0].Result; // 69

Source: AbiEncodingDocExampleTests.ShouldDecodeFunctionOutput

Event topic decoding

csharp
[Event("Transfer")]
public class TransferEventDTO
{
    [Parameter("address", "_from", 1, true)]
    public string From { get; set; }

    [Parameter("address", "_to", 2, true)]
    public string To { get; set; }

    [Parameter("uint256", "_value", 3, true)]
    public BigInteger Value { get; set; }
}

var topics = new[]
{
    "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef",
    "0x0000000000000000000000000000000000000000000000000000000000000000",
    "0x000000000000000000000000c14934679e71ef4d18b6ae927fe2b953c7fd9b91",
    "0x0000000000000000000000000000000000000000000000400000402000000001"
};

var transferDto = new TransferEventDTO();
new EventTopicDecoder().DecodeTopics(transferDto, topics, "0x");

Source: AbiEncodingDocExampleTests.ShouldDecodeTransferEventTopic

ABI JSON deserialization

csharp
var abi = @"[{""constant"":false,""inputs"":[{""name"":""a"",""type"":""uint256""}],
""name"":""multiply"",""outputs"":[{""name"":""d"",""type"":""uint256""}],""type"":""function""}]";

var des = new ABIJsonDeserialiser();
var contract = des.DeserialiseContract(abi);
// contract.Functions, contract.Events

Source: AbiEncodingDocExampleTests.ShouldDeserializeContractAbi

Custom error decoding

csharp
var error = new ErrorABI("InsufficientBalance");
error.InputParameters = new[]
{
    new Parameter("address", "account", 1),
    new Parameter("uint256", "balance", 2)
};

var errorSelector = error.Sha3Signature;
var encodedData = "0x" + errorSelector +
    "000000000000000000000000c14934679e71ef4d18b6ae927fe2b953c7fd9b91" +
    "0000000000000000000000000000000000000000000000000000000000000064";

var decoder = new FunctionCallDecoder();
var decoded = decoder.DecodeError(error, encodedData);
// decoded[0].Result = address, decoded[1].Result = BigInteger(100)

Source: AbiEncodingDocExampleTests.ShouldDecodeCustomError

Individual type encoding

csharp
var addressEncoded = new AddressType().Encode("1234567890abcdef1234567890abcdef12345678");
var intEncoded = new IntType("uint256").Encode(new BigInteger(42));
var boolEncoded = new BoolType().Encode(true);

var bytes32Value = new byte[32];
bytes32Value[0] = 0xAB;
var bytes32Encoded = new Bytes32Type("bytes32").Encode(bytes32Value);
// All produce 32-byte padded output

Source: AbiEncodingDocExampleTests.ShouldEncodeIndividualTypesWithPadding

Required usings

csharp
using Nethereum.ABI;
using Nethereum.ABI.ABIDeserialisation;
using Nethereum.ABI.FunctionEncoding;
using Nethereum.ABI.FunctionEncoding.Attributes;
using Nethereum.ABI.Model;
using Nethereum.Hex.HexConvertors.Extensions;
using Nethereum.Util;
using System.Numerics;

© Nethereum, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

Just SKILL.md in plugins/nethereum-skills/skills/abi-encoding of Nethereum/Nethereum.

Open the folder on GitHubat commit 229f278

Compare with similar skills

Abi Encoding next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Abi Encoding compared with similar skills
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Abi Encoding this skillNethereum/Nethereum2.3k—~1.3kAutomated safety check: PassMIT
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Explorer Contract Verificationsablier-labs/evm-monorepo353—~1.9kAutomated safety check: PassCustom licence
Developing Smart ContractsLFDT-Lineth/lineth-monorepo126—~1.4kAutomated safety check: PassAGPL-3.0
Deposit QrSuperior-Trade/superior-skills214—~1.1kAutomated safety check: PassMIT
Squash BugbotLFDT-Lineth/lineth-monorepo126—~3.3kAutomated safety check: PassApache-2.0

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Works with

Categories

Questions about Abi Encoding

What does Abi Encoding do?

Encode and decode Ethereum ABI data with Nethereum. An agent skill from Nethereum/Nethereum. Abi Encoding is an agent skill from Nethereum/Nethereum. Encode and decode Ethereum ABI data with Nethereum.

When should I use Abi Encoding?

Abi Encoding fits situations like: the user needs to encode function calls; decode contract output; work with event topics; handle custom errors.

How do I install Abi Encoding in Claude Code?

Run `npx skills add Nethereum/Nethereum --skill abi-encoding -a claude-code`. Or copy the skill folder (plugins/nethereum-skills/skills/abi-encoding in Nethereum/Nethereum) into .claude/skills/abi-encoding in your project. Claude Code loads it when a task matches its description.

How do I install Abi Encoding in Codex?

Run `npx skills add Nethereum/Nethereum --skill abi-encoding -a codex`. Or copy the skill folder (plugins/nethereum-skills/skills/abi-encoding in Nethereum/Nethereum) into .agents/skills/abi-encoding in your project. Codex loads it when a task matches its description.

Can I use Abi Encoding in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add Nethereum/Nethereum --skill abi-encoding -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/abi-encoding, .gemini/skills/abi-encoding, .github/skills/abi-encoding and .opencode/skills/abi-encoding in your project.

What does Abi Encoding need to run?

SKILL.md names no scripts, command-line tools or credentials: Abi Encoding is instructions for the agent only.

Does Abi Encoding access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is Abi Encoding safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Abi Encoding use?

Abi Encoding is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Abi Encoding use?

About 1.3k tokens (SKILL.md is roughly 5.1k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Abi Encoding?

Skills that share tags, products or a category with Abi Encoding: NEAR Intents Swap Integration (internet-court/internet-court-skill, 6.4k stars), Explorer Contract Verification (sablier-labs/evm-monorepo, 353 stars), Developing Smart Contracts (LFDT-Lineth/lineth-monorepo, 126 stars) and Deposit Qr (Superior-Trade/superior-skills, 214 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Abi Encoding?

Nethereum (a GitHub organization) maintains it in Nethereum/Nethereum, which has 2,260 GitHub stars. The repository holds 71 skills in this directory. The repository was last updated on October 5, 2026.

Source: Nethereum/Nethereum on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.