New: 98,000+ skills indexed from GitHub repos with 100+ stars · every skill safety-checkedBrowse top skillsTop skills
Esc to closeBrowse all skills
Submit a skillBrowse skills
Submit a skillBrowse skills

Agent skill

Assert Specific Error In Tests

by 0xMiden in 0xMiden/protocol

A skill your agent uses when writing a Rust test that exercises a failure path or a MASM test that expects a panic / assert — assert on the specific expected error variant or error code.

MITAuto-check passedDevelopment

Install Assert Specific Error In Tests

skills CLI
$ npx skills add 0xMiden/protocol --skill assert-specific-error-in-tests -a claude-code

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

GitHub CLI
$ gh skill install 0xMiden/protocol assert-specific-error-in-tests --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/0xMiden/protocol.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.claude/skills/assert-specific-error-in-tests .claude/skills/assert-specific-error-in-tests && 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
assert-specific-error-in-tests
GitHub stars
133
Token cost
~374 tokens
SKILL.md length
125 words
Files
1
Skills in repo
35
Repo updated
First seen
Licence
MIT

At a glance

A skill your agent uses when writing a Rust test that exercises a failure path or a MASM test that expects a panic / assert — assert on the specific expected error variant or error code.

  • Writing a Rust test that exercises a failure path
  • SKILL.md covers Rule, Why and Examples
  • Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
  • A MASM test that expects a panic / assert — assert on the specific expected error variant

What it does

Assert Specific Error In Tests is an agent skill from 0xMiden/protocol. Use when writing a Rust test that exercises a failure path or a MASM test that expects a panic / assert — assert on the specific expected error variant or error code.

Its SKILL.md is about 370 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 Development. It works with Rust. The repository describes itself as: Core components of the Miden protocol. The licence is MIT.

When your agent uses it

  • Writing a Rust test that exercises a failure path
  • A MASM test that expects a panic / assert — assert on the specific expected error variant

Example prompts

  • “/assert-specific-error-in-tests”

What it can do on your machine

Read from SKILL.md and the folder at commit 474c88e. 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 rust).

    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

Assert Specific Error In Tests loads about 374 tokens when it runs. Until then it costs about 50 tokens; SKILL.md has 125 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it
~50
When it runs · the whole SKILL.md, loaded when a task matches
~374

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 0xMiden/protocol at commit 474c88e, republished under its MIT licence (© 0xMiden). 125 words, ~374 tokens.

Download SKILL.mdSave it as .claude/skills/assert-specific-error-in-tests/SKILL.md (or your agent's skills folder).
name
assert-specific-error-in-tests
description
Use when writing a Rust test that exercises a failure path or a MASM test that expects a `panic` / `assert` — assert on the specific expected error variant or error code.

Negative Tests Must Pin the Expected Error

Rule

A test that exercises an error path must assert on the specific error returned:

  • In Rust: use assert_matches!(result, Err(MyError::SpecificVariant { .. })) or destructure the error and assert on its fields. Don't accept "any Err" via assert!(result.is_err()).
  • In MASM: assert that the trapping error code matches the expected ERR_* constant, not just that the transaction failed.

If multiple error conditions could plausibly fire on the same input, assert on the one this test is actually exercising.

Why

A test that only checks is_err() passes even when an unrelated bug breaks the function, so it no longer validates the failure mode it claims to. Pinning the exact variant also catches reorderings where one error path starts firing instead of another.

Examples

rust
// Good
use assert_matches::assert_matches;

let result = AccountId::try_from(&bytes);
assert_matches!(result, Err(AccountError::InvalidLength { expected: 32, got: 5 }));

// Bad
let result = AccountId::try_from(&bytes);
assert!(result.is_err());
rust
// Good (MASM test)
let err = run_kernel(...).unwrap_err();
assert_eq!(err.code(), ERR_NOTE_NOT_FOUND);

// Bad
assert!(run_kernel(...).is_err());

© 0xMiden, 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 .claude/skills/assert-specific-error-in-tests of 0xMiden/protocol.

Open the folder on GitHubat commit 474c88e

Compare with similar skills

Assert Specific Error In Tests 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.

Assert Specific Error In Tests compared with similar skills
SkillStarsUsed inTokensAuto-checkLicenceRepo updated
Assert Specific Error In Tests this skill0xMiden/protocol133—~374Automated safety check: PassMIT
Migrate Core Code to Submodulestinyhumansai/openhuman42k—~2.6kAutomated safety check: PassGPL-3.0
Rust Best Practicesfarm-fe/farm5.6k3 repos~1.1kAutomated safety check: PassMIT
OpenLogi macOS Permissions TriageAprilNEA/OpenLogi23k—~2.5kAutomated safety check: NotesApache-2.0
RTK Rust Design Patternsrtk-ai/rtk83k—~1.9kAutomated safety check: PassApache-2.0
Release Skillsnexmoe/eve4213 repos~3.3kAutomated safety check: PassNone

Similar skills

  • Migrate Core Code to Submodules

    tinyhumansai/openhuman

    Plans and carries out moving non-host-specific code and its tests from the OpenHuman core into vendored tiny submodule libraries, then releases the submodule and re-pins the host.

    42k GitHub stars~2.6k tokensUpdated today
    DevelopmentAuto-check passed

  • Rust Best Practices

    farm-fe/farm

    Guide for writing idiomatic Rust code based on Apollo GraphQL's best practices handbook.

    5.6k GitHub starsUsed in 3 repos~1.1k tokens
    DevelopmentAuto-check passed

  • OpenLogi macOS Permissions Triage

    AprilNEA/OpenLogi

    Decides whether an OpenLogi device problem on macOS is a privacy-permission (TCC) problem, using agent log lines, and says which identity needs which grant.

    23k GitHub stars~2.5k tokensUpdated 4 days ago
    DevelopmentAuto-check: notes

  • RTK Rust Design Patterns

    rtk-ai/rtk

    Describes seven Rust design patterns for the RTK CLI filter modules, with when to use each, RTK examples, and notes on when a pattern is overkill.

    83k GitHub stars~1.9k tokensUpdated today
    DevelopmentAuto-check passed

  • Release Skills

    nexmoe/eve

    Universal release workflow. An agent skill from nexmoe/eve.

    421 GitHub starsUsed in 3 repos~3.3k tokens
    DevelopmentAuto-check passed

  • Pnpm Engine

    teambit/bit

    Work on the pnpm Rust engine (@pnpm/napi, the pacquet crates) that bit install runs through.

    18k GitHub stars~1.9k tokensUpdated today
    DevelopmentAuto-check passed

More from 0xMiden/protocol

All 35 skills in this repo

  • Advice Provider Hygiene

    0xMiden/protocol

    A skill your agent uses when writing kernel, account, or note MASM code that reads from or writes to the advice provider (advice stack / advice map) — validate advice data.

    133 GitHub stars~1.1k tokensUpdated today
    Auto-check passed

  • Cheap Masm Equivalents

    0xMiden/protocol

    A skill your agent uses when writing or reviewing MASM hot paths or loops — prefer the cheaper equivalent: loop counters and pointers on the operand stack instead of procedure locals, neq.0 over…

    133 GitHub stars~804 tokensUpdated today
    Auto-check passed

  • Concise Changelog Entries

    0xMiden/protocol

    Keep CHANGELOG.md entries to a single concise sentence. An agent skill from 0xMiden/protocol.

    133 GitHub stars~805 tokensUpdated today
    Auto-check passed

  • Concise PR And Issue Descriptions

    0xMiden/protocol

    Keep PR and issue descriptions short and decision-focused. An agent skill from 0xMiden/protocol.

    133 GitHub stars~1.8k tokensUpdated today
    Auto-check passed

  • Conversion Method Naming

    0xMiden/protocol

    A skill your agent uses when naming a conversion or accessor method in Rust — follow the Rust API naming conventions for the method's cost and ownership.

    133 GitHub stars~450 tokensUpdated today
    Auto-check passed

  • Decouple Component From Storage

    0xMiden/protocol

    A skill your agent uses when writing a generic MASM utility that accesses a caller-selected account storage slot — receive the slot as a parameter so the utility is portable across storage layouts.

    133 GitHub stars~529 tokensUpdated today
    Auto-check passed

Works with

Categories

Questions about Assert Specific Error In Tests

What does Assert Specific Error In Tests do?

A skill your agent uses when writing a Rust test that exercises a failure path or a MASM test that expects a panic / assert — assert on the specific expected error variant or error code. Assert Specific Error In Tests is an agent skill from 0xMiden/protocol. Use when writing a Rust test that exercises a failure path or a MASM test that expects a panic / assert — assert on the specific expected error variant or error code.

When should I use Assert Specific Error In Tests?

Assert Specific Error In Tests fits situations like: writing a Rust test that exercises a failure path; A MASM test that expects a panic / assert — assert on the specific expected error variant.

How do I install Assert Specific Error In Tests in Claude Code?

Run `npx skills add 0xMiden/protocol --skill assert-specific-error-in-tests -a claude-code`. Or copy the skill folder (.claude/skills/assert-specific-error-in-tests in 0xMiden/protocol) into .claude/skills/assert-specific-error-in-tests in your project. Claude Code loads it when a task matches its description.

How do I install Assert Specific Error In Tests in Codex?

Run `npx skills add 0xMiden/protocol --skill assert-specific-error-in-tests -a codex`. Or copy the skill folder (.claude/skills/assert-specific-error-in-tests in 0xMiden/protocol) into .agents/skills/assert-specific-error-in-tests in your project. Codex loads it when a task matches its description.

Can I use Assert Specific Error In Tests 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 0xMiden/protocol --skill assert-specific-error-in-tests -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/assert-specific-error-in-tests, .gemini/skills/assert-specific-error-in-tests, .github/skills/assert-specific-error-in-tests and .opencode/skills/assert-specific-error-in-tests in your project.

What does Assert Specific Error In Tests need to run?

SKILL.md names no scripts, command-line tools or credentials: Assert Specific Error In Tests is instructions for the agent only.

Does Assert Specific Error In Tests 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 Assert Specific Error In Tests 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 Assert Specific Error In Tests use?

Assert Specific Error In Tests 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 Assert Specific Error In Tests use?

About 374 tokens (SKILL.md is roughly 1.5k 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 Assert Specific Error In Tests?

Skills that share tags, products or a category with Assert Specific Error In Tests: Migrate Core Code to Submodules (tinyhumansai/openhuman, 42k stars), Rust Best Practices (farm-fe/farm, 5.6k stars), OpenLogi macOS Permissions Triage (AprilNEA/OpenLogi, 23k stars) and RTK Rust Design Patterns (rtk-ai/rtk, 83k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Assert Specific Error In Tests?

0xMiden (a GitHub organization) maintains it in 0xMiden/protocol, which has 133 GitHub stars. The repository holds 35 skills in this directory. The repository was last updated on October 7, 2026.

Source: 0xMiden/protocol on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.