Fizz Convert
pashov/skills
Convert English-language properties in PROPERTIES.md (produced by the Fizz skill) into Solidity assertions inside the existing fuzz harness, then flip their checkboxes.
Adds, reviews or tightens Diffyscan alloweddiffs rules for explained source or bytecode differences, including replacing any wildcards with granular rules.
Install Allowed Diffs
$ npx skills add lidofinance/diffyscan --skill allowed-diffs -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install lidofinance/diffyscan allowed-diffs --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/lidofinance/diffyscan.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.claude/skills/allowed-diffs .claude/skills/allowed-diffs && rm -rf skills-srcUse ~/.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/
Install the "allowed-diffs" agent skill from https://github.com/lidofinance/diffyscan/tree/main/.claude/skills/allowed-diffs into .claude/skills/allowed-diffs/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "allowed-diffs", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/lidofinance/diffyscan/tree/main/.claude/skills/allowed-diffsType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add lidofinance/diffyscan --skill allowed-diffs -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install lidofinance/diffyscan allowed-diffs --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/lidofinance/diffyscan.git skills-src && mkdir -p .agents/skills && cp -r skills-src/.claude/skills/allowed-diffs .agents/skills/allowed-diffs && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "allowed-diffs" agent skill from https://github.com/lidofinance/diffyscan/tree/main/.claude/skills/allowed-diffs into .agents/skills/allowed-diffs/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "allowed-diffs", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add lidofinance/diffyscan --skill allowed-diffs -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install lidofinance/diffyscan allowed-diffs --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/lidofinance/diffyscan.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/.claude/skills/allowed-diffs .cursor/skills/allowed-diffs && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "allowed-diffs" agent skill from https://github.com/lidofinance/diffyscan/tree/main/.claude/skills/allowed-diffs into .cursor/skills/allowed-diffs/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "allowed-diffs", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/lidofinance/diffyscan.git --path .claude/skills/allowed-diffs--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add lidofinance/diffyscan --skill allowed-diffs -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install lidofinance/diffyscan allowed-diffs --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/lidofinance/diffyscan.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/.claude/skills/allowed-diffs .gemini/skills/allowed-diffs && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "allowed-diffs" agent skill from https://github.com/lidofinance/diffyscan/tree/main/.claude/skills/allowed-diffs into .gemini/skills/allowed-diffs/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "allowed-diffs", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install lidofinance/diffyscan allowed-diffsInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add lidofinance/diffyscan --skill allowed-diffs -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/lidofinance/diffyscan.git skills-src && mkdir -p .github/skills && cp -r skills-src/.claude/skills/allowed-diffs .github/skills/allowed-diffs && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "allowed-diffs" agent skill from https://github.com/lidofinance/diffyscan/tree/main/.claude/skills/allowed-diffs into .github/skills/allowed-diffs/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "allowed-diffs", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add lidofinance/diffyscan --skill allowed-diffs -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install lidofinance/diffyscan allowed-diffs --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/lidofinance/diffyscan.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/.claude/skills/allowed-diffs .opencode/skills/allowed-diffs && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "allowed-diffs" agent skill from https://github.com/lidofinance/diffyscan/tree/main/.claude/skills/allowed-diffs into .opencode/skills/allowed-diffs/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "allowed-diffs", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
- Skill name
allowed-diffs- GitHub stars
- 142
- Token cost
- ~1.2k tokens
- SKILL.md length
- 592 words
- Files
- 2 (incl. references)
- Skills in repo
- 5
- Repo updated
- First seen
- Licence
- MIT
At a glance
Adds, reviews or tightens Diffyscan alloweddiffs rules for explained source or bytecode differences, including replacing any wildcards with granular rules.
- Works in 3 steps: Establish evidence → Choose a rule → Verify the result
- Accepting an expected diff
- SKILL.md covers 1. Establish evidence, 2. Choose a rule and 3. Verify the result
- Calls uv
What it does
Allowed Diffs is an agent skill from lidofinance/diffyscan. Adds, reviews or tightens Diffyscan alloweddiffs rules for explained source or bytecode differences, including replacing any wildcards with granular rules. Use when accepting an expected diff or narrowing an exception; use debug-diff first if its cause is unknown.
Its SKILL.md is about 1.2k tokens, which your agent loads only when the skill is triggered. The skill folder holds 2 other files, including reference files (for example `references/check-immutable-rule.md`).
It sits in Backend & APIs, covering Smart contracts. It works with Solidity. The repository describes itself as: Diffyscan detects deployment drift by comparing GitHub source with explorer-verified source and on-chain bytecode across EVM networks. The licence is MIT.
When your agent uses it
- Accepting an expected diff
- Narrowing an exception
- Use debug-diff first if its cause is unknown
Example prompts
- “/allowed-diffs”
Workflow steps
3 steps, taken from the step headings in SKILL.md.
What it can do on your machine
Read from SKILL.md and the folder at commit 9fd6833. 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
Shell commands in SKILL.md call:
uv
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md. Its commands use uv, which can reach the network depending on how they are called.
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
Allowed Diffs loads about 1.2k tokens when it runs, and up to ~1.7k if it reads all its reference files. Until then it costs about 70 tokens; SKILL.md has 592 words of instructions outside code blocks.
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 lidofinance/diffyscan at commit 9fd6833, republished under its MIT licence (© lidofinance). 592 words, ~1,244 tokens.
Download SKILL.mdSave it as
.claude/skills/allowed-diffs/SKILL.md (or your agent's skills folder). This skill also uses 1 other file; get the full folder from GitHub.- name
- allowed-diffs
- description
- Adds, reviews or tightens Diffyscan allowed_diffs rules for explained source or bytecode differences, including replacing any wildcards with granular rules. Use when accepting an expected diff or narrowing an exception; use debug-diff first if its cause is unknown.
Encode an explained difference without accepting unrelated drift. Run commands from the repository root.
For review-only requests, inspect existing evidence and report findings or proposed rules; edit configs and run live diagnostics only when the task includes those actions.
1. Establish evidence
Read the target config, bytecode comparison and JSON output. Confirm chain, contract, pinned source and why the difference is intended. If unknown, use debug-diff before changing policy.
Use suggested_rule and actual diff evidence as a starting point. Suggestions describe observations; they do not justify accepting them. To replace a wildcard, remove only that rule for a diagnostic run or use a temporary config copy, then inspect uncovered differences. Preserve other rules and contract scope.
A files suggestion can come from a source file missing on GitHub. Resolve the missing file's provenance, path or dependency before accepting the suggestion; it would otherwise allow the entire source omission.
2. Choose a rule
Inspect evaluate_source_rules, evaluate_bytecode_rules and matchers in diffyscan/utils/allowed_diffs.py when coverage is unclear. Rules are alternatives: one rule must cover the differences; separate entries do not accumulate coverage. Combine necessary facets within one rule.
- Prefer source
line_rangesfor exact hunk coordinates. Coordinates are 1-based;count: 0represents insertion/deletion. These rules do not pin line contents: different edits at the same coordinates are also accepted.filesaccepts future changes throughout named files. - Prefer bytecode
immutableswith exact on-chain values at compiler-derived offsets when those values explain the difference.byte_rangesconstrains offsets and lengths but does not pin values there. - Add
cbor_metadata: truefor explained metadata differences, combined with other necessary facets in the same rule. - Use
constructor_argsorconstructor_calldatafor an explained alternate simulation, respecting mutual exclusion. Verify the resulting runtime; an override alone does not prove a match. - Runtime length and string-literal mismatches currently cannot be accepted by granular byte ranges. Report that limitation without silently widening an exception.
Every rule needs a concrete reason describing deployment evidence and intended scope. any: true excludes other facets and accepts future drift. Bytecode any can also suppress deployment-simulation errors, but not arbitrary compilation or calldata failures. Difficulty reproducing bytecode alone does not justify it. If a wildcard is justified within the requested policy change, document the limitation and align KNOWN_WILDCARDS in tests/test_no_wildcard_regression.py. Remove stale registry entries when removing wildcards; do not weaken the guard.
Show full SKILL.md (210 more words)Show less
The exclusivity of any applies inside one allowed_diffs rule. A constructor override in the separate bytecode_comparison section can coexist with an any rule; that combination is broad policy, not a schema conflict.
Constructor overrides inside rules are evaluated only after the base simulation succeeds and still differs. They cannot recover missing base calldata or a reverting base constructor. Evidence-backed overrides in bytecode_comparison supply the base simulation inputs.
3. Verify the result
Apply validate-config, then:
uv run pytest -q tests/test_allowed_diffs.py tests/test_no_wildcard_regression.py tests/test_configs.py
uv run diffyscan path/to/config.yaml --json -E -GConfirm the intended contract is allowed or exact, matched reason/facets fit the change, and requested contracts and comparisons remain covered. Check JSON status and errors even with exit code 0. For a new granular rule, evaluate an unrelated hunk, byte offset or immutable value against the matcher and confirm it stays rejected, scoped to the rule's intended guarantees.
In the CLI JSON report, use contracts[].bytecode.facets and .reason; matched_facets and matched_rule are internal result fields, not report keys.
For a runnable immutable-rule check, adapt the matcher example. evaluate_bytecode_rules requires a callable analysis provider; each negative case must supply its changed analysis to that callback as well as to the base argument.
Report evidence, accepted scope, remaining drift protection and checks actually run. If live verification is unavailable, state that the rule has not been verified on chain.
© lidofinance, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file
Files
SKILL.md and 1 other file (references) in .claude/skills/allowed-diffs of lidofinance/diffyscan.
- SKILL.md
- references/check-immutable-rule.md
Open the folder on GitHubat commit 9fd6833
Compare with similar skills
Allowed Diffs 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.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| Allowed Diffs this skilllidofinance/diffyscan | 142 | — | ~1.2k | Automated safety check: Pass | MIT | |
| Fizz Convertpashov/skills | 1.2k | 2 repos | ~3.7k | Automated safety check: Pass | MIT | |
| Feynman Auditor0xiehnnkta/nemesis-auditor | 244 | 1 repos | ~11k | Automated safety check: Pass | MIT | |
| Smart Contract Auditgreatpie/smart-contract-audit-skill | 101 | — | ~1.1k | Automated safety check: Pass | None | |
| RadarAuditware/radar | 154 | — | ~2.1k | Automated safety check: Pass | GPL-3.0 | |
| Solidity AuditorGabson0x/bountyforge | 443 | — | ~3.7k | Automated safety check: Pass | None |
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Related
Works with
Categories
Questions about Allowed Diffs
What does Allowed Diffs do?
Adds, reviews or tightens Diffyscan alloweddiffs rules for explained source or bytecode differences, including replacing any wildcards with granular rules. Allowed Diffs is an agent skill from lidofinance/diffyscan. Adds, reviews or tightens Diffyscan alloweddiffs rules for explained source or bytecode differences, including replacing any wildcards with granular rules.
When should I use Allowed Diffs?
Allowed Diffs fits situations like: accepting an expected diff; narrowing an exception; use debug-diff first if its cause is unknown.
How do I install Allowed Diffs in Claude Code?
Run `npx skills add lidofinance/diffyscan --skill allowed-diffs -a claude-code`. Or copy the skill folder (.claude/skills/allowed-diffs in lidofinance/diffyscan) into .claude/skills/allowed-diffs in your project. Claude Code loads it when a task matches its description.
How do I install Allowed Diffs in Codex?
Run `npx skills add lidofinance/diffyscan --skill allowed-diffs -a codex`. Or copy the skill folder (.claude/skills/allowed-diffs in lidofinance/diffyscan) into .agents/skills/allowed-diffs in your project. Codex loads it when a task matches its description.
Can I use Allowed Diffs 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 lidofinance/diffyscan --skill allowed-diffs -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/allowed-diffs, .gemini/skills/allowed-diffs, .github/skills/allowed-diffs and .opencode/skills/allowed-diffs in your project.
What does Allowed Diffs need to run?
Going by SKILL.md and its folder, Allowed Diffs needs the command-line tools its instructions call (uv).
Does Allowed Diffs access the network?
SKILL.md contains no URLs. Its commands use uv, which can reach the network depending on how they are called. This is read from the text; nothing was executed.
Is Allowed Diffs 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 Allowed Diffs use?
Allowed Diffs 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 Allowed Diffs use?
About 1.2k tokens (SKILL.md is roughly 5k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full. Its references folder adds about 414 tokens, read only when the agent opens those files.
What are the alternatives to Allowed Diffs?
Skills that share tags, products or a category with Allowed Diffs: Fizz Convert (pashov/skills, 1.2k stars), Feynman Auditor (0xiehnnkta/nemesis-auditor, 244 stars), Smart Contract Audit (greatpie/smart-contract-audit-skill, 101 stars) and Radar (Auditware/radar, 154 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Allowed Diffs?
lidofinance (a GitHub organization) maintains it in lidofinance/diffyscan, which has 142 GitHub stars. The repository holds 5 skills in this directory. The repository was last updated on October 6, 2026.
Source: lidofinance/diffyscan on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.