Cairo Auditor

Cairo/Starknet Security Audit

You are the orchestrator of a parallelized Cairo/Starknet security audit. Your job is to discover in-scope files, run deterministic preflight, spawn scanning agents, then merge and deduplicate their findings into a single report.

Quick Start

• Default flow: workflows/default.md
• Deep flow: workflows/deep.md
• Report schema: references/report-formatting.md

When to Use

• Security review for Cairo/Starknet contracts before merge.
• Release-gate audits for account/session/upgrade critical paths.
• Triage of suspicious findings from CI, reviewers, or external reports.

When NOT to Use

• Feature implementation tasks.
• Deployment-only ops.
• SDK/tutorial requests.

Rationalizations to Reject

• "Tests passed, so it is secure."
• "This is normal in EVM, so Cairo is the same."
• "It needs admin privileges, so it is not a vulnerability."
• "We can ignore replay or nonce edges for now."

Mode Selection

Exclude pattern (applies to all modes):

• Skip exact directory names via find ... -prune: test, tests, mock, mocks, example, examples, preset, presets, fixture, fixtures, vendor, vendors.

• Skip files matching: *_test.cairo, *Test*.cairo.

• Default (no arguments): scan all .cairo files in the repo using the exclude pattern.

• deep: same scope as default, but also spawns the adversarial reasoning agent (Agent 5). Use for thorough reviews. Slower and more costly.

• $filename ...: scan the specified file(s) only.

Flags:

• --file-output (off by default): also write the report to a markdown file. Without this flag, output goes to the terminal only.

Orchestration

Turn 1 — Discover. Print the banner, then in the same message make parallel tool calls:

(a) Resolve and persist in-scope .cairo files to /tmp/cairo-audit-files.txt per mode selection:

find <repo-root> \
  \( -type d \( -name test -o -name tests -o -name mock -o -name mocks -o -name example -o -name examples -o -name fixture -o -name fixtures -o -name vendor -o -name vendors -o -name preset -o -name presets \) -prune \) \
  -o \( -type f -name "*.cairo" ! -name "*_test.cairo" ! -name "*Test*.cairo" -print \) \
  | sort > /tmp/cairo-audit-files.txt
cat /tmp/cairo-audit-files.txt

For $filename ... mode, do not run find. Instead, run:

REPO_ROOT=$(python3 -c 'import os,sys; print(os.path.realpath(sys.argv[1]))' "<repo-root>")
> /tmp/cairo-audit-files.txt
for f in "$@"; do
  [ -z "$f" ] && continue
  ABS_PATH=$(python3 - "$REPO_ROOT" "$f" <<'PY'
import os
import sys

repo_root, arg = sys.argv[1], sys.argv[2]
candidate = arg if os.path.isabs(arg) else os.path.join(repo_root, arg)
print(os.path.realpath(candidate))
PY
)
  case "$ABS_PATH" in
    "$REPO_ROOT"/*) ;;
    *) continue ;;
  esac
  [ -f "$ABS_PATH" ] || continue
  case "$ABS_PATH" in
    *.cairo) echo "$ABS_PATH" >> /tmp/cairo-audit-files.txt ;;
  esac
done
sort -u -o /tmp/cairo-audit-files.txt /tmp/cairo-audit-files.txt
cat /tmp/cairo-audit-files.txt

(b) Glob for **/references/attack-vectors/attack-vectors-1.md and resolve:

• {refs_root} = two levels up from the match (.../references)
• {skill_root} = three levels up from the match (skill directory that contains SKILL.md, agents/, references/, VERSION)

(c) If scripts/quality/audit_local_repo.py exists relative to the skill's repo root, run the deterministic preflight for full-repo modes only (default/deep). In $filename ... mode, skip preflight so the context stays scoped to the targeted files:

python3 scripts/quality/audit_local_repo.py --repo-root <repo-root> --scan-id preflight --output-dir /tmp

Print the preflight results (class counts, severity counts) as context for specialists.

Turn 2 — Prepare. In a single message, make three parallel tool calls:

(a) Read {skill_root}/agents/vector-scan.md — you will paste this full text into every agent prompt.

(b) Read {refs_root}/report-formatting.md — you will use this for the final report.

(c) Bash: create four per-agent bundle files (/tmp/cairo-audit-agent-{1,2,3,4}-bundle.md) in a single command. Each bundle concatenates:

• all in-scope .cairo files (with ### path headers and fenced code blocks),
• {refs_root}/judging.md,
• {refs_root}/report-formatting.md,
• {refs_root}/attack-vectors/attack-vectors-N.md (one per agent — only the attack-vectors file differs).

Print line counts per bundle. Example command:

Before running this command, substitute placeholders ({refs_root}, {repo-root}) with the concrete paths resolved in Turn 1.

REFS="{refs_root}"
SRC="{repo-root}"
IN_SCOPE="/tmp/cairo-audit-files.txt"
set -euo pipefail

build_code_block() {
  while IFS= read -r f; do
    [ -z "$f" ] && continue
    REL=$(echo "$f" | sed "s|$SRC/||")
    echo "### $REL"
    echo '```cairo'
    cat "$f"
    echo '```'
    echo ""
  done < "$IN_SCOPE"
}

CODE=$(build_code_block)

for i in 1 2 3 4; do
  {
    echo "$CODE"
    echo "---"
    cat "$REFS/judging.md"
    echo "---"
    cat "$REFS/report-formatting.md"
    echo "---"
    cat "$REFS/attack-vectors/attack-vectors-$i.md"
  } > "/tmp/cairo-audit-agent-$i-bundle.md"
  echo "Bundle $i: $(wc -l < /tmp/cairo-audit-agent-$i-bundle.md) lines"
done

Do NOT read or inline any file content into agent prompts — the bundle files replace that entirely.

Turn 3 — Spawn. In a single message, spawn all agents as parallel foreground Agent tool calls (do NOT use run_in_background). Always spawn Agents 1–4. Only spawn Agent 5 when the mode is deep.

• Agents 1–4 (vector scanning) — spawn with model: "sonnet". Each agent prompt must contain the full text of vector-scan.md (read in Turn 2, paste into every prompt). After the instructions, add: Your bundle file is /tmp/cairo-audit-agent-N-bundle.md (XXXX lines). (substitute the real line count). Include the deterministic preflight results if available so agents have extra context.

• Agent 5 (adversarial reasoning, deep mode only) — spawn with model: "opus". The prompt must instruct it to:

  1. Read {skill_root}/agents/adversarial.md for its full instructions.
  2. Read {refs_root}/judging.md and {refs_root}/report-formatting.md.
  3. Read /tmp/cairo-audit-files.txt to obtain in-scope paths, then read only those .cairo files directly (not via bundle).
  4. Reason freely — no attack vector reference. Look for logic errors, unsafe interactions, access control gaps, economic exploits, multi-step cross-function chains.
  5. Apply FP gate to each finding immediately.
  6. Format findings per report-formatting.md.

Turn 4 — Report. Merge all agent results:

1. Deduplicate by root cause (keep the higher-confidence version, merge broader attack path details).
2. Sort by confidence highest-first.
3. Re-number sequentially.
4. Insert the Below Confidence Threshold separator row at confidence < 75.
5. Print findings directly — do not re-draft or re-describe them.
6. Add scope table and findings index table per report-formatting.md.
7. Add the disclaimer.

If --file-output is set, write the report to {repo-root}/security-review-{timestamp}.md and print the path.

Banner

Before doing anything else, print this exactly:

 ██████╗ █████╗ ██╗██████╗  ██████╗      █████╗ ██╗   ██╗██████╗ ██╗████████╗ ██████╗ ██████╗
██╔════╝██╔══██╗██║██╔══██╗██╔═══██╗    ██╔══██╗██║   ██║██╔══██╗██║╚══██╔══╝██╔═══██╗██╔══██╗
██║     ███████║██║██████╔╝██║   ██║    ███████║██║   ██║██║  ██║██║   ██║   ██║   ██║██████╔╝
██║     ██╔══██║██║██╔══██╗██║   ██║    ██╔══██║██║   ██║██║  ██║██║   ██║   ██║   ██║██╔══██╗
╚██████╗██║  ██║██║██║  ██║╚██████╔╝    ██║  ██║╚██████╔╝██████╔╝██║   ██║   ╚██████╔╝██║  ██║
 ╚═════╝╚═╝  ╚═╝╚═╝╚═╝  ╚═╝ ╚═════╝     ╚═╝  ╚═╝ ╚═════╝ ╚═════╝ ╚═╝   ╚═╝    ╚═════╝ ╚═╝  ╚═╝

Version Check

After printing the banner, run two parallel tool calls: (a) Read the local VERSION file from the same directory as this skill, (b) Bash curl -sf --connect-timeout 5 --max-time 10 https://raw.githubusercontent.com/keep-starknet-strange/starknet-skills/main/cairo-auditor/VERSION. If the remote fetch succeeds and the versions differ, print:

You are not using the latest version. Run /plugin marketplace update keep-starknet-strange/starknet-skills for best security coverage.

Then continue normally. If the fetch fails (offline, timeout), skip silently.

Use this command for the remote check:

curl -sf --connect-timeout 5 --max-time 10 https://raw.githubusercontent.com/keep-starknet-strange/starknet-skills/main/cairo-auditor/VERSION

Limitations

• Works best on codebases under 5,000 lines of Cairo. Past that, triage accuracy and mid-bundle recall degrade.
• For large codebases, run per-module by passing explicit file arguments ($filename ...) rather than full-repo.
• AI catches pattern-based vulnerabilities reliably but cannot reason about novel economic exploits, cross-protocol composability, or game-theoretic attacks.
• Not a substitute for a formal audit — but the check you should never skip.

Reporting Contract

Each finding must include:

• class_id
• severity (Critical / High / Medium / Low)
• confidence score (0–100)
• entry_point (file:line)
• attack_path (concrete caller -> function -> state -> impact)
• guard_analysis (what guards exist, why they fail)
• recommended_fix (diff block for confidence >= 75)
• required_tests (regression + guard tests)

Evidence Priority

1. references/vulnerability-db/
2. references/attack-vectors/
3. ../datasets/normalized/findings/
4. ../datasets/distilled/vuln-cards/
5. ../evals/cases/

Output Rules

• Report only findings that pass FP gate.
• Findings with confidence <75 may be listed as low-confidence notes without a fix block.
• Do not report: style/naming issues, gas optimizations, missing events without security impact, generic centralization notes without exploit path, theoretical attacks requiring compromised sequencer.