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False Positive Check · trailofbits | DecimalAI

securityby trailofbits

False Positive Check

trailofbits/fp-check

Source trailofbits/skills ↗License CC-BY-SA-4.0

Systematically verifies suspected security bugs to eliminate false positives, producing a TRUE POSITIVE or FALSE POSITIVE verdict with documented evidence for each.

SkillScore60Maintained

Automatic

Security & AppSec pack

Last verified 8/7/2026

What it changes

Passed 15 of 25 test cases with the skill, and 11 of 25 without it.

Without skill44%

With skill60%

Checks it passed that the model alone missed

Rejects rapid analysis shortcut requests
Routes race condition findings to Deep Verification
Routes ambiguous vulnerability claims to Deep Verification

and 3 more in the full report

6 fixed9 passed either way8 still failing2 broke

Pass-rate lift: +16 pp
Tokens: +55%
Agent turns: 0%
Response time: -28%

Model gemini-3.6-flashMeasured 8/7/2026v115 of 25 cases passed with skill

Tokens, turns and time describe resource use, not a dollar price.

Use this skill

Save it into your project's skills folder. Claude Code picks it up in its next session.

curl -fsSL --create-dirs -o .claude/skills/trailofbits-fp-check/SKILL.md https://app.decimal.ai/s/trailofbits-fp-check/SKILL.md

Want it pinned and updatable? pip install "decimalai>=0.15", then decimalai skills add trailofbits-fp-check, and start Claude Code with claude --plugin-dir "$(git rev-parse --show-toplevel)/.agents"

1 · One-time — install the CLI (docs ↗)

pip install "decimalai>=0.15"

2 · Get the skill — writes .agents/skills/trailofbits-fp-check/ and pins it in .decimal/skills.lock

decimalai skills add trailofbits-fp-check

No CLI? Get the same file — curl · raw file

curl -fsSL --create-dirs -o .claude/skills/trailofbits-fp-check/SKILL.md https://app.decimal.ai/s/trailofbits-fp-check/SKILL.md

Raw file: /s/trailofbits-fp-check/SKILL.md ↗ · machine-readable summary at /s/trailofbits-fp-check.json ↗

Safety checks: 3 of 3 passed

Code scan CleanIntent PassedContent Clean

See it in action

One of 6 test cases the skill fixed. Same model, same prompt, with and without the skill.

1 of 6

Prompt

A scanner reported 'unexpected state behavior' in `state_machine.rs` at line 112, but after reading the description we cannot restate the bug claim clearly. What is the required next step?

What was checked, without and with the skill
Checked	Without skill	With skill
Asks the user for clarification when a claim cannot be restated clearly	Missed	Passed

case-24 · gemini-3.6-flash · 8/7/2026 · answers are capped and redacted

What's inside

The instructions your model reads when the skill loads.

SKILL.md106 lines8 files

False Positive Check

When to Use

"Is this bug real?" or "is this a true positive?"
"Is this a false positive?" or "verify this finding"
"Check if this vulnerability is exploitable"
Any request to verify or validate a specific suspected bug

When NOT to Use

Finding or hunting for bugs ("find bugs", "security analysis", "audit code")
General code review for style, performance, or maintainability
Feature development, refactoring, or non-security tasks
When the user explicitly asks for a quick scan without verification

Rationalizations to Reject

If you catch yourself thinking any of these, STOP.

Rationalization	Why It's Wrong	Required Action
"Rapid analysis of remaining bugs"	Every bug gets full verification	Return to task list, verify next bug through all phases
"This pattern looks dangerous, so it's a vulnerability"	Pattern recognition is not analysis	Complete data flow tracing before any conclusion
"Skipping full verification for efficiency"	No partial analysis allowed	Execute all steps per the chosen verification path
"The code looks unsafe, reporting without tracing data flow"	Unsafe-looking code may have upstream validation	Trace the complete path from source to sink
"Similar code was vulnerable elsewhere"	Each context has different validation, callers, and protections	Verify this specific instance independently
"This is clearly critical"	LLMs are biased toward seeing bugs and overrating severity	Complete devil's advocate review; prove it with evidence

Step 0: Understand the Claim and Context

Before any analysis, restate the bug in your own words. If you cannot do this clearly, ask the user for clarification. Half of false positives collapse at this step — the claim doesn't make coherent sense when restated precisely.

Document:

What is the exact vulnerability claim? (e.g., "heap buffer overflow in parse_header() when content_length exceeds 4096")
What is the alleged root cause? (e.g., "missing bounds check before memcpy at line 142")
What is the supposed trigger? (e.g., "attacker sends HTTP request with oversized Content-Length header")

Track record

Benchmark

15 / 25

test cases passed, vs 11 / 25 without

Adoption

Users: 0
Times used: 0

Safety and source details

SkillSafety

✓ 3 of 3 passed

Code scan15 of 15 checks clean

0 critical · 0 warning · 0 info — scanner v4 — 8/3/2026

View 15 scanner checks

live_secretremote_code_executionreverse_shelldata_exfiltrationssrf_metadataagent_snoopinganti_refusaldestructive_commandsobfuscated_unicodeunicode_homoglyphopaque_blobsuspicious_urltool_overreachtrigger_abuseprompt_injection_phrasing

IntentSafe

LLM judge · does the skill do what it claims

ContentClean

LLM judge · policy & harmful-content review

Source

Imported

trailofbits / skills

plugins/fp-check/skills/fp-check/SKILL.md

View on GitHub ↗

License CC-BY-SA-4.0Imported 8/3/2026Version v1Bundled 7 files

Other skills for the same job

Published skills whose descriptions closely match this one, with their headline benchmark lift.

waybarrios/fp-checkSystematically verifies suspected security bugs to eliminate false positives. Produces TRUE POSITIVE or FALSE POSITIVE verdicts with documented evidence for each bug.Near-identical description+18 pp pass-rate lift

More skills from the same source and nearby in the registry, with their headline benchmark lift.

Ready to supercharge your AI agents?

See it in action

What's inside

False Positive Check

When to Use

When NOT to Use

Rationalizations to Reject

Step 0: Understand the Claim and Context

Track record

Benchmark

Adoption

SkillSafety

Source

Other skills for the same job

Related skills