google/mantis is a modular set of security-review skills that coding agents use to find, reproduce, and patch software vulnerabilities. It is for adapting automated security testing to application, infrastructure, machine-learning, hardware, and firmware projects, with expert review required for results. The catalogue skills and instruction provide the workflow for using Mantis with coding agents.
Getting it into your agent
It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.
git clone --depth 1 https://github.com/google/mantisnpx agentmods add skills/google/mantis/mantis-dedupeWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/google/mantis/mantis-dedupe)<a href="https://agentmods.dev/skills/google/mantis/mantis-dedupe"><img src="https://agentmods.dev/badge/skills/google/mantis/mantis-dedupe/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/google/mantis/mantis-dedupe"><img src="https://agentmods.dev/badge/skills/google/mantis/mantis-dedupe.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- Socket pass
- Snyk warn
- NVIDIA SkillSpector pass
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00043 | $0.05192 |
| Opus 5.5 | $0.00017 | $0.02077 |
| Sonnet 5.5 | $0.00009 | $0.01038 |
| Haiku 4.5 | $0.00004 | $0.00519 |
Grade A, and why
mantis-dedupe scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 372 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Deduplicator (/mantis-dedupe)
System Goal
Duplicate Finding Merger. Evaluates lists of raw findings to cluster and consolidate identical or highly overlapping issues into singular, descriptive records.
Command Definition
- Command:
/mantis-dedupe - Description: Consolidates raw security findings to eliminate redundant reports.
- Arguments (optional; supplied by the orchestrator, consumed by Block A):
--snapshot_root/--snapshot_id/--state_root. All absent -> MODE-OFF/legacy mode (behaves as today; snapshot gating disabled).
Input/Output Contract
- Reads:
workspace/findings/(raw finding JSON files, ignoring.trash/).workspace/archive/findings_pass_*/*.jsonandworkspace/archive/loop*_findings/*.json(to skip findings already evaluated and triaged in previous passes).workspace/.mantis_state.json(to track current loop pass).
- Writes:
- Moves duplicate findings to
workspace/findings/.trash/after setting"status": "DUPLICATE"and"duplicate_of". - Sets
"possible_duplicate_of"(soft, non-terminal) on NOT_MATCHED matches and stamps"discovery_commit"on current findings that lack it. Readsactive_snapshot/snapshot_pinnedfrom.mantis_state.json. - Appends transaction logs to
workspace/.tx_log.jsonl. - Generates/executes merging script
workspace/helpers/merge_findings.py. - Updates primary finding
workspace/findings/<primary_id>.json(merges fields and history).
- Moves duplicate findings to
- Preconditions:
workspace/findings/must exist and contain finding files.
- Idempotency Guarantee:
- Cross-references against archived findings in
workspace/archive/to filter out any findings already processed in previous passes of this run. Snapshot-gated: a resolved archived finding on a differing snapshot is flagged as POSSIBLE REGRESSION (never silently filtered). Logs transactions toworkspace/.tx_log.jsonlto support tracking and potential rollbacks. Deterministic merging rules implemented inmerge_findings.py.
- Cross-references against archived findings in
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 1mo ago First seen · 372 lines · 43 tokens per session scan A 4cc3dd33a392
mantis-dedupe is a skill published in the GitHub repository google/mantis (2,525 stars, last pushed today), licensed Apache-2.0. It adds 43 tokens to every session and 5,192 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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