Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add skills/dsifry/metaswarm/external-toolsnpx skills add dsifry/metaswarm --skill external-toolsgit clone --depth 1 https://github.com/dsifry/metaswarmWrote 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/dsifry/metaswarm/external-tools)<a href="https://agentmods.dev/skills/dsifry/metaswarm/external-tools"><img src="https://agentmods.dev/badge/skills/dsifry/metaswarm/external-tools.svg" alt="Measured on agentmods" height="20"></a>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 | $0.00025 | $0.03579 |
| Opus 5 | $0.00013 | $0.01790 |
| Sonnet 5 | $0.00005 | $0.00716 |
| Haiku 4.5 | $0.00003 | $0.00358 |
Grade A, and why
external-tools 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 4d 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 — 401 lines — stays where its author put it; the contents beside it link to each section on GitHub.
External Tools Skill
Purpose
This skill delegates implementation and review tasks to external AI CLI tools (OpenAI Codex CLI, Google Gemini CLI), enabling cost savings through cheaper models and cross-model adversarial review that eliminates single-model blind spots. Three core principles govern every interaction: one job per invocation (an external tool implements OR reviews, never self-validates), minimal permissions (sandboxed execution scoped to the task's working directory with only the tool's own API key), and the orchestrator verifies independently (external tools report facts only, the orchestrator judges pass/fail).
Prerequisites
Required Tools
| Tool | Install | Auth |
|---|---|---|
| OpenAI Codex CLI | npm i -g @openai/codex |
API key or ChatGPT subscription |
| Google Gemini CLI | npm i -g @google/gemini-cli |
Google login (free 1K req/day) or API key |
Neither tool is strictly required. The skill adapts based on what is available (see Escalation Model below).
Configuration
Per-project config at .metaswarm/external-tools.yaml (optional -- if absent, external tools are not used):
adapters:
codex:
enabled: true
model: "gpt-5.3-codex"
timeout_seconds: 300
sandbox: docker # docker | platform | none
gemini:
enabled: true
model: "pro"
timeout_seconds: 300
sandbox: docker
routing:
default_implementer: "cheapest-available"
escalation_order: ["codex", "gemini", "claude"]
budget:
per_task_usd: 2.00 # circuit breaker per task
per_session_usd: 20.00 # circuit breaker per session
Fallback Behavior
- Both tools available: Full cross-model delegation and review
- One tool available: Reduced chain with mutual review between the tool and Claude
- No tools available: Existing metaswarm behavior unchanged; skill is a no-op
Quick Reference
Health Check
# Check if Codex is installed, authenticated, and reachable
adapters/codex.sh health
# Check Gemini
adapters/gemini.sh health
What ships with it
5 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 4d ago First seen · 401 lines · 25 tokens per session scan A 9aa9b71dbb8f
external-tools is a skill published in the GitHub repository dsifry/metaswarm (407 stars, last pushed 2mo ago), licensed MIT. It adds 25 tokens to every session and 3,579 once invoked, about $0.0001 per session on Opus 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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