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 skills add synthesisengineering/synthesis-skills --skill synthesis-repo-guardgit clone --depth 1 https://github.com/synthesisengineering/synthesis-skillsWrote 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/synthesisengineering/synthesis-skills/synthesis-repo-guard)<a href="https://agentmods.dev/skills/synthesisengineering/synthesis-skills/synthesis-repo-guard"><img src="https://agentmods.dev/badge/skills/synthesisengineering/synthesis-skills/synthesis-repo-guard/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/synthesisengineering/synthesis-skills/synthesis-repo-guard"><img src="https://agentmods.dev/badge/skills/synthesisengineering/synthesis-skills/synthesis-repo-guard.svg" alt="Reviewed on agentmods" width="80" 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 5.1 | $0.00048 | $0.04626 |
| Opus 5 | $0.00024 | $0.02313 |
| Sonnet 5 | $0.00010 | $0.00925 |
| Haiku 4.5 | $0.00005 | $0.00463 |
Grade B, and why
synthesis-repo-guard scanned grade B with 1 finding 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 today.
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.
Reads agent configuration directoriesmediumAgent snooping
.claude/, .codex/, .gemini/ hold keys, settings and other credentials a mod has no legitimate need for.
### Claude Code (`~/.claude/settings.json`) How it starts
The opening of the file, as written. The whole thing — 357 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Synthesis Repo Guard
The Problem
AI coding assistants and project-management tooling create and modify files continuously. A stopped task needs lightweight same-machine recovery immediately, while another computer needs a deliberate publication boundary. Treating both cases as an automatic commit creates noisy history and network latency; treating neither creates invisible local-only state. Tools that write files outside agent sessions (a project console writing status markers, manual edits) need the same attribution contract.
v1 of this skill detected stranded state and alerted with a count ("N repositories have unsynced changes"). Two failures emerged in practice:
- The alert was unactionable — and leaky if made actionable. A count says nothing useful; speaking repo names would fix that, but repo/workspace names are often client names, and audio reaches whoever is nearby or on an unmuted call. Notification banners leak the same way during screen-shares.
- The alert fired on machine-fixable states. Most unsynced state is exactly what automation should heal at the next sensible checkpoint. Alerting humans about machine-fixable problems trains them to ignore alerts.
The Architecture — three layers
| Layer | Component | Job |
|---|---|---|
| Detector | repo_sync_check.py (scan) |
Find dirty / ahead / behind / detached repos under a workspace root |
| Messenger | repo_sync_check.py (output) |
Generic audio/banner ping + detailed report files + console tile data |
| Checkpointer | checkpoint_sync.py |
Record local handoffs; batch exact context paths at explicit remote-sync events |
End state: same-computer client switching is filesystem-local and fast. Cross-computer publication is batched and explicit. The synthesis-console shows ambient status, and alerts remain rare and actionable.
Confidentiality rule for alert surfaces (ABSOLUTE)
Audio (say, alert sounds) and macOS notification banners never carry repo names, workspace names, or client names — only counts and a pointer ("details are in your synthesis console"). This holds at all times, not only while screen-sharing: presence detection is unreliable, and one leak outweighs the convenience. Identifying detail belongs exclusively in pull channels the user deliberately opens:
What ships with it
6 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.
- today Changed · +62 lines 69a3124ac292
- 2d ago Changed · +9 lines b8f1a9c81147
- 6d ago Changed · +4 lines 86a96652a2ba
- 8d ago Changed · +7 lines ce5925e7fc0b
- 12d ago First seen · 275 lines · 48 tokens per session scan B d5259de42d1e
synthesis-repo-guard is a skill published in the GitHub repository synthesisengineering/synthesis-skills (19 stars, last pushed today), licensed Apache-2.0. It adds 48 tokens to every session and 4,626 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it B with 1 finding (reads agent configuration directories). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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