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/harnessprotocol/harness-kit/harness-syncnpx skills add harnessprotocol/harness-kit --skill harness-syncgit clone --depth 1 https://github.com/harnessprotocol/harness-kitWhat 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 | $0.00106 | $0.04123 |
| Opus 5 | $0.00053 | $0.02062 |
| Sonnet 5 | $0.00021 | $0.00825 |
| Haiku 4.5 | $0.00011 | $0.00412 |
Grade B, and why
harness-sync 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 2d 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.
Reads agent configuration directoriesmediumAgent snooping
.claude/, .codex/, .gemini/ hold keys, settings and other credentials a mod has no legitimate need for.
- Codex, Windsurf: no project-level file exists for either (Codex uses `~/.codex/config.toml`, Windsurf uses a global config) — report their MCP row as `(global-only, not scanned)` rather than `(none)`, since `(none)` wo How it starts
The opening of the file, as written. The whole thing — 323 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Sync Harness Configurations Across Platforms
You are syncing AI tool configurations across any combination of the 8 supported targets: Claude Code, Cursor, GitHub Copilot, Codex, OpenCode, Windsurf, Gemini CLI, and Junie. You will inventory what is installed and configured on each platform, report any divergence, and execute the sync direction the user chooses.
This skill depends on harness-compile: the push path reuses harness-compile's compilation logic to write the selected source platform's content to all target platforms.
Workflow Order (MANDATORY)
Follow these steps in order. Do not skip any step.
Step 1: Detect platforms
Check for any --target <platform> flag the user passed. If present, restrict the entire workflow to that platform only. Valid values: claude-code, cursor, copilot, codex, opencode, windsurf, gemini, junie. For sync, --target <platform> means "treat this platform as the only target for push output." It does not restrict which platforms are scanned in Step 2 — all detected platforms are still inventoried so divergence can be identified.
Otherwise, scan the working directory for platform indicators:
Claude Code is present if any of these exist: CLAUDE.md, .claude/, .mcp.json
Cursor is present if any of these exist: .cursor/, .cursor/rules/, .cursor/mcp.json, .cursor/skills/
Copilot is present if any of these exist: .github/, .vscode/mcp.json, .github/skills/
Codex is present if .codex/ exists
OpenCode is present if opencode.json or .opencode/ exists
Windsurf is present if .windsurf/ exists
Gemini CLI is present if .gemini/ exists
Junie is present if .junie/ exists
Never assume a platform is present. Detect each independently. If .github/ is the only Copilot indicator, ask the user:
"I found a
.github/directory but no other Copilot indicators. Are you using GitHub Copilot in this project?"
A bare AGENTS.md with none of the tool-specific directories above is ambiguous — it's the shared instruction file for Codex, OpenCode, Windsurf, Gemini CLI, and Junie, so its presence alone doesn't identify which one. Ask which of those five the user actually uses rather than assuming or offering all of them.
What ships with it
1 file 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.
- 2d ago First seen · 323 lines · 106 tokens per session scan B 3f931cedbdfc
harness-sync is a skill published in the GitHub repository harnessprotocol/harness-kit (10 stars, last pushed 3d ago), licensed Apache-2.0. It adds 106 tokens to every session and 4,123 once invoked, about $0.0005 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 2026-08-31.
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