Getting it into your agent
This one installs as part of its plugin. Adding the marketplace and installing the plugin brings it with everything else the plugin ships.
/plugin marketplace add motlin/claude-code-plugins/plugin install upstream-syncWrote 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/motlin/claude-code-plugins/upstream-sync)<a href="https://agentmods.dev/skills/motlin/claude-code-plugins/upstream-sync"><img src="https://agentmods.dev/badge/skills/motlin/claude-code-plugins/upstream-sync/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/motlin/claude-code-plugins/upstream-sync"><img src="https://agentmods.dev/badge/skills/motlin/claude-code-plugins/upstream-sync.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 | $0.00114 | $0.02957 |
| Opus 5.5 | $0.00046 | $0.01183 |
| Sonnet 5.5 | $0.00023 | $0.00591 |
| Haiku 4.5 | $0.00011 | $0.00296 |
Grade A, and why
upstream-sync 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 7d 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 — 127 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Upstream sync
Bring a local app to near-exact parity with the upstream product it mirrors: same features, DOM structure, class names and CSS values, minus anything with no local meaning. The investigation only writes under .llm/upstream-sync/. Implementation comes afterward, from the roadmap, on agent branches that each pass a per-commit gate before local main moves.
The engine is a Workflow script, <plugin-root>/scripts/upstream-sync-workflow.js. Resolve <plugin-root> first: in Claude Code use ${CLAUDE_PLUGIN_ROOT}; in Codex use the plugin root that contains this skills/upstream-sync/SKILL.md file. Codex has no Workflow tool, so it runs the same phases by hand; see the Codex section below. The script runs:
- Broad: a code-only local inventory and a browser survey of upstream, in parallel. The survey seeds the feature queue.
- Investigate: one browser investigator per feature, strictly serial because they share Chrome. Priority order is P1, then P2, then P3. Each investigator writes
features/<slug>.mdand returns any new features it discovered, which join the queue, so the investigation recurses. - Critic: up to
maxCriticRoundscompleteness reviews, each adding missed features, until a round adds nothing. - Synthesize:
SUMMARY.md, a roadmap ordered by milestone.
The orchestrator owns features.md and rewrites it every registryEvery investigations. Investigators never edit it, so the queue never gets duplicate or conflicting rows.
Settle the safety model before anything else
Find out whether interacting with upstream or the local app changes real data. For example, both sides may write to the user's real account, or opening a page may create a record. Ask the user (with AskUserQuestion in Claude Code), offering these options:
- Sandbox: create one dedicated container, such as a top-level node, a scratch project or a test document. Investigators may edit only inside it, and may only read everywhere else.
- Strictly read-only: no edits anywhere. Editing behavior is decoded from the DOM and the JS bundle.
- User performs edits: investigators stop and ask the user to take any action that mutates data.
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.
- 7d ago Changed · +24 lines · +14 tokens per session f1642801000e
- 9d ago First seen · 103 lines · 100 tokens per session scan A 85aae403ad9c
upstream-sync is a skill published in the GitHub repository motlin/claude-code-plugins (20 stars, last pushed yesterday), licensed Apache-2.0. It adds 114 tokens to every session and 2,957 once invoked, about $0.0005 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 2026-10-12.
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