set-core: Skill for Claude Code

.claude/skills/cross-project-channel/SKILL.md

cross-project-channel is a skill for Claude Code from tatargabor/set-core. It costs 82 tokens per session (3,109 once invoked), scanned A, original, MIT.

A temporary file-based message channel between sessions belonging to different projects. It defines how those sessions append messages, resume after context is cleared, and check for existing messages without duplicates.

In plain words
What is it for?
Use it when coordinating one project's coding assistant with another project's assistant through files, including resuming communication after a session reset.
Why use it?
It provides a shared place for cooperating project sessions when no dedicated communication system is available, while documenting how to avoid lost or repeated messages.

Skill for Claude Code

Written for Claude Code: installed under .claude/. Also seen: mentions CLAUDE.md.

This is tatargabor/set-core's own configuration. It tells Claude Code how to work on set-core itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything set-core configures →

Reuse

Borrowing it

Nothing to install: this file belongs to tatargabor/set-core. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/tatargabor/set-core/main/.claude/skills/cross-project-channel/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/tatargabor/set-core

Made for: Claude Code.

Wrote 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.

agentmods badge for cross-project-channel

README.md
[![agentmods](https://agentmods.dev/badge/skills/tatargabor/set-core/cross-project-channel.svg)](https://agentmods.dev/skills/tatargabor/set-core/cross-project-channel)
Your own site
<a href="https://agentmods.dev/skills/tatargabor/set-core/cross-project-channel"><img src="https://agentmods.dev/badge/skills/tatargabor/set-core/cross-project-channel.svg" alt="Measured on agentmods" height="20"></a>
Per session 82 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,109 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 2 findings, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • medium Rogue Agent · line 55
    Skill establishes unauthorized persistence across sessions via cron jobs, startup scripts, or state files. Session persistence allows an attacker to maintain access beyond the current interaction.
    Fix: Remove any persistence mechanisms (cron jobs, startup scripts, state files). Skills should not maintain state across sessions without explicit user consent.
  • medium Excessive Agency · line 95
    Skill enables autonomous high-impact decisions without human-in-the-loop verification. Critical operations (destructive commands, financial transactions, data deletion) should require explicit user confirmation.
    Fix: Add human-in-the-loop confirmation for destructive, irreversible, or high-impact operations. Never auto-execute commands that modify files, send data, or alter system state.
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00082 $0.03109
Opus 5 $0.00041 $0.01554
Sonnet 5 $0.00016 $0.00622
Haiku 4.5 $0.00008 $0.00311

Measured yesterday against content hash 46f4fb7119fc, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

cross-project-channel 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 yesterday.

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.

.claude/skills/cross-project-channel/SKILL.md · 180 lines

How it starts

The opening of the file, as written. The whole thing — 180 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Cross-project agent channel

Moved out of CLAUDE.md on 2026-08-22 so it loads when it is needed rather than in every session. Nothing was cut — the text below is the section verbatim.

Cross-project agent channel — TEMPORARY (from 2026-07-24)

While set-core and a consumer project are being integrated, their two copilot sessions coordinate over a file channel, because no shared transport exists. Remove this section once the real transport ships.

Corrected 2026-07-29 — the stated reason was wrong, and wrong in the direction that closes off a working option. This said .set-control is per-project, so send_message/get_inbox "cannot cross a project boundary". Measured: the registry is global (~/.config/set-core/projects.json, 38 entries), and _find_control_worktree() (mcp-server/set_mcp_server.py:462) walks it and returns the first project that has a .set-control directory — regardless of which project the server was started in. So both sides would resolve to the same worktree; the project boundary was never the obstacle. The real ones are that no .set-control exists anywhere (checked on both trees → both tools return Error: No .set-control worktree found), and that the git-based ~15 s commit cycle is rejected below. This is the proxy-instead-of-the-thing class applied to a code path: the sentence described what the resolution ought to scope to, not what the function does.

DECISION 2026-07-24 — do not revive the git-based control sync for this. The existing agent-messaging path (set-control-sync, .set-control worktree, ~15 s commit cycle) is rejected as the cross-project channel: it caused problems in practice, and it carries ephemeral messages where this coordination needs durable state. A live (non-git) transport may be built later as its own piece of work; until then the file channel below is the agreed mechanism.

Protocol — one file, one writer. Channel dir: ~/.local/share/set-core/channels/<consumer-slug>/ (the slug is runtime-derived; never hard-code a consumer name here — see External Project Confidentiality below). Each side appends only to its own file and reads the other's:

Read the full file on GitHub · 180 lines

Changes

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.

  1. yesterday First seen · 180 lines · 82 tokens per session scan A 46f4fb7119fc

Subscribe to this mod's changes

cross-project-channel is a skill published in the GitHub repository tatargabor/set-core (35 stars, last pushed yesterday), licensed MIT. It adds 82 tokens to every session and 3,109 once invoked, about $0.0004 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 2026-09-06.

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