hcom-agent-messaging

hcom-agent-messaging is a skill for Claude Code from scchearn/hcom-mcp. It costs 60 tokens per session (1,863 once invoked), scanned C, original, MIT.

A communication system that connects AI coding agents running in separate terminals through hooks and a shared database. It lets them exchange messages, share handoff context, observe activity, and start related agents.

In plain words
What is it for?
Use it to assign work between Claude, Gemini, Codex, or OpenCode agents, send real-time updates, monitor file edits and transcripts, and hand tasks to another agent.
Why use it?
Separate terminal sessions normally cannot see or coordinate with one another, making multi-agent work harder to manage.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter. Also seen: mentions subagents; mentions Claude Code; mentions Codex.

Part of the hcom-mcp plugin — 2 skills, 1 MCP server shipped together

Good fit Use it to assign work between Claude, Gemini, Codex, or OpenCode agents…

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Install with agentmods
npx agentmods add skills/scchearn/hcom-mcp/hcom-agent-messaging
Install

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.

Any agent
npx skills add scchearn/hcom-mcp --skill hcom-agent-messaging
Clone the repo
git clone --depth 1 https://github.com/scchearn/hcom-mcp

Made for: Claude Code.

Or install hcom-mcp, the plugin that ships this one along with the rest of its 2 skills, 1 MCP server.

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 hcom-agent-messaging

README.md
[![agentmods](https://agentmods.dev/badge/skills/scchearn/hcom-mcp/hcom-agent-messaging.svg)](https://agentmods.dev/skills/scchearn/hcom-mcp/hcom-agent-messaging)
Your own site
<a href="https://agentmods.dev/skills/scchearn/hcom-mcp/hcom-agent-messaging"><img src="https://agentmods.dev/badge/skills/scchearn/hcom-mcp/hcom-agent-messaging.svg" alt="Measured on agentmods" height="20"></a>
Per session 60 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,863 The whole file, excluding the scripts and references it only reads on demand.
Security scan C 2 findings. A grade says what 26 rules found in the file — not that it is safe.
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 $0.00060 $0.01863
Opus 5 $0.00030 $0.00932
Sonnet 5 $0.00012 $0.00373
Haiku 4.5 $0.00006 $0.00186

Measured 6d ago against content hash 1bda5133d2ed, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade C, and why

hcom-agent-messaging scanned grade C with 2 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 6d ago.

The scan reads SKILL.md. This mod also ships 6 executable files (references/scripts/basic-messaging.sh, references/scripts/cascade-pipeline.sh, references/scripts/codex-worker.sh, …), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

Downloads and executes remote codehighSupply chain

curl | sh runs whatever the server returns today, which is not necessarily what it returned when this was reviewed.

curl -fsSL https://github.com/aannoo/hcom/releases/latest/download/hcom-installer.sh | sh

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

curl -fsSL https://github.com/aannoo/hcom/releases/latest/download/hcom-installer.sh | sh
skills/hcom-agent-messaging/SKILL.md · 205 lines

How it starts

The opening of the file, as written. The whole thing — 205 lines — stays where its author put it; the contents beside it link to each section on GitHub.

hcom — multi-agent communication for AI coding tools

AI agents running in separate terminals are isolated. hcom connects them via hooks and a shared database so they can message, watch, and spawn each other in real-time.

If the user wants a quick operating pattern from the current session, one headed hub with mostly headless workers, or practical thread and handoff defaults, use the separate using-hcom skill instead of this one.

curl -fsSL https://github.com/aannoo/hcom/releases/latest/download/hcom-installer.sh | sh
hcom claude       # or: hcom gemini, hcom codex, hcom opencode
hcom              # TUI dashboard

what humans can do

tell any agent:

send a message to claude

when codex goes idle send it the next task

watch gemini's file edits, review each and send feedback if any bugs

fork yourself to investigate the bug and report back

find which agent worked on terminal_id code, resume them and ask why it sucks


what agents can do

Message each other in real-time, bundle context for handoffs.

Observe each other: transcripts, file edits, terminal screens, command history.

Subscribe to each other: notify on status changes, file edits, specific events. React automatically.

Spawn, fork, resume, kill each other, in any terminal emulator.

run hcom --help for full command syntax and flags.


tool support

tool delivery connect
claude code (incl. subagents) automatic hcom claude
gemini cli (>= 0.26.0) automatic hcom gemini
codex automatic hcom codex
opencode automatic hcom opencode
any other ai tool manual via hcom listen hcom start (run inside tool)

session binding (hcom transcript, hcom r/f by session id) happens on first message or first prompt for all hcom-launched tools.


setup

if the user invokes this skill without arguments:

  1. run hcom status — if "command not found", install first:
    curl -fsSL https://github.com/aannoo/hcom/releases/latest/download/hcom-installer.sh | sh
    
  2. run hcom hooks add to install hooks for all detected tools
  3. restart the AI tool for hooks to activate

Read the full file on GitHub · 205 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. 6d ago First seen · 205 lines · 60 tokens per session scan C 1bda5133d2ed

Subscribe to this mod's changes

hcom-agent-messaging is a skill published in the GitHub repository scchearn/hcom-mcp (1 stars, last pushed 13d ago), licensed MIT. It adds 60 tokens to every session and 1,863 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it C with 2 findings (downloads and executes remote code, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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