What is hcom-agent-messaging?

A communication system for AI coding agents running in separate terminals. It lets agents exchange messages and observe or react to each other's work.

It is for sending tasks and feedback, watching transcripts and file edits, subscribing to events, and spawning, resuming, or stopping other agents.

Separate agent sessions normally lack a shared way to coordinate, hand off context, inspect changes, or respond to status updates.

hcom-agent-messaging — Skill for Claude Code and Codex by aannoo/hcom

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 aannoo/hcom --skill hcom-agent-messaging

Clone the repo

git clone --depth 1 https://github.com/aannoo/hcom

Made for: Claude Code, Codex.

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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/aannoo/hcom/hcom-agent-messaging/github.svg)](https://agentmods.dev/skills/aannoo/hcom/hcom-agent-messaging)

Your own site

<a href="https://agentmods.dev/skills/aannoo/hcom/hcom-agent-messaging"><img src="https://agentmods.dev/badge/skills/aannoo/hcom/hcom-agent-messaging/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/aannoo/hcom/hcom-agent-messaging"><img src="https://agentmods.dev/badge/skills/aannoo/hcom/hcom-agent-messaging.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 35 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,013 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.

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.

Model	Per session	Once invoked
Fable 5.1	$0.00035	$0.01013
Opus 5.5	$0.00014	$0.00405
Sonnet 5.5	$0.00007	$0.00203
Haiku 4.5	$0.00003	$0.00101

Measured 3d ago against content hash dc2f775b0d62, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

hcom-agent-messaging 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 3d 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.

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.

skills/hcom-agent-messaging/SKILL.md · 156 lines

How it starts

The opening of the file, as written. The whole thing — 156 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.

Start an agent with hcom in front, then prompt normally.

Use hcom to:

coordinate multi-agent pipelines
run different AI CLIs as each other's subagents
avoid copy-pasting

uv tool install hcom
hcom claude       # or: hcom gemini, hcom codex, hcom opencode, hcom kilo, hcom pi, hcom omp, hcom agy, hcom cursor, hcom kimi, hcom copilot, hcom qoder, hcom grok, hcom hermes
hcom              # TUI dashboard

Quickstart:

# terminal 1
hcom claude

# terminal 2
hcom codex

Prompt normally — e.g. review what claude did and send it fixes

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: mid-turn or wake immediately when idle

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

Subscribe and notify on status changes, file edits, collisions, specific events. React automatically.

Spawn, fork, resume, kill in any terminal emulator or headless.

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

Works with Claude Code, Gemini CLI, Codex, OpenCode, Kilo Code, Pi, Oh My Pi, Antigravity, Cursor, Kimi, Copilot, Qoder CLI, Grok Build, Hermes Agent, and other tools

setup

When this skill is invoked, first run:

hcom status

If hcom status works: run hcom list

If hcom list shows "Your name: " where <name> is not "(not participating)": congratulations!

If running hcom status returns "command not found", install first:

uv tool install hcom

Read the full file on GitHub · 156 lines

Files

What ships with it

10 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.

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.

3d ago Changed dc2f775b0d62
14d ago Changed · -37 lines · -7 tokens per session scan C → A f34e0d41d499
19d ago Changed · +2 lines 03cf122e7885
1mo ago First seen · 191 lines · 42 tokens per session scan C 7714c97abebc

Subscribe to this mod's changes

hcom-agent-messaging is a skill published in the GitHub repository aannoo/hcom (579 stars, last pushed 3d ago), licensed MIT. It adds 35 tokens to every session and 1,013 once invoked, about $0.0001 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 2026-08-30.

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