session-send

session-send is a skill for Claude Code, Codex from Chachamaru127/claude-code-harness. It costs 35 tokens per session (757 once invoked), scanned A, original, MIT.

A procedure for sending confirmed facts, handoffs, and completion notices to another active coding-agent session.

In plain words
What is it for?
Use it to identify the correct team and agent, then send a subject and message through the session inbox.
Why use it?
It prevents messages from going to the wrong session and discourages sending guesses or unfinished discussions.

Skill for Claude CodeCodex

Part of the claude-code-harness plugin — 25 skills, 5 commands, 5 agents, 27 hooks shipped together

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.

agentmods
npx agentmods add skills/chachamaru127/claude-code-harness/session-send
Any agent
npx skills add Chachamaru127/claude-code-harness --skill session-send
Clone the repo
git clone --depth 1 https://github.com/Chachamaru127/claude-code-harness

Made for: Claude Code, Codex.

Or install claude-code-harness, the plugin that ships this one along with the rest of its 25 skills, 5 commands, 5 agents, 27 hooks.

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 session-send

README.md
[![agentmods](https://agentmods.dev/badge/skills/chachamaru127/claude-code-harness/session-send.svg)](https://agentmods.dev/skills/chachamaru127/claude-code-harness/session-send)
Your own site
<a href="https://agentmods.dev/skills/chachamaru127/claude-code-harness/session-send"><img src="https://agentmods.dev/badge/skills/chachamaru127/claude-code-harness/session-send.svg" alt="Measured on agentmods" 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 757 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00035 $0.00757
Opus 5 $0.00017 $0.00378
Sonnet 5 $0.00007 $0.00151
Haiku 4.5 $0.00003 $0.00076

Measured 3d ago against content hash afd326bb34a2, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

session-send 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.

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.

codex/.codex/skills/session-send/SKILL.md · 76 lines

What it actually says

Session Send

確定した事実を別セッションのエージェントへ送る。

1. 宛先の確認

まず稼働中のセッションを一覧し、相手の teamagent を確認する。

bin/harness session list

出力は session_id / team / agent / label / task / since / elapsed のタブ区切り。 --to に入れるのは agentであって session_id 列ではない。 この 2 つは一致することもあるが、breezing 実行中のセッションでは agentBREEZING_ROLE になるため一致しない。inbox は team + agent の完全一致でしか引かないので、 session_id--to に入れるとエラーも出ないまま相手に届かない

team / agent 列が空のセッションは、まだ身分証を publish していない。 そのセッションには送らず、相手が名乗るのを待つ。名前が似ていても推測で送らない。

自分の送信元は、Phase 141.3 の hook が書き出す環境変数から取得する。

team="${HARNESS_LIVEMSG_TEAM:?HARNESS_LIVEMSG_TEAM is not set}"
from_agent="${HARNESS_LIVEMSG_AGENT:?HARNESS_LIVEMSG_AGENT is not set}"

2. 送信

確認した宛先へ次の形式で送る。本文は最後の positional 引数にする。

bin/harness inbox send \
  --team <team> \
  --from <自分のagent> \
  --to <相手のagent> \
  --subject "<件名>" \
  "<本文>"

自分の値を環境変数から渡す場合は次の形にする。

bin/harness inbox send \
  --team "$team" \
  --from "$from_agent" \
  --to <相手のagent> \
  --subject "<件名>" \
  "<本文>"

3. 送ってよいものの判断基準

送る:

  • 完了通知
  • これから触る場所の宣言
  • 引き継ぎ

送らない:

  • 作業中の相談
  • 推測
  • 未検証の主張

根拠: CooperBench の測定では、同一ファイルを 2 エージェントが触ると成功率が単独の約半分に落ち、失敗の 63% が相手の変更についての誤った思い込みから来ていた。だから「確定した事実」だけを送る。

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. 3d ago First seen · 76 lines · 35 tokens per session scan A afd326bb34a2

Subscribe to this mod's changes

session-send is a skill published in the GitHub repository Chachamaru127/claude-code-harness (3,081 stars, last pushed 3d ago), licensed MIT. It adds 35 tokens to every session and 757 once invoked, about $0.0002 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 2026-08-30.

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