ox-session-start

A command that starts recording the current coding-agent session in the project's SageOx ledger. It also returns instructions and any one-time notice that the agent must handle.

In plain words
What is it for?
Starting an agent session, reading its recording notice, and applying the returned guidance about plans, session boundaries, and troubleshooting.
Why use it?
It provides a consistent way to begin session recording and pass project-specific guidance to the agent. This avoids losing required setup or transparency messages at the start of a session.

Command for Claude Code

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 commands/sageox/ox/ox-session-start
Clone the repo
git clone --depth 1 https://github.com/sageox/ox

Made for: Claude Code.

Per session 0 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 198 The whole file, excluding the scripts and references it only reads on demand.
Security scan C 1 finding. 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 $0.00000 $0.00198
Opus 5 $0.00000 $0.00099
Sonnet 5 $0.00000 $0.00040
Haiku 4.5 $0.00000 $0.00020

Measured 3d ago against content hash b5223b9408bb, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade C, and why

ox-session-start scanned grade C with 1 finding 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.

Hidden instructionshighPrompt injection

Directives inside HTML comments, invisible characters or bidirectional overrides are read by the model and not by the person reviewing the file.

<!-- Keep this file thin. Behavioral guidance (use-when, common-issues, errors) belongs in the ox CLI JSON output (guidance field), not here. Skills are agent-specific wrappers; ox serves all agents (Codex, etc.). Except
.claude/commands/ox-session-start.md · 16 lines

What it actually says

Start recording this agent session to the project ledger.

Post-Command (REQUIRED)

After the command completes, check the JSON output:

  • notice: If present, display the notice text to the user verbatim. This is a one-time transparency notice about session recording.
  • guidance: Follow this guidance throughout the session. It contains instructions about plan capture, session boundaries, and troubleshooting.

$ox agent session start

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 · 16 lines · 0 tokens per session scan C b5223b9408bb

Subscribe to this mod's changes

ox-session-start is a command published in the GitHub repository sageox/ox (50 stars, last pushed 4d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 198 tokens. A static security scan graded it C with 1 finding (hidden instructions). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.