Your subagents are expensive.
Ours are guarded.
The April 2026 Tokenocalypse exposed the gap: every existing tool reports cost after the burn. Septim Subagent Cost Guard fires a PreToolUse hook that halts runaway subagents mid-flight when your budget threshold is breached. Reserves your launch-day founding-rate price.
Not yet buyable — join the launch list below. You pay $0 now and receive a single email with the Stripe link the moment we ship. Cancel anytime before paying.
Every existing tool is a post-mortem reporter.
What they do · after the burn
ccusage, Claude Code Usage Monitor, Anthropic workspace limits — all of these tell you after your subagent spent $4,700.
- Dashboard refreshes every 15 minutes
- Workspace limits trigger on monthly cap, not per-session
- Alerts arrive in email 20 minutes after spike
- No mechanism to kill the live agent loop
- You check after the invoice lands
What we do · mid-flight
Cost Guard runs as a PreToolUse hook. Your budget threshold is checked before each agent tool call.
- Threshold check on every subagent tool call
- Per-session, per-run, per-day budget ceilings
- Hard halt: agent terminates with a logged reason
- Optional Slack DM, email, or webhook ping
- Reads your local ~/.claude/projects/**/*.jsonl for accurate token accounting
Three install commands. One never-again.
Install once per machine
Single binary drop into ~/.claude/hooks/. No daemon. No always-on process. No Docker.
Set your ceilings
One YAML file at ~/.claude/cost-guard.yaml: per-session, per-run, per-day. Override per-agent by name. Defaults are sane.
Walk away safely
Agent starts, hits threshold, exits cleanly with a logged reason. Your budget is the ceiling, not the floor.
Optional: notify
Wire a Slack webhook or email address. Get a three-line summary: "Agent X halted at 112% of session budget. 3 tool calls. Stack trace attached."
$29 for the first 50 buyers. $49 after.
You pay $0 now. Join the list. We ship May 2026. You get a single email with your Stripe link at the founding rate. Cancel anytime by replying to that email.
What real devs are asking.
Is this a wrapper on Anthropic’s rate limits?
No. Anthropic limits are enforced server-side and trigger after a 10-30 second window. Cost Guard enforces your own budget threshold locally, before the tool call goes out.
Does this work with parallel subagents?
Yes — that’s the primary use case. The hook tracks cumulative cost across every concurrent subagent in the same Claude Code session.
Does it send my data to Septim?
No. The hook runs entirely on your machine. It reads your local JSONL session files and fires the PreToolUse hook in-process. No telemetry, no callback.
When does it ship?
May 2026. The wait-list locks your $29 founding rate. We email you once with the Stripe link when it’s ready. No autobill, no drip campaign.