Borrowing it
Nothing to install: this file belongs to provos/ironcurtain. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/provos/ironcurtain/master/.github/instructions/session.instructions.mdgit clone --depth 1 https://github.com/provos/ironcurtainWrote 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.
[](https://agentmods.dev/instructions/provos/ironcurtain/session)<a href="https://agentmods.dev/instructions/provos/ironcurtain/session"><img src="https://agentmods.dev/badge/instructions/provos/ironcurtain/session/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.
<a href="https://agentmods.dev/instructions/provos/ironcurtain/session"><img src="https://agentmods.dev/badge/instructions/provos/ironcurtain/session.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00366 | $0.00366 |
| Opus 5.5 | $0.00146 | $0.00146 |
| Sonnet 5.5 | $0.00073 | $0.00073 |
| Haiku 4.5 | $0.00037 | $0.00037 |
Grade A, and why
ironcurtain session.instructions.md 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 1mo 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.
What it actually says
Session Review Rules
The session layer manages the agent conversation lifecycle, including the AI SDK integration and escalation IPC.
Mandatory Checks
generateText()must usestopWhen: [stepCountIs(n)], NOTmaxSteps. ThemaxStepsAPI does not exist in AI SDK v6.tool()must useinputSchema, NOTparameters. TheparametersAPI does not exist in AI SDK v6.- Tool call results use
toolCalls[].input, NOTtoolCalls[].args. - The tool type is
ToolSet, NOTCoreTool. SessionStatusfollows a linear state machine:initializing -> ready -> processing -> ready -> closed. Theprocessingstate prevents reentrantsendMessage()calls. Do not remove or bypass this guard.- Escalation resolution writes a JSON file to the escalation directory. The file naming convention (
response-{escalationId}.json) must match what the proxy expects. Changing the naming breaks the IPC contract. writeUserContext()writes the user's message for the auto-approver and must usetry/catchwith silent failure. The escalation directory may not exist yet.- On
sendMessage()failure, the message history must be truncated back tomessageCountBeforeto avoid leaving partial state. Removing this truncation corrupts the conversation history. - User-facing output MUST use
process.stdout.write()orprocess.stderr.write(), NOTconsole.log(). The logger module intercepts console methods and redirects to the session log file. - The
SandboxFactorytype exists for test injection. The default factory creates a real sandbox; tests provide a mock. Do not remove this abstraction.
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.
- 1mo ago First seen · 21 lines · 366 tokens per session scan A 7f2b211988a0
ironcurtain session.instructions.md is an instructions file published in the GitHub repository provos/ironcurtain (615 stars, last pushed yesterday), licensed Apache-2.0. It adds 366 tokens to every session, about $0.0015 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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