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.
npx skills add arcjet/arcjet-plugin --skill integrate-arcjet-guard-claude-agent-sdk-pygit clone --depth 1 https://github.com/arcjet/arcjet-pluginWrote 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/skills/arcjet/arcjet-plugin/integrate-arcjet-guard-claude-agent-sdk-py)<a href="https://agentmods.dev/skills/arcjet/arcjet-plugin/integrate-arcjet-guard-claude-agent-sdk-py"><img src="https://agentmods.dev/badge/skills/arcjet/arcjet-plugin/integrate-arcjet-guard-claude-agent-sdk-py/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/skills/arcjet/arcjet-plugin/integrate-arcjet-guard-claude-agent-sdk-py"><img src="https://agentmods.dev/badge/skills/arcjet/arcjet-plugin/integrate-arcjet-guard-claude-agent-sdk-py.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 | $0.00106 | $0.02699 |
| Opus 5 | $0.00053 | $0.01350 |
| Sonnet 5 | $0.00021 | $0.00540 |
| Haiku 4.5 | $0.00011 | $0.00270 |
Grade A, and why
integrate-arcjet-guard-claude-agent-sdk-py 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 5d 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.
This is a copy
92% identical to integrate-arcjet-guard-claude-agent-sdk-py — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 236 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Integrate Arcjet Guard into the Python Claude Agent SDK
arcjet.guard.claude_agent_sdk wraps the agent's existing Arcjet client.
It never talks to the Arcjet API itself. Shared Guard fundamentals
(client, rules, labels, decisions, capture, registration) live in
../arcjet/references/guards_python.md.
Load that reference for anything that is not Claude Agent SDK-specific.
Official claude-agent-sdk>=0.2.127,<1 only — not the JS
@anthropic-ai/claude-agent-sdk adapter
(@arcjet/guard/claude-agent-sdk/v0, docs
https://docs.arcjet.com/guards/claude-agent-sdk/), not Vercel AI, not
community forks, and not Claude Managed Agents hosted
client.beta.sessions (arcjet.guard.claude_managed_agents). Importing
arcjet.guard.claude_agent_sdk does not load LangChain, CrewAI, or the
JS adapter. The extra is safe (no chromadb).
Exports: guard_tool, guard_hooks, claude_agent_context. Authored
@tool + create_sdk_mcp_server for tools you own; guard_hooks for
inbound UserPromptSubmit and unwrapped built-ins / MCP PreToolUse.
There is no inbound helper and no guard_can_use_tool.
Three surfaces, one decision rule:
- An authored
@tool→guard_tool. Denial is JSON-in-content +is_error: True. Python does not forwardstructuredContent(that is the JS adapter). Do not raise. - Inbound text →
guard_hooksUserPromptSubmit(decision: "block"). That is the only place a turn can be declined before the model reads the prompt. - Built-ins / unwrapped MCP →
guard_hooksPreToolUse(permissionDecision: "deny").PostToolUseis capture only. - Correlation →
claude_agent_contextreads a caller-owned UUIDsession_id. It never mints.
Docs: https://docs.arcjet.com/guards/claude-agent-sdk/.
Unwrapped tools deny on PreToolUse via guard_hooks
Built-ins (Bash, Write, …) and MCP tools you did not pass through
guard_tool have no authored handler. PreToolUse is the only deny for
those. PostToolUse cannot undo a tool that already ran. List every
guard_tool wrapper in exclude or each authored tool is guarded twice
(two round trips, two quota units). Entries match the reported name:
pass {"server": "support", "name": "lookup_order"} for an authored MCP
tool (it resolves to mcp__support__lookup_order) and a bare string for
a built-in such as "Bash". A bare authored name deliberately does not
match every server's tool of that name.
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.
- 5d ago Changed · +7 lines 224fa7cced85
- 6d ago First seen · 229 lines · 106 tokens per session scan A ace4d0e680b8
integrate-arcjet-guard-claude-agent-sdk-py is a skill published in the GitHub repository arcjet/arcjet-plugin (1 stars, last pushed 6d ago), licensed Apache-2.0. It adds 106 tokens to every session and 2,699 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it A with 0 findings. It is 92% identical to integrate-arcjet-guard-claude-agent-sdk-py, differing in 0 lines, and is treated as a copy.
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