blast-radius
Holds risky Bash commands, shows what they would hit, and waits for Proceed or Cancel.
newpanebandguardprocess
Holds risky Bash commands, shows what they would hit, and waits for Proceed or Cancel.
hooks/blast-radius.tsx 148 lines1import { atom, read, update } from "claude-code";
2import type { EngineInterface, Register } from "claude-code";
3
4import type { BlastRadiusHeld, BlastRadiusRisk } from "../types";
5import { classify } from "./classify";
6
7const PANE = "blast-radius";
8const SHOWN = 8;
9const held = atom({ plugin: "blast-radius", key: "held" } as const, null);
10
11// The decision lives in the module, not in $.state: every $.state.get of one
12// dispatch reads one moment, so the waiting hook would never see a press.
13type Decision = "proceed" | "cancel";
14let isHolding = false;
15let decision: Decision | null = null;
16
17export const register: Register = (on) => {
18 on("tool.call", { tool: "Bash" }, async ($, e, next) => {
19 const command = String(e.command ?? "");
20 const risk = classify(command);
21 if (risk === null) return next(e);
22
23 if (isHolding) {
24 return { deny: "Blast Radius is already holding another command; run this one after it." };
25 }
26
27 isHolding = true;
28 decision = null;
29 try {
30 const report = await measure($, risk, await $.session.cwd());
31 await update($, held, (): BlastRadiusHeld => ({ command, ...report, where: "pane" }));
32 const opened = await $.ui.open({ id: PANE, title: "Blast Radius", focus: true });
33 if (!opened.isPlaced) await update($, held, (cur) => (cur ? { ...cur, where: "band" as const } : cur));
34
35 // A `$` call in flight does not count against the hook's budget, so
36 // short sleeps let us wait on the person for as long as they need.
37 while (decision === null && !next.signal.aborted) {
38 await $.process.run(["sleep", "0.25"]);
39 }
40 } finally {
41 isHolding = false;
42 await update($, held, () => null);
43 await $.ui.close({ id: PANE });
44 }
45
46 if (decision === "proceed") return next(e);
47 return {
48 deny: `Blast Radius held this command and the user chose not to run it: ${command}. Ask them how to proceed instead of retrying.`,
49 };
50 });
51
52 // Closing the pane by hand (Escape, its close mark) counts as Cancel.
53 on("ui.close", { id: PANE }, async ($, e, next) => {
54 if (e.origin.kind === "person") decide("cancel");
55 return next(e);
56 });
57
58 on("ui.render", { component: "Pane", requestId: PANE }, async ($, e) => {
59 const { Box, Text } = $.ui.resolve(e);
60 const current = await read($, held);
61 if (current === null) return <Box><Text dimColor>Nothing held.</Text></Box>;
62 return warning($, e, current);
63 });
64
65 on("ui.render", { component: "AbovePrompt" }, async ($, e, next) => {
66 const current = await read($, held);
67 if (current === null || current.where !== "band" || e.props.hasSurvey) return next(e);
68 return warning($, e, current);
69 });
70};
71
72function warning($: EngineInterface, e: Parameters<EngineInterface["ui"]["resolve"]>[0], shown: BlastRadiusHeld) {
73 const { Box, Text, Button } = $.ui.resolve(e);
74 return (
75 <Box flexDirection="column" paddingX={1}>
76 <Text color="red" bold>⚠ {shown.title}</Text>
77 <Text dimColor>$ {shown.command}</Text>
78 {shown.lines.slice(0, SHOWN).map((line) => <Text> {line}</Text>)}
79 {shown.lines.length > SHOWN && <Text dimColor> … and {shown.lines.length - SHOWN} more</Text>}
80 <Box flexDirection="row" gap={2} marginTop={1}>
81 <Button key="proceed" label="Proceed" hotkey="1" plain onPress={() => decide("proceed")} />
82 <Button key="cancel" label="Cancel" hotkey="2" plain onPress={() => decide("cancel")} />
83 </Box>
84 </Box>
85 );
86}
87
88function decide(choice: Decision) {
89 if (isHolding && decision === null) decision = choice;
90}
91
92type Report = { title: string; lines: string[] };
93
94async function measure($: EngineInterface, risk: BlastRadiusRisk, cwd: string): Promise<Report> {
95 const run = async (argv: string[]) => {
96 try {
97 const r = await $.process.run(argv, { cwd });
98 return r.exitCode === 0 ? r.stdout.split("\n").filter(Boolean) : null;
99 } catch {
100 return null;
101 }
102 };
103
104 switch (risk.kind) {
105 case "rm": {
106 if (risk.targets.length === 0) return { title: "Recursive force delete", lines: [] };
107 const entries = (await run(["find", ...risk.targets])) ?? [];
108 const sizes = (await run(["du", "-sh", ...risk.targets])) ?? [];
109 const dirty = (await run(["git", "status", "--porcelain", "--", ...risk.targets])) ?? [];
110 return {
111 title: `Deletes ${entries.length} files and folders`,
112 lines: [
113 ...sizes.map((s) => s.replace(/\s+/, " ")),
114 ...(dirty.length > 0 ? [`${dirty.length} of them have uncommitted changes:`, ...dirty] : []),
115 ],
116 };
117 }
118 case "git-reset-hard": {
119 const dirty = (await run(["git", "status", "--porcelain", "--untracked-files=no"])) ?? [];
120 return {
121 title: dirty.length > 0 ? `Discards uncommitted changes in ${dirty.length} files` : "Resets the branch (working tree is clean)",
122 lines: dirty,
123 };
124 }
125 case "git-clean": {
126 const extra = risk.flags.filter((f) => /^-[a-zA-Z]*[dxX]/.test(f)).flatMap((f) => f.slice(1).replace(/[^dxX]/g, "").split("").map((c) => `-${c}`));
127 const gone = (await run(["git", "clean", "-n", ...extra])) ?? [];
128 return { title: `Removes ${gone.length} untracked files`, lines: gone.map((l) => l.replace(/^Would remove /, "")) };
129 }
130 case "force-push": {
131 const lost = await run(["git", "log", "--oneline", "HEAD..@{u}"]);
132 if (lost === null) return { title: "Force push (no upstream to compare)", lines: [] };
133 return {
134 title: lost.length > 0 ? `Overwrites ${lost.length} commits on the remote` : "Force push (remote has nothing that would be lost)",
135 lines: lost,
136 };
137 }
138 case "migration": {
139 if (risk.tool === "django") {
140 const plan = (await run(["python", "manage.py", "showmigrations", "--plan"])) ?? [];
141 const pending = plan.filter((l) => l.startsWith("[ ]")).map((l) => l.slice(4));
142 return { title: `Applies ${pending.length} pending migrations`, lines: pending };
143 }
144 return { title: "Runs database migrations", lines: ["Check which database this targets before going on."] };
145 }
146 }
147}
148hooks/classify.ts 52 lines1import type { BlastRadiusRisk } from "../types";
2
3// Reads the command text only: `$(…)`, aliases and scripts that call rm
4// themselves slip past. A reminder, not a security boundary.
5export function classify(command: string): BlastRadiusRisk | null {
6 for (const segment of command.split(/&&|\|\||[;|\n]/)) {
7 const words = segment.trim().split(/\s+/).map(unquote).filter(Boolean);
8 while (words[0] === "sudo" || /^\w+=/.test(words[0] ?? "")) words.shift();
9 const risk = classifyWords(words);
10 if (risk) return risk;
11 }
12 return null;
13}
14
15function classifyWords(words: string[]): BlastRadiusRisk | null {
16 const [cmd, sub, ...rest] = words;
17 const flags = words.filter((w) => w.startsWith("-"));
18
19 if (cmd === "rm") {
20 const isRecursive = flags.some((f) => f === "--recursive" || /^-[a-zA-Z]*[rR]/.test(f));
21 const isForced = flags.some((f) => f === "--force" || /^-[a-zA-Z]*f/.test(f));
22 if (!isRecursive || !isForced) return null;
23 return { kind: "rm", targets: words.slice(1).filter((w) => !w.startsWith("-")) };
24 }
25
26 if (cmd === "git") {
27 if (sub === "reset" && rest.includes("--hard")) return { kind: "git-reset-hard" };
28 if (sub === "clean" && rest.some((f) => /^-[a-zA-Z]*f/.test(f) || f === "--force")) {
29 return { kind: "git-clean", flags: rest.filter((f) => f.startsWith("-")) };
30 }
31 if (sub === "push" && rest.some((f) => f === "-f" || f.startsWith("--force") || /^\+/.test(f))) {
32 return { kind: "force-push" };
33 }
34 return null;
35 }
36
37 if (words.includes("manage.py") && words.includes("migrate")) return { kind: "migration", tool: "django" };
38 if (/^(rails|rake|bin\/rails)$/.test(cmd ?? "") && /^db:(migrate|rollback|reset|drop)/.test(sub ?? "")) {
39 return { kind: "migration", tool: "other" };
40 }
41 if (words.some((w) => w === "migrate" || w.startsWith("migrate:")) && /^(npx|bunx|prisma|knex|flyway|alembic|sequelize)$/.test(cmd ?? "")) {
42 return { kind: "migration", tool: "other" };
43 }
44 if (cmd === "alembic" && (sub === "upgrade" || sub === "downgrade")) return { kind: "migration", tool: "other" };
45
46 return null;
47}
48
49function unquote(word: string) {
50 return word.replace(/^['"]|['"]$/g, "");
51}
52types/index.d.ts 20 lines1export type BlastRadiusRisk =
2 | { kind: "rm"; targets: string[] }
3 | { kind: "git-reset-hard" }
4 | { kind: "git-clean"; flags: string[] }
5 | { kind: "force-push" }
6 | { kind: "migration"; tool: "django" | "other" };
7
8export type BlastRadiusHeld = {
9 command: string;
10 title: string;
11 lines: string[];
12 where: "pane" | "band";
13};
14
15declare module "claude-code" {
16 interface PluginState {
17 "blast-radius": { held: BlastRadiusHeld | null };
18 }
19}
20