/**
* Modification shortcut tools — convenience wrappers for common rule patterns.
*/
import type { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { z } from "zod";
import { proxyManager } from "../state.js";
import type { RuleMatcher, RuleHandler } from "../state.js";
export function registerModificationTools(server: McpServer): void {
server.tool(
"proxy_inject_headers",
"Add or overwrite headers on matching traffic. Creates a passthrough rule with header transforms.",
{
hostname: z.string().optional().describe("Hostname to match (optional)"),
url_pattern: z.string().optional().describe("URL regex pattern to match (optional)"),
headers: z.record(z.string().nullable()).describe("Headers to inject (key-value pairs, set value to null to delete a header)"),
direction: z.enum(["request", "response", "both"]).optional().default("request")
.describe("Where to inject: request, response, or both"),
priority: z.number().optional().default(50).describe("Rule priority (default: 50)"),
},
async ({ hostname, url_pattern, headers, direction, priority }) => {
try {
const matcher: RuleMatcher = {};
if (hostname) matcher.hostname = hostname;
if (url_pattern) matcher.urlPattern = url_pattern;
const handler: RuleHandler = { type: "passthrough" };
if (direction === "request" || direction === "both") {
handler.transformRequest = { updateHeaders: headers };
}
if (direction === "response" || direction === "both") {
handler.transformResponse = { updateHeaders: headers };
}
const rule = await proxyManager.addRule({
priority,
enabled: true,
description: `Inject headers: ${Object.keys(headers).join(", ")} (${direction})`,
matcher,
handler,
});
return {
content: [{
type: "text",
text: JSON.stringify({ status: "success", rule_id: rule.id, description: rule.description }),
}],
};
} catch (e) {
return { content: [{ type: "text", text: JSON.stringify({ status: "error", error: String(e) }) }] };
}
},
);
server.tool(
"proxy_rewrite_url",
"Rewrite request URLs matching a pattern. Creates a passthrough rule with body match-replace on the URL.",
{
match_pattern: z.string().describe("Regex pattern to match in URLs"),
replace_with: z.string().describe("Replacement string"),
hostname: z.string().optional().describe("Limit to this hostname"),
priority: z.number().optional().default(50).describe("Rule priority (default: 50)"),
},
async ({ match_pattern, replace_with, hostname, priority }) => {
try {
const matcher: RuleMatcher = {};
if (hostname) matcher.hostname = hostname;
matcher.urlPattern = match_pattern;
const handler: RuleHandler = {
type: "passthrough",
transformRequest: {
matchReplaceBody: [[match_pattern, replace_with]],
},
};
const rule = await proxyManager.addRule({
priority,
enabled: true,
description: `URL rewrite: ${match_pattern} → ${replace_with}`,
matcher,
handler,
});
return {
content: [{
type: "text",
text: JSON.stringify({ status: "success", rule_id: rule.id, description: rule.description }),
}],
};
} catch (e) {
return { content: [{ type: "text", text: JSON.stringify({ status: "error", error: String(e) }) }] };
}
},
);
server.tool(
"proxy_mock_response",
"Return a mock response for matched requests. Creates a mock rule.",
{
method: z.string().optional().describe("HTTP method to match (optional)"),
url_pattern: z.string().optional().describe("URL regex pattern to match (optional)"),
hostname: z.string().optional().describe("Hostname to match (optional)"),
status: z.number().describe("Response status code"),
body: z.string().optional().default("").describe("Response body"),
content_type: z.string().optional().default("application/json").describe("Content-Type header"),
priority: z.number().optional().default(10).describe("Rule priority (default: 10, high priority)"),
},
async ({ method, url_pattern, hostname, status, body, content_type, priority }) => {
try {
const matcher: RuleMatcher = {};
if (method) matcher.method = method;
if (url_pattern) matcher.urlPattern = url_pattern;
if (hostname) matcher.hostname = hostname;
const handler: RuleHandler = {
type: "mock",
status,
body: body ?? "",
headers: { "content-type": content_type ?? "application/json" },
};
const rule = await proxyManager.addRule({
priority,
enabled: true,
description: `Mock ${status} for ${method || "ANY"} ${url_pattern || hostname || "*"}`,
matcher,
handler,
});
return {
content: [{
type: "text",
text: JSON.stringify({ status: "success", rule_id: rule.id, description: rule.description }),
}],
};
} catch (e) {
return { content: [{ type: "text", text: JSON.stringify({ status: "error", error: String(e) }) }] };
}
},
);
}
