oppi.li
source dump of claude code
1/**
2 * Pure string utility functions for MCP tool/server name parsing.
3 * This file has no heavy dependencies to keep it lightweight for
4 * consumers that only need string parsing (e.g., permissionValidation).
5 */
6
7import { normalizeNameForMCP } from './normalization.js'
8
9/*
10 * Extracts MCP server information from a tool name string
11 * @param toolString The string to parse. Expected format: "mcp__serverName__toolName"
12 * @returns An object containing server name and optional tool name, or null if not a valid MCP rule
13 *
14 * Known limitation: If a server name contains "__", parsing will be incorrect.
15 * For example, "mcp__my__server__tool" would parse as server="my" and tool="server__tool"
16 * instead of server="my__server" and tool="tool". This is rare in practice since server
17 * names typically don't contain double underscores.
18 */
19export function mcpInfoFromString(toolString: string): {
20 serverName: string
21 toolName: string | undefined
22} | null {
23 const parts = toolString.split('__')
24 const [mcpPart, serverName, ...toolNameParts] = parts
25 if (mcpPart !== 'mcp' || !serverName) {
26 return null
27 }
28 // Join all parts after server name to preserve double underscores in tool names
29 const toolName =
30 toolNameParts.length > 0 ? toolNameParts.join('__') : undefined
31 return { serverName, toolName }
32}
33
34/**
35 * Generates the MCP tool/command name prefix for a given server
36 * @param serverName Name of the MCP server
37 * @returns The prefix string
38 */
39export function getMcpPrefix(serverName: string): string {
40 return `mcp__${normalizeNameForMCP(serverName)}__`
41}
42
43/**
44 * Builds a fully qualified MCP tool name from server and tool names.
45 * Inverse of mcpInfoFromString().
46 * @param serverName Name of the MCP server (unnormalized)
47 * @param toolName Name of the tool (unnormalized)
48 * @returns The fully qualified name, e.g., "mcp__server__tool"
49 */
50export function buildMcpToolName(serverName: string, toolName: string): string {
51 return `${getMcpPrefix(serverName)}${normalizeNameForMCP(toolName)}`
52}
53
54/**
55 * Returns the name to use for permission rule matching.
56 * For MCP tools, uses the fully qualified mcp__server__tool name so that
57 * deny rules targeting builtins (e.g., "Write") don't match unprefixed MCP
58 * replacements that share the same display name. Falls back to `tool.name`.
59 */
60export function getToolNameForPermissionCheck(tool: {
61 name: string
62 mcpInfo?: { serverName: string; toolName: string }
63}): string {
64 return tool.mcpInfo
65 ? buildMcpToolName(tool.mcpInfo.serverName, tool.mcpInfo.toolName)
66 : tool.name
67}
68
69/*
70 * Extracts the display name from an MCP tool/command name
71 * @param fullName The full MCP tool/command name (e.g., "mcp__server_name__tool_name")
72 * @param serverName The server name to remove from the prefix
73 * @returns The display name without the MCP prefix
74 */
75export function getMcpDisplayName(
76 fullName: string,
77 serverName: string,
78): string {
79 const prefix = `mcp__${normalizeNameForMCP(serverName)}__`
80 return fullName.replace(prefix, '')
81}
82
83/**
84 * Extracts just the tool/command display name from a userFacingName
85 * @param userFacingName The full user-facing name (e.g., "github - Add comment to issue (MCP)")
86 * @returns The display name without server prefix and (MCP) suffix
87 */
88export function extractMcpToolDisplayName(userFacingName: string): string {
89 // This is really ugly but our current Tool type doesn't make it easy to have different display names for different purposes.
90
91 // First, remove the (MCP) suffix if present
92 let withoutSuffix = userFacingName.replace(/\s*\(MCP\)\s*$/, '')
93
94 // Trim the result
95 withoutSuffix = withoutSuffix.trim()
96
97 // Then, remove the server prefix (everything before " - ")
98 const dashIndex = withoutSuffix.indexOf(' - ')
99 if (dashIndex !== -1) {
100 const displayName = withoutSuffix.substring(dashIndex + 3).trim()
101 return displayName
102 }
103
104 // If no dash found, return the string without (MCP)
105 return withoutSuffix
106}