File size: 3,968 Bytes
064bfd6 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 | /**
* Pure string utility functions for MCP tool/server name parsing.
* This file has no heavy dependencies to keep it lightweight for
* consumers that only need string parsing (e.g., permissionValidation).
*/
import { normalizeNameForMCP } from './normalization.js'
/*
* Extracts MCP server information from a tool name string
* @param toolString The string to parse. Expected format: "mcp__serverName__toolName"
* @returns An object containing server name and optional tool name, or null if not a valid MCP rule
*
* Known limitation: If a server name contains "__", parsing will be incorrect.
* For example, "mcp__my__server__tool" would parse as server="my" and tool="server__tool"
* instead of server="my__server" and tool="tool". This is rare in practice since server
* names typically don't contain double underscores.
*/
export function mcpInfoFromString(toolString: string): {
serverName: string
toolName: string | undefined
} | null {
const parts = toolString.split('__')
const [mcpPart, serverName, ...toolNameParts] = parts
if (mcpPart !== 'mcp' || !serverName) {
return null
}
// Join all parts after server name to preserve double underscores in tool names
const toolName =
toolNameParts.length > 0 ? toolNameParts.join('__') : undefined
return { serverName, toolName }
}
/**
* Generates the MCP tool/command name prefix for a given server
* @param serverName Name of the MCP server
* @returns The prefix string
*/
export function getMcpPrefix(serverName: string): string {
return `mcp__${normalizeNameForMCP(serverName)}__`
}
/**
* Builds a fully qualified MCP tool name from server and tool names.
* Inverse of mcpInfoFromString().
* @param serverName Name of the MCP server (unnormalized)
* @param toolName Name of the tool (unnormalized)
* @returns The fully qualified name, e.g., "mcp__server__tool"
*/
export function buildMcpToolName(serverName: string, toolName: string): string {
return `${getMcpPrefix(serverName)}${normalizeNameForMCP(toolName)}`
}
/**
* Returns the name to use for permission rule matching.
* For MCP tools, uses the fully qualified mcp__server__tool name so that
* deny rules targeting builtins (e.g., "Write") don't match unprefixed MCP
* replacements that share the same display name. Falls back to `tool.name`.
*/
export function getToolNameForPermissionCheck(tool: {
name: string
mcpInfo?: { serverName: string; toolName: string }
}): string {
return tool.mcpInfo
? buildMcpToolName(tool.mcpInfo.serverName, tool.mcpInfo.toolName)
: tool.name
}
/*
* Extracts the display name from an MCP tool/command name
* @param fullName The full MCP tool/command name (e.g., "mcp__server_name__tool_name")
* @param serverName The server name to remove from the prefix
* @returns The display name without the MCP prefix
*/
export function getMcpDisplayName(
fullName: string,
serverName: string,
): string {
const prefix = `mcp__${normalizeNameForMCP(serverName)}__`
return fullName.replace(prefix, '')
}
/**
* Extracts just the tool/command display name from a userFacingName
* @param userFacingName The full user-facing name (e.g., "github - Add comment to issue (MCP)")
* @returns The display name without server prefix and (MCP) suffix
*/
export function extractMcpToolDisplayName(userFacingName: string): string {
// This is really ugly but our current Tool type doesn't make it easy to have different display names for different purposes.
// First, remove the (MCP) suffix if present
let withoutSuffix = userFacingName.replace(/\s*\(MCP\)\s*$/, '')
// Trim the result
withoutSuffix = withoutSuffix.trim()
// Then, remove the server prefix (everything before " - ")
const dashIndex = withoutSuffix.indexOf(' - ')
if (dashIndex !== -1) {
const displayName = withoutSuffix.substring(dashIndex + 3).trim()
return displayName
}
// If no dash found, return the string without (MCP)
return withoutSuffix
}
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