import { TrimCompressor } from 'slimcontext';
import {
TrimMessagesArgsSchema,
SlimContextError,
MCPToolResult,
} from '../types/index.js';
export async function handleTrimMessages(
args: unknown
): Promise<MCPToolResult> {
try {
const validatedArgs = TrimMessagesArgsSchema.parse(args);
const trimCompressor = new TrimCompressor({
maxModelTokens: validatedArgs.maxModelTokens,
thresholdPercent: validatedArgs.thresholdPercent,
minRecentMessages: validatedArgs.minRecentMessages,
});
const compressedMessages = await trimCompressor.compress(
validatedArgs.messages.map((msg) => ({
...msg,
role: msg.role === 'human' ? ('user' as const) : msg.role,
}))
);
const originalCount = validatedArgs.messages.length;
const compressedCount = compressedMessages.length;
const removedCount = originalCount - compressedCount;
return {
content: [
{
type: 'text',
text: JSON.stringify(
{
success: true,
original_message_count: originalCount,
compressed_message_count: compressedCount,
messages_removed: removedCount,
compression_ratio: compressedCount / originalCount,
compressed_messages: compressedMessages,
},
null,
2
),
},
],
};
} catch (error) {
const errorMessage =
error instanceof Error ? error.message : 'Unknown error occurred';
return {
content: [
{
type: 'text',
text: JSON.stringify(
{
success: false,
error: errorMessage,
error_type:
error instanceof SlimContextError
? 'SlimContextError'
: 'UnknownError',
},
null,
2
),
},
],
};
}
}
