app/lib/mcp/call-log.ts

Functions

Imports

It imports app/db/schema.ts, app/lib/ai.server.ts. Imported by app/lib/mcp/tools.ts.

Source

1// The append-only log of every tool call (ruling capsid/rulings/mcp-2026-10-10.md, rule 12.4):
2// caller, arguments, result. The table (0012_mcp_calls.sql) refuses UPDATE and DELETE itself.
3//
4// The row is written after the call returns, with what the client was told. A failed write never
5// changes the answer the client gets (the call already happened), and it is never silent: it goes to
6// Workers Logs with the tool and the caller, so the gap in the table is itself on record.
7
8import { drizzle } from "drizzle-orm/d1";
9
10import { mcpCalls } from "~/db/schema";
11import type { AiSession } from "~/lib/ai.server";
12
13/** The most of the arguments and of the result a row keeps. */
14const ARGUMENTS_LIMIT = 8_000;
15const RESULT_LIMIT = 2_000;
16
17/** Each long string cut to a preview, so a 500,000-character draft is logged by its start and its length. */
18function shorten(args: Record<string, unknown>): { text: string; truncated: boolean } {
19  let truncated = false;
20  const shortened = JSON.stringify(args, (_key, value: unknown) => {
21    if (typeof value === "string" && value.length > 1_000) {
22      truncated = true;
23      return `${value.slice(0, 1_000)}... [${value.length} characters]`;
24    }
25    return value;
26  });
27  if (shortened.length > ARGUMENTS_LIMIT) return { text: `${shortened.slice(0, ARGUMENTS_LIMIT)}... [cut]`, truncated: true };
28  return { text: shortened, truncated };
29}
30
31export async function logCall(
32  db: D1Database,
33  session: AiSession,
34  call: { tool: string; args: Record<string, unknown>; ok: boolean; result: string },
35): Promise<void> {
36  const args = shorten(call.args);
37  try {
38    await drizzle(db)
39      .insert(mcpCalls)
40      .values({
41        personId: session.viewer.id,
42        caller: session.viewer.email,
43        client: session.client,
44        tool: call.tool,
45        arguments: args.text,
46        argumentsTruncated: args.truncated,
47        outcome: call.ok ? "ok" : "refused",
48        result: call.result.length > RESULT_LIMIT ? `${call.result.slice(0, RESULT_LIMIT)}... [cut]` : call.result,
49      })
50      .run();
51  } catch (error) {
52    console.error(JSON.stringify({ mcp: "call-log-failed", tool: call.tool, caller: session.viewer.email, client: session.client, error: String(error) }));
53  }
54}