/**
 * M-BUG-20 — shared implementation-log clobbering under parallel agents.
 *
 * implement.md step 4 spawns implementer agents in parallel batches, and every
 * agent appends its result to the SAME implementation-log.md. Dogfooding
 * (2026-07-17, throwaway linkedin-posts copy) showed agents satisfying
 * "Append result to:" with a full-file Write: each agent read the log, added
 * its entry, and wrote the whole file back — the last writer silently
 * clobbered 4 of 6 entries.
 *
 * Contract: both the command template and the agent prompt must pin the append
 * mechanism — Bash `>>`, never the Write/Edit tool — on the shared log.
 */

import { test } from 'node:test';
import { strict as assert } from 'node:assert';
import { readFile } from 'node:fs/promises';
import { resolve, dirname } from 'node:path';
import { fileURLToPath } from 'node:url';

const __dirname = dirname(fileURLToPath(import.meta.url));
const ROOT = resolve(__dirname, '..', '..');

const APPEND_MECHANISM_REGEX = />>/;
const FORBID_WRITE_TOOL_REGEX = /never[^.\n]*\bwrite\b[^.\n]*tool|\bwrite\b[^.\n]*tool[^.\n]*never/i;

test('implement.md: agent-spawn template pins Bash >> append on the shared log', async () => {
  const content = await readFile(resolve(ROOT, 'commands', 'implement.md'), 'utf-8');
  assert.match(content, APPEND_MECHANISM_REGEX,
    'implement.md must instruct appending to implementation-log.md with Bash >>');
  assert.match(content, FORBID_WRITE_TOOL_REGEX,
    'implement.md must forbid the Write tool on the shared implementation log');
});

test('implementer-agent.md: output section pins Bash >> append and forbids Write tool on the log', async () => {
  const content = await readFile(resolve(ROOT, 'agents', 'implementer-agent.md'), 'utf-8');
  assert.match(content, APPEND_MECHANISM_REGEX,
    'implementer-agent.md must instruct appending to the log with Bash >>');
  assert.match(content, FORBID_WRITE_TOOL_REGEX,
    'implementer-agent.md must forbid the Write tool on the shared implementation log');
});