Row 332 R2 (#1830): lead correction for the GPT review F1 and F2

F1 fixed in da1f0ceda, with the federation acceptance red and green runs and
the script suite results. F2: the invalid-proxy-context BundleError is raised
at launcher.mjs:569, outside the try at :655, so :686 never sees it;
fromSession maps it at :1199 and launchPm rethrows it at :1215.

agents/fethry/work/queue-332/BUILD.md

@@ -641,3 +641,29 @@ No test process of mine is left running, checked through the /proc cwd links of
 commit the node_modules links (`node_modules` and `packages/webui/node_modules`) and the TMPDIR come out, as the
 brief asks. The logs behind these tables lived in that TMPDIR and are not kept. The counts and times here are
 copied from them.
+
+## Lead correction after the R2 GPT review (2026-11-02)
+
+Written by the lead (T3 c5c1e8ba). The GPT review of 6e9f3d723 asked for changes with two findings. This section
+corrects the R2 text above; the earlier sections stay as written.
+
+F1 (P2), fixed by the lead in da1f0ceda. `packages/cli/tests/federation-acceptance.test.mjs:122` built each
+host's env from HOME, PATH, TMPDIR, MOSAIC_CONFIG and NODE_EXTRA_CA_CERTS only. With no pi key there, the R1
+preflight refused the assistant launch with `no-session-credential` and the RESULT wait failed. The cli suite does
+not run this file; `scripts/test-federation-acceptance.sh` does. The fix adds `ZAI_API_KEY: 'fx332-fake-pi'`,
+the same fake value `FAKE_PI_KEY` in helpers.mjs holds. `bash scripts/test-federation-acceptance.sh` on 6e9f3d723:
+rc 1, 21:42:03Z to 21:42:26Z, "start refused: no-session-credential". With the fix: rc 0, 21:42:34Z to
+21:42:39Z, pass 1, fail 0. Every `scripts/test-*.sh` then ran on the fixed tree, all rc 0: auth 15/0, conductor
+17/0, config 55/0, discord 82/0, extension-package 18/0, federation 1/0, foundation 44/0, land-work 86/0,
+push-check rc 0, queue 156/0 and 28/0, release 15/0, task 92/0. test-task skips the live provider cases (row 244)
+as the batch 2b gate did; its count is 3 lower than that gate because ee151685e (#156) added cases after base
+09a847eda.
+
+F2 (P3), a wrong citation in the R2 text above. It says the launcher catch at `launcher.mjs:686` turns the new
+`invalid-proxy-context` BundleError into launch-failed. That catch never sees it. `buildBundle` runs at
+`launcher.mjs:569`, before the `try` at `:655` that holds the `:686` line. The error leaves `start()` as a plain
+BundleError. `fromSession` maps any non-Refusal to `launch-failed` at `:1199`. `launchPm` rethrows a non-Refusal
+at `:1215`, so a PM launch fails with the BundleError itself, whose code is now `invalid-proxy-context` instead of
+R1's default `bundle-refused`. The only other `proxy-` prefix check, `launcher.mjs:365`, wraps `sessionModel`
+and never sees an error from `buildBundle`. So the prefix choice changes no path today. A session launch ends as
+launch-failed, as in R1. No test asserts what a PM launch reports for this error.