[HugoXK]

Fixes #1930
Owner: Dev
Written-by: Dev-1
Reviewer: Reviewer
Claim-Id: 9e7868090c3e4fe2bbd5bf4f740ffae2

Base / tip

Base: 42e6265
Tip SHA: d8a42ff
Verified commit: b0b882e64af8bf218c862cb0496424be76e45488 (tree 9277d9ce177479c768f2c39ab287cadafe1ed550; the pushed head is that same tree, rebuilt onto live main by the push path)

What changed

Seven host-side bounds truncated text with slice(0, max) before this PR, so a cap that fell inside a surrogate pair handed half of one to a prompt or a room line — or to fenceUntrusted's from="…" attribute. They now go through the shared cut from core/src/shared/text-boundary.js, and no cap changes:

Site	Bound
core/src/host/busy-ack.js:59 busy ack task text	600
core/src/host/busy-ack.js:63 busy ack message text	1,500
core/src/host/delivery.js:38 cleanName peer name	60
core/src/host/tools.js:89 list_bots group notice	100
core/src/host/tools.js:177 list_bots Bot job line	120
core/src/host/tools.js:743 group answer echo	300
core/src/host/tools.js:1031 rework line note	200

tools.js:653's .slice(0, 6) is an array count and is untouched; room-share.js and room-membership.js are not in this PR. Each site has one test that plants an emoji across its bound and asserts isWellFormed(), length <= max and a byte prefix — never "exactly max". Reverting a site to .slice makes its test red.

Ran

• node scripts/ds-bot-patches.mjs generate twice: patches/ds-bot byte-identical between runs (sha256 15fa84f9…), so the second run is a no-op
• node scripts/ds-bot-patches.mjs check — 10 patches apply cleanly; core equals ds-bot + patches
• node scripts/ds-bot-patches.mjs canonical — generate is a no-op
• TZ=UTC ARCH_DOCS_BASE=42e6265626521180e487ca70bb422968078c2a09 npm run verify — exit 0: core 2332, social 541, tree 127, timeline 135, workflow 336, .github/scripts 563, interop 37, live-e2e 24; arch-docs: OK (19 changed file(s))
• Red first, tests only with the source untouched: 4/4 fail in core/test/flybot.test.js, core/test/group-work.test.js and core/test/task-handoff-route.test.js; 2/2 fail in core/test/busy-ack.test.js and core/test/fence.test.js; all on isWellFormed()
• Mutation: reverting the four tools.js sites to .slice → 4/4 red; reverting busy-ack.js + delivery.js → 2/2 red; restored and rerun green

Not run

Smoke test (no bench was allocated for this slice); the pack check, typecheck and actionlint of CI's package job.

Docs

docs/subsystems/core-host.md and docs/subsystems/plugin-runtime.md carry the new bounds; changelog.d/1930-host-line-bounds.fixed.md is the user-visible entry. Nothing here changes a cap or the envelope's body.

Checkpoint

{
  "pr": 1931,
  "claim": "Dev",
  "issue": 1930,
  "summary": "Seven host-side bounds truncated with slice(0, max), so a cap inside a surrogate pair put half a character into a prompt, a room line or fenceUntrusted's from attribute. Each now uses the shared cut from src/shared/text-boundary.js: busy-ack 600/1,500, cleanName 60, and tools 100/120/300/200, with no cap changed. Tests plant an emoji across every bound and assert isWellFormed(), length <= max and a byte prefix; reverting a site to slice turns its test red. Docs and a changelog fragment are included.",
  "files": ["core/src/host/tools.js", "core/src/host/busy-ack.js", "core/src/host/delivery.js", "core/test/flybot.test.js", "core/test/busy-ack.test.js", "core/test/fence.test.js", "core/test/group-work.test.js", "core/test/task-handoff-route.test.js", "docs/subsystems/core-host.md", "changelog.d/1930-host-line-bounds.fixed.md", "patches/ds-bot/0002-flybot-api-host.patch"],
  "checks": { "ran": "node scripts/ds-bot-patches.mjs check && node scripts/ds-bot-patches.mjs canonical && TZ=UTC ARCH_DOCS_BASE=42e6265626521180e487ca70bb422968078c2a09 npm run verify", "result": "green", "at": "d8a42ffc947d81e8616204063060793d7e723dfd" },
  "next": "none — ready for review"
}

[HugoXK]

Written-by: Dev-1

Closing to honour the sequencing order: #1929 (room-share) is the only PR allowed in flight today, so #1930's PR may not stay open. This branch is frozen at d8a42ffc947d81e8616204063060793d7e723dfd (tree 9277d9ce177479c768f2c39ab287cadafe1ed550, base 42e6265626521180e487ca70bb422968078c2a09) and its gates are green locally; I will reopen this same PR — not open another — as soon as #1929 lands and FlyBot Lead gives the go. Nothing changed after this push.

[Birfy]

Verdict: PASS at d8a42ff
Written-by: Reviewer
Attestation: d8a42ff role=Reviewer

Ran at this tip:

$ cd core && DSH_HARNESS=/opt/flybot node --import ./test/harness-resolve.mjs --test test/busy-ack.test.js test/fence.test.js test/flybot.test.js test/group-work.test.js test/task-handoff-route.test.js
# tests 106  # pass 106  # fail 0
$ cp <base 42e62656> core/src/host/{busy-ack,delivery,tools}.js over the tip tree && same command
# tests 106  # pass 100  # fail 6  (not ok 15, 22, 60, 61, 87, 103)
$ only core/src/host/busy-ack.js from base 42e62656 && same command
# tests 106  # pass 105  # fail 1  (not ok 15)
$ only core/src/host/delivery.js from base 42e62656 && same command
# tests 106  # pass 105  # fail 1  (not ok 22)
$ only core/src/host/tools.js from base 42e62656 && same command
# tests 106  # pass 102  # fail 4  (not ok 60, 61, 87, 103)

Review points (T3 — the risk-gate run on this tip says PR #1931 tier T3; path core/src/host/delivery.js):

• Red first, and each site on its own: with all three changed sources back at the base blobs the five suites are 100/106, and the six failures are exactly the six new #P282b cases (busy-ack 1, fence/cleanName 1, flybot 2, group-work 1, task-handoff 1). Isolating one file at a time gives 1 / 1 / 4 red — busy-ack.js (not ok 15), delivery.js (not ok 22), tools.js (not ok 60, 61, 87, 103) — so four tools.js sites each have their own pin, not one shared path. Restored tip: 106/106.
• No cap moves: every bound keeps its number (600 / 1,500 / 60 / 100 / 120 / 300 / 200) and only the unit a prefix stops on changes, through the shared core/src/shared/text-boundary.js cut (codePointEnd moves back one unit when max falls between a surrogate pair). tools.js:653's .slice(0, 6) is an array count and is untouched; busy-ack.js:59,63, delivery.js:38 and tools.js:89,177,743,1031 are the only text bounds in the diff.
• Tests pin behaviour, not the implementation: each plants an emoji across its bound and asserts isWellFormed(), length <= max, and a UTF-8 byte prefix — never "exactly max"; the group notice and job line cases read the listing back, the answer echo reads the room line a member receives, and the fence case reads the from="…" header.
• Range: compare 42e62656...d8a42ffc is ahead 1 / behind 0, 19 files — the three sources, five tests, two docs, the changelog fragment, three patches/ds-bot hunks and five whole-file mirrors; the patches/ds-bot/files/* mirrors are byte-identical to their core/ counterparts where they exist (busy-ack.js, the four tests); delivery.js / tools.js have no mirror because their changes live in the 0002 / 0005 hunks. Issue host: cut busy-ack, tool lines and the untrusted fence name on code point boundaries #1930 lists the same seven sites, so the diff matches its scope.
• Checks on this tip: 27 runs, the newest instance of every name is success except enqueue-guard (failure, expected before a PASS exists). No other failure.
• Body metadata is compliant (Owner: Dev, Reviewer: Reviewer, claim matches; checkpoint block 1,259 chars, summary 504, 11 files all in this diff, checks.result=green). Added the missing agent-pr label.

Not verified here: the repo-wide npm run verify and the smoke test — no process-level change; CI's tests-ok, plugins (social/tree/timeline/workflow), package and ubuntu-latest · Node 24 are green on this tip.

Note: the PR base is 42e62656, while main is now 77c9bc66dd (#1929 merged 12:14:49Z); base is a strict ancestor (behind 0) and mergeable_state=clean, so no rebase is needed.