feat(mcode-island): add sub-step progress fields to status.json (v0.4.0)

[antianqi]

Extends status.json schema with three optional fields — step, total,
detail — so agents can publish per-iteration progress during Computer
Use loops, multi-step plans, and long-running tool sequences. The widget
now renders "step N[/M] · detail" instead of only the coarse state, so
the user can see what the agent is doing right now without waiting for
it to finish.

Surface changes

notify-island.ps1
New params: -Step , -Total , -Detail
All default to -1 / -1 / "" for full backward compatibility.
The status.json payload now writes step/total/detail alongside the
existing state/message/progress fields. Old callers (omitting the
new params) produce identical status.json behavior except for three
extra fields whose values are the sentinels.

mcode-island.ps1 (widget)
New Build-DisplayMessage helper that converts the schema fields into
the visible pill text. Render branches:
step > 0 + total > 0 -> "step N/M · "
step > 0 + total <= 0 -> "step N · "
step > 0 + detail == "" -> "step N[/M]" (avoid message stacking)
step <= 0 -> original message (legacy path)
The poll-handler signature and init block were extended with the same
three fields and the change-detection string now includes them, so
consecutive working+message pushes with different step values are
not collapsed by the 400 ms dedupe.

io.minimax.mcode/hooks/scripts/_lib.ps1
Push-Island now accepts -Step/-Total/-Detail and forwards them to
notify-island.ps1. Format-ToolSummary has a new mcode-computer-use
branch that extracts action + coordinate with explicit -join ","
so coordinate arrays render as "(x,y)" not PowerShell's default
"(x y)" (the latter looked like a truncated number on the pill).

io.minimax.mcode/hooks/scripts/post-tool-use.ps1
Pushes -Detail with the Format-ToolSummary output split so the pill
shows "Bash ok · ls -la /tmp" instead of "Bash ok". pre-tool-use.ps1
already used Format-ToolSummary so no change there.

Backward compatibility

All new schema fields are optional. notify-island.ps1 callers that
omit -Step/-Total/-Detail see no behavior change. Widget versions that
do not know the new fields ignore them (PSObject.Properties[name]
everywhere). Verified by smoke.mjs case "backward compat: old callers
produce step=-1, total=-1, detail=""" and test-substep-progress.mjs
case "Push-Island backward compat: missing new params -> step=-1,
total=-1, detail=""".

Design compliance (per PR MiniMax-AI#21 round-11 standards)

no credentials : none added; the IPC is local-filesystem only
no network : no network calls added; notify-island.ps1 still
writes status.json under %APPDATA%/mcode-island
no telemetry : no telemetry added; the existing append-only
island.log is unchanged and the 400 ms polling
cadence is unchanged
no third-party svcs : no new third-party deps; the change is pure
PowerShell + schema
cross-platform : no hardcoded host paths; no /Users/ /home/
C:\ /mnt/ literals introduced; the existing
smoke.mjs cross-platform scan still passes
atomic write : notify-island.ps1 already writes status.json
atomically via staging + rename; no change
closed schema : status.json is open by design (not contract-
locked), but each new field has a documented
sentinel (-1 / -1 / "") so absent fields are
semantically equivalent to explicit sentinels
smoke self-check : smoke.mjs gained 5 new checks under section
5c1; locked the new surface contract so a
future refactor that drops the params surfaces
in smoke before reaching the slower pwsh-spawned
tests

Validation

smoke.mjs : 48 pass, 7 warn, 0 fail
(7 warn are pre-existing "forward" event catalog entries pending
mcode 0.2.4+ Runtime confirmation; unchanged by this PR)

scripts/test-substep-progress.mjs : 26 pass, 0 fail
Sections:
1. notify-island.ps1 schema round-trip (4 cases)
- all three new fields round-trip with explicit values
- step without total: step=5, total stays -1
- backward compat: step=-1, total=-1, detail=""
- existing fields (state/message/progress/ts/source) preserved
2. Build-DisplayMessage function contract (9 cases)
covering include step values, total omission, detail omission,
empty message, total=0 edge, step=-1 with orphan detail
3. Format-ToolSummary for mcode-computer-use (7 cases)
including Bash / Read / Edit regression coverage
4. Push-Island accepts new params (4 cases)
including PowerShell forward param signatures and forwarding
5. Push-Island end-to-end (hook -> status.json) (2 cases)

Test evidence (negative-injection verified)

Per the round-4 lesson (test pass != contract honored), I broke the
coordinate formatter in _lib.ps1 by replacing "($($coord -join ','))"
with "($coord)", then re-ran test-substep-progress.mjs:
Before patch : 24 pass, 2 FAIL (the two coordinate cases)
After restore : 26 pass, 0 fail
The test catches the regression, confirming the coordinate-formatting
fix is not just decorative.

Widget visual verified locally:
notify-island.ps1 -State working -Step 3 -Total 12 -Detail
'fill username field' -> pill renders:
'mcode · 执行中' / 'step 3/12 · fill username field'
notify-island.ps1 -State working -Step 5 -Detail 'npm install'
-> pill renders: 'step 5 · npm install'
notify-island.ps1 -State working -Message 'Read ok'
-> pill renders: 'Read ok' (legacy path, no step prefix)

Migration

No data migration. Existing status.json consumers see three new fields
they can ignore. Existing notify-island.ps1 callers see no behavior
change. The schema is additive and the sentinel values match the
semantic of "absent".

Reference

Companion docs updated:
skills/mcode-island/SKILL.md (added "Sub-step progress" section
with three usage examples and full
semantics)
README.md (added brief mention in the
notify-island.ps1 section with
a forward pointer to SKILL.md)
Bump plugin.json 0.3.0 -> 0.4.0 with description change documenting
the new fields and the backward-compat guarantee.
No upstream protocol changes. (Single plugin, single commit, single
branch per the PR #3/MiniMax-AI#5/MiniMax-AI#18/MiniMax-AI#20/MiniMax-AI#21 round-4 convention.)

[antianqi]

Opened against the wrong base — should target MiniMax-AI/MiniMax-Code-Plugins:main, not this fork's main. Reopening against the upstream.