tools: run-plan: pure sessions, resume after the limit, row named

Three changes from the M5b run (implementer lessons T47, T48):
- each session runs `opencode run --pure` with
  OPENCODE_DISABLE_CLAUDE_CODE=1, so no global plugin or borrowed rules
  file reaches the implementer; PLUGINS=1 restores both;
- with RESUME=1, a session stopped at SESSION_LIMIT_MIN with work left
  uncommitted is resumed once, as one that ended by itself already was;
  an idle stop is still not resumed;
- the prompt names the log row's Task cell, so a task's heading cannot
  mislead the row the driver then looks for.

Checked against a stub opencode in scratch repositories (17 checks:
the flags and variable, PLUGINS=1, a resume after the limit, no resume
without work or without RESUME).

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

tools/run-plan.sh

@@ -8,14 +8,18 @@
 #   OPENCODE_MODEL     model to use (default straylight/laguna-s-2.1; OpenCode's own default differs).
 #                      The part after the provider (`ornith-1.5-35b-a3b`) names the model in each
 #                      commit's `Co-Authored-By: <model> <agent@wntrmute.dev>` trailer and in the log.
-#   OPENCODE_FLAGS     extra flags for `opencode run`, for example "--pure"
+#   OPENCODE_FLAGS     extra flags for `opencode run`
+#   PLUGINS=1          load OpenCode's external plugins and let it read ~/.claude/CLAUDE.md. By
+#                      default each session runs with `--pure` and OPENCODE_DISABLE_CLAUDE_CODE=1:
+#                      a global plugin that rewrites the prompt forces a full re-read on a model
+#                      that cannot rewind its cache (implementer lessons, T48).
 #   SESSION_LIMIT_MIN  minutes a session may run before it is stopped (default 90)
 #   SLOTS_URL          llama-server's slots URL, for example
 #                      http://127.0.0.1:8081/slots?model=ornith-1.5-35b-a3b. When set, a session is
 #                      stopped once no slot has been busy for IDLE_LIMIT_MIN minutes (default 10).
 #                      Trial: not yet used on a run.
-#   RESUME=1           when a session ends with work left uncommitted, resume it once. Trial: not
+#   RESUME=1           when a session ends, or is stopped at SESSION_LIMIT_MIN, with work left
-#                      yet used on a run.
+#                      uncommitted, resume it once, in a new session with the same limit.
 #   DRY_RUN=1          print what would be run and stop
 # Each session runs as the `implement` agent of ./opencode.json: its permissions deny edits to the
 # plans and design documents, reads outside the repository, subagents and pushes.
@@ -42,9 +46,15 @@ mkdir -p "$runs"
 # `pkill`, which would match this script too.
 run_session() {
     set -m
+    if [ "${PLUGINS:-0}" = 1 ]; then
+        pure=""
+    else
+        pure="--pure"
+        export OPENCODE_DISABLE_CLAUDE_CODE=1
+    fi
     # shellcheck disable=SC2086
-    opencode run --agent implement -m "$model" ${OPENCODE_FLAGS:-} --title "$milestone/$name" "$1" \
+    opencode run $pure --agent implement -m "$model" ${OPENCODE_FLAGS:-} --title "$milestone/$name" \
-        >> "$runs/$name.log" 2>&1 &
+        "$1" >> "$runs/$name.log" 2>&1 &
     pid=$!
     set +m
     started=$(date +%s)
@@ -83,7 +93,8 @@ for task in "$plan"/[0-9][0-9]-*.md; do
     name=$(basename "$task" .md)
     number=$(echo "$name" | cut -c1-2)
     [ "$number" -ge "$first" ] || continue
-    prompt="Read \`$task\` and do exactly that task. You are $agent: write $agent in the log row's Model column, and end the commit message with this line, exactly: $trailer"
+    row="Your log row's Task cell is \`$milestone/$name\`, and you are $agent: write $agent in its Model column, and end the commit message with this line, exactly: $trailer"
+    prompt="Read \`$task\` and do exactly that task. $row"
 
     if [ "${DRY_RUN:-0}" = 1 ]; then
         echo "opencode run --agent implement -m $model ${OPENCODE_FLAGS:-} --title $milestone/$name \"$prompt\""
@@ -100,11 +111,16 @@ for task in "$plan"/[0-9][0-9]-*.md; do
     # A new `opencode run` is a new session: nothing carries over from the task before.
     rc=0
     run_session "$prompt" || rc=$?
-    if [ "$rc" = 0 ] && [ "${RESUME:-0}" = 1 ] && [ "$(git rev-parse HEAD)" = "$before" ] \
+    # A session that ended, or ran out of time, part-way through a task is resumed once. One stopped
-        && [ -n "$(git status --porcelain)" ]; then
+    # for idling (125) is not: the server, not the task, is the likely cause.
+    if { [ "$rc" = 0 ] || [ "$rc" = 124 ]; } && [ "${RESUME:-0}" = 1 ] \
+        && [ "$(git rev-parse HEAD)" = "$before" ] && [ -n "$(git status --porcelain)" ]; then
+        if [ "$rc" = 124 ]; then
+            echo "=== $milestone/$name: stopped at $limit minutes with work uncommitted"
+        fi
         echo "=== $milestone/$name: work left uncommitted; resuming once $(date '+%H:%M:%S')"
         rc=0
-        run_session "The previous session on \`$task\` left uncommitted work (see \`git diff\`). Do not start over. Finish the task, run the gate, commit, and write the log row. You are $agent: write $agent in the log row's Model column, and end the commit message with this line, exactly: $trailer" || rc=$?
+        run_session "The previous session on \`$task\` left uncommitted work (see \`git diff\`). Do not start over. Finish the task, run the gate, commit, and write the log row. $row" || rc=$?
     fi
     case "$rc" in
         0) ;;