Implement Improvements

Implement Improvements

Validate improvements from .turbo/improvements.md, propose a specific working set based on the backlog's actual contents, and run one lane per session: direct, investigate, or plan. Mixing lanes in a single run tangles commits, so the skill processes exactly one lane each time. Entries outside the confirmed working set stay in the backlog for future runs.

Task Tracking

At the start, use update_plan to track each step, restating any remaining steps of a parent workflow alongside them:

1. Read the backlog
2. Validate and classify
3. Recommend, confirm, and update the backlog
4. Run the chosen lane
5. Prune working-set entries from the backlog

Step 1: Read the Backlog

Read .turbo/improvements.md, relative to the repo root resolved with git rev-parse --show-toplevel, except inside a linked worktree — where git rev-parse --git-dir differs from --git-common-dir — in which case use the parent of the common dir. If the file does not exist, there are no improvements to implement; stop.

Parse all entries, extracting for each:

• Summary (the ### heading)
• Type (direct, investigate, or plan; may be missing in older entries — trivial and standard are accepted as legacy aliases for direct and plan)
• Category
• Where (file paths or areas)
• Why (rationale)
• Ceiling and Revisit (present when the entry records a deliberate simplification; Revisit alone when the entry waits on an outside event)
• Noted (date)

Step 2: Validate and Classify

Improvements drift: files get renamed, code gets refactored, issues get fixed as side effects of other work. Before routing, validate each improvement and settle the Type of any entry whose Type is missing or wrong.

Validate

For each entry, verify whether the specific problem or opportunity described still exists. Do not rely on git log alone. Recent commits touching the same files do not mean the specific issue was addressed. Read the actual code and confirm:

1. Files exist — Do the referenced files/paths still exist? When one was renamed or its code moved, validate the entry at the current location instead. This check marks the entry stale only when the code it names is gone.
2. Problem persists — Read the relevant code sections. Is the exact issue or opportunity described in the entry still present? Check the specific claims: if the entry says a function is uncalled, verify it has no callers; if it says error handling is missing, check whether it was added.
3. Revisit condition met — For an entry carrying a Revisit field, check whether the recorded condition now holds. A shipped simplification is present by construction, so its presence alone says nothing about whether the fuller version is worth building yet.
4. Stated scope matches the real gap — For an entry claiming missing coverage, read what existing tests already pin before accepting its scope: a test that substitutes a test double at a boundary pins the behavior on one side of it and leaves the boundary itself unpinned, so a request to cover several variants often reduces to the single boundary they share. Before dropping an item on the grounds that an existing check covers it, confirm that the check pins that item through its own inputs or match patterns rather than inferring it from the check's name or description; an item no existing check pins stays in the entry's scope. Restate such an entry at its real scope, classify it Active, and use the restatement as its summary in Step 3.
5. Claimed consequence holds — For an entry claiming that two paths behave differently, that a change would alter observable behavior, or that the code as it stands leads to a stated outcome, verify the consequence itself rather than confirming only that the code it points at exists. For a claimed difference, between two paths or between the behavior before and after a change, read what each actually returns, exercising both when reading cannot settle it. For a claimed outcome, follow the path from the named code to that outcome and confirm nothing later on that path already stops it. When the claim is that nothing but the case it names reaches or relies on the named code, read that code's own tests: they surface dependents an entry written from a single path routinely omits, and turning up none leaves the claim unproven. When the named code is present but its stated consequence is false, restate the entry at the benefit it actually delivers, classify it Active, and use the restatement as its summary in Step 3; classify it Stale when no benefit survives.

Before using a restatement as an entry's summary in Step 3, confirm each fact it adds to the entry against the code, or against the dependency's shipped artifact when the fact concerns a dependency.

Classify each entry as:

• Active — The described problem or opportunity is confirmed present in the current code
• Deferred — The entry carries a Revisit condition that does not yet hold: the shipped approach remains the right one, or the event the entry waits on has not happened
• Stale — The code the entry names no longer exists, the specific issue has been resolved, or the entry's premise never held (cite evidence: what changed and where, or why the claim is false)
• Unclear — Cannot determine from code alone, needs user input

When in doubt, classify as Active. The cost of re-examining a resolved issue is low; dismissing a valid improvement is high.

Classify or Correct the Type

For any Active entry without a Type field, infer one on the fly. For an Active entry whose Type the code read contradicts, correct it. Base the classification on the code you just read during validation, not just the entry's one-line summary.

• direct — Clear scope and a known approach, ready to apply via $implement.
• investigate — A symptom that needs root-cause analysis first: unclear root cause, performance question, intermittent bug, "something feels off".
• plan — Everything else: the approach warrants writing down before implementing (multi-file refactor, test additions, feature work). Dispatched to $turboplan, which routes the work itself.

Pick the type without asking the user. Default to plan when a missing Type is genuinely ambiguous, and keep a recorded Type the code read does not contradict.

Step 3: Recommend, Confirm, and Update the Backlog

Output the backlog status as text first, grouped by type and status. Include each entry's category inline and a category tally across active entries:

## Improvement Backlog Status

### Active (N)
Categories: refactor (N), performance (N), testing (N), docs (N)

**Direct (N)**
- [summary] (category) — [one-line reason it's still relevant]

**Investigate (N)**
- [summary] (category) — [one-line reason it's still relevant]

**Plan (N)**
- [summary] (category) — [one-line reason it's still relevant]

### Deferred (N)
- [summary] — [the revisit condition, and what still has to happen]

### Stale (N)
- [summary] — [one-line reason it's stale]

### Unclear (N)
- [summary] — [what's ambiguous]