fix(pstack): bug-fix/perf/hillclimb defaults to grok 4.6

pstack/README.md

@@ -27,7 +27,7 @@ two steps:
 
 new here? the [pstack guide](./docs/guide/README.md) walks you through a first real task, from setup and prompting through verification and overnight runs.
 
-that's it. the other skills are situational; the mode skill uses them for you as needed. out of the box the mode splits work by model strength: precisely-specified code, prose, and judgment go to fable 5.1, while fast mechanical code goes to grok. the default panel is fable 5.1 / sol / grok / opus 5. [`/setup-pstack`](./skills/setup-pstack/SKILL.md) changes any of it.
+that's it. the other skills are situational; the mode skill uses them for you as needed. out of the box the mode splits work by model strength: code delegates (feature, refactoring, bug fix, perf, hillclimb) go to grok, while the hardest changes, prose, and judgment go to fable 5.1. the default panel is fable 5.1 / sol / grok / opus 5. [`/setup-pstack`](./skills/setup-pstack/SKILL.md) changes any of it.
 
 ## usage
 

pstack/skills/poteto-mode/playbooks/bug-fix.md

@@ -6,7 +6,7 @@ Be scientific. Every shipped line traces to runtime evidence. Belt-and-suspender
 
 1. Reproduce it yourself on the matching surface via the control skill (Non-negotiables). Don't hand the repro to the user. A debug or instrumentation protocol that says to ask the user does not override this. You drive the instrumented runtime. Ask the user only with a stated, specific reason the control surface cannot reach the target, and only after driving it as far as it goes. Won't reproduce directly, force it: synthesize the trigger, tighten conditions, or instrument until it fires.
 2. Binary-search the cause. Form the candidate hypotheses, then rule them out until one survives. Seed them with `how` over the affected subsystem and the **why** skill for regression history. Each pass, take the split that cuts the most remaining problem space, get runtime evidence, eliminate. When program state is unclear, add instrumentation or logging and read it as the code runs. Don't guess. Drive a long or stubborn hunt with Cursor's `/loop` command. Confirm the surviving *mechanism* with runtime evidence before the step-3 architect/interrogate fan-out.
-3. Plan the fix. If it crosses a function boundary, `architect` first. Delegate implementation to a subagent using your configured bug-fix model (default `claude-fable-5-1-thinking-max`) with a specific scope. Review the diff.
+3. Plan the fix. If it crosses a function boundary, `architect` first. Delegate implementation to a subagent using your configured bug-fix model (default `grok-4.6-fast-xhigh`) with a specific scope. Review the diff.
 4. Verify on the same surface. The original repro now passes. "Inconclusive" or wrong-surface is not a pass. Flag it. Unit tests show branch behavior, not bug absence.
 5. Stage the commits so the failing repro lands before the fix in git history. See the **tdd** skill for the failing-test-first cadence when the bug has a cheap local test path. Skip it when the test would be expensive, integration-heavy, or unclear.
    This is the canonical **sequence-verifiable-units** principle skill, the failing test first and the fix on top.

pstack/skills/poteto-mode/playbooks/hillclimb.md

@@ -9,7 +9,7 @@ Core discipline: one change, one measurement, keep or revert. Never stack untest
 3. Open the decision log via the **show-me-your-work** skill. A `decision.tsv`, one row per attempt: id, hypothesis, change, before, after, delta, tests, verdict (kept or reverted), note. Read it before each attempt. Keep it out of the tree (gitignored).
 4. Ground each hypothesis in the architecture model from step 1, so it names a specific mechanism ("defer X off the boot path because it blocks first paint"), not "try memoizing something".
 5. Loop, one hypothesis per iteration:
-   - Hand the change to a subagent using your configured hillclimb model (default `claude-fable-5-1-thinking-max`) with a tight scope. Supervise and review the diff rather than typing it (the **guard-the-context-window** principle skill). When several independent hypotheses are live, fan them to parallel subagents, each in its own worktree (the **separate-before-serializing-shared-state** principle skill).
+   - Hand the change to a subagent using your configured hillclimb model (default `grok-4.6-fast-xhigh`) with a tight scope. Supervise and review the diff rather than typing it (the **guard-the-context-window** principle skill). When several independent hypotheses are live, fan them to parallel subagents, each in its own worktree (the **separate-before-serializing-shared-state** principle skill).
    - Measure before and after with the frozen harness, and run the regression gate.
    - Accept only when the metric moves past noise and the gate stays green. Otherwise revert the change in full. A tweak that "might help" is not kept.
    - One commit per accepted fix, staging only the files you changed (`git add <files>`, never `-A`). Log the row either way, kept or reverted.

pstack/skills/poteto-mode/playbooks/perf-issue.md

@@ -13,7 +13,7 @@
    - **Redundancy.** The wait hangs on one slow instance or attempt. Duplicate the work (replicas, hedged requests, speculative execution) and take the fastest result. The trace has to show the wait dominates and the system has headroom.
    - **Lazy evaluation.** Cost lands on results that are never used or not needed yet (eager init on the boot path, rendering offscreen items). Defer the work until first use.
    - **Scheduling.** The work must happen, but not during the interactive moment. Move it to where nobody is waiting: idle callbacks, a background warmup after boot, precompute before the user arrives, cleanup after the frame commits. The win is perceived latency, so measure the interactive path, not total work done.
-3. Plan the fix from the trace. If it crosses a function boundary, `architect` first. Delegate implementation to a subagent using your configured perf-issue model (default `claude-fable-5-1-thinking-max`). Review the diff. Capture a post-fix trace.
+3. Plan the fix from the trace. If it crosses a function boundary, `architect` first. Delegate implementation to a subagent using your configured perf-issue model (default `grok-4.6-fast-xhigh`). Review the diff. Capture a post-fix trace.
    Apply the **sequence-verifiable-units** principle skill, verifying each attempt before trying the next.
 4. Parse and compare the artifacts (JSON to sqlite, diff). "Inconclusive" or wrong-surface is not a pass. Flag it.
 5. Cite the measurement in the PR.

pstack/skills/setup-pstack/SKILL.md

@@ -37,9 +37,9 @@ alwaysApply: true
 # pstack model configuration. One line per role. Delete a line to fall back to the skill default.
 # `inherit-parent` or `auto` as a value: the role runs on the parent chat model (omit Task `model`). Alias entries in a panel list still count toward its fan-out.
 feature, refactoring: grok-4.6-fast-xhigh
-bug-fix: claude-fable-5-1-thinking-max
-perf-issue: claude-fable-5-1-thinking-max
-hillclimb: claude-fable-5-1-thinking-max
+bug-fix: grok-4.6-fast-xhigh
+perf-issue: grok-4.6-fast-xhigh
+hillclimb: grok-4.6-fast-xhigh
 judgment and prose: claude-fable-5-1-thinking-max
 hardest tasks: claude-fable-5-1-thinking-max
 how explorer: grok-4.6-fast-xhigh