daily-fix: pre-commit hook for agent-memory index size

Overview / Motivation

Auto-filed by /daily 2026-07-30 Step C (parked workflow-fix-candidate routing) from a prose follow-up parked on task #1891 (emitting source: #1891's session, recursion-guarded; parked 2026-07-31T00:31:24Z). #1891 itself landed the --check-agent-memory-index-size lint check + curation (merged 28bb5842dcac); this is the pre-commit parity leg it deferred.

Goal

Add a .pre-commit-config.yaml local hook running workflow_lint.py --check-agent-memory-index-size so direct-to-main memory-save commits are gated at commit time, matching the agent-spec sibling hook (#1661).

Workflow gap

• Bug observed: MEMORY.md regrowth is mostly direct-to-main memory-save commits that no worktree gate lints — the new --check-agent-memory-index-size check (landed via #1891) only fires at worktree-mediated gates, so a direct root-side memory append can push an index back over the 24,000-byte FAIL threshold with no local signal until a later unrelated gate goes red.
• Why it is a workflow gap: the check's agent-spec sibling gained a local pre-commit hook for exactly this direct-to-main offender class (#1661); the new agent-memory check lacks that parity, leaving its primary regrowth channel ungated.
• Confidence (emitter): medium
• verified-at-filing: grep -c 'check-agent-memory-index-size\|check_agent_memory_index_size' scripts/workflow_lint.py → 5 hits (the check is landed on main); grep -n 'agent-memory' .pre-commit-config.yaml → 0 hits (the hook is absent) (2026-07-31 filing time). #1891 merged 2026-07-31T03:51:57Z as 28bb5842dcac.

Proposed change (candidate diff sketch — refine in planning)

Add a .pre-commit-config.yaml local hook running workflow_lint.py --check-agent-memory-index-size (files regex .claude/agent-memory/.*/MEMORY\.md + scripts/workflow_lint.py, pass_filenames false), plus a hook-coverage pin test.

Scope / surfaces

• Primary target: .pre-commit-config.yaml
• Model on the #1661 agent-spec sibling hook; keep hook runtime bounded (the check is file-size based, fast).

Constraints / invariants

• Workflow-surface only. The hook must not slow every commit materially (scope via files regex).
• scripts/workflow_lint.py --check-references passes after the change; add the hook-coverage pin test.
• This session runs under EPM_WORKFLOW_FIX_SESSION=1 and carries a workflow_fix_target: Provenance line — recursion guard applies.

Provenance

• workflow_fix_target: .pre-commit-config.yaml
• fingerprint: 66ff9973db84 (tag-authoritative; supersedes body-carried fingerprint: 6fc2af2d68e4)
• origin: parked candidate-block on #1891 events.jsonl, ts 2026-07-31T00:31:24Z (routed by /daily 2026-07-30 Step C)