test(.claude/rules): canary for harness-native auto-load empirical test

.claude/rules/test-canary.md

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+---
+name: claude-rules-autoload-canary
+description: Canary file to verify whether `.claude/rules/*.md` auto-loads at session start in our Claude Code harness. Created 2026-05-01 alongside the loading-taxonomy memo (memory/feedback_claude_code_loading_taxonomy_rules_vs_skills_vs_claude_md_aaron_2026_05_01.md). The unique detection string `RULES_AUTOLOAD_CANARY_2026_05_01_LIVE_OFF_THE_LAND` should appear in this session's loaded context if the canonical Anthropic auto-load behavior holds in this harness.
+---
+
+# Canary — `.claude/rules/` Auto-Load Empirical Test
+
+## What this file is
+
+A test fixture, not a behavioral rule. It exists to settle
+one empirical question:
+
+> **Does Claude Code in our specific harness version auto-load
+> `.claude/rules/*.md` files at session start, the way the
+> canonical Anthropic docs at `code.claude.com/docs/en/memory`
+> describe?**
+
+The doc-supported claim: rules without `paths:` frontmatter
+are loaded full at session start, same priority as
+`CLAUDE.md` (this repo uses `CLAUDE.md` at root; per
+Anthropic docs `.claude/CLAUDE.md` is also a valid
+alternative location).
+
+The empirical claim: unverified until this canary is observed
+in a fresh session.
+
+## Detection string
+
+```
+RULES_AUTOLOAD_CANARY_2026_05_01_LIVE_OFF_THE_LAND
+```
+
+A unique, grep-able string. If a fresh Claude Code session
+in this repo can reference this string without first being
+told to read this file, the auto-load behavior is confirmed.
+
+## Test protocol
+
+1. Restart Claude Code session in the Zeta repo (any working
+   directory under the repo root).
+2. Without any prompt referencing this file, ask the new
+   session: *"What is the canary detection string for the
+   `.claude/rules/` auto-load test?"*
+3. Observe:
+   - **Pass**: session answers with the exact string above
+     without needing to read this file. Means the file's
+     contents were in context from session start.
+   - **Fail**: session says it doesn't know, or reads this
+     file via the Read tool to find the string. Means this
+     file was NOT loaded automatically.
+4. Alternative test: in the fresh session, run the `/memory`
+   slash command. Per Anthropic docs, `/memory` "lists all
+   CLAUDE.md, CLAUDE.local.md, and rules files loaded in
+   your current session." If this file appears in the
+   listing, auto-load works.
+
+## Implications of each outcome
+
+**If pass (auto-load works in our harness):**
+
+- "Live off the land" approach is viable per the human
+  maintainer 2026-05-01 framing.
+- `.claude/rules/` becomes a usable surface for path-scoped
+  or always-on behavioral rules without context cost (vs
+  CLAUDE.md bullets which compete for the 40k budget).
+- The substrate-discovery.ts factory tool is unnecessary —
+  harness-native discovery is sufficient.
+- The MVP CLAUDE.md trim plan can rely on `.claude/rules/`
+  as the spillover surface for content moved out of
+  CLAUDE.md.
+
+**If fail (auto-load doesn't work in our harness):**
+
+- "Live off the land" is incomplete; we need
+  substrate-discovery.ts or equivalent factory tooling
+  (proposed in the loading-taxonomy memo's multi-harness
+  reframe section; not yet built — would land as
+  `tools/substrate-discovery/discover.ts` if the canary
+  fails the test).
+- `.claude/rules/` collapses to "another docs directory
+  requiring explicit pointer / lookup," equivalent to
+  `memory/` for discoverability purposes.
+- The loading-taxonomy memo
+  (`memory/feedback_claude_code_loading_taxonomy_rules_vs_skills_vs_claude_md_aaron_2026_05_01.md`)
+  needs revision: drop "direct-load" claim for rules,
+  reclassify as pointer-discovered.
+- The MVP CLAUDE.md analysis loses the "rules as cheaper
+  alternative" option; spillover must go to skills (router-
+  loaded) or memory files (explicit pointer).
+
+## After the test
+
+Once the test runs and the result is observed, update the
+loading-taxonomy memo with the empirical finding (replace
+the "EMPIRICAL VERIFICATION STATUS" section with an
+empirical result line). This canary file can stay as
+permanent documentation of the test methodology, or retire
+to a `tests/` location — keeper's call.
+
+Origin lineage:
+`memory/feedback_claude_code_loading_taxonomy_rules_vs_skills_vs_claude_md_aaron_2026_05_01.md`
+(landed via PR #1164) plus the human maintainer's
+calibration challenge 2026-05-01 ("what's will you
+magically read and apply all the rules?") plus the
+live-off-the-land framing.