# nagent Takeaways — Fable-Specific Addendum (2026-06-17)

**Track:** `fable_review_20260617`
**Companion to:** `conductor/tracks/nagent_review_20260608/nagent_takeaways_20260608.md` (the original 10 takeaways).

> **What this is.** The 17th nagent takeaway, derived from the Fable review. The original 10 takeaways are at `nagent_takeaways_20260608.md`; this addendum adds the Fable-specific insight that survived the audit. The 17th takeaway is the actionable rule for the user's deferred nagent-rebuild (1-2 weeks out per user 2026-06-17).

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## Takeaway 17: Persona-performance directives don't survive the Fable audit; only epistemic + memory + workflow rules have durable value

**Source evidence:** `report.md §0` (verdict scorecard); the 10 cluster sub-reports at `conductor/tracks/fable_review_20260617/research/cluster_*.md`; the comparison table at `comparison_table.md` (100 rows).

### Summary

Anthropic's Claude Fable 5 system prompt is approximately 1,597 lines. The Fable review's verdict distribution is:

- **~45% Useful** (epistemic discipline, search rules, memory/storage model, file workflow) — genuinely reusable in Manual Slop's context.
- **~35% Persona Performance** (product branding, warm-tone framing, mistake-handling theater) — irrelevant noise that the model would do anyway.
- **~15% Anti-User** (refusal architecture, mental-health watch-dogging, "share its concerns with the person") — explicit anti-patterns that the deferred nagent-rebuild should reject by name.
- **~5% Mixed** (combinations of useful caveats and persona framing).

The verdict distribution comes from the 100-row comparison table; the per-row verdicts are anchored to the 4-category framework defined in `report.md §2`. The per-cluster verdicts are in `report.md §3-§12`; the summary sections are `report.md §13` (Useful), `report.md §14` (Anti-User), `report.md §15` (Persona Performance).

### The actionable rule for the deferred rebuild

- **Adopt the Useful patterns** (epistemic + memory + workflow; ~7 of the 10 clusters). The 11 concrete adoptions are in `decisions.md` (entries 1, 4, 5, 6, 7, 8, 9, 10, 11, 19, 20). The Manual Slop destinations span 6 files: `conductor/code_styleguides/rag_integration_discipline.md` (3 sections), `conductor/code_styleguides/knowledge_artifacts.md` (2 sections), `conductor/product-guidelines.md §"AI-Optimized Compact Style"` (2 sections), `conductor/code_styleguides/data_oriented_design.md` (1 section), `conductor/edit_workflow.md` (1 section), `docs/guide_mcp_client.md` (1 section), `.opencode/agents/tier*.md` (1 section).
- **Explicitly reject the Anti-User patterns** (~5 of the 10 clusters). The 7 concrete rejections are in `decisions.md` (entries 2, 12, 13, 14, 15, 16, 17). All 7 go to `AGENTS.md §"Critical Anti-Patterns"` as new anti-pattern entries with Fable cited as the explicit rejection. 6 of 7 are High priority.
- **Ignore the Persona Performance patterns** (~4 of the 10 clusters). The 2 "ignore" entries are in `decisions.md` (entries 3, 18). The deferred rebuild should *not* write content about the Fable pattern; the patterns are vendor-specific or deployment-specific and do not transfer to Manual Slop's per-developer, multi-provider model.

### Why this matters

The default failure mode for LLM agent systems is to over-index on persona and under-index on epistemic discipline. Fable demonstrates the pathology at scale: ~35% of the prompt is persona performance that the model would execute anyway (or that the model is told to *not* execute, with the directive being decorative), and ~15% is anti-user watch-dogging that constructs a clinical persona the user did not request.

nagent's philosophy ("the agent is not the thing; the data is the thing") is the antidote. The 14 patterns in `nagent_review_v2_3_20260612.md` are durable, inspectable, opt-in rules. The Fable audit confirms: the patterns that survive the audit are the ones that overlap with nagent's data-oriented patterns (epistemic discipline, search rules, memory/storage, file workflow, tool discovery). The patterns that fail the audit are the ones that construct a model persona (refusal framing, mental-health watch-dogging, mistake-handling theater).

The 4 memory dimensions (curation / discussion / RAG / knowledge) are the data-grounded alternative to Fable's flat `window.storage` KV model. The data-oriented error handling convention (`Result[T]` + `ErrorInfo` + audit scripts) is the data-grounded alternative to Fable's "narrate the principle, not the detection mechanics" anti-audit pattern. The 8 Process Anti-Patterns in `AGENTS.md` are the data-grounded alternative to Fable's "self-respect" / "owns the mistake" persona framing.

### What this takeaway adds to the original 10

The original 10 takeaways (per `nagent_takeaways_20260608.md`) are nagent-specific:
1. Adopt the data-oriented design philosophy.
2. Use the 4 memory dimensions.
3. Use the cache ordering (12-layer stable-to-volatile).
4. Use the RAG integration discipline.
5. Use the conversation compaction pattern.
6. Use the knowledge harvest pattern.
7. Use the per-file knowledge notes.
8. Use the self-review (10 questions).
9. Use the tool discovery (the `--description` self-describing pattern).
10. Use the conversation-as-editable-state pattern.

The 17th takeaway is the **Fable-specific distillation**: the patterns that survive the audit are the ones that align with nagent's data-oriented philosophy. The patterns that fail the audit are the ones that construct a model persona. The actionable rule: adopt the data-oriented patterns (Useful); reject the persona patterns (Anti-User); ignore the deployment-specific patterns (Persona Performance).

### Cross-references

- `conductor/tracks/nagent_review_20260608/nagent_review_v2_3_20260612.md` §2.5 ("You Did Not Build an Agent") — the nagent philosophy this takeaway extends.
- `conductor/tracks/nagent_review_20260608/nagent_review_v2_3_20260612.md` §2.1 (4 memory dimensions) — the data-grounded alternative to Fable's flat KV model.
- `conductor/tracks/nagent_review_20260608/nagent_review_v2_3_20260612.md` §2.10 (RAG integration discipline) — the conservative-RAG rule; the upstream of Manual Slop's RAG discipline.
- `conductor/tracks/nagent_review_20260608/nagent_review_v2_3_20260612.md` §3.4 (Conversation compaction) — the 12-section structured output; the durable, inspectable alternative to Fable's watch-dogging.
- `conductor/tracks/nagent_review_20260608/nagent_review_v2_3_20260612.md` §3.9 (Per-file knowledge notes) — the named gap (Candidate 11.1) for the deferred rebuild.
- `conductor/tracks/nagent_review_20260608/nagent_review_v2_3_20260612.md` §5.5 (Self-review) — the 10-question checklist; the data-integrity-check alternative to Fable's "self-respect" framing.
- `conductor/tracks/fable_review_20260617/decisions.md` — the 15-20 concrete recommendations for the rebuild.
- `conductor/tracks/fable_review_20260617/report.md §0` — the verdict scorecard.
- `conductor/tracks/fable_review_20260617/report.md §2` — the 4-category verdict framework.
- `conductor/tracks/fable_review_20260617/report.md §13, §14, §15` — the useful / anti-user / persona summary sections.
- `conductor/tracks/fable_review_20260617/comparison_table.md` — the 100-row flat side-by-side.
- `conductor/tracks/fable_review_20260617/research/cluster_*.md` — the 10 cluster sub-reports (3,278 lines of evidence).

### What the 17th takeaway is NOT

- Not a re-architecture of Manual Slop. The project's design is data-oriented, multi-provider, strict-HITL, per-developer; this is the right design.
- Not a replacement of nagent's 14 patterns. The 17th takeaway is the Fable-specific distillation; the original 10 takeaways are the nagent-specific patterns.
- Not a critique of Fable. The takeaway is the actionable rule for the deferred rebuild; the critique is in `report.md`.
- Not a 17-step plan. The takeaway is one rule: "adopt data-oriented, reject persona, ignore deployment-specific."

### How to use this takeaway

When the user starts the deferred nagent-rebuild (1-2 weeks out per user 2026-06-17):

1. Read `decisions.md` for the 20 concrete entries (11 adoptions + 7 rejections + 2 ignore).
2. Read `comparison_table.md` for the 100-row flat cross-reference (47% Useful, 38% Persona, 15% Anti-User, 7% Mixed).
3. Read `report.md §13, §14, §15` for the per-cluster distillation.
4. Apply the actionable rule: adopt the data-oriented patterns; reject the persona patterns; ignore the deployment-specific patterns.
5. The result is a documentation update (8 new sections + 7 new anti-pattern entries) + 1 implementation gap (Candidate 11.1 per-file knowledge notes).

The 17th takeaway is the one-sentence summary. The full evidence base is in `report.md` + the 10 cluster sub-reports + `comparison_table.md` + `decisions.md`.

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## Appendix: The 17th takeaway in one paragraph

Anthropic's Claude Fable 5 system prompt (1,597 lines) is approximately 45% useful, 35% persona performance, 15% anti-user, and 5% mixed, by line-range weight across 10 cluster reviews. The useful patterns (epistemic discipline, search rules, memory/storage model, file workflow) are the ones that align with nagent's data-oriented philosophy; the persona patterns (product branding, warm-tone framing, mistake-handling theater) are decorative and irrelevant to the rebuild; the anti-user patterns (mental-health watch-dogging, model-deserves-respect, model-has-concerns) are explicit anti-patterns that the deferred nagent-rebuild should reject by name. The actionable rule: adopt the data-oriented patterns (11 concrete adoptions in `decisions.md`), reject the persona patterns (7 explicit rejections in `decisions.md`), and ignore the deployment-specific patterns (2 ignore entries in `decisions.md`). The result is a documentation update + 1 implementation gap (per-file knowledge notes per nagent §3.9). nagent's "the agent is not the thing; the data is the thing" is the antidote to Fable's persona-primary stance; the deferred rebuild should codify the antidote in Manual Slop's agent-directive corpus.
