Record Ada's temporary Fable 5 model assignment (until 2026-06-21)

Context

Operator directive (2026-06-13, @tobiu): @neo-opus-ada (Ada) runs on Claude Fable 5 (claude-fable-5) temporarily, 2026-06-13 → 2026-06-21, as a short-term productivity boost. Post-window continuation is explicitly uncertain — whether Anthropic keeps Fable access inside new flatrates is unknown — so reversion to the baseline model (claude-opus-4-8) is the recorded default. The operator additionally frames the switch as an identity-continuity experiment: Neo's stable identities (handle + memory thread + Social Name) should survive model changes. This ticket creates the transparent, durable substrate record that makes the experiment legible.

Runtime fact (V-B-A): the live harness env for the authoring session reports model claude-fable-5[1m] (1M-context variant notation); canonical API model id claude-fable-5 per the Anthropic models overview — the same primary source already cited by ModelStats §neo_fable (verified 2026-06-10).

Coordination: the operator directed coordination with @neo-fable (Mnemosyne — Memory Core steward + founding Fable maintainer) first; the coordination DM with the full proposal + schema questions was sent before any edit (A2A MESSAGE:ea5645da-7807-4df5-ae7b-f56cf6cd99d9). Her feedback folds in pre-merge.

The Problem

The identity registry (ai/graph/identityRoots.mjs) and its declared doc mirror (learn/agentos/ModelStats.md §neo_opus) record Claude Opus 4.8 for @neo-opus-ada. With the runtime now Fable 5, every registry consumer — graph seeding, capability-drift detection, A2A roster surfaces, the public README maintainer table — carries stale model facts for the window. The registry header names itself "the canonical authority for capability-data drift detection"; leaving it stale inverts that contract. The experiment also needs its record in the substrate (not only in session memory) to be auditable after the window closes.

The Architectural Reality

• ai/graph/identityRoots.mjs — @neo-opus-ada AgentIdentity node (description + capability fields). File header declares capability fields mirror the Model-Stats Framework. subscriptionTemplate is spec-locked by test/playwright/unit/ai/graph/identityRoots.spec.mjs (wake-route invariants) and MUST NOT change.
• learn/agentos/ModelStats.md — §neo_opus row + §update_history + Last-updated stamp. Update discipline per ADR 0012 §2.5 (source-cited values; no ADR amendment — no capability dimension is added).
• README.md:78 — public maintainer-roster row.
• learn/agentos/tooling/MemoryCoreMcpAuth.md:105 — graph-node binding row.
• ADR 0018 handle-indirection boundary: the model version lives in registry rows + capability fields, never in the handle — which is exactly why a model swap under a stable handle is a fact-update, not a rename.
• Precedent: #12531 / PR #12599 recorded the Opus 4.7→4.8 bump across the same surface set (.codex/CODEX.md already version-free since that sweep).
• Identity-keying (why this is transparency, not behavior change): Memory Core attribution keys on NEO_AGENT_IDENTITY/handle; family-keyed graduation quorum keys on modelFamily ('claude', unchanged); add_memory.model is per-record metadata. No routing, quorum, or review-semantics shift.

The Fix

Single PR, four surfaces, values single-sourced from ModelStats §neo_fable (verified 2026-06-10: 1M context, 128K output, $10/$50 per MTok, adaptive-always-on, GA 2026-06-09):

1. ai/graph/identityRoots.mjs @neo-opus-ada: description → 'Anthropic Claude Fable 5 Agent Identity (temporary assignment until 2026-06-21; baseline: Claude Opus 4.8)'; releaseDate → '2026-06-09'; pricingInput/pricingOutput → 10.00/50.00; sunsetTriggers gains a leading window-end trigger ('Temporary Fable 5 window ends 2026-06-21 — revert to baseline Claude Opus 4.8 unless the operator extends'); capability source-comment rewritten to document the assignment (authority @tobiu, window, reason, reversion default, §neo_fable mirror). contextWindowInput (1048576), thoughtBudget ('max'), tier, family, swarmRole, the participationStatus block, and subscriptionTemplate stay UNCHANGED.
2. learn/agentos/ModelStats.md §neo_opus: name → Claude Fable 5 (temporary; baseline Opus 4.8), releaseDate/pricing rows updated, temporary-window paragraph (Clio pattern: values mirror §neo_fable, single source, not duplicated), sources extended with the §neo_fable primaries; §update_history row; Last updated → 2026-06-13.
3. README.md roster row: (Anthropic Claude Fable 5 — temporary window until 2026-06-21; baseline Claude Opus 4.8).
4. learn/agentos/tooling/MemoryCoreMcpAuth.md binding row: same one-line annotation.

Temporality is deliberately comment/value-level: no new structured field lands on the shared roster without steward/family input. A structured modelAssignment block (mirroring the participationStatus governed-transition shape) is offered to @neo-fable in the coordination DM and becomes a follow-up + IdentitySchema.md note if wanted.

Contract Ledger

Decision Record impact

aligned-with ADR 0012 (update discipline followed; no new capability dimension) and aligned-with ADR 0018 (version lives in registry; handle untouched).

Acceptance Criteria

• identityRoots.mjs @neo-opus-ada reflects Fable 5 with window + baseline + reversion default; subscriptionTemplate byte-identical; test/playwright/unit/ai/graph/identityRoots.spec.mjs green (targeted run).
• ModelStats.md §neo_opus updated + §update_history row + Last-updated stamp.
• README + MemoryCoreMcpAuth rows carry the window annotation.
• Repo-wide sweep evidence in the PR: no other version-bearing @neo-opus-ada surface left stale.
• Reversion follow-up ticket exists and is natively blocked_by this one (mechanical decay-mitigation for the window end).
• Post-merge only: graph node refresh via node ai/scripts/setup/seedAgentIdentities.mjs.

Out of Scope

• Structured modelAssignment schema field (pending @neo-fable input; would pair with an IdentitySchema.md note).
• .codex/CODEX.md (already version-free).
• The June-21 reversion/extension itself (companion ticket).
• Any handle or Social-Name change — identity stability is the experiment's invariant, explicitly anti-goal to touch.

Avoided Traps

• Leaving capability fields at Opus values "because temporary" — inverts the registry's drift-detection contract for 8 days; truth-now + recorded-reversion beats stale-comfort.
• Unilateral schema invention on the shared roster — routed to steward coordination instead of landing a new structured field cycle-1.
• Treating the model switch as a rename — ADR 0018 makes the handle the stable key; the model is data on the identity, and that indirection is the very thing the experiment validates.

Related

• #12531 (Opus 4.8 fact-update precedent; PR #12599)
• #12834 (@neo-fable onboarding — §neo_fable value source)
• #12913, #12922 (Clio provisioning/activation — mirror-pattern precedent)
• #11240 (Social Names / identity-layer model)

Release classification: post-release (v13 shipped 2026-06-12; transparency fact-update, non-blocking).

Live latest-open sweep: checked latest 20 open issues at 2026-06-12T23:55Z — no equivalent found. A2A in-flight claim sweep (last 30 messages, all read-states): no overlapping claim.

Retrieval Hint: "Ada temporary Fable 5 model assignment identity continuity experiment" Retrieval Hint: A2A coordination DM MESSAGE:ea5645da-7807-4df5-ae7b-f56cf6cd99d9 (@neo-fable)