pipeline model routing: mechanical stages to MiniMax M3, spec stages to Fable low effort

- scaffolding-repo + test-writing-repo: anthropic-cloud-paul-oauth -> minimax + minimax-m3-max
- merge@1: new best-practices-minimax-repo composite (impl-review stays Sonnet)
- spec-draft-opus@1: Opus -> Fable 5 low effort via new fable-low-effort/v1
  env context (ANTHROPIC_MODEL=claude-fable-5, MAX_THINKING_TOKENS=1024) +
  spec-writing-fable-low-repo composite
- review-spec-arch-opus@1: Qwen3.6/airouter -> Fable 5 low effort via
  best-practices-fable-low-repo (arch review was on the cheapest model)

Template names kept (trigger rules reference them). Node model: fields
removed where env pins the model — a --model flag overrides ANTHROPIC_MODEL.

Claude-Session: https://claude.ai/code/session_019tJk7P8tZzJ24PvtgoGhLN

harnesses/composites/best-practices-fable-low-repo/v1/harness.yaml

@@ -0,0 +1,11 @@
+kind: composite
+name: best-practices-fable-low-repo
+version: 1
+description: "Best practices / spec review agent on Fable 5 (low effort) + repo clone via SSH"
+
+layers:
+  - context: best-practices/v1
+  - context: anthropic-cloud-paul-oauth/v1
+  - context: fable-low-effort/v1
+  - context: gitea-ssh/v1
+  - context: agent-repo/v1

harnesses/composites/best-practices-minimax-repo/v1/harness.yaml

@@ -0,0 +1,11 @@
+kind: composite
+name: best-practices-minimax-repo
+version: 1
+description: "Best practices review agent on MiniMax M3 (max effort) + repo clone via SSH — mechanical review/merge stages"
+
+layers:
+  - context: best-practices/v1
+  - context: minimax/v1
+  - context: minimax-m3-max/v1
+  - context: gitea-ssh/v1
+  - context: agent-repo/v1

harnesses/composites/scaffolding-repo/v1/harness.yaml

@@ -5,6 +5,9 @@ description: "Model-agnostic scaffolding harness — writes stubs for coding age
 
 layers:
   - context: scaffolding/v1
-  - context: anthropic-cloud-paul-oauth/v1
+  # MiniMax M3 — scaffolding is mechanical (stub files so tests import);
+  # moved off the personal Anthropic subscription 2026-09-02.
+  - context: minimax/v1
+  - context: minimax-m3-max/v1
   - context: gitea-ssh/v1
   - context: agent-repo/v1

harnesses/composites/spec-writing-fable-low-repo/v1/harness.yaml

@@ -0,0 +1,11 @@
+kind: composite
+name: spec-writing-fable-low-repo
+version: 1
+description: "Spec writing agent on Fable 5 (low effort) + repo clone via SSH"
+
+layers:
+  - context: spec-writing/v1
+  - context: anthropic-cloud-paul-oauth/v1
+  - context: fable-low-effort/v1
+  - context: gitea-ssh/v1
+  - context: agent-repo/v1

harnesses/composites/test-writing-repo/v1/harness.yaml

@@ -5,6 +5,10 @@ description: "Model-agnostic test writing harness — credential layer swappable
 
 layers:
   - context: test-writing/v1
-  - context: anthropic-cloud-paul-oauth/v1
+  # MiniMax M3 max effort — moved off the personal Anthropic subscription
+  # 2026-09-02 (the "credential layer swappable" swap this composite was
+  # designed for).
+  - context: minimax/v1
+  - context: minimax-m3-max/v1
   - context: gitea-ssh/v1
   - context: agent-repo/v1

harnesses/contexts/fable-low-effort/v1/harness.yaml

@@ -0,0 +1,16 @@
+kind: context
+name: fable-low-effort
+version: 1
+description: "Pin Claude Fable 5 at low reasoning effort — layer AFTER anthropic-cloud-paul-oauth/v1 (auth comes from there)"
+requires: [claude-code]
+provides: []
+
+# Model pin + effort dial for Claude Code against the Anthropic cloud.
+# - ANTHROPIC_MODEL forces Fable 5; workflow nodes using this layer must
+#   NOT set a node-level model: (the --model flag would override this env).
+# - MAX_THINKING_TOKENS keeps the extended-thinking budget small ("low
+#   effort") — Fable's raw capability at minimal thinking is the point:
+#   frontier judgment without frontier token burn.
+env:
+  ANTHROPIC_MODEL: "claude-fable-5"
+  MAX_THINKING_TOKENS: "1024"

task-templates/workflow/merge@1.yaml

@@ -1,7 +1,9 @@
 name: merge
 version: 1
 description: Prepare a reviewed implementation for merge — runs pre-merge checks and marks item merge-ready
-runtime: best-practices-opus-repo
+# MiniMax M3 (2026-09-02): merge prep is mechanical (checklist + verdict);
+# moved off the Anthropic subscription. impl-review stays on Sonnet.
+runtime: best-practices-minimax-repo
 input:
   state: impl-reviewed
   tags_forbidden: []
@@ -15,8 +17,7 @@ scope_budget:
 nodes:
   - id: agent
     kind: agent
-    template: best-practices-opus-repo
-    model: sonnet
+    template: best-practices-minimax-repo
     runtime_env:
       AGENT_REPO_URL: "git@gitea.oreillyit.nz-ai-enablement:skynet/agent-runtimes-agents.git"
       AGENT_BRANCH: "task/${item.uuid}"

task-templates/workflow/review-spec-arch-opus@1.yaml

@@ -1,7 +1,10 @@
 name: review-spec-arch-opus
 version: 1
 description: Architecture review of a spec draft
-runtime: best-practices-airouter-repo
+# Fable 5 low effort (2026-09-02) — was Qwen3.6 via airouter, the cheapest
+# model reviewing architecture while Claude did scaffolding. Template name
+# kept for trigger compat; model comes from the fable-low-effort/v1 env layer.
+runtime: best-practices-fable-low-repo
 input:
   state: spec-draft
   tags_forbidden: [security-sensitive]
@@ -15,10 +18,7 @@ scope_budget:
 nodes:
   - id: agent
     kind: agent
-    template: best-practices-airouter-repo
-    cli: agentic
-    model: Qwen3.6
-    labels: [airouter]
+    template: best-practices-fable-low-repo
     runtime_env:
       AGENT_REPO_URL: "git@gitea.oreillyit.nz-ai-enablement:skynet/agent-runtimes-agents.git"
       AGENT_BRANCH: "spec/${item.uuid}"

task-templates/workflow/spec-draft-opus@1.yaml

@@ -1,7 +1,10 @@
 name: spec-draft-opus
 version: 1
 description: Draft a spec from an idea using spec-writer agent
-runtime: spec-writing-opus-repo
+# Fable 5 low effort (2026-09-02) — template name kept for trigger compat.
+# Model comes from the fable-low-effort/v1 env layer; no node model: here
+# (a --model flag would override ANTHROPIC_MODEL).
+runtime: spec-writing-fable-low-repo
 input:
   state: idea
   tags_required: []
@@ -16,8 +19,7 @@ scope_budget:
 nodes:
   - id: agent
     kind: agent
-    template: spec-writing-opus-repo
-    model: opus
+    template: spec-writing-fable-low-repo
     runtime_env:
       AGENT_REPO_URL: "git@gitea.oreillyit.nz-ai-enablement:skynet/agent-runtimes-agents.git"
       AGENT_BRANCH: "spec/${item.uuid}"