Model & cost

The goal is good-enough model per task to lower spend without hurting code quality. Code quality is driven more by conventions + verification than by raw model size, so a strong default plus tuned subagents goes a long way.

Default model

settings.json sets "model": "opusplan" — Opus while planning, Sonnet while executing. You get Opus-grade design (where rework is prevented) and Sonnet’s strong, cheaper execution against your rules.

Switch anytime with /model (pick + Enter to save as default, or s for session-only). Drop to sonnet for routine work; bump to opus/fable when a task is genuinely hard.

Subagent routing

Set via model: in each agent’s frontmatter (agents/*.md):

Subagent	Model	Why
architect-reviewer	opus	High-value, infrequent design judgment
backend-architect	opus	Design decisions prevent downstream rework
frontend-architect	opus	Rendering/state/component design — same rationale
ux-designer	opus	UX flow/journey/usability design — design-tier, upstream of frontend-architect
figma-designer	sonnet	Figma execution — materializes specs via MCP; execution-tier like developer agents
code-reviewer	opus	A strong reviewer = less manual review for you
backend-developer	sonnet	Implementation/execution — fast + cheap against the conventions
frontend-developer	sonnet	Implementation/execution — fast + cheap against the conventions
debugger	sonnet	Iterative; escalate with /model if stuck
feature-investigator	sonnet	Requirements/spec investigation (upstream default)
saas-legal-advisor	opus	Legal reasoning + compliance assessment — wrong guidance is costly
cloud-architect	opus	Infra design + review — mistakes are costly and often hard to reverse
devops-engineer	sonnet	Implementation/execution against a design

Future mechanical agents (test-runners, formatters) should use haiku. Override all subagents at once with CLAUDE_CODE_SUBAGENT_MODEL.

Manual levers to cut tokens

• /effort low|medium for straightforward tasks (less thinking spend).
• /clear between unrelated tasks; /context to see what’s using space; /compact near the limit.
• Delegate noisy work (test output, log scans, doc fetches) to a subagent — its output stays in its context, not yours.
• Prompt caching is automatic (CLAUDE.md/system prompt reused cheaply).
• Pin the background model with ANTHROPIC_DEFAULT_HAIKU_MODEL (ANTHROPIC_SMALL_FAST_MODEL is deprecated).

Rough trade-off

Verify current pricing — but roughly: Haiku ≈ cheapest (mechanical work), Sonnet ≈ daily-driver coding, Opus/Fable ≈ hardest reasoning at top cost.

Next

• Subagents — full agent descriptions.
• Concepts — why “good-enough model per task” is the design goal, not just a cost note.