model-tiering-convention

model-tiering-convention

TL;DR

Three tiers, picked by agent role:

• haiku — fast + cheap, used for explorer (with permissionMode: plan), doc-writer, anything that reads/lists/summarises
• sonnet — workhorse, used for code-reviewer, test-writer, migration-writer, default for delivery agents
• opus — high-quality, used for security-reviewer, pr-investigator, deep-research, high-stakes architectural decisions

Picked from Triora's mature convention; promoted to cross-cutting in Wave 1.

Decision table

Agent role	Tier	Why
explorer	haiku	Read-only with permissionMode: plan; speed > sophistication
doc-writer	haiku	Format-heavy work where consistency > insight
summariser	haiku	Lossy compression; sonnet is overkill
code-reviewer	sonnet	Catches most issues; cost-efficient at scale
test-writer	sonnet	Pattern-matching test generation
migration-writer	sonnet	Mechanical transformation work
qa-runner	sonnet	Executing test suites + interpreting results
ops-auto	sonnet	Routine deploy / sync / status operations
security-reviewer	opus	Stakes are high; misses are expensive
pr-investigator	opus	Synthesises across many files
deep-researcher	opus	Open-ended exploration
architect	opus	Design decisions with long-term impact
takeoff-estimator (Pillarworks BOQ)	sonnet	Domain-specific, well-structured
handoff-protocol mediator	sonnet	Coordinates between agents
Default if unsure	sonnet	Workhorse default

How to declare in a subagent file

---
name: code-reviewer
description: Reviews code changes for security, performance, and correctness.
tools: [Read, Grep, Glob]
model: sonnet
permissionMode: plan
color: yellow
---

Permission modes by tier

Tier	Default permissionMode	Why
haiku	plan (read-only)	Speed agents shouldn't be allowed to write
sonnet	acceptEdits (writes OK, no bash without confirm)	Workhorse delivery default
opus	acceptEdits (or default)	High-stakes; trust the more capable model

The explorer agent uniquely has model: haiku + permissionMode: plan — combining speed-tier model with read-only mode. This is the smart pattern Triora pioneered.

Cost considerations

Tier	~ Cost relative to opus	When NOT worth it
haiku	1/15×	Anything requiring multi-file synthesis
sonnet	1/5×	Open-ended exploration; ambiguous decisions
opus	1×	High-volume routine work (deploy checks, lint suggestions)

A typical Orryx Group session: 1 opus orchestrator + 3-5 sonnet workers + 1-2 haiku explorers. Cost dominated by opus, but its calls are sparse.

Gotchas

• Don't default everything to opus. Cost runs away fast. Opus is for synthesis + high-stakes calls.
• Don't default everything to haiku. Haiku misses subtle issues; using it for code review is false economy.
• Match tier to permissionMode. Haiku with full write access is a footgun; opus with plan-only loses value.
• Triora's specific roles aren't the only legal set. Add new roles as needed; pick tier by the decision table.

See also

• Anthropic model documentation — for capability/cost details
• D:\Clinical.Trials\.claude\agents\ — Triora's mature tier assignments (the canonical reference)
• references/triora-agent-inventory.md — full Triora agent → tier map