Skip to content

Model Routing

The G-MODEL-ROUTING-AT-EXEC gate. When a task fires, this tree picks the model. Wrong tier = governance violation OR wasted budget.

yes

no

yes

no

yes

no

when execution mode

fires, MUST

dispatch Sonnet

return + verify

independently

Task arrives

Novel architecture?

Rule arbitration?

Henry decision gate?

First instance of pattern?

Mechanical execution?

Per-file transform?

Pre-specified rubric?

Pattern already proven?

Trivial read-only?

file-existence?

single-value fetch?

Opus 4.7

$5 / $25 per Mtok

Stays in main conversation

Sonnet 4.6

$3 / $15 per Mtok

Dispatched via Agent tool

with 8-element prompt

Haiku 4.5

$1 / $5 per Mtok

Dispatched via Agent tool

tight scope

Opus 4.7 stays in the main conversation. It does:

  • Plan authoring + amendments
  • Audit verdict synthesis (mapping raw evidence → decisions)
  • Multi-phase coordination + dependency sequencing
  • Novel architectural decisions
  • Henry interaction + decision gating
  • Rule compliance gating

Sonnet 4.6 runs as a subagent dispatched via the Agent tool. It handles:

  • Tool-driven mechanical execution (e.g. run a shipped tool against a target file)
  • Per-file code transforms against pre-specified rubric
  • Batch operations with deterministic success criteria
  • Test authoring against behavior spec Opus wrote
  • Grep-heavy evidence gathering
  • Documentation generation from structured data

Haiku 4.5 runs as a subagent for trivial reads only:

  • File-existence checks
  • Glob searches
  • Single-value fetches

When Opus dispatches Sonnet, the prompt MUST include all 8 of:

  1. Task goal (one sentence)
  2. Evidence already gathered (file paths, line numbers, grep counts)
  3. Tool to use (shipped lib/tool path)
  4. Test requirements (how many, exact behavior)
  5. Acceptance criteria (deterministic checks)
  6. Rollback command (exact revert steps)
  7. Rule constraints the subagent must self-check
  8. Output format (what to report back)

After Sonnet returns, Opus runs an independent verification (grep, test count, file existence). Trusted-but-verified.

If the pattern isn’t already proven (prior site migrated successfully, prior test passing, prior edit verified), Opus does the first instance itself to establish the pattern.