Reference: Endpoints, Model SKUs & Headers

Base Endpoints

Endpoint	Format	Path examples	Used by
https://router.neosmith.ai	Anthropic Messages API	/v1/messages	Claude Code
https://router.neosmith.ai/v1	OpenAI API	/v1/chat/completions, /v1/responses, /v1/models	Cline, Continue, JetBrains AI, Cursor, Codex

Important: The OpenAI-format clients need the /v1 suffix in the base URL. The Anthropic-format client (Claude Code) uses the bare host (it appends /v1/messages itself).

Supported API Surfaces

Route	Method	Format	Notes
/v1/messages	POST	Anthropic	Claude Code, Anthropic SDK
/v1/chat/completions	POST	OpenAI	Most BYOM agents
/v1/responses	POST	OpenAI Responses	OpenAI Codex, newer agents
/v1/models	GET	OpenAI	Model list (for clients that query it)
/whoami	GET	—	Auth + identity check

Model SKUs

NeoSmith exposes branded model SKUs. Set whichever your agent requires in its model field. Routing is automatic behind each SKU.

Model SKU	Tier	Behavior
neosmith.intelligent-pro	Opus-tier (default)	SLM-first, escalates to Claude Opus on hard tasks / verifier-fail
neosmith.intelligent-basic	Sonnet-tier	SLM-first with Sonnet fallback; no Opus
neosmith.intelligent-lite	Haiku/SLM-only	Lowest cost, SLM-only, no frontier escalation
neosmith.intelligent-maestro	Highest-accuracy agentic coding	Fable-tier; top-of-ladder agentic lane

Anthropic-style model ids (e.g. claude-opus-4) are also accepted for Claude Code compatibility and map to the intelligent-pro tier. Unknown model names (e.g. gpt-4o) are rejected with HTTP 400.

Authentication

All requests authenticate with your NeoSmith API key. Keys come in three prefixes by tier — sk-plus-*, sk-slm-*, sk-std-* — and a Cognito JWT (starts with eyJ) is also accepted. Examples below use sk-plus-yourname-xxxxxx.

Format	Header
Anthropic (/v1/messages)	x-api-key: sk-plus-... or Authorization: Bearer sk-plus-...
OpenAI (/v1/...)	Authorization: Bearer sk-plus-...

Optional NeoSmith Headers

These headers add attribution and governance metadata (all optional):

Header	Purpose
x-neosmith-session	Group requests into a session for routing stickiness
x-neosmith-project	Attribute cost to a project/repo
x-neosmith-agent	Tag which agent/tool sent the request (e.g. github-actions)
x-neosmith-customer	Explicit customer/dev id override
x-neosmith-tier	Request a specific tier

Response Metadata

Every response includes a neosmith_meta side-channel object (clients that don’t recognize it ignore it):

{
  "neosmith_meta": {
    "model": "neosmith.intelligent-pro",
    "model_class": "slm",
    "reason": "default_codegen",
    "verdict": "pass",
    "escalated": false,
    "latency_ms": 850
  }
}

Use this to see which model served the request and whether it escalated to Opus.

Environment Variable Summary

Variable	Value	Used by
ANTHROPIC_BASE_URL	https://router.neosmith.ai	Claude Code
ANTHROPIC_API_KEY / ANTHROPIC_AUTH_TOKEN	sk-plus-yourname-xxxxxx	Claude Code
ANTHROPIC_MODEL	neosmith.intelligent-pro (default SKU)	Claude Code
ANTHROPIC_DEFAULT_{OPUS,SONNET,HAIKU,FABLE}_MODEL	per-tier NeoSmith SKU (see ladder below)	Claude Code /model picker
ANTHROPIC_DEFAULT_{...}_MODEL_NAME / _DESCRIPTION	branded label + description per tier	Claude Code /model picker
OPENAI_BASE_URL	https://router.neosmith.ai/v1	OpenAI SDK clients, Codex
OPENAI_API_KEY	sk-plus-yourname-xxxxxx	OpenAI SDK clients, Codex

Claude Code per-tier ladder (written by neosmith claude on):

Slot	SKU	Display name
OPUS	neosmith.intelligent-pro	NeoSmith Pro
SONNET	neosmith.intelligent-basic	NeoSmith Basic
HAIKU	neosmith.neolite	NeoSmith NeoLite
FABLE	neosmith.intelligent-maestro	NeoSmith Maestro