kosha-discovery

Tells your agent — or your code — which model to use and what it costs.

Website: kosha.srinivas.dev

kosha discovers models across 46 providers and local runtimes, finds your API keys wherever they already live (env vars, Claude CLI, Codex, gcloud ADC, AWS SSO), fills in pricing and context limits, and answers questions like the cheapest model with tool use and 128k context that I actually hold a key for. It ships as a TypeScript library, a CLI, an HTTP API, an OpenAI-compatible proxy with a spend ledger, and an MCP server.

It works with no API keys at all — discovery falls back to the public models.dev and LiteLLM catalogs, so kosha list is useful on a fresh machine.

Install

npm install @sriinnu/kosha-discovery       # library / server
npm install -g @sriinnu/kosha-discovery    # global `kosha` CLI
brew install sriinnu/tap/kosha             # same CLI and MCP server, via Homebrew

Requires Node.js 22+.

Related MCP server: io.github.0xzr/freellmpool

Quick start

Library

import { createKosha } from "@sriinnu/kosha-discovery";

const kosha = await createKosha();

const models   = kosha.models();                          // ModelCard[] across every provider
const cheapest = kosha.cheapestModels({ role: "image" }); // ranked by price, with missingCredentials
const sonnet   = kosha.model("sonnet");                   // alias → canonical ID; undefined if unknown
console.log(sonnet?.pricing); // { inputPerMillion: 2, outputPerMillion: 10, cacheReadPerMillion: 0.2, ... }

CLI

kosha discover                       # query every provider; writes ~/.kosha/cache and the manifest
kosha list --provider anthropic      # read from the local cache
kosha model sonnet                   # one model, alias-aware
kosha routes claude-opus-5-5         # every serving route for a model (direct, OpenRouter, Bedrock, …)
kosha cheapest --role embeddings     # rank by price for a role
kosha doctor --ci --model opus,gpt6  # fail CI if a model you pin is deprecated, retiring, or gone
kosha spend --since 2026-09-01       # roll up the proxy's spend ledger
kosha refresh                        # bypass the cache and re-discover
kosha serve --port 3000              # HTTP API + proxy; binds 127.0.0.1 (see Proxy below)

Every command takes --json. kosha --help lists the rest.

After each discovery, a stable v1 manifest lands at ~/.kosha/registry.json:

jq '.models[] | select(.pricing.inputPerMillion < 0.1) | .modelId' ~/.kosha/registry.json

GitHub Action

Fail a build when a model your code pins is deprecated, about to be retired, or listed by no provider any more:

- uses: sriinnu/kosha-discovery@v1
  with:
    models: |
      claude-opus-5-5
      gpt-6-sol
      sonnet

Pin it to a commit SHA rather than a moving tag, as you would any action. The action runs the kosha version it was released with, not latest, so a new npm publish does not change what your CI runs until you move the pin.

It runs kosha doctor --ci --model … against the public catalogs (no provider keys needed), writes a table to the job summary, and annotates each failing model. A reseller retiring one of its routes is reported but does not fail the build while the model's own provider still serves it; deprecation-window (default 30 days) sets how far ahead a sunset counts.

Public snapshot

A weekly discovery run publishes a full snapshot — every provider, model, price and limit kosha can see without your keys — at a stable URL:

curl -sL https://github.com/sriinnu/kosha-discovery/releases/download/snapshot-latest/kosha-latest.json \
  | jq '.modelCount, .providerCount'

It is a release asset rather than a file in the repository: at ~2.8 MB growing with every provider added, committing it weekly would put roughly 150 MB of already-stale data a year into a repo people are meant to clone. Dated snapshot-YYYY-MM-DD pre-releases keep a short trail for diffing, pruned to the two most recent, and an older one is only removed once a newer one exists.

Each snapshot's release notes list what changed since the previous one — new models, repricings, new deprecations, removals. The same diff runs locally with pnpm snapshot:diff old.json new.json.

HTTP API

GET  /api/models?provider=&originProvider=&mode=&capability=
GET  /api/models/:idOrAlias             GET  /api/models/:idOrAlias/routes
GET  /api/models/cheapest?role=…        GET  /api/capabilities
GET  /api/providers[/:id]               GET  /api/roles
GET  /api/resolve/:alias                GET  /api/discovery-errors
GET  /api/discovery[/delta|/watch|/cheapest|/binding]   (stable v1 contract)
POST /api/refresh                       GET  /health          GET  /metrics
GET  /proxy/v1/models                   POST /proxy/v1/chat/completions

Parameters and response shapes: docs/api.md.

Proxy

kosha serve also exposes an OpenAI-compatible endpoint at /proxy/v1. Point any OpenAI SDK at it; the proxy resolves the model or alias, picks a provider you hold credentials for, injects the upstream key, forwards the request, and writes a row to the spend ledger.

kosha serve   # start on :3000

import OpenAI from "openai";

const client = new OpenAI({
  baseURL: "http://localhost:3000/proxy/v1",
  apiKey:  "not-used",   // kosha resolves credentials from env
});

// Use any canonical model ID or alias
const res = await client.chat.completions.create({
  model: "sonnet",
  messages: [{ role: "user", content: "hello" }],
});

// Let kosha pick the cheapest model you have a key for
const cheap = await client.chat.completions.create({
  model: "kosha:cheapest",
  messages: [{ role: "user", content: "hello" }],
});

// Cheapest model with tool_use and at least 128k context
const routed = await client.chat.completions.create({
  model: "kosha:cheapest[tool_use,128k]",
  messages: [{ role: "user", content: "hello" }],
});

kosha:cheapest filter syntax (comma-separated, combinable):

kosha:fastest, kosha:reliable, and kosha:balanced take the same filters and rank on observed latency and circuit-breaker state instead of price.

Every response carries x-kosha-model, x-kosha-provider, x-kosha-requested, x-kosha-attempt-chain, and x-kosha-estimated-cost-usd; non-streaming responses add x-kosha-actual-cost-usd when the upstream returned a usage block.

What the proxy can forward:

Defaults that matter before you expose it: the server binds 127.0.0.1. Pass --host 0.0.0.0 (or KOSHA_HOST) to listen on a network interface, and set KOSHA_PROXY_TOKEN so /proxy/* and POST /api/refresh require Authorization: Bearer <token> or x-kosha-token. KOSHA_MONTHLY_BUDGET_USD caps spend per calendar month. Reference: docs/api.md, docs/operations.md.

MCP server

kosha-mcp serves the registry over the Model Context Protocol on stdio, so an agent can call kosha_query_models, kosha_cheapest_model, kosha_ranked_routes, kosha_model_detail, kosha_model_routes, kosha_resolve_alias, kosha_provider_health, and kosha_context_strategy without an HTTP server.

claude mcp add kosha -- kosha-mcp

It is published to the MCP registry as io.github.sriinnu/kosha-discovery, so clients that read the registry can install it without a manual command. The manifest is server.json.

Every provider key is optional. With no credentials at all the server still answers from the public models.dev and LiteLLM catalogs plus a curated offline list, so it is useful on a fresh machine.

Tools and protocol details: docs/mcp.md.

Supported providers

46 providers. Each has a descriptor in src/provider-catalog.ts; most OpenAI-compatible ones are driven from GENERIC_OPENAI_PROVIDERS in src/discovery/generic-openai.ts rather than a hand-written class.

Regional pairs

Several providers run separate hosts for international and mainland-China traffic, with separate keys and separate price sheets — Qwen 2.5 72B is $1.40/M input internationally against $0.574/M in China. Merging them would make a model's price depend on which host answered last, so each region is its own provider:

kosha routes <model> lists every region a model is served from, so you can compare prices across them directly.

Without a key, providers fall back to the public models.dev + LiteLLM catalog, then to kosha's own weekly snapshot if those are unreachable, then to a curated static list, so kosha list works on a fresh machine. The same fallback applies when a key is present but rejected: the provider stays listed from the public catalog, shows as unauthenticated, and the error is kept for kosha doctor. Exact env var names: docs/credentials.md.

To take models.dev and LiteLLM out of the loop, set KOSHA_CATALOG_SOURCE=pinned (kosha's snapshot only) or local (a file from kosha registry export, no network). See Catalog Source.

Non-chat modes

Most models are chat, but mode also covers embedding, image, video, audio, moderation, rerank, and judgment. A judgment model — TypeSafe's System One family — answers a question with a typed value (a choice and its probability distribution, a probability, or a score on described levels) instead of generating text. It carries no chat capability on purpose: routing a prompt to one would be a category error.

kosha cheapest --role judgment    # rank judgment models by price
kosha model jev                   # mode: judgment, $0.042/M in, $0 out

How it works

1. Discovery — one discoverer per provider runs concurrently (Promise.allSettled); each returns normalized ModelCards. A failing provider is recorded in discoveryErrors() and doesn't block the others.

2. Enrichment — pricing, context window, and output cap are filled from models.dev and LiteLLM where the provider API doesn't publish them; pricingSource on each card says which. Cards also carry releaseDate and a lifecycle status where a catalog publishes them.

3. Resilience — a per-provider circuit breaker with exponential cooldown, plus stale-cache fallback, so a provider outage degrades to cached data rather than an error.

4. Cache and manifest — results are cached under ~/.kosha/cache/ (24 h TTL) and exported as a versioned snapshot at ~/.kosha/registry.json for other tools to read.

5. Proxy — resolves the requested model or kosha:<strategy>[filters] selector against the registry, ranks candidate routes, forwards with failover, and records estimated and reconciled cost in ~/.kosha/ledger-YYYY-MM.jsonl.

Details: docs/architecture.md, docs/resilience.md.

Development

pnpm install
pnpm run build        # compile to dist/
pnpm run typecheck    # tsc --noEmit
pnpm run lint         # biome lint
pnpm test             # vitest run
pnpm run check        # lint + build + test

pnpm aliases:check snapshot.json        # built-in aliases that are dead or a generation behind
pnpm snapshot:diff old.json new.json    # what changed between two snapshots

The alias table in src/aliases.ts is the one part of the catalog written by hand. aliases:check compares it against a snapshot, and the weekly snapshot run annotates itself with the result, so a bare alias like opus falling behind shows up there rather than in a bug report.

Project layout

src/
  cli.ts                 # CLI entry point and arg parsing
  cli-commands.ts        # command implementations (+ cli-cmd-*.ts for the larger ones)
  registry.ts            # ModelRegistry public API
  registry-runtime.ts    # discovery orchestration, enrichment, cache, manifest export
  registry-query.ts      # model / role / capability queries
  registry-selection.ts  # cheapest candidates, binding hints
  registry-routing.ts    # cheapest / fastest / reliable / balanced ranking
  discovery/             # one discoverer per provider + static and public-seed catalogs
  enrichment/            # models.dev + LiteLLM pricing enrichment
  credentials/           # credential resolution (env, CLI files, ADC, OAuth)
  provider-catalog.ts    # provider descriptors: base URLs, transport, env var names
  aliases.ts             # built-in short names → canonical model IDs
  claude-generation.ts   # which Claude generation accepts which API parameters
  model-features.ts      # tool dialect / structured-output inference per model
  proxy.ts               # OpenAI-compatible proxy: routing, failover, ledger
  wire-anthropic.ts      # OpenAI ↔ Anthropic request / response / SSE translation
  cost.ts                # spend ledger, budget gates, usage reconciliation
  tally.ts               # zero-dependency token usage + USD tally (also exported as ./tally)
  server.ts              # Hono HTTP API + operator token gate
  mcp-server.ts          # MCP stdio server
  types.ts               # shared types

Adding a provider

For an OpenAI-compatible provider — most of them — it is two table entries:

1. Add a descriptor to PROVIDER_CATALOG in src/provider-catalog.ts (id, base URL, transport, credential env vars).

2. Add a spec to GENERIC_OPENAI_PROVIDERS in src/discovery/generic-openai.ts. It registers its own discoverer, resolves credentials from the descriptor's credentialEnvVars, and falls back to the public catalog when there is no key.

3. Map the provider to its models.dev / LiteLLM slug in src/discovery/modelsdev-seed.ts and litellm-seed.ts so keyless discovery works. Check the slug — GLM is published as zhipuai, and a missing mapping means no keyless models at all.

4. Add a case to test/discovery/generic-openai.test.ts and document the env vars in docs/credentials.md.

Write a discoverer class only when classification genuinely needs code — per-route pricing (OpenRouter), a non-OpenAI response envelope (TypeSafe), or origin remapping (Vercel):

1. Create src/discovery/<provider>.ts extending BaseDiscoverer or OpenAICompatibleDiscoverer; fetchJSON and makeCard are provided.

2. Export it from src/discovery/index.ts and add a factory entry to DISCOVERER_REGISTRY.

3. Add a resolver branch in src/credentials/resolver.ts only for a bespoke search order (CLI files, OAuth, ADC, SSO). A plain API key in env vars needs no branch — the descriptor covers it.

4. Add test/discovery/<provider>.test.ts (mock fetch; see typesafe.test.ts).

Docs

The same pages are mirrored to the wiki, alongside guides that only live there (troubleshooting, the release runbook). docs/ is the source: the mirror is regenerated on every push to main, so edit here, not there.

Release

1. Bump version in package.json and server.json (both places), and date the [Unreleased] section in CHANGELOG.md; merge that as a PR.

2. Tag and push:

git tag -s vX.Y.Z -m "vX.Y.Z" && git push origin vX.Y.Z
gh workflow run release-npm.yml --ref vX.Y.Z -f tag=vX.Y.Z

The workflow checks that the tag matches package.json, runs lint / build / test, stages the package on npm with provenance, and creates the GitHub Release. Staging authenticates through npm trusted publishing (OIDC); there is no npm token. The version goes live only after a maintainer approves it with 2FA:

npm stage list @sriinnu/kosha-discovery
npm stage approve <id>
gh workflow run release-npm.yml --ref vX.Y.Z -f tag=vX.Y.Z -f publish_npm=false -f create_github_release=false   # then publish to the MCP registry

Support

kosha is free and open source. If it helps you pick cheaper models, consider sponsoring its upkeep:

• GitHub Sponsors

• Buy Me a Coffee

License

MIT