Anymodel

AnyModel Development Skill

You are working on AnyModel — a universal AI coding proxy that lets you use any AI model through one interface. This skill contains everything you need: architecture, conventions, deployment rules, and debugging guidance.

Product Identity

• Name: AnyModel (capital A, capital M — never "anymodel" or "Any Model" in user-facing text)
• Package: anymodel on npm
• Website: https://anymodel.dev
• GitHub (proxy): https://github.com/anton-abyzov/anymodel
• Client bundle: cli.js in this repo/package is the shipped Claude Code-compatible TUI
• Author: Anton Abyzov (@aabyzov on X, @AntonAbyzov on YouTube)
• License: MIT

Architecture

AnyModel client (cli.js) --> anymodel proxy (:9090) --> OpenRouter / Ollama / OpenAI-compatible

Three components:

1. Proxy (proxy.mjs) — HTTP server intercepting /v1/messages, sanitizes requests, translates formats, routes to providers
2. CLI (cli.mjs) — entry point for starting proxy, connecting, managing presets
3. Bundled client (cli.js) — modified Claude Code client with violet diamond character and AnyModel branding

Providers

Presets (update version in KNOWLEDGE-BASE.md when changing)

When adding a new preset: add to MODEL_PRESETS in cli.mjs, update help text, update KNOWLEDGE-BASE.md, update site/index.html, update README.md.

Proxy Sanitization (proxy.mjs)

The sanitizeBody() function is the heart of AnyModel. It makes any model work with Claude Code's request format.

What it does (in order):

1. Strips Anthropic-only fields: betas, metadata, speed, raw output_config, context_management; preserves output_config.effort internally for compatible OpenAI forwarding
2. Preserves thinking — reasoning models (DeepSeek R1) need this for chain-of-thought
3. Preserves cache_control for OpenRouter (Anthropic models support it), strips for Ollama/OpenAI
4. Clamps max_tokens to minimum 16 — Claude Code sends max_tokens: 1 for probes, OpenAI/GPT rejects anything below 16
5. Fixes tool schemas:
   • Missing input_schema entirely -> adds a minimal object schema
   • Empty properties: {} -> keeps it empty and adds additionalProperties:false
   • Missing type field -> adds "type": "object"
   • Recursively fixes nested schemas (anyOf, oneOf, allOf, items)
   • Never injects or strips _unused; real _unused params must round-trip
6. Strips Anthropic-only tool fields: cache_control, defer_loading, eager_input_streaming, strict
7. Normalizes tool_choice: converts string format to object format
8. Local providers (Ollama, LMStudio, llama.cpp): capability-aware tool passthrough — since v1.12.0 the proxy no longer blanket-strips tools. Behavior is controlled by OLLAMA_TOOLS env var (auto default, on, off). In auto mode, the proxy tries tools and caches per-model capability; on "does not support tools" errors it retries without tools and remembers that model as no-tool-support. Tools are then compressed and budget-trimmed via providers/tool-compressor.mjs to fit local context windows (core tools Bash/Read/Write/Edit always kept). Translation: Anthropic tool definitions -> OpenAI function format -> Ollama message.tool_calls[] -> translated back to Anthropic tool_use content blocks with stop_reason: "tool_use". Streaming supported.
9. tool_choice always stripped for Ollama — Ollama doesn't support tool_choice; proxy removes it unconditionally.
10. Auto-retry without tools — if a provider returns "No endpoints found that support tool use" / "does not support tools", proxy retries with tools removed AND caches model as no-tool-support.

Why this matters

Without sanitization, MCP tools break on non-Anthropic models. Claude Code sends 80+ tool definitions including MCP servers (Slack, Figma, Gmail, etc.) with every request. The proxy ensures these schemas are valid for the target model, so MCP works seamlessly through any provider — including local Ollama/LMStudio/llama.cpp models that support function calling (Qwen 3/Coder, Llama 3.1+, Mistral, DeepSeek R1, Gemma 4).

Regression guard: test/ollama-tool-passthrough.test.mjs asserts that in auto mode with an uncached model, tools are forwarded (not stripped). See also test/ollama-tools.test.mjs for the capability-cache logic.

Client Identity

• Character: Violet diamond-themed (diamond-head and diamond-feet ASCII art)
• Color: Light violet rgb(147,130,255), ANSI fallback magentaBright
• Branding: "AnyModel" everywhere (not "Claude Code"). Tips say "Ask AnyModel" not "Ask Claude"
• Version: Synced with npm package via prepublishOnly script
• ANYMODEL_MODEL: Env var displayed in client UI showing active model name

When modifying the client: never break the violet identity. The diamond character and "AnyModel" branding are what distinguish this from standard Claude Code.

Environment Variables

Client Discovery (findClient())

When npx anymodel connects, it finds the client in this order:

1. ANYMODEL_CLIENT env var (explicit path)
2. cli.js next to cli.mjs (bundled in npm package)
3. cli.js in current directory
4. Global claude binary (last resort fallback)

Deployment Pipeline (MANDATORY)

Every change MUST follow this pipeline. Never skip steps, never publish without tests passing.

# 1. Run all tests
npm test

# 2. Commit and push
git add <changed-files>
git commit -m "description of change"
git push

# 3. Version bump and publish to npm
npm version patch
npm run sync-version    # syncs version to cli.js
npm publish

# 4. Deploy website (only if site/ changed)
vercel --prod

The prepublishOnly script in package.json handles version syncing. After npm version patch, run npm run sync-version to update the version in the bundled client, then npm publish.

Adding a New Provider

1. Create providers/newprovider.mjs following the pattern in existing providers
2. Export: { name, transformRequest, transformResponse, buildUrl, getHeaders }
3. Add detection logic in cli.mjs (PROVIDERS array)
4. Add env var documentation
5. Handle tool schema translation if the provider's format differs
6. Add tests in test/
7. Update KNOWLEDGE-BASE.md
8. Run the full deployment pipeline

Adding a New Preset

1. Add to MODEL_PRESETS in cli.mjs
2. Update the help text in showUsage()
3. Update KNOWLEDGE-BASE.md preset table
4. Update site/index.html preset section
5. Update README.md
6. Run the full deployment pipeline

Debugging Guide

Common Issues

Debugging Proxy Traffic

The proxy logs every request with color-coded output:

• [OPENROUTER] / [OLLAMA] / [OPENAI] — provider prefix
• tools=N — number of tools in request
• stream=true — streaming mode
• Yellow [OLLAMA] Stripping N tools — tool removal for local models
• Green 200 — successful response
• Red status codes — errors with body excerpt

Competitive Context

Anthropic Third-Party Cutoff (April 4, 2026)

Claude subscriptions no longer cover third-party tools. AnyModel proxy mode is NOT affected (routes through OpenRouter, never touches Anthropic OAuth). This is a key selling point — AnyModel users don't need a Claude subscription.

URLs and Links

File Structure

anymodel/
  cli.mjs              # CLI entry point
  cli.js               # Bundled client (12MB modified Claude Code)
  proxy.mjs            # HTTP proxy server + sanitization
  package.json         # npm config
  providers/
    openrouter.mjs     # OpenRouter provider (passthrough)
    ollama.mjs         # Ollama provider (OpenAI translation + num_ctx)
    openai.mjs         # OpenAI provider (bidirectional translation)
  site/
    index.html         # anymodel.dev homepage
    styles.css / script.js / sitemap.xml / robots.txt
  test/                # 93+ tests
  KNOWLEDGE-BASE.md    # Single source of truth (keep in sync with this skill)

Testing

Run all tests before any commit:

npm test

Tests cover: sanitization, tool schema fixing, provider translation, preset resolution, max_tokens clamping, streaming, error handling. When adding features, add corresponding tests. The test count should only go up.

Changelog

• 1.0.1: Added version tracking support