claude-max-bridge

A small FastAPI server that exposes an OpenAI-compatible /v1/chat/completions endpoint and translates each request into a claude CLI subprocess call. This lets LiteLLM (or any OpenAI-compatible client) consume a Claude Max subscription through the locally-installed claude binary without needing an Anthropic API key.

How it works

1. Client sends an OpenAI chat-completions request (streaming or non-streaming).
2. The bridge extracts the system prompt and conversation turns.
3. It spawns claude --print --output-format stream-json --input-format stream-json ... and pipes the conversation as NDJSON to stdin.
4. It parses the NDJSON stdout, computes text deltas from partial assistant messages, and re-emits them as OpenAI SSE chunks (or buffers for non-streaming).
5. Usage totals and cost from the result event are forwarded in the response.

Authentication is handled entirely by the claude binary; the bridge bind-mounts the existing ~/.claude credentials directory (rw, so the CLI can refresh expired OAuth tokens automatically).

Environment variables

Variable	Default	Description
CLAUDE_BIN	/usr/local/bin/claude	Path to the claude CLI binary
CLAUDE_HOME	/root/.claude	Path to the Claude config / credentials directory
LOG_LEVEL	INFO	Python logging level
REQUEST_TIMEOUT_S	120	Per-request subprocess timeout in seconds

Running with Docker

docker build -t claude-max-bridge .

docker run -d \
  --name claude-max-bridge \
  -p 8000:8000 \
  -v /usr/local/bin/claude:/usr/local/bin/claude:ro \
  -v /root/.claude:/root/.claude:rw \
  -v /root/.claude.json:/root/.claude.json:rw \
  claude-max-bridge

Supported models

• claude-sonnet-4-6 (default fallback)
• claude-opus-4-7
• claude-haiku-4-5
• claude-opus-4-5
• claude-opus-4-0
• claude-sonnet-3-7
• claude-haiku-3-5
• Short aliases: sonnet, opus, haiku

Unknown model names fall back to claude-sonnet-4-6.

Extended parameters (extra_body)

The bridge maps several CLI flags via the extra_body field:

extra_body key	CLI flag	Notes
effort	--effort <level>	low/medium/high/xhigh/max. Overrides temperature mapping.
fallback_model	--fallback-model <model>	Model used when primary hits rate limit
system_prompt_mode	--system-prompt / --append-system-prompt	"replace" (default) or "append"
max_turns	--max-turns <n>	Cap agentic turns (non-interactive)
max_budget_usd	--max-budget-usd <amount>	Per-request cost cap
json_schema	--json-schema <schema>	Structured JSON output
exclude_dynamic_system_prompt_sections	--exclude-dynamic-system-prompt-sections	Better cache reuse for multi-user

temperature is also mapped to --effort when no explicit effort is set: <0.2→low, <0.4→medium, <0.7→high, <0.9→xhigh, ≥0.9→max.

response_format.json_schema (OpenAI standard) is also recognised and forwarded to --json-schema automatically.

Response extensions

Non-streaming responses and streaming done-chunks include:

Field	Description
x_claude_cost_usd	Actual cost as reported by CLI (total_cost_usd). $0 for Max subscription.
x_claude_rate_limit	Rate-limit info: utilization, resetsAt, rateLimitType

LiteLLM configuration

model_list:
  - model_name: claude-sonnet-4-6
    litellm_params:
      model: openai/claude-sonnet-4-6
      api_base: http://claude-max-bridge:8000/v1
      api_key: "unused"
      stream_timeout: 120
      timeout: 120
      input_cost_per_token: 0.000003    # for dashboard visibility; actual cost $0
      output_cost_per_token: 0.000015

Endpoints

Method	Path	Description
GET	/health	Liveness check, always returns 200 OK
GET	/v1/models	Lists supported models
POST	/v1/chat/completions	OpenAI-compatible chat completions

Notes

• Rate-limit responses from the CLI are translated to HTTP 429.
• Auth errors are translated to HTTP 401.
• The subprocess is killed on client disconnect or timeout.
• top_p, frequency_penalty, presence_penalty, seed, stop, n are ignored.
• MCP servers are explicitly disabled (--mcp-config '{"mcpServers":{}}' --strict-mcp-config) to prevent credential leakage and side-effects.