using-the-mcp-server

Using the MCP Server

The liter-llm MCP server exposes 22 tools that mirror the proxy's REST endpoints, so an MCP-compatible client (Claude Code, Claude Desktop) can call 165 LLM providers as tools with no glue code.

How it runs in this plugin

The plugin auto-registers the server. Its command is the bundled launcher scripts/mcp-launch.sh, which execs liter-llm mcp --transport stdio. On first run the launcher resolves a liter-llm binary: it reuses one on PATH, then tries npx/uvx, then Homebrew, then downloads a checksum-verified prebuilt from the tool's latest GitHub release. Override with LITER_LLM_LAUNCHER=auto|npx|uvx|brew|download.

To run it manually:

liter-llm mcp --transport stdio          # for Claude Code / Claude Desktop
liter-llm mcp --transport http --port 3001

The 22 tools

Modality tools: chat, embed, generate_image, speech, transcribe, moderate, rerank, search, ocr.

Model listing: list_models.

File operations: create_file, list_files, retrieve_file, delete_file, file_content.

Batch operations: create_batch, list_batches, retrieve_batch, cancel_batch.

Responses API: create_response, retrieve_response, cancel_response.

Authentication

stdio has no per-request auth headers, so the server binds auth once at startup via [mcp] config: set mcp.stdio_key_id to bind a specific virtual key, or mcp.stdio_trust_local = true for fully trusted local environments. Provider keys still come from env vars.

When to prefer MCP over the CLI or SDK

• Prefer MCP inside an agent session: the agent invokes tools directly, with no code to write or process to manage.
• Prefer the SDK when building application software in a specific language.
• Prefer the proxy when many apps or teams need a shared OpenAI-compatible endpoint with keys, budgets, and rate limits.