Drop-in capture
Change one base URL. Every request and response — streamed or not — captured byte-for-byte with timing, TTFT, and token counts. Unknown traffic passes through untouched.
See what your agents are actually doing.
vessel sits between your LLM clients and any backend — Ollama, OpenAI, Anthropic, or anything compatible. Change one base URL and every request is captured live: prompts, responses, timing, token counts. Search it, replay it against a different model, compare the results. One small binary. No account. Nothing leaves your machine.
Finding the latest release for your operating system…
Find the one that went wrong
Full-text search across prompts and responses. Filter by model, backend, or agent tag. Truncations, errors, and cold model loads are badged, not buried.
Replay against any model
Re-send a captured request to a different backend or model — no client changes — and compare output, speed, and tokens side by side.
Ask your AI about it
A built-in read-only MCP server lets Claude Code — or any MCP client — search and inspect your captured traffic directly. “Why did my agent stall?” is now a question you can just ask.
Quickstart
OLLAMA_HOST=127.0.0.1:4550 ollama run llama3.2
# or any SDK: base_url = "http://127.0.0.1:4550/b/openai/v1"