chatviz

Real-time visualization of AI agent conversations. chatviz sits between your agent and its LLM, capturing every message and rendering it live in a browser.

Install

uvx chatviz          # run directly, no install needed
pip install chatviz  # or install persistently

Two modes of operation

Standalone proxy

You run chatviz separately, then point your agent at it.

┌─────────┐   Anthropic API    ┌─────────┐   Anthropic API    ┌──────────────┐
│  Agent  │ ─────────────────► │ chatviz │ ─────────────────► │  LLM (upstream)│
└─────────┘                    └────┬────┘                    └──────────────┘
                                    │ SSE
                                    ▼
                              ┌───────────┐
                              │  Browser  │
                              │ :7890     │
                              └───────────┘

Start chatviz:

uvx chatviz [--port 7890] [--upstream URL] [--profile AWS_PROFILE]

Then configure your agent to use http://localhost:7890 as its base URL. For Claude Code:

export ANTHROPIC_BASE_URL=http://localhost:7890
export ANTHROPIC_API_KEY=any-value   # chatviz ignores it
claude

Open http://localhost:7890 in a browser to watch the conversation.

Inline — chatviz launches your agent

chatviz starts the proxy, then launches your agent as a subprocess with the right environment already set.

                              ┌─────────────────────────────────┐
                              │           chatviz               │
                              │                                 │
┌─────────┐  spawns + env    │  ┌────────────┐                 │
│ terminal│ ───────────────► │  │   Agent    │                 │
└─────────┘                  │  └─────┬──────┘                 │
                              │        │ Anthropic API          │
                              │        ▼                        │
                              │  ┌─────────────┐   upstream    │
                              │  │ proxy :7890 │ ────────────► │ LLM
                              │  └──────┬──────┘               │
                              │         │ SSE                   │
                              └─────────┼───────────────────────┘
                                        ▼
                                  ┌───────────┐
                                  │  Browser  │
                                  │ :7890     │
                                  └───────────┘

Start chatviz and Claude Code together:

uvx chatviz claude

With options:

uvx chatviz --port 7890 --upstream https://bedrock-mantle.eu-west-1.api.aws/anthropic --profile MyProfile claude

• The proxy server logs go to chatviz.log in the current directory.
• Claude's own output appears in the terminal as normal.
• chatviz checks that the upstream speaks the Anthropic Messages API before starting. Pass --force to skip this check.

Options

Environment variables

AWS Bedrock Mantle

See docs/bedrock.md for full setup instructions.

uvx chatviz --upstream https://bedrock-mantle.eu-west-1.api.aws/anthropic --profile MyProfile claude

Visualization

Open http://localhost:7890 while a conversation is running.

• Color-coded messages by role: system prompt, user, assistant, tool calls, and tool results each have distinct colors. Each message is tagged with the API family and model used.
• Token counter — the header shows cumulative input/output token totals across all captured messages (e.g. ↑12.3k ↓4.1k tokens).
• Sequence view — when tool calls are present the UI automatically switches to a timeline/sequence layout showing the full call-and-result chain. Pure chat sessions use the standard chat bubble view.
• Detail panel — click any message to open a side panel with full content, metadata, and the raw request body. Tool call panels show the tool name, input arguments, and the matching result in a structured layout.
• JSON modal — double-click any message bubble to open a full-screen folding JSON viewer with collapsible nodes and path highlighting. Press Escape or click outside to close.