tracer

Turn the session transcripts your AI coding CLI leaves on disk into one self-contained HTML page you can read, keep, mail or publish.

Every AI coding CLI writes its sessions somewhere: Claude Code under ~/.claude/projects, Codex under ~/.codex/sessions, OpenCode in a store of its own. Each format is different, and each is append-only JSON written for the tool rather than for you. None of them is readable when you want to know what the agent actually did. cs-tracer reads all three and writes a page: the timeline, the tool calls, the sub-agents, the tokens and the cost.

The whole product is one static Go binary. The viewer is compiled into it, so an export needs no server, no network and no runtime dependency. The page it writes opens from file:// years later, on a machine that has never heard of this tool. Other viewers exist as web applications you upload a transcript to. cs-tracer is a file you run and a file you keep, which is what makes the output something you can commit beside the code it describes.

 session files            cs-tracer                                   what you open
 ────────────────         ─────────────────────────────────────       ──────────────────
 ~/.claude/projects  ┐                                            ┌─  trace.html
 ~/.codex/sessions   ├──►  normalizer  ──►  trajectory  ──►  viewer│   (one file, inlined)
 an OpenCode store   ┘     one adapter      ordered JSON:    React │
                           per CLI          events, totals,  app   └─  trace-site/
                           family           metadata                   (index + one page
                                                                        per trajectory)

Quickstart

Build it, or get it any of the other ways in INSTALL.md:

git clone https://github.com/codesweep-ai/tracer && cd tracer
make install                    # -> ~/.local/bin/cs-tracer

That build needs Go 1.26 or newer. It also rebuilds the viewer whenever npm is on your PATH, which needs Node 20 or newer. INSTALL.md shows how to build from the committed viewer assets instead.

Then point it at a session directory and open the result:

cs-tracer ~/.claude/projects/my-project -o trace.html
open trace.html

That is the whole tool for most uses. It prints the size of what it is about to write to stderr, then the destination to stdout once the file lands. INSTALL.md walks the same run end to end with its real output.

Point at the directory, not at one transcript file. Sub-agent runs live in sibling files, and a lone file has no siblings, so every sub-agent flattens onto the root and the nesting is lost.

Trajectories

A trajectory is one agent session after normalizing: its metadata, its totals, and its ordered events. An event is one step, which is a message, a tool call, a tool result, or a record the viewer shows because nothing classified it. A sub-agent run is its own trajectory, linked from the event that spawned it.

The page opens on an index of trajectories, each with its model, its token count, its duration and a cost estimate. Beside each one sits an activity strip, and clicking a cell opens the timeline at that event. The search box matches event text and tool names, and #ev-1050 is a deep link.

One file or a directory

cs-tracer ./session --single -o trace.html    # the default
cs-tracer ./session --split  -o ./trace-site

--single inlines the viewer, the styles and all the data into one HTML file. --split writes a directory instead: index.html, shared assets/, and one page per trajectory under traces/. Choose it when one file would be unwieldy, or when you publish to a static host and want each page to load on its own.

Both modes render the same page. Only the transport differs, and a gate compares the two: the DOM digest, the full-page pixels, and the end state after an interaction.

The JSON underneath

normalize stops one step earlier and hands you the data the pages are built from:

cs-tracer normalize ./session --out ./normalized   # a tree of JSON files
cs-tracer normalize ./session                      # JSON Lines on stdout

The normalizer is the part that reads a CLI's own format, one adapter per family, and produces a trajectory. Its output is specified byte for byte, so two runs over one input give identical files and a diff between versions means something. SPEC.md is the whole contract.

Docs

• INSTALL.md · getting the binary, and checking that it works
• MANUAL.md · every command, option, file, exit code and diagnostic
• SPEC.md · what the output must be, and how the binary is built
• CONTRIBUTING.md · working on cs-tracer itself

cs-tracer manual prints the manual from inside the binary, so a machine with only the executable still has the reference.

License

Apache-2.0.