What cctop reads, per harness

← back to the README

Nine harnesses, nine pages. Each one says where that harness’s sessions live, what shape they are in, which columns cctop can fill from them, and — the part worth writing down — where the format says something other than what it appears to say.

These are cctop’s own notes, written from the parsers in crates/core/src/session/. They are not a description of the harness: they are a description of what our code believes about it, which is a narrower and more useful thing. Every claim here should be traceable to a function you can open.

And adding a harness, which is the list of places a tenth one has to be registered before it works — derived from what the nine already touch, not from a design.

Why this is not docs/harnesses/

docs/harnesses/ is a mirror: seven of these nine projects’ own documentation, pulled wholesale by pull.sh and overwritten wholesale on the next pull. Nothing in it is edited by hand, because the next refresh would delete the edit — and its value is precisely that it does not move, so a format change can be read against yesterday’s copy of the upstream prose.

That leaves nowhere to say what we do, so this directory says it: one page per harness, ours, versioned with the parser it describes. The two are meant to be read together — the mirror tells you what the harness says it writes, and these pages tell you what cctop found when it went and read it.

The reason behind each ─

The README’s capability table marks with ─ anything a harness does not record. That table is deliberately terse; the reason lives here.

Devin is the odd one out in the other direction: it records everything except the price. Neither its transcript nor its database holds a dollar figure, so its $ is a ─ rather than an estimate — and doctor skips it in the unpriced-model check for the same reason, since a blank is not a price of zero.

Three of those cells are conditional rather than absolute, and the pages say so: OpenCode’s context needs LiteLLM to know the model’s window, since OpenCode records no ceiling of its own; Devin’s is the same case, its num_tokens_preceding without a window of its own; and Windsurf’s tool count is read from a bubble shape nobody has yet confirmed against a live install.

“Estimated” against “reported” is a policy, not a per-harness accident — What the cost figures mean is where that policy lives, and these pages only record how each harness happens to land on one side of it.

A note on the traps

Most of what is on these pages started as a bug. A resume that pointed a live process at a dead transcript, two thirds of Codex’s tool calls rendering with no arguments, an oversized line that silently dropped a turn’s cost. They are written down because the format made each of them look correct, and the next person reading the same field will draw the same conclusion unless the page warns them.