`doc/images.md` holds the message shape, how `@path` attaches a file, the
per-surface mapping, the provider limits, what a live probe against DeepSeek
confirmed (`tool_result` and `function_call_output` images work, `detail: low`
is 3.4x cheaper, an assistant-message image is a 400), and why the Files API is
not used.
AGENTS.md gets the invariants and the mention/config keys; `doc/architecture.md`
and the example TOML point at it.
doc/turns-and-rounds.md defines the two nested units the loop is built on: a round is one request→response plus the tool batch it asked for, a turn is one user message through the explicit stop (0..N rounds), and a session is a stored sequence of turns. It records what bounds each unit (max_rounds, truncation continues, retries), which work is round-scoped (request assembly, context reduction, the aggregated soft confirm) and which state resets per turn (read-before-edit, yyy auto-continue, /yolo once, the todo touched flag, usage totals) versus what outlives it (rows, todo stack, grants, reminder bands).
Linked from the architecture doc, with the short version in AGENTS.md.
README and the example config cover the [skills] section, the five tools, and
the read/write split; AGENTS.md gains the skills/ package, the tool family, the
config fields, and the /skills + /status surface; architecture.md lists the
package. doc/skills.md is the author guide: layout, the frontmatter subset and
how a broken one degrades, roots and shadowing, what the agent sees, the
grant story for reads and writes, and the warning that a skill is data —
third-party skill directories are untrusted input.