Codex's stale-prose pass found seven more spots still describing the
result diff as ALWAYS an applied contextual hunk, or a create/binary
overwrite as rendering "only the call-time card": the DiffCallView JSDoc
and the acp bridge diff-arm comment, the FsWriteOutcome.before and
readTextForDiff JSDoc, and three RFC lines. All now say: the result diff
is the applied change — a contextual hunk when there is a before-image,
else a whole-file diff (create / undiffable binary) — and a successful
mutation always returns the result diff so the model-facing text can't
clobber it. Regenerate the cordis catalog (source line shift).
A Write CREATE rendered its completed tool_call_update as the model-facing
result TEXT (`<path>…</path>…Created file`), which — because an ACP
tool_call_update.content REPLACES the call's content — clobbered the
new-file diff the pending call installed. So Zed showed the diff, then
replaced it with raw XML-ish text; only overwrite/edit looked right
(their result re-sends a diff).
write's presentResult now ALWAYS returns a diff card for a successful
write: the applied contextual hunk from `meta` when there is one
(overwrite), else an args-derived whole-file diff (`oldText: null`) for a
create or an unchanged-content overwrite. This matches claude-agent-acp,
where the create diff rides on the update and no result text replaces it.
An error still falls through to generic rendering so its message shows.
edit is unchanged (it always has a hunk; no whole-file fallback).
Re-recorded fs-write / fs-write-overwrite goldens; the create's completed
update is now a {type:'diff'} block, not the XML result text.
Address the applied-hunk-diffs review:
- CRLF write overwrite emitted bogus every-line-changed hunks: write's
`before` was LF-normalized but `after` kept the raw model content, so a
CRLF rewrite of an LF file diffed every line. Normalize write's `after`
to LF so both sides share the diff basis (edit already did). Regression
test proves it fails on the raw-after path.
- The tool-private `meta` payload is now typed `unknown` (opaque) at every
seam instead of `JsonValue`. This drops the `dsh-tools -> dsh-session`
package edge that existed only to name the type, and removes the
`FileDiff` index signature that had been widening the type solely for
JsonValue-assignability. Serializability is still enforced at runtime by
`Session.append`'s isJsonValue check, which was always the real guard.
- Sync the docs the new result/meta surface left stale: ToolResultView's
diff card + ToolExecutionResult.meta in tools.md/session.md type-equiv
blocks, the acp/tools READMEs, and the adding-a-tool cookbook; regenerate
the cordis catalog and module graph.
fs write/edit now emit a result-time contextual-diff tool_call_update
(the applied hunk with ±3 context lines, one hunk per replace_all site),
matching what claude-agent-acp sends and what makes an editor render the
change in place. The call-time snippet diff stays; the result hunk
supersedes it (ACP content-replace).
Mechanism:
- A persisted tool-private `meta` channel: execute may return
`{ content, meta }`; `meta` (JsonValue) rides on the tool/result event
and is handed back to presentResult, so the diff reproduces on replay
(event-sourced). JsonValue is now exported from dsh-session.
- The backend returns raw before/after text (storage facts) on
FsWriteOutcome/FsEditOutcome; the tool computes the hunk via the npm
`diff` package's structuredPatch. A create has no before → no result
diff; a failed/aborted mutation carries no meta.
- ToolResultView gains a DiffResultView; the bridge's result-side switch
renders it as {type:'diff'} content blocks.
RFC: docs/rfc/implemented/architecture/2026-07-02-result-time-applied-hunk-diffs.md
(justifies the npm `diff` runtime dep over vendoring and the meta channel);
the render-intent-union RFC's Non-goal is updated to record this shipped.
All fs snapshot goldens re-recorded; edit/overwrite gain the contextual
result diff, create/read/policy-reject unchanged in structure.
Tianyi Cui