A settled top-level `read_image` call printed its raw attachment object as
literal text in the tool card — `{"type":"image","attachment":{…}}` —
instead of the image, because no presentation metadata told a client card
how to present the reference and the tool-card layer had no image concept.
Host: `read_image` declares an `output.presentationMeta` persisting
`{ path }` only. The attachment reference deliberately lives in the
settled result content — the single record a `tools/post-execute`
replacement rewrites — not in `meta`; the id is opaque and
provider-owned, checked for existence only.
Client: `imageCardModel` derives the card from the call head, the meta
path, the result's own image block, and a shape-matched envelope. ToolRow
gains an `image` card slot; the `read_image` toolview declares the
Tool-owned `tool.call.images` slot as its child and dispatches the
gallery through it. ui-chat down-threads the session-authorized loader
(`ChatNodeOwnerProps.loadImage`), so the tool layer supplies only derived
references plus the loader and never imports an attachment
implementation; ui-attachment fills the slot with its message gallery
renderer. The card keeps the envelope text below the gallery for the
no-attachment-plugin deployment. An image-bearing tool registers a keyed
toolview; the generic fallback keeps its flattened text. `read_image`
joins the read variant with its own locale title key; both rows share
`read-family-row.tsx`.
Verification: `read-image.spec.ts` (metadata projection, envelope by
shape, reference narrowing, real-execution round trip, rejection
branches incl. non-digest ids), `image-card.client.spec.tsx` (derivation,
row render site dispatching the slot, keyed registration with the
child-slot declaration, empty-slot fallbacks, media-type enum), keyless
snapshots (`read-image-gif` added; read-image/-dimension/-reencode
updated to the `{path}` meta), five injected-defect negative controls,
and a demo GIF recorded from this PR's head through the official
image-capable model.
Rename the tool-presentation transport from code-mode to ptc everywhere
that is not written into session logs: the mode config value becomes 'ptc',
the preset directory/id becomes ptc, the demo becomes demo:ptc, the
dispatch waterfall becomes tools/ptc-dispatch-log (types PtcDispatch*), the
prompt rule becomes tools:ptc-only, source/test files become ptc.ts etc.,
and prose says PTC mode / PTC 模式. The session-persistent vocabulary
(durable events tool/code-dispatch*, logged plugin name tools-code-mode,
sub-call id segment :code:) intentionally stays and moves in the stacked
persistence PR, which is blocked until the SESSION_FORMAT_VERSION v0→v1
migration lands with it. run_code, its code parameter, CodeSdkLanguage,
CodeRunFailedError, the dsh-code-runtime family, third-party codex names,
and frozen archived notes keep their names.
The model reads a PNG/JPEG/WebP/GIF file, the bytes commit through the
durable attachment lifecycle, and the tool result carries the real
ImageBlock so the image enters context from the next request onward.
FileSystem gains a bounded readBytes primitive (local + E2B providers);
registration is conditional on the attachment store, and a strict
execution gate refuses routes that do not declare image input, so a
text route's durable history stays free of image blocks. llm-replay
models may declare inputModalities, letting keyless ACP snapshots pin
both the sha256-referenced success and the verbatim refusal.
Supersedes the withdrawn route-scoped design of PR #598; the decision
record is .agents/notes/implemented/feature/2026-08-10-minimal-read-image-tool.md.
