dsh-composer-input-history

Shell-style input history for the DeepSeek Harness Web composer — the behaviour you know from opencode and other terminal agents.

Press ↑ in the composer to pull back a message you already sent in this Session. Press ↓ to walk forward again; past the newest message your original draft comes back.

What it does

Gesture	Behaviour
↑ with an empty draft	recalls the newest sent message
↑ again	walks one message older each time
↑ on the first line of a single-line draft	recalls; the draft you were writing is remembered
↑ inside a multi-line draft, below the first line	left to the editor, so the caret still moves
↓ while browsing	walks one message newer
↓ past the newest message	restores the draft you were writing before browsing
typing anything while browsing	leaves browse mode; the recalled text becomes your draft

History is what you sent in this Session, oldest to newest, read from the Chat node store the view itself renders (snapshot.nodes, ordered by anchor sequence): ordinary user messages, steering messages, and the message that woke a turn. Skipped: hidden nodes (compacted or interrupted), attachment-only messages, and everything the Harness authors on your behalf — goal rounds, skill catalogs, runtime snapshots, job notices, model notices, approval answers, and compaction checkpoints.

Why it is a keyboard observer

The Harness composer deliberately leaves ↑/↓ to its shell-owned Lexical editor, so no slot or command seam owns them. This plugin therefore:

• registers an invisible Session-scoped occupant in conversation.composer.dock;
• reads the Session's Chat nodes through the standard useChat hook (snapshot.nodes) and the draft through the standard useInput hook;
• writes the recalled text through the standard inputActions.setDraft API, so the edit stays part of the composer's own draft history;
• watches the key on two paths: a document-level keydown listener and the shortcuts service's observeFixedInput seam. The document listener runs after the composer's own keymap, so a slash menu or an IME that already handled the key still wins; the fixed-input seam covers compositions where a native Desktop adapter owns the DOM feed. Exactly one path acts, because the first one to act cancels the event.

A key is declined when the slash/reference menu already consumed it, when an IME is composing, when a modifier is held, when the event is outside the composer editor, or when the composer is submitting/adjudicating. The plugin imports no Harness Client package and styles nothing.

Install

From this repository (available now):

dsh plugin --profile web add https://github.com/liumorrisclaw/dsh-composer-input-history

Once the package is on npm, the short form is:

dsh plugin --profile web add dsh-composer-input-history

Or add it in the Web UI's Plugins page, or list the package directory with the plugin manager. The bundle ships off until the profile selects it.

For a local checkout, install by path:

dsh plugin --profile web add /absolute/path/to/dsh-composer-input-history

Relationship to other plugins

The npm name dsh-input-history is already taken by a different community plugin that also recalls prompts with ↑/↓. The two differ in mechanism and behaviour:

	dsh-composer-input-history (this plugin)	dsh-input-history
History source	the Session transcript the Chat view already loads	a separate local store of submitted prompts
Non-empty draft	recalls and remembers the draft, restoring it below the newest message	recalls only from an empty composer
Attachments	not part of the recalled text	persists and re-attaches them
Menu/IME	yields the key to an open slash/reference menu and to IME composition	—

Pick this one if you want recall driven by the conversation you can see, including from a draft you are already typing.

Compatibility

Developed and verified against @deepseek-ai/dsh 0.2.0-rc.2. The plugin uses only documented seams: ctx.slots, the Session standard props (useChat, useInput, inputActions), and ctx.shortcuts.observeFixedInput. It declares dsh.client.inject on dsh-client-ui-conversation, dsh-client-ui-chat, and dsh-client-shortcuts so activation order is deterministic.

Verified

• 27 unit tests over the pure history reader and browse state machine (npm test), run on every push by .github/workflows/ci.yml on Node 20 and 22.
• The composed profile contains the bundle row (dsh --profile <name> --dump-config).
• The browser boot graph announces the bundle with its inject list and immediately: true, and the web host serves the bundle body byte-for-byte.

Not yet verified by automated browser control: the in-page interaction itself. Pressing ↑ in a running composer is the acceptance check.

Limitations

• History is per Session. Cross-session recall (recent Sessions' inputs) is not implemented yet.
• History reflects the loaded transcript window; messages hidden by compaction are not recalled.
• The recalled text is plain text: reference chips and attachments from the original message are not restored.
• One resident composer per Web page is assumed, matching the shell's own design.

License

MIT