Mulmoterminal Header

Header buttons and chips

A session header carries buttons (things you can do) and chips (things you can read). Both are configured in two places and merged, and the two merge by different rules — that asymmetry is the thing to get right, and it has no UI anywhere.

Where to write it

Ask which the user means. "A button for yarn build" is usually per-project (the command only exists there); "show me the branch everywhere" is global.

Global writes are a partial POST /api/config merge — send only buttons / chips. Per-project writes go through your Write/Edit tool, and writing the file is itself the live-reload signal; there is no filesystem watcher.

"Partial" is per TOP-LEVEL key, and buttons / chips are each replaced WHOLE. The merge is body[key] !== undefined ? sanitize(body[key]) : current (server/config/app-config.ts), so posting

{ "buttons": [{ "id": "build", "icon": "build", "label": "Build", "run": "shell", "cmd": "yarn build" }] }

does not add a button — it makes that the entire global set, deleting every other button the user had. Nothing warns, and the reply is a success.

So a global write always sends the complete array: read the current one first, add or change your entry in memory, and post the whole thing. Every example below shows the entries under discussion on their own for readability — none of them is a body to post as-is unless the user genuinely has no others.

Three different "replace" rules live here and are easy to run together:

How the two are merged — not the same rule

Buttons merge by id. Global buttons load first, then the project's: a project button with the same id replaces the global one, a new id is added. The result sorts by order (lower first, unset last), ties keeping insertion order. So a project can override one button without restating the rest.

Chips replace wholesale. A project that sets chips discards the global list entirely; one that omits the key inherits it. There is no per-chip override.

null (absent) and [] are different.

• buttons absent at both levels → the built-in starter set below.
• buttons: [] → no buttons at all, not "the defaults". And setting it globally means a project that configures nothing also gets nothing, since the empty list is what it inherits.
• chips absent → the client's default chip set. chips: [] → every chip hidden.

Omit the key you were not asked about. Writing chips: [] to a user who only wanted a button silently strips their header.

The built-in buttons

With buttons unset anywhere, these show. Each is an ordinary config button, so the way to trim or reorder them is to list the ones you want — there is no "remove" syntax.

Dropping just one means writing the other.

The four that are no longer buttons

Reveal in the file manager, the in-app file explorer, a new terminal here, and Open on GitHub used to be default buttons. They are now items in the path menu — click the directory path on a session's terminal header row and they are all there, with Issues and Pull requests as well.

They moved because every one of them answered "do something with the directory this cell is in", which is the question the path itself asks; reveal was the path's own click outright. Four permanent icons in a tiled cell for four occasional navigations was the wrong trade.

Nothing about them changed as CONFIG. If a user wants any of them back as a button — one click instead of two — list it and it works exactly as before:

{ "id": "files", "icon": "folder_open", "label": "Browse files in the app", "run": "open", "open": { "files": "${dir}" } }

Say when you do that: they will then have it twice, once as their button and once in the path menu. The menu is fixed and does not know what is on the toolbar.

Say the other thing too, for this one button. The label is the same and the destination is not: the MENU item opens the file pane beside the enlarged cell (enlarging it first if the cell is tiled), while this BUTTON opens the full-screen Files view. Both are correct — open.files takes whatever path it is given, and the pane can only ever be rooted at the enlarged cell's directory, so the button could not be the pane even if it wanted to be. A user who expected the pane and got the full screen has hit exactly this, and there is nothing to fix in their config.

Propose only buttons that work here

Look at the directory before suggesting anything, and say what you skipped and why:

• package.json → offer only scripts that exist (yarn build, yarn test, …).
• git rev-parse --is-inside-work-tree → gate git buttons with "when": "isGitRepo".
• git remote get-url origin → without a remote, ${repo} resolves to nothing and a GitHub button is dead. Don't offer it.

Ones that work anywhere: /compact (run: "input", when: "agent == claude"), the file explorer, the OS reveal.

Buttons — schema

An array, ≤ 32 entries:

{ "id": "build", "icon": "build", "label": "Build", "run": "shell", "cmd": "yarn build", "when": "isGitRepo", "order": 10 }

• id (required, unique — it is also the merge key), label (required), run (required): "shell" / "input" / "open" / "action".
• icon — a Material Symbols name (build, folder, bar_chart). Prefer it. An emoji field exists and wins when both are set, but this project ships icons only.
• Payload, by run:
  • "shell" → cmd — runs in a command cell. Resolved server-side by id at exec time; the command is never sent to the browser.
  • "input" → text — typed into the running Claude/Codex, e.g. "/compact".
  • "open" → open, with at least one of: url (http/https only) · reveal (dir → OS file manager) · files (dir → in-app explorer) · view ("diff" / "prs" / "wiki" / "collections" / "accounting") · terminal (dir → a new cell running $SHELL) · pr: true (this branch's PR; the button hides when there is none) · pickFile: true (OS file dialog → insert the path).
  • "action" → action — acts on the cell itself. One value: "restart".
• when — visibility condition (below). order — sort key, lower first, unset last.

run: "action" — restart the agent in this cell

{ "buttons": [{ "id": "restart", "icon": "restart_alt", "label": "Restart the agent", "run": "action", "action": "restart" }] }

Ends the agent process and starts it again in the same cell, on the same conversation — no trip back through the launcher. It is what makes a changed MCP registration, an edited ~/.mulmoterminal/config.json or an updated plugin take effect, because those are read once, when the process starts.

Three things to say when you offer it:

• It costs a resume. The conversation is read back from its transcript, with the token cost that implies. This is not a free "reload".
• No confirmation, even mid-turn. It ends whatever the agent is doing. That is deliberate — the button only exists because someone wrote it — but it means the icon sits next to buttons that are harmless, and it is not.
• Nothing else changes: same directory, same agent, same model, same custom agent.

There is no built-in Restart button and no default binding; this and the terminal-restart shortcut (the mulmoterminal-keys skill) are the two ways to have one.

Chips — schema

An array, ≤ 16 entries. Each is either a built-in id or a custom read-only chip.

Built-ins, shown in the order you list them (omit one to hide it): "dir" "git" "work" "ctx" "usage" "status" "diff" "tools".

work is the one people miss: it names the PR or issue the cell is on. It is in the client's default set, so a header nobody has configured shows it — but the moment you write chips at all, you must list it or it disappears, and that reads as a feature breaking rather than a chip being deselected.

Custom:

{ "label": "env", "text": "⎇ ${branch}", "when": "isGitRepo" }

Custom chips are display only — no click behaviour. Something clickable is a button.

${var} substitution

Available in cmd, text, open.*, and a custom chip's text:

${dir} ${dirName} ${branch} ${repo} ${model} ${agent} ${session} ${remoteUrl} ${dirty} ${ahead} ${behind} ${task}

when — the visibility mini-language

Atoms: isGitRepo, !isGitRepo, key == value, key != value (keys are the ${var} names, written bare). Combine with && (binds tighter) and ||. No parentheses. Empty or absent → always shown.

agent == claude && isGitRepo

key != with the right-hand side left empty tests "resolves to something" — "when": "repo != " is what a GitHub button needs so it never renders as a bare https://github.com/. Use that rather than isGitRepo: a git repo with no remote, or one whose remote is not GitHub, is still a git repo.

After writing

• Per-project: live. The header re-resolves; nothing to reload.
• Global: a partial POST /api/config merge takes effect for sessions as they re-resolve their header; a hand-edit of the file while the server is running needs a restart.

Then check the real header. A button that doesn't appear is nearly always when (a non-git directory, an agent mismatch) or a pr button on a branch with no PR — both are working as designed, and both look like a broken config.

• Every other button vanished — a partial write. buttons is replaced whole; always send the array complete. Same for chips.

Example — pinning the defaults, globally

The default set is short, so writing it out is the whole of it — this is the complete current default configuration, useful as the starting point for adding to or trimming:

{
  "buttons": [
    { "id": "pick-file", "icon": "attach_file", "label": "Insert a file path", "run": "open", "open": { "pickFile": true } },
    { "id": "pr", "icon": "merge", "label": "Open this branch's PR", "run": "open", "when": "isGitRepo", "open": { "pr": true } }
  ]
}

A project can then add its own build button without restating any of these — different id, so it is merged in, not replacing them.