Agent layer

Fifteen components, and all of them are about one thing: showing a human the work of a machine that is going on right now. Hence the differences — not in the look but in what exactly is shown: the unit of work, its output, its time or its price.

	the unit	the form
The run	a phase, an attempt, a shard	countable dots
The queue row	a task	a flat row, and there are hundreds
The step	a tool call	it expands, with the output inside
The log	a line from the machine	a stream with a level and a time
The diff	an edit in a file	two sides
The lanes	a worker	segments on a shared axis
The history	an attempt with an outcome	a row of equal events
The budget	a resource with a limit	spending against a ceiling
The tree	a node	a hierarchy of unknown depth
The approval	a decision by a human	it stays in the flow
The failure	a breakdown	a reason and a retry

The comparison stands here rather than on the pages: "take instead" is a statement about NEIGHBOURS, and repeated fifteen times it parts from them by one line per edit.

What to show

What is wanted	Take	Why not the neighbour
Tasks as a list, hundreds of them, each with a state	The queue	The row is flat: a step has a body, and at a hundred rows it does not read
A tool call with its input and its output	The step	A queue has no output, and there is nothing to collapse
A uniform stream of lines from a machine	The log	Steps have a body, a timeline has a varying make-up
What the agent changed in a file	The diff	A diff with no changes is just code
Parallel workers on a shared axis	The lanes	A queue has no axis of time
A row of equal attempts with an outcome	The history	On a sparkline what matters is the value rather than the outcome
Spending against an explicit limit	The budget	A metric has no ceiling, a meter has no forecast of exhaustion
Countable units of work: phases, shards	The run	Fifty dots are not counted by eye — there a meter with a number is wanted
A hierarchy of unknown depth	The tree	A tree of one level is a list with superfluous roles
One step of an exchange, holding everything above	The turn	A queue row is flat and a step is one call: neither holds an answer
The working the machine did before answering	Thinking	A step is a call with a result that can fail; this has no status at all
The field the next turn is written in	The composer	A field beside a toolbar is two objects, and focus lights up half of one

What to do when the work has stopped

What happened	Take	Why not the neighbour
The agent is waiting for permission to go on	The approval	A modal blocks everything else, and the decision here is part of the feed
The agent has failed	The failure	An approval has no reason and nothing about what has already been tried
The decision has to be taken immediately	a modal	An approval stays in the flow and waits
A message with no choice	a banner with the `warn` tone	An approval has options, and they are enumerable

When none of them fits

What is wanted	Take	Why not from here
Named steps known in advance	wizard steps	There the sequence is finite, here the make-up comes from the work
Events of a varying make-up	a timeline	A log has uniform lines and columns
A continuous quantity	a meter	A run counts units rather than percentages
Comparing records by fields	a table	A tree is about structure rather than about comparison
The properties of one object	a property list	The nodes of a tree expand, and properties have nothing to expand

Common to all fifteen

The state lives in data-state rather than in a class. The vocabulary is closed: a value outside it gives an error nowhere — it simply does nothing, and that is why it is guarded by the registry.

Infinite motion means "running". A pulsing dot, a turning ring, a travelling caret — all of it slows at prefers-reduced-motion without stopping: a stopped indicator says "nothing is happening" at exactly the moment something is.

The nodes arrive while the work goes on. Queue rows, steps and tree nodes appear one at a time, so instrument.js works by delegation and watches for groups appearing with an observer — more in behaviour.

Why the kit works this way — the constitution · Open source under MIT, github.com/keshon/instrument