Terminal Agents and IDE Agents: Ambient Versus Explicit Context

If you can point at the problem, use the IDE agent. If you would have to explain where it is, use the terminal — explaining is the work it is built for.

The same model, very different systems

Terminal agents and IDE-embedded agents frequently run the same underlying model. They behave differently anyway, because the surrounding system differs in three ways that matter more than the model choice.

Ambient versus explicit context

This is the deepest difference and the source of most of the others.

An IDE agent starts with the editor's state for free: the open file, the cursor position, the selection, the current diagnostics, the symbol index. Ask it "why is this failing" and "this" is unambiguous.

A terminal agent starts with nothing but a working directory. It must decide what to read, which costs turns and tokens, and it may decide wrong. Ask it the same question and it has to find out what you mean.

The trade is symmetric, though, and the terminal side is easy to undervalue. Ambient context is narrow: it is this file, right now. An agent that acquires context deliberately can range across the repository, run commands, read output and follow a chain of reasoning over many files. That is why longer autonomous work happens in terminals.

Interruption changes what you should ask for

A less obvious consequence of the interaction model: in an IDE you can stop an agent mid-change cheaply, so asking for something imprecise is fine — you watch, and redirect. A terminal agent working autonomously for ten minutes has usually committed to an approach by the time you notice it is wrong, and the cost of redirecting is the whole run.

That asymmetry should change how you write the request. IDE prompts can be short and exploratory. Terminal prompts benefit from stating the constraint up front — which files are in scope, what must not change, what done looks like — because there is no cheap correction later.

It is the same reason CI prompts need to be the most explicit of all: the looser the supervision, the more the instruction has to carry.

Verification loops differ in tightness

An IDE agent's feedback is immediate: it makes an edit and the language server reports errors within a second, in structured form, without spending a turn.

A terminal agent must run a command, wait, parse text output, and interpret it. Slower, and less reliable — compiler output is designed for humans, not for parsing.

The practical consequence is that the terminal agent's quality depends heavily on how good your commands are at reporting failure. A test runner with clear, machine-readable output produces better agent behaviour than one that prints a wall of prose. This is a rare case where investing in developer experience has a direct, measurable effect on agent output.

Where each one fits

Where the boundary is moving

These two surfaces are converging. IDEs have added terminal-style agent panels that can run long autonomous tasks; terminal agents have added editor-awareness through language-server integrations. The distinction in the table above is about architecture, not product categories, and product categories are the part that keeps changing.

What is unlikely to converge is the underlying trade. Ambient context is precise and narrow; explicit context is broad and costly to acquire. A tool cannot have both for free — it can only choose which to default to, and give you a way to reach the other. When evaluating any new tool in this space, that is the question worth asking: what does it know without being told, and what does it have to go and find?

Using both, without the seams showing

Most people who use both settle into a similar rhythm: terminal for exploration and the large change, IDE for the refinement afterwards. That works well, with one thing to watch.

The IDE agent will not know what the terminal agent did. They do not share a context window. If a terminal session made a structural decision — introduced an interface, chose a pattern, deliberately left something out — the IDE agent picking up the work sees only the resulting code, not the reasoning.

The fix is unglamorous: have the terminal session write down what it decided and why, in the PR description or a scratch file, before you switch tools. This also happens to be the note a human reviewer needs, so it is not extra work — it is work you were going to do at a worse moment.

The transcript is the missing artifact

A reviewer looking at agent-authored code has less to go on than usual. With a human author you can ask what they tried and why they rejected the obvious approach. With an agent, that reasoning existed in a context window that has since been discarded.

Terminal sessions have an advantage here, and it is underused: the transcript is in your scrollback, and it records what was attempted, what failed, and what the agent read before deciding. Saving it alongside the branch costs nothing.

# keep the transcript with the work, gitignored
mkdir -p .agent-logs
script -q ".agent-logs/$(git branch --show-current).log"

When a reviewer asks "why is it done this way", the answer is frequently in that file — often as an approach the agent tried, watched fail, and abandoned for a reason nobody would guess from the final diff.

Context files serve both

One thing that transfers cleanly is AGENTS.md. Both surfaces read it, and it is the mechanism that keeps their behaviour consistent — the same test command, the same boundaries, the same protected paths, regardless of which tool is running.

That consistency is worth more in a mixed-tool team than in a single-tool one. Without a shared context file, an IDE agent and a terminal agent effectively operate under different rules, and reviewers start noticing that changes look different depending on who made them and how.