Guide
How to Keep AI Coding Agents Focused
Keep AI coding agents focused by giving them a small task, a clear file boundary, a done state and a check they must run. If the agent starts redesigning nearby code, stop the run, keep the useful part of the diff and restart with a narrower prompt.

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What does a reviewable agent task look like?
Give the agent one named task, only the context it needs and a check you can rerun. A task shaped this way produces a diff small enough to review and a result you can repeat.
- Move
- Start with a bounded task
- Use this when
- You have a named owner, target files and a clear done state
- Proof to save
- Issue, files, checks and owner are named
- Move
- Give the agent context
- Use this when
- The repo has patterns the agent must follow
- Proof to save
- Prompt cites files, errors and constraints
- Move
- Review the diff
- Use this when
- The task changes production code
- Proof to save
- Changed files, test output and risks are visible
| Move | Use this when | Proof to save |
|---|---|---|
| Start with a bounded task | You have a named owner, target files and a clear done state | Issue, files, checks and owner are named |
| Give the agent context | The repo has patterns the agent must follow | Prompt cites files, errors and constraints |
| Review the diff | The task changes production code | Changed files, test output and risks are visible |
Each move leaves proof that a reviewer can check later.
Each move fails in its own way. Without a boundary, the agent edits files you never meant to open, and the diff becomes hard to read. Thin context fails more quietly: the code compiles and the tests pass, but the change ignores patterns the rest of the repo follows. Without a check you can rerun, you are taking the agent's word that the work is done.
Asking for a plan before the agent writes code is the easiest step to skip. It means a short wait while nothing visible happens, and the price of skipping it shows up later, in review.
If the plan names files you didn't expect, you learn that before any code exists. If it names the right files, you have a list to check the diff against. Once four hundred lines of diff are on screen, changing the approach means throwing that work away.
Interactive widget. Tab through its controls; the result updates in the panel below as you change them.
Open each stage to see what a reviewer should be able to inspect.
This is covered hands-on in Agent Mode Foundations — 6 short Units, free to read.
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How should a team run each agent task?
The habit that matters most for a team is leaving a trail the next reviewer can follow. The steps below keep the prompt and its proof attached to the change.
- 1Pick one real backlog item with a clear owner and expected result.
- 2Add only the context the agent needs: files, failing output, constraints and done state.
- 3Ask for a plan before code when the task touches more than one file.
- 4Run checks that match the risk: unit test, typecheck, visual pass or review checklist.
- 5Capture the prompt, diff, result and reviewer note so the workflow can be repeated.
Match the effort to the change. A one-file fix needs a clear done state and a typecheck, and a plan adds little. A change across several files is where a plan pays for itself, and where the check should include tests and a reviewer who knows that code.
What should you keep after the run?
Keep whatever lets someone rerun the work or pick it up later. A finished task is the merged code plus a short trail that shows how it got there.
- The prompt or plan that shaped the work.
- The files changed and the reason each file changed.
- The command, screenshot or review note that proved the result.
- The rule, checklist or template you would reuse next time.
The last item pays off over time. A rule or template saved from one good run means the next run starts from what already worked, not from a blank prompt.
Why does tight context keep an agent focused?
A model has only so much attention to spread across a large context, much like a person. The more you put in, the thinner that attention spreads, and quality drops. Cursor's field engineers describe output quality as two levers, the model you pick and the context you supply, and weight them roughly 60/40 to 70/30 in favor of model choice. Context is the smaller share, but it is the lever you control.
Cursor's field engineers teach this ceiling because they see quality drop noticeably by 70 to 80% of the window, and definitely before 90%. Some move on at around 50%. The context ring next to the prompt input shows how full the window is.
Start a fresh agent for any logically new feature or topic. Continuing a chat drags all prior context into every future request.
When the window gets close to full, Cursor compresses older parts of the conversation into a summary. The same field engineers warn that compaction near the limit behaves like missing context: the agent works as if it never had the detail, while you still pay for all the tokens. You get the cost of a full window without its benefit, so don't run a chat to its limit on purpose.
Summarize and hand off
Before you hit the limit, ask the agent for a short summary of what it has done, then paste that summary into a fresh agent and continue. Or point the new agent at the old chat with @Chats, so it reads only the parts it needs. The next agent doesn't need the chat back-and-forth. It needs the codebase, the commits and the new code the previous agent left, so treat the codebase as the source of truth instead of the chat.
When should I start a new agent instead of continuing the chat?
Start a new agent whenever the task changes. Continuing the same task in one session is fine, but a different feature, file area or question deserves a fresh agent. Field engineers repeat a simple rule: be specific, be precise and stay isolated. A new agent discards prior history, which helps you, because stale context can throw the model off its tracks.
Each agent should work on its own thing, with no scope creep bleeding in from an unrelated topic.
general best practices for prompting is be specific, be precise and stay isolated. You want to make sure that each agent is working on its own thing and there's no scope creep there.
Treat each chat as a task-by-task agent. You don't run a whole project end to end in one window. You break the work into logical steps: build the foundational architecture in one agent, then open a new chat for the landing page, and another for a single tab or feature. Each context window then holds about one topic, and switching tasks is also the natural moment to switch models. Stay modular, and keep each chat light.
Cursor compacts context by default. A Cursor speaker still recommended starting fresh agents, because that clears stale context compactionAutomatic compression of earlier conversation when the context window fills up; it can read like lost context while still costing tokens. Press Enter for the full definition. leaves behind.
The same speaker said that, in Cursor's own data, someone kept the exact same agent running for a couple hundred days. Don't do that.
How do you keep an agent following its rules on a long task?
A near-empty window also protects your rules. A presenter in Cursor's QA workshop found that after a very long conversation, rule context can be silently overwritten as the window fills, and the agent stops following a rule it was given. If a scoped task, such as running tests, keeps going off-pattern, open a fresh agent that does only that one thing, with a lean, specific rule and nothing else competing for attention. For verification, add a validator: a skill or sub-agentA child agent a main agent spawns to work in parallel with its own context window, handing results back so the parent's context stays clean. Press Enter for the full definition. that runs the task, reads the output and reruns it to confirm the real result shows up.
When running the app takes too many steps, such as build, cd into the sandbox and run, tell the agent to create a skill that starts it based on the context we have. It writes a SKILL.md file in a folder under .cursor/skills that captures the single action.
The skill becomes a command, such as "start game", that you and the agent can both call. Because it lives in the repo, it travels with the code, and cloud agents inherit it too. Folding a multi-step run command into one named action keeps each agent's context lean.
Frequently asked questions
Who is this guide for?
Developers whose agents tend to over-edit or widen scope.
What should I do next?
Click the context ring on your longest-running chat. If it is past about 60%, ask the agent for a summary of its work and continue the task in a fresh agent.
Isn't a longer chat better because the agent remembers more?
No. A longer chat carries every earlier turn into each request, which spreads the model's attention thin and pushes the window toward its limit. Near the limit, Cursor compresses older turns into a summary, and Cursor's field engineers say the agent then behaves as if that detail is missing. Summarize, hand off to a fresh agent, and treat the codebase as the real source of truth.
How full should the context window get before I start a new agent?
Keep it under about 60 to 65%, the rule of thumb Cursor's field engineers teach. They see quality drop noticeably by 70 to 80% and definitely before 90%. The context ring next to the prompt input shows how full the window is. Before you reach the limit, ask the agent for a summary of its work and paste it into a fresh agent.
Sources & last verified
- Cursor agent best practices
- Cursor Learn: working with agents
- Cursor Learn: context
- Cursor docs: prompting agents
- Cursor docs: Skills
Cursor ships frequently. Facts verified against primary sources on October 28, 2026.