Agentic & Tool-Use

Plan-and-Act

Long tasks trip up agents that decide their next move one step at a time; they lose the thread. Plan-and-Act splits the job in two: a Planner writes a high-level plan for the whole task, and an Executor turns each plan step into concrete actions in the environment. Separating the strategy from the doing keeps the agent on course across many steps, which is where single-loop agents tend to drift.

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The Core Insight

Separate the Strategy From the Doing

An agent that both plans and acts in the same breath has a hard job on long tasks. Every step it must hold the overall goal, decide the next concrete action, and track everything that has happened so far. Over dozens of steps, that combined load causes drift: the agent loses sight of the goal, repeats itself, or wanders down a path that no longer serves the plan.

Plan-and-Act gives each responsibility its own model. A Planner focuses only on strategy, producing a structured, high-level plan for the whole task. An Executor focuses only on doing, translating one plan step at a time into the specific actions the environment needs. Neither has to do the other's job, so each does its own job better.

Because good plans are scarce as training data, the authors also introduce a way to generate them: they take real successful trajectories and annotate them with the feasible high-level plans that would have produced them, giving the Planner strong examples to learn from. The payoff shows up on long-horizon tasks like navigating a website, where keeping a stable plan in view is exactly what a single-loop agent struggles to do.

Why the Split Helps Long Tasks

On a long task, a single agent must juggle the goal, the next action, and the whole history at once. Splitting into a Planner and an Executor means the plan stays fixed and visible while the Executor works step by step, so the agent does not lose the thread across many actions. The plan is the anchor.

The Plan-and-Act Process

Plan the whole task, then execute it step by step

1

Plan: Draft a High-Level Plan

The Planner reads the task and produces a structured plan of high-level steps that, together, accomplish the goal. It reasons about strategy without worrying about the exact clicks or commands that come later.

Example

Task: book a flight. Plan: search the route, filter by time and price, select a flight, enter passenger details, pay.

2

Execute: Turn a Step Into Actions

The Executor takes the current plan step and produces the concrete environment actions that carry it out, the specific fields to fill, buttons to click, or commands to run. It handles the low-level detail the plan deliberately left abstract.

Example

Plan step "search the route" becomes: type the origin, type the destination, choose the date, click search.

3

Advance and Adapt

Once a step is done, the agent moves to the next plan step, and the plan can be revised if the environment throws a surprise. The high-level plan stays the anchor, so progress is tracked against strategy rather than lost in a stream of actions.

Example

If no flights match the filters, the plan adds a step to relax the time window before selecting.

4

Complete the Long-Horizon Task

Step by step, the Executor works through the plan to the goal. Because the Planner held the whole task in view from the start, the agent reaches the end without the drift that catches single-loop agents on long tasks.

Example

All plan steps done, the booking is confirmed, with the agent never having lost track of the overall goal.

See the Difference

One loop for everything versus a planner and an executor

Single-Loop Agent

Decide Each Step in the Moment

One model plans and acts at once, choosing the next action from the current state without a stable overall plan to anchor it.

On Long Tasks

The agent drifts: it loses the goal, repeats steps, or heads down a path that no longer fits, because it never held a full plan.

Drifts over many steps
VS

Plan-and-Act

Plan First, Then Execute

A Planner sets a high-level plan for the whole task; an Executor carries out one step at a time, with the plan as a stable anchor.

On Long Tasks

The agent stays on course across many steps, improving performance on long-horizon tasks like web navigation.

Stays on course to the goal

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Plan-and-Act in Action

See how the planner and executor divide the work

Task

"Find and order a replacement charger for a specific laptop model on a shopping site."

Plan and Execute

Planner: search the model, open the accessories, pick a compatible charger, add to cart, check out.

Executor: for "search the model", it types the model name and submits; for "pick a compatible charger", it reads listings and clicks the matching one.

Result: the plan keeps the many clicks pointed at the goal, so the agent does not get lost in the site.

Task

"Pull last quarter's numbers from three reports and assemble a summary table."

Plan and Execute

Planner: locate each report, extract the relevant figures, normalize the units, build the table, sanity-check totals.

Executor: carries out each extraction and the table assembly step by step.

Result: because the plan lists every stage up front, no report is skipped and the final check is not forgotten.

Surprise

Midway through checkout, the site asks the agent to create an account, a step the plan did not anticipate.

Replan and Continue

The plan is revised to insert an account-creation step before payment, then the Executor resumes.

Result: the high-level plan absorbs the surprise cleanly, where a single-loop agent might have stalled or abandoned the goal.

When to Use Plan-and-Act

Best for long-horizon tasks in interactive environments

Perfect For

Long-Horizon Tasks

Jobs that take many steps benefit most, because a stable high-level plan keeps the agent from drifting over a long sequence of actions.

Interactive Environments

Web navigation, app automation, and similar settings, where actions are concrete and numerous, are a natural fit for the planner-executor split.

Tasks With Clear Sub-Goals

When a job breaks cleanly into high-level stages, the Planner can lay them out and the Executor can carry each one through.

Recoverable Surprises

When the environment can throw unexpected steps, revising the high-level plan absorbs them without losing the overall goal.

Skip It When

Short, Simple Tasks

If a job takes only a step or two, a separate planning stage adds overhead with little drift to prevent.

Highly Unpredictable Settings

When the environment changes so much that any plan is quickly invalid, the cost of constant replanning can outweigh the benefit.

Pure Reasoning, No Actions

For tasks that are all thinking and no environment interaction, a reasoning method is a better fit than a planner-executor split.

Use Cases

Where Plan-and-Act delivers the most value

Web Automation

Drive multi-page web tasks such as booking, purchasing, or form-filling, where a stable plan keeps the many clicks aimed at the goal.

Desktop and App Agents

Complete workflows across an application's screens, using the plan to sequence the stages and the executor to handle each interface.

Multi-Report Analysis

Sequence extraction, normalization, and assembly across several documents, so no source is skipped and no final check is missed.

Tool-Chaining Agents

Coordinate a sequence of tool calls toward a goal, letting the plan decide the order and the executor make each call.

Process Execution

Run standard operating procedures that span many steps, keeping the whole procedure visible so nothing falls through the cracks.

Reliable Long Runs

Improve success rates on tasks where single-loop agents tend to drift, by anchoring every action to a high-level plan.

Where Plan-and-Act Fits

A planner-executor split for acting agents

Plan-and-Solve Plan Then Reason Devise a plan, then solve
ReAct Reason and Act Interleave thought and action
Plan-and-Act Planner and Executor Split roles for long tasks
ReCAP Recursive Planning Refine plans with context
Chain These

Plan-and-Solve introduced planning before reasoning; Plan-and-Act extends the idea to acting agents by giving planning and execution separate models. Reach for it on long-horizon tasks in real environments, where a single reasoning-and-acting loop tends to lose the thread.

Plan First, Then Act

Explore how separating a plan from its execution keeps long tasks on track in the Prompt Builder, or see related agentic techniques.