Context design
Draft for human review
August 2026 · 8 min read
Context is a budget.
Spend it on the next decision.
Longer prompts and bigger windows do not remove the need to choose what an agent needs to know. They make that choice easier to postpone—and harder to inspect.
An agent does not need a complete archive of your company to make the next useful move. It needs the smallest trustworthy packet that lets it act without guessing at the decision in front of it.
Anthropic describes context as a finite resource and frames context engineering as the work of curating the information that enters an agent’s working state.[1] That is a useful operational idea even if your team is not building its own model stack. Every brief, retrieved document, tool result, and prior message competes for attention. More material can improve a decision—but irrelevant, stale, or contradictory material can also make the decision less clear.
01. Treat every added detail as a trade-off
The practical mistake is not “giving an agent too much context” in the abstract. It is adding information without being able to say which decision it helps. A giant project dump may feel safe because nothing was omitted. But it often hides the boundary, buries the current task, and makes it harder for a reviewer to tell why the agent chose a path.
A better default is to separate stable rules from task-specific evidence. Keep stable rules short, explicit, and maintained. Bring in changing material only when it supports the current job. If a detail does not affect the next action, acceptance check, or escalation route, it probably does not belong in the first packet.
The question is not “what might be relevant?”
It is “what must be true for this next decision to be responsible?”
02. Build a packet around the decision, not the repository
For a small team, a decision packet can stay plain. It does not need a new platform, a memory graph, or an elaborate retrieval pipeline. It needs a predictable shape that a human can inspect before work starts.
01 / Outcome
What should exist when this run is done? Include the format, audience, and acceptance check.
02 / Boundary
What may the agent read, change, call, or recommend? Name exclusions and the person who can expand the boundary.
03 / Evidence
Which current documents, files, records, or examples are authoritative for this specific job? Prefer direct sources over broad summaries.
04 / Failure route
What should happen when evidence conflicts, a required input is missing, or the task reaches a consequential decision?
This is deliberately narrower than a “full briefing.” It asks a team to make the goal, source of truth, and stopping conditions visible before an agent turns them into output. The packet should be small enough that a reviewer can notice a missing rule or a bad source before the run becomes expensive.
03. The handoff is part of the work
Context does not only enter at the start. It also has to survive a pause, a compaction, a shift change, or a different reviewer. Anthropic’s long-running-agent guidance describes agents making more reliable incremental progress when the environment contains clear requirements, a record of progress, and a clean state for the next session.[2] The principle applies to supervised work too: do not make the next person reconstruct the story from artifacts alone.
A four-line handoff
The job in one sentence
State the outcome and the boundary. “Improve onboarding” is not a handoff; “rewrite this screen’s empty state, preserve existing events, and leave a reviewable diff” is.
What is already true
Record the relevant files, decisions, constraints, and the one or two facts a fresh operator would otherwise have to rediscover.
What changed
Name the artifact, not the feeling: a commit, a draft, a test result, a rejected option, or an unresolved failure.
What happens next
Give the next smallest checkable move. A successor should not have to infer whether to investigate, test, ask, or ship.
A handoff should not pretend that a result is final. It should make uncertainty legible: what was checked, what failed, what changed, and what a responsible person should inspect next. That leaves a smaller and more useful context for the next run than a long narrative of everything that happened.
Related decision
Make the work easy to replaySources and review note
Read the material behind the note.
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