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tai/research/prompt-context-scaling/cursor-subagents.md
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retoor af080fe68e Strict goal verification, approval hardening, retrieval eval, work limits, sandbox caps (1.38.0)
- Approval: re-prompt unknown answers (max 3), shell-only affirmative
  guidance recovery; destructive actions stay strict
- GoalVerifier subagent with strict JSON verdicts, bounded follow-up
  rounds, nonzero exit plus open turn on unverified one-shots
- Retrieval eval (Hit@K/MRR/nDCG/Context Precision), FTS cascade with
  title weighting, query/read event logging, --eval-retrieval CLI
- Supervisor caps (8 parallel, 64 records) and scheduler hardening
  (4 fires/tick, per-schedule lease, stated misfire policy)
- Sandbox box resource trio: 2g/2.0/256 at create, best-effort
  update for existing boxes, rm -f recovery pointer
- Research archive: 12 subjects, 667 sources, 27 conclusions;
  suites 979 + 16 green
2026-10-18 12:13:24 +02:00

2.5 KiB

Subagents

Metadata

Field Value
Institute Molodetz Institute — Research & Retrieval Division
Subject prompt-context-scaling
Document type Source Dossier
Tier 1
Source title Subagents
Source URL https://cursor.com/docs/subagents
Source publisher / author Cursor
Source type vendor docs
Source date (published) Unknown — not stated (living documentation page)
Date researched 2026-10-18
Researched by tai (agent), model: Muse Spark, on behalf of retoor
Research method both
Confidence High
Status Active

Summary

Cursor's subagent docs describe context isolation as the primary motive for delegation: each subagent gets a clean window, noisy intermediate output never touches the main conversation, and purpose-built Explore/Browser subagents run on faster, cheaper models. The built-in subagents were designed from analysis of conversations where context limits were actually hit.

Key findings

  • "Each subagent operates in its own context window" and "Long research or exploration tasks don't consume space in your main conversation."
  • "Intermediate output stays in the subagent. The parent only sees the final summary."
  • "The explore subagent uses a faster model by default. This enables running 10 parallel searches in the time a single main-agent search would take."
  • "Faster models cost less. Isolating token-heavy work in subagents with appropriate model choices reduces overall cost."
  • "These subagents were designed based on analysis of agent conversations where context window limits were hit."

Pros / strengths

  • Production evidence from the most-used coding agent that delegation-for-isolation plus cheaper-models-for-bulk-work is the economical shape.
  • The foreground/background mode split matches tai's fork/poll split (collect now versus later).

Cons / limitations / caveats

  • Product docs for a managed agent; no failure rates or quality comparisons between main-model and fast-model subagent output.
  • Cursor-specific built-ins (Explore, Browser); the pattern transfers, the implementations do not.

Relevance to tai

Validates tai's fork guidance ("fork background subagents for independent, long, or context-heavy work") as the same architecture Cursor ships. Suggests one refinement worth pricing later: letting context-heavy workers run on a cheaper pinned model instead of the session default.

Changelog

Date Change
2026-10-18 Initial dossier created.