# Subagent Delegation Audit — Main-Context Pressure Analysis

**Status:** Exploratory brief — findings + options, not a decision
**Date:** 2026-04-19
**Scope:** trekplan v2.3.2, all six user-facing commands

## Problem

Main context fills up quickly during trekplan runs. The plugin's
design principle is Context Engineering — the main context should
**orchestrate**, subagents should **execute**. In practice, the exploration
phases do delegate aggressively, but the **synthesis and writing phases
remain inline**, which is where the bulk of heavy reading and reasoning
actually happens.

## Verified findings

### 1. Exploration is already well-delegated

Agent-spawn density per command (nominal):

| Command                  | Agents spawned                                                    |
|--------------------------|-------------------------------------------------------------------|
| trekresearch      | ~9–14 (5 local + 4 external + 1 bridge + up to 2 follow-ups)      |
| trekplan          | ~10 (6 initial + conditional research-scout + up to 3 deep-dives) |
| trekbrief         | 1–3 (brief-reviewer per iteration, max 3)                         |
| trekexecute       | 0 (explicit no-agent rule)                                        |
| voyage-skill-author-local | 3 (concept-extractor → skill-drafter → ip-hygiene-checker)        |

This part is healthy.

### 2. Synthesis and writing is inline

The main context does the heavy cognitive work after swarm completion:

- **`commands/trekplan.md:483–498` (Phase 7 Synthesis):**
  "Read all agent results carefully" + "Build a mental model of the codebase
  architecture" + "Catalog reusable code" + "Integrate research findings".
  This forces 6–10 agent outputs to remain resident in main context simultaneously.

- **`commands/trekplan.md:499–548` (Phase 8 Deep Planning):**
  Main context writes the entire plan.md from scratch, including all required
  sections, quality standards, and file-path validation.

- **`commands/trekresearch.md:302–323` (Phase 6 Triangulation):**
  Explicitly labelled "the KEY phase that makes trekresearch more than
  aggregation". Dimension-by-dimension comparison of local vs external
  findings, contradiction flagging, confidence rating — all inline.

- **`commands/trekresearch.md:325–341` (Phase 7 Synthesis):**
  Writes the research brief inline using the template.

### 3. Root cause — v2.4.0 foreground migration

Each command carries a `> **Why foreground?**` block
(`trekplan.md:330`, `trekresearch.md:192`) documenting that the
background orchestrators were removed because agents spawned from background
orchestrators silently degraded. The swarm-spawn logic was lifted into the
main context — but so was the synthesis logic the orchestrators used to
carry. The "summarizer" link is missing.

## Candidate interventions

Presented as options, ordered by estimated main-context savings. Numbers
are rough estimates based on the size of the phase bodies — not measured.

| # | Intervention                                                        | Target phase                        | Rough saving |
|---|---------------------------------------------------------------------|-------------------------------------|--------------|
| 1 | `synthesis-agent` — digests all exploration outputs into findings + reuse catalog + gaps | trekplan Phase 7                   | 40–50%       |
| 2 | `plan-writer-agent` — writes plan.md from synthesis + template      | trekplan Phase 8                   | part of #1   |
| 3 | `triangulation-synthesizer` — per-dimension local vs external diff + confidence rating | trekresearch Phase 6               | 25–30%       |
| 4 | `research-brief-writer` — writes research brief from triangulation output | trekresearch Phase 7               | part of #3   |

## Tradeoffs (important)

- **Iteration friction.** A synthesis- or writer-agent does not see the
  live conversation. If the user wants to push back on the plan ("split
  step 3 in two", "re-phrase the risks"), refinement still has to happen
  in main context. Delegation works best for the first pass; the revision
  loop is harder to delegate.

- **Adversarial review still needs main.** `plan-critic` and
  `scope-guardian` already return findings to main context — which then
  has to act on them. If the plan was written by an agent, main must
  either re-invoke the writer agent with critic feedback, or absorb the
  plan back in to revise it. Neither is free.

- **Artifact quality gates.** The current inline phases enforce
  quality rules (e.g., "every file path must exist in the codebase").
  A writer-agent needs the same codebase context the exploration agents
  had — re-delivering that context to the writer burns tokens the
  delegation was meant to save.

- **Debuggability.** Inline synthesis is inspectable in the transcript.
  Agent-synthesis hides the reasoning inside the agent's return message —
  fine when it works, harder to diagnose when it doesn't.

## Recommendation (tentative)

If only one change is made, **intervention #1 (synthesis-agent for
trekplan Phase 7)** has the largest ROI. It isolates the heaviest read
(all 6–10 agent outputs) behind a summarizer, and its output — a compact
findings document — is small enough to keep resident for Phase 8 planning
and Phase 9 review.

Intervention #3 is a smaller-scope and lower-risk proof-of-concept
that could validate the pattern before touching the main planner.

## Open questions

1. Should the synthesis-agent write to disk (`synthesis.md` alongside
   `plan.md`) for inspectability, or return in-memory?
2. Does the adversarial review phase (plan-critic + scope-guardian) need
   access to the full exploration outputs, or is the synthesis artifact
   enough?
3. Is there a way to measure current main-context usage per phase so the
   savings estimates above can be replaced with real numbers before
   committing to changes?
4. Does this interact with `REMEMBER.md`'s note that "trekplan schema-drift
   on 4.7 produces Phase-plans instead of v1.7 step-schema"? A writer-agent
   might either help (isolated, more controllable) or hurt (another layer
   where drift can happen) the schema-drift problem.

## Out of scope for this brief

- Implementation details of the new agents
- Changes to trekexecute (no-agent by design)
- Changes to trekbrief Phase 3 interview (must be inline to drive
  user dialogue)