git:20260730.0bf7183 to git:20260825.fe04035

---

name: token-budget

description: |

Context/token discipline: subagent isolation, output = summary, move-to-file, delegation threshold, lean skills.

---

# Token & Context Discipline

<!-- routing-eval reads this line; it lives in the BODY so the always-on skill LISTING stays inside

Claude Code's budget (1% of the context window) — an overflowing listing gets descriptions

truncated or dropped, which strips the very keywords a match depends on. -->

Trigger phrases: "token budget", "token cost", "context", "context management", "context is full", "clear context"

A subagent exists for context management: it runs in its own window and returns **only its summary**

to the main thread — intermediate noise (file reads, searches, logs) never enters the main context.

**Warning — measured, not guessed.** Each subagent re-pays its **full context from scratch**: in a real

transcript the first turn was `cache_read=0`, every token `cache_creation` — nothing is shared with the main

thread's cache. A **no-op** subagent (task = "reply DONE") already cost **~10k tokens with restricted tools and

~16k with full tool access**; that floor is base system prompt + tool schemas, paid fresh every time. Of the

always-on material only the **skill listing (~2.5–3k tokens) is inherited** by a subagent — the discipline

(`DISCIPLINE.md`/CLAUDE.md) and the agent descriptions are **not** injected into it. So a delegation is worth it

for **isolation / parallelism / a clean window**, or when the isolated work would otherwise cost the main thread

**more than that ~10–16k floor** — never by default.

## Rules

1. **Output = summary.** The agent returns a short, structured summary to the main thread; it does **not** return raw logs / file dumps / long code.

2. **Move to a file.** Heavy output (a plan, scan report, inventory) is written to `docs/*.md`; a **summary + pointer** comes back. (local, in gitignore)

3. **Delegation threshold.** Noisy/heavy work (reading many files, scanning, research) → subagent. A single tool-call / small work → **main thread**. Concretely: if the isolated work won't save the main thread more than the **~10–16k fresh-context floor** a subagent costs, keep it on the main thread — delegate for isolation, not to shave a few reads.

4. **Least tooling.** An agent holds only the tools it needs; extras accidentally pollute the context + burn the limit.

5. **Lean SKILL.md.** Skills load into the main context; heavy reference goes to a separate file, only when needed.

6. **Targeted reading.** Instead of reading a whole file, pinpoint with Grep/Glob.

7. **Manage with /context.** session-manager-csk recommends continue/handoff+clear based on the real percentage; at a phase boundary, `/clear`.