How do I install the Context Cost Tree skill?

Run npx skillmds@latest add horizonbrute/context-cost-tree in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

Is Context Cost Tree safe to use?

This skill has not completed SkillMD's automated safety review yet. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Context Cost Tree?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Context Cost Tree free to use?

Yes. Installing skills from SkillMD is free, and the skill stays under its author's original license.

Who published Context Cost Tree?

HorizonBrute (@horizonbrute) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Context Cost Tree by horizonbrute — Agent Skill

Name: Context Cost Tree
Author: HorizonBrute

Context Cost Tree

Map Claude Code harness context overhead across the ENTIRE AIOS as an ASCII tree — brute-forces every directory under $HORIZON_ROOT, attributes each auto-loaded CLAUDE.md / agents.md / @-import file to the directory it lives in, and reports per-directory, subtree, and grand-total context cost. Use when the user types /context-cost-tree, wants a whole-AIOS context map, or asks where context cost accrues across the tree (as opposed to /context-cost, which measures one path's upward load).

HorizonBrute df01b28 3.6 KB Updated Sep 17, 2026

File contents

Skill: /context-cost-tree

Model preference: #lowcost (per horizon_aios_model_prefs.md; overridable by a prompt directive).

Show, as ASCII-tree art, where harness context overhead lives across the whole AIOS. Where /context-cost answers "what will a session started here load?" (an upward walk from one path), /context-cost-tree brute-forces the whole tree: it walks down from $HORIZON_ROOT, finds every auto-load file (CLAUDE.md, CLAUDE.local.md, agents.md) plus everything they @-import, de-duplicates, and attributes each file to the directory it physically lives in — so you can see at a glance which directories carry the context weight.

Arguments

/context-cost-tree [path]

path — optional; defaults to $HORIZON_ROOT (the whole AIOS). Pass a path to scope the map to a subtree.

Step-by-step execution

Step 1 — Run the mapper

1.1 Run (no path arg needed — it defaults to $HORIZON_ROOT):

python "$HORIZON_SYSTEM/bin/context_cost_tree.py"

To scope to a subtree, pass a path: python "$HORIZON_SYSTEM/bin/context_cost_tree.py" <path>.

1.2 The script prints the ASCII tree directly. Relay it to the user verbatim inside a code block — the tree art and alignment matter.

1.3 For programmatic use, add --json to get {root, directories[], external, total_files, total_kb, total_tokens} instead of the tree.

If the command fails (non-zero exit, missing script, $HORIZON_ROOT unset), report the error clearly and stop. An unset $HORIZON_ROOT means the AIOS environment is not active — tell the user to source their profile or run the AIOS switcher.

Step 2 — Read the output

Each node shows the tokens/KB/file-count for auto-load files physically in that directory, plus a [subtree: N tok] roll-up for structural (pass-through) directories. Directories with no auto-load weight and no weighted descendants are pruned, so the tree highlights where context accrues rather than dumping every folder.

The grand total sums the de-duplicated auto-load fileset inside the root. A separate External line accounts for files pulled in from outside the tree (e.g. ~/.claude imports).

Step 3 — Flag heavy nodes (optional)

If any single directory dominates the total (e.g. a subtree carrying a large share of the tokens), point it out as the first place to trim CLAUDE.md / agents.md / @-imports.

Notes for the executing agent

$HORIZON_SYSTEM and $HORIZON_ROOT must be set. If not, report that the AIOS environment is not active.
Measurement and @-import resolution are reused from context_cost.py (/context-cost's engine) — it is the single source of truth for tokenization and import semantics. Do not reimplement counting; just run context_cost_tree.py and relay its output.
A file @-imported by several CLAUDE.md files is counted once (de-duplicated) and attributed to where it physically lives — so the tree is a map of where the bytes are, not of every place they get pulled into.
Token counts are estimates (chars ÷ 4), same convention as /context-cost.

---name: context-cost-treedescription: Map Claude Code harness context overhead across the ENTIRE AIOS as an ASCII tree — brute-forces every directory under $HORIZON_ROOT, attributes each auto-loaded CLAUDE.md / agents.md / @-import file to the directory it lives in, and reports per-directory, subtree, and grand-total context cost. Use when the user types /context-cost-tree, wants a whole-AIOS context map, or asks where context cost accrues across the tree (as opposed to /context-cost, which measures one path's upward load).---# Skill: /context-cost-tree**Model preference:** `#lowcost` (per `horizon_aios_model_prefs.md`; overridable by a prompt directive).Show, as ASCII-tree art, where harness context overhead lives across the whole AIOS. Where `/context-cost` answers "what will a session started *here* load?" (an upward walk from one path), `/context-cost-tree` brute-forces the whole tree: it walks **down** from `$HORIZON_ROOT`, finds every auto-load file (`CLAUDE.md`, `CLAUDE.local.md`, `agents.md`) plus everything they `@`-import, de-duplicates, and attributes each file to the directory it physically lives in — so you can see at a glance which directories carry the context weight.---## Arguments`/context-cost-tree [path]`- `path` — optional; defaults to `$HORIZON_ROOT` (the whole AIOS). Pass a path to scope the map to a subtree.---## Step-by-step execution### Step 1 — Run the mapper1.1 Run (no path arg needed — it defaults to `$HORIZON_ROOT`):```python "$HORIZON_SYSTEM/bin/context_cost_tree.py"```To scope to a subtree, pass a path: `python "$HORIZON_SYSTEM/bin/context_cost_tree.py" <path>`.1.2 The script prints the ASCII tree directly. Relay it to the user verbatim inside a code block — the tree art and alignment matter.1.3 For programmatic use, add `--json` to get `{root, directories[], external, total_files, total_kb, total_tokens}` instead of the tree.If the command fails (non-zero exit, missing script, `$HORIZON_ROOT` unset), report the error clearly and stop. An unset `$HORIZON_ROOT` means the AIOS environment is not active — tell the user to source their profile or run the AIOS switcher.### Step 2 — Read the outputEach node shows the tokens/KB/file-count for auto-load files **physically in that directory**, plus a `[subtree: N tok]` roll-up for structural (pass-through) directories. Directories with no auto-load weight and no weighted descendants are pruned, so the tree highlights where context accrues rather than dumping every folder.The grand total sums the de-duplicated auto-load fileset inside the root. A separate `External` line accounts for files pulled in from outside the tree (e.g. `~/.claude` imports).### Step 3 — Flag heavy nodes (optional)If any single directory dominates the total (e.g. a subtree carrying a large share of the tokens), point it out as the first place to trim `CLAUDE.md` / `agents.md` / `@`-imports.---## Notes for the executing agent- `$HORIZON_SYSTEM` and `$HORIZON_ROOT` must be set. If not, report that the AIOS environment is not active.- Measurement and `@`-import resolution are **reused** from `context_cost.py` (`/context-cost`'s engine) — it is the single source of truth for tokenization and import semantics. Do not reimplement counting; just run `context_cost_tree.py` and relay its output.- A file `@`-imported by several `CLAUDE.md` files is counted once (de-duplicated) and attributed to where it physically lives — so the tree is a map of *where the bytes are*, not of every place they get pulled into.- Token counts are estimates (chars ÷ 4), same convention as `/context-cost`.

Frequently asked questions