Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add endorphin-ai/hasbrains-agent-kit --skill build-braingit clone --depth 1 https://github.com/endorphin-ai/hasbrains-agent-kitWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/endorphin-ai/hasbrains-agent-kit/build-brain)<a href="https://agentmods.dev/skills/endorphin-ai/hasbrains-agent-kit/build-brain"><img src="https://agentmods.dev/badge/skills/endorphin-ai/hasbrains-agent-kit/build-brain/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/endorphin-ai/hasbrains-agent-kit/build-brain"><img src="https://agentmods.dev/badge/skills/endorphin-ai/hasbrains-agent-kit/build-brain.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00058 | $0.02604 |
| Opus 5.5 | $0.00023 | $0.01042 |
| Sonnet 5.5 | $0.00012 | $0.00521 |
| Haiku 4.5 | $0.00006 | $0.00260 |
Grade A, and why
build-brain scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 193 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Parse arguments as:
- SOURCE = first positional path. Required. Points to EITHER (a) an existing skill folder (a SKILL.md plus references/), OR (b) a folder or set of data files: .md, .json, .xlsx/.csv.
- --out = REQUIRED output directory for the rebuilt skill. The user always specifies this. NEVER write outside it.
- --apply = write files for real. If absent, do everything up to and including the proposal + before/after preview, then STOP without writing.
- --no-gate = skip the confirmation gate in PHASE 3 and write immediately after the proposal.
If SOURCE or --out is missing, ask for it in one line and stop. Do not guess paths.
<core_objective> Produce, inside --out, an "AI-optimized skill" with this shape:
/ SKILL.md # the MAP: lean, ~under 150 lines. Loaded every time. references/ # the BRAIN: many small notes. Loaded on demand only. .md # one concept per file, Obsidian-style frontmatter + [[wikilinks]] ... maps/ index.json # master navigation map — the single source of truth for "what exists + when to load it" tags.json # tag -> [note ids], for tag search links.json # note id -> [linked note ids], the Obsidian-style graph manifest.json # build metadata: source, timestamp, version, counts, token estimates REPORT.md # before/after improvement report, junior-engineer voice
The point of this shape: an AI reads SKILL.md + index.json (cheap), then loads ONLY the one or two reference notes it needs (cheap). It never has to read the whole brain to answer one question. That is the token efficiency. Protect it in every decision. </core_objective>
PHASE 0 — INGEST (read only)
- Resolve SOURCE and --out.
- Recursively list SOURCE. Read every file. For .xlsx/.csv, extract each sheet/table as structured rows.
- Detect source type: "existing-skill" (a SKILL.md is present) or "raw-data".
- Build a raw inventory: path, type, line count, rough token estimate (~chars/4), and a one-line summary of each file's content.
- Do NOT modify SOURCE. SOURCE is read-only, always.
PHASE 1 — ANALYZE THE "BEFORE" Build an honest picture of the current state. Capture:
- Total files, total tokens, largest files, and how many tokens an AI must load today to answer a typical question.
- Structural problems: oversized files (one file doing many jobs), duplicated content, stale/contradictory info, missing or flat tags, dead or absent links, no machine-readable index.
- If existing-skill: is SKILL.md lean or bloated? Does it act as a map, or does it dump everything inline?
- If raw-data: what natural concepts exist? What is the smallest sensible unit to atomize into? State numbers, not adjectives. "SKILL.md is 1,900 tokens and inlines 6 topics" — not "it's a bit big".
PHASE 1.5 — TRIPLE CHECK (mandatory, three distinct passes) Re-examine your PHASE 1 analysis THREE times, each pass with a different lens. Write one short finding line per pass.
- Pass 1 — Completeness: Did I read every file? Any content I ignored, any sheet I skipped, any concept I missed?
- Pass 2 — Correctness: Are my token counts, file sizes, and "duplicate" claims actually true? Re-check the two biggest claims against the raw text.
- Pass 3 — Tradeoffs: For every change I am about to propose, what does it COST? (More files = more links to maintain. Aggressive dedup = risk of losing nuance. Smaller SKILL.md = more on-demand loads.) Name the cost honestly. Only after all three passes may you propose anything.
PHASE 2 — PROPOSE (with tradeoffs and before/after) Output the plan as text BEFORE writing. Include:
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 1mo ago First seen · 193 lines · 58 tokens per session scan A 1301bd12045f
build-brain is a skill published in the GitHub repository endorphin-ai/hasbrains-agent-kit (9 stars, last pushed 12d ago), licensed MIT. It adds 58 tokens to every session and 2,604 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
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