marrow-health

marrow-health is a skill for Claude Code from skeletonarmytech/marrow-mcp. It costs 77 tokens per session (592 once invoked), scanned A, original, MIT.

A guide for reading and recording a person's health data through Marrow, including information synced from Apple Health. It covers measures such as sleep, steps, heart rate, weight, food, training, symptoms, and mood.

In plain words
What is it for?
Use it for daily health summaries, personal baselines, weekly changes, sleep and workout reviews, nutrition and symptom history, and questions about preparing for a doctor visit.
Why use it?
It helps answer health questions from the person's own records rather than guessing or applying general assumptions. It also checks for missing or outdated data before drawing conclusions.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the marrow-health plugin — 1 skill, 4 commands, 1 MCP server shipped together

Good fit Use it for daily health summaries, personal baselines, weekly changes, sleep and workout reviews, nutrition and symptom history, and questions about preparing for a doctor visit.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/skeletonarmytech/marrow-mcp/marrow-health
Install

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.

Any agent
npx skills add skeletonarmytech/marrow-mcp --skill marrow-health
Clone the repo
git clone --depth 1 https://github.com/skeletonarmytech/marrow-mcp

Made for: Claude Code.

Or install marrow-health, the plugin that ships this one along with the rest of its 1 skill, 4 commands, 1 MCP server.

Wrote 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.

agentmods badge for marrow-health

README.md
[![agentmods](https://agentmods.dev/badge/skills/skeletonarmytech/marrow-mcp/marrow-health/github.svg)](https://agentmods.dev/skills/skeletonarmytech/marrow-mcp/marrow-health)
Your own site
<a href="https://agentmods.dev/skills/skeletonarmytech/marrow-mcp/marrow-health"><img src="https://agentmods.dev/badge/skills/skeletonarmytech/marrow-mcp/marrow-health/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.

agentmods 80×15 button for marrow-health

Your own site · 80×15
<a href="https://agentmods.dev/skills/skeletonarmytech/marrow-mcp/marrow-health"><img src="https://agentmods.dev/badge/skills/skeletonarmytech/marrow-mcp/marrow-health.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 77 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 592 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00077 $0.00592
Opus 5.5 $0.00031 $0.00237
Sonnet 5.5 $0.00015 $0.00118
Haiku 4.5 $0.00008 $0.00059

Measured yesterday against content hash 719f3b74f00c, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

marrow-health 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 yesterday.

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.

plugins/marrow-health/skills/marrow-health/SKILL.md · 49 lines

How it starts

The opening of the file, as written. The whole thing — 49 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Marrow Health

The marrow MCP server is the user's own Marrow mirror, synced from their iPhone. Everything it returns is their data, reconciled the way the app shows it. Answer from it, never from assumptions.

Which tool answers what

  • "How am I doing" or anything about today: daily_brief. Each key metric comes with a phrase against the user's own trailing normal (normal for you, above your normal, well below your normal), food and water against targets, last night's sleep, training done, mood, symptoms and flags. Start here before giving any advice.
  • Is a number high or low for this person: baselines (mean, spread, z, phrase, 7-day mean, 90-day trend). Use its phrases, not population ranges.
  • What is different lately, weekly reviews: what_changed (recent days against the period before, notable items first, food, training, sleep, bedtime shift, streams that started or stopped).
  • Before concluding something did not happen: data_quality. A stale or missing stream is not a zero.
  • Raw detail: health_summary (a plain day table), metric_daily, metric_samples (page with before), workouts, nutrition_log, strength_log, sleep_log (the only correct source for nights), symptoms_and_mood, targets.
  • Every read takes days back or from and to on the phone's calendar (YYYY-MM-DD).

Logging

Only when the user asks. log_meal, log_water, log_weight, log_workout, log_strength, log_sleep, log_symptom, log_mood, edit_entry, delete_entry, set_targets, undo_entry. The phone applies each change and writes it to Apple Health. If a write answers that write-back is turned off, tell the user where the switch is (Marrow, Export, Connect your AI, Allow AI write). Never log, change or remove anything the user did not ask for. Confirm what was logged in one line.

Wording

Neutral wellness wording. Describe, compare with the user's own normal, suggest. Do not diagnose or alarm. Quote units. Say plainly when data is missing or stale.

Read the full file on GitHub · 49 lines

Changes

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.

  1. yesterday First seen · 49 lines · 77 tokens per session scan A 719f3b74f00c

Subscribe to this mod's changes

marrow-health is a skill published in the GitHub repository skeletonarmytech/marrow-mcp (3 stars, last pushed yesterday), licensed MIT. It adds 77 tokens to every session and 592 once invoked, about $0.0003 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 2026-10-22.

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