natal-chart-reading

natal-chart-reading is a skill for Claude Code, Codex from openephemeris/openephemeris-MCP. It costs 68 tokens per session (2,918 once invoked), scanned A, original, MIT.

A guide for interpreting a natal chart, which is an astrology chart based on a person's birth date, time, and location. It explains planetary placements, houses, aspects, and related chart features.

In plain words
What is it for?
Use it for questions about the Sun, Moon, Rising sign, planets, houses, aspects, personality themes, or other individual birth-chart placements.
Why use it?
It helps produce a chart reading from the right birth details and handles location, time-zone, and house-system choices that affect the result.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it for questions about the Sun, Moon, Rising sign, planets, houses, aspects, personality themes, or other individual birth-chart placements.

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Install with agentmods
npx agentmods add skills/openephemeris/openephemeris-mcp/natal-chart-reading
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 openephemeris/openephemeris-MCP --skill natal-chart-reading
Clone the repo
git clone --depth 1 https://github.com/openephemeris/openephemeris-MCP

Made for: Claude Code, Codex.

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 natal-chart-reading

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

Your own site · 80×15
<a href="https://agentmods.dev/skills/openephemeris/openephemeris-mcp/natal-chart-reading"><img src="https://agentmods.dev/badge/skills/openephemeris/openephemeris-mcp/natal-chart-reading.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 68 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,918 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 $0.00068 $0.02918
Opus 5 $0.00034 $0.01459
Sonnet 5 $0.00014 $0.00584
Haiku 4.5 $0.00007 $0.00292

Measured 12d ago against content hash a27b2832cdf2, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

natal-chart-reading 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 12d 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.

skills/natal-chart-reading/SKILL.md · 258 lines

How it starts

The opening of the file, as written. The whole thing — 258 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Natal Chart Reading

Use this skill whenever a user asks about their birth chart or any individual placement (Sun, Moon, Rising, planets, houses, aspects, nodes, Chiron, dignities, midpoints, hermetic lots).

Required Information

Ask for, in this order:

  1. Full birth date (year, month, day)
  2. Birth time (hour and minute — accuracy matters; see "Time-unknown handling" below)
  3. Birth location (city, state/region, country)
  4. (Optional) Preferred house system. Default Placidus. Offer alternatives if they sound traditional/Hellenistic-inclined.

Standard Procedure for Birth-Data Endpoints

Any endpoint that takes a birth chart (natal, synastry, composite, transits, returns, progressions, Human Design, Vedic, ACG) MUST follow this sequence. Skipping any step produces a wrong chart — usually wrong by hours of arc.

Step 1 — Resolve location to coordinates

If you don't already have precise lat/lon, call:

GET /location/autocomplete?query=<city, country>&limit=5

Confirm the right hit with the user if there's ambiguity (e.g. "Portland, OR" vs "Portland, ME"). Record the latitude and longitude of the chosen result.

Step 2 — Resolve timezone for that location AT THE BIRTH DATE

Historical timezone rules matter. A city's UTC offset in 1962 may differ from today (DST rules, war time, jurisdiction changes). Always look up the timezone for the specific birth date.

POST /timezone/lookup
{ "latitude": <lat>, "longitude": <lon> }

Response gives an IANA timezone string like "America/Los_Angeles". The BirthLocation field below REQUIRES this — it is not optional.

Step 3 — Build the request body

The SubjectRequest schema requires birth_datetime, birth_location, and name. The IANA timezone goes into birth_location.timezone:

{
  "subject": {
    "name": "Subject",
    "birth_datetime": { "iso": "1990-04-15T14:30:00" },
    "birth_location": {
      "latitude": 41.8781,
      "longitude": -87.6298,
      "timezone": "America/Chicago",
      "city": "Chicago",
      "country": "United States"
    }
  }
}

Read the full file on GitHub · 258 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. 12d ago First seen · 258 lines · 68 tokens per session scan A a27b2832cdf2

Subscribe to this mod's changes

natal-chart-reading is a skill published in the GitHub repository openephemeris/openephemeris-MCP (4 stars, last pushed yesterday), licensed MIT. It adds 68 tokens to every session and 2,918 once invoked, about $0.0003 per session on Opus 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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