Open Ephemeris

Progressed Chart

ephemeris_progressed_chart

Read-onlyIdempotent

Computes progressed planet positions, house cusps, aspects and retrograde status for a target date using secondary, solar arc, tertiary or minor methods, including converse directions.

Instructions

Use this when the user asks 'what's my progressed chart', 'my secondary progressions', 'where is my progressed Moon right now' or 'my solar arc directions'. Returns progressed planet positions, house cusps, aspects and retrograde status for a target date — method = secondary (1 day = 1 year, default), solar_arc, tertiary or minor; converse counts backward.

CREDIT COST: 1 credit per call.

Input Schema

Name	Required	Description
`name`	No	Optional subject label.
`method`	No	Default secondary (1 day = 1 year).
`converse`	No	Count backward from birth.
`timezone`	No	IANA zone for a local datetime.
`birth_datetime`	Yes	ISO 8601; zone required (`Z`/offset, or local time plus `timezone`).
`birth_latitude`	Yes	Birth latitude.
`include_visual`	No	Also return a natal-inside, progressed-outside bi-wheel as an image (+2 credits).
`birth_longitude`	Yes	Birth longitude.
`include_aspects`	No	Add the aspect grid. Default false.
`target_datetime`	Yes	Progress to. ISO 8601 date or zoned datetime.

Schema Changelog

Changes observed during successful MCP inspections.

Changed8 schema fields changedv4.29.0Oct 28, 2026

changedInput schema / properties / birth_datetime / description

Previous value: -"ISO 8601 datetime. A datetime with no zone is rejected; give a `Z` or ±HH:MM suffix, or a local time with the `timezone` argument. Date-only resolves to 12:00 UTC."New value: +"ISO 8601; zone required (`Z`/offset, or local time plus `timezone`)."

changedInput schema / properties / birth_latitude / description

Previous value: -"Birth latitude in decimal degrees."New value: +"Birth latitude."

changedInput schema / properties / birth_longitude / description

Previous value: -"Birth longitude in decimal degrees."New value: +"Birth longitude."

changedInput schema / properties / include_aspects / description

Previous value: -"Whether to include aspect grid in the response. Default false."New value: +"Add the aspect grid. Default false."

changedInput schema / properties / method / description

Previous value: -"Progression method. Defaults to 'secondary' (1 day = 1 year)."New value: +"Default secondary (1 day = 1 year)."

changedInput schema / properties / name / description

Previous value: -"Optional label for the subject, echoed back in both natal_subject and progressed_subject. Defaults to a generic label if omitted."New value: +"Optional subject label."

changedInput schema / properties / target_datetime / description

Previous value: -"Date to progress the chart to. ISO 8601 date or zoned datetime; a naive clock time is rejected. Date-only resolves to 12:00 UTC."New value: +"Progress to. ISO 8601 date or zoned datetime."

changedInput schema / properties / timezone / description

Previous value: -"IANA timezone (e.g. `America/Chicago`); required when the datetime is naive, ignored otherwise."New value: +"IANA zone for a local datetime."

Changed2 schema fields changedv4.27.0Oct 25, 2026

addedInput schema / properties / converse

Added value: +{
+  "description": "Count backward from birth.",
+  "type": "boolean"
+}

changedInput schema / properties / method / enum

Previous value: -[
-  "secondary",
-  "solar_arc",
-  "tertiary"
-]New value: +[
+  "secondary",
+  "solar_arc",
+  "tertiary",
+  "minor"
+]

Changed5 schema fields changedv4.24.2Oct 24, 2026

changedInput schema / properties / birth_datetime / description

Previous value: -"ISO 8601 datetime; zone required — a `Z`/±HH:MM suffix or the `timezone` argument. Date-only resolves to 12:00 UTC. Full rule: server `instructions`."New value: +"ISO 8601 datetime. A datetime with no zone is rejected; give a `Z` or ±HH:MM suffix, or a local time with the `timezone` argument. Date-only resolves to 12:00 UTC."

changedInput schema / properties / birth_latitude / description

Previous value: -"Birth latitude in decimal degrees. Resolve from a place name with location_search; never recall coordinates from memory."New value: +"Birth latitude in decimal degrees."

changedInput schema / properties / include_visual / description

Previous value: -"When true, renders the progressed chart wheel as an SVG and embeds it in the response. The chart image will display in the conversation alongside the data. Costs 2 additional credits on top of the base call cost."New value: +"Also return a natal-inside, progressed-outside bi-wheel as an image (+2 credits)."

addedInput schema / properties / name

Added value: +{
+  "description": "Optional label for the subject, echoed back in both natal_subject and progressed_subject. Defaults to a generic label if omitted.",
+  "type": "string"
+}

removedInput schema / properties / visual_config

Removed value: -{
-  "additionalProperties": false,
-  "description": "Optional rendering preferences (only used when include_visual=true).",
-  "properties": {
-    "size": {
-      "description": "Canvas size in pixels, 200–4000. Default: 800.",
-      "type": "number"
-    },
-    "theme": {
-      "description": "Color theme. Default: light.",
-      "enum": [
-        "light",
-        "dark"
-      ],
-      "type": "string"
-    }
-  },
-  "type": "object"
-}

Changed4 schema fields changedv4.8.0Aug 3, 2026

changedInput schema / properties / birth_datetime / description

Previous value: -"ISO 8601 natal birth date/time."New value: +"ISO 8601 datetime; zone required — a `Z`/±HH:MM suffix or the `timezone` argument. Date-only resolves to 12:00 UTC. Full rule: server `instructions`."

changedInput schema / properties / birth_latitude / description

Previous value: -"Birth latitude in decimal degrees."New value: +"Birth latitude in decimal degrees. Resolve from a place name with location_search; never recall coordinates from memory."

changedInput schema / properties / target_datetime / description

Previous value: -"Target date to progress the chart to (ISO 8601)."New value: +"Date to progress the chart to. ISO 8601 date or zoned datetime; a naive clock time is rejected. Date-only resolves to 12:00 UTC."

addedInput schema / properties / timezone

Added value: +{
+  "description": "IANA timezone (e.g. `America/Chicago`); required when the datetime is naive, ignored otherwise.",
+  "type": "string"
+}

First observedv0.1.0Apr 24, 2026

TDQS

A4.2/5.0

Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), and the description adds real value beyond them: method semantics (1 day = 1 year), converse direction, and a credit cost including the +2 surcharge for include_visual. It doesn't mention pagination or performance, but for a read-only calculation tool that is minor.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Trigger phrasing is front-loaded, the return contents follow, and the credit line is a single trailing sentence. No wasted words.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema, the description compensates by enumerating the returned artifacts (positions, cusps, aspects, retrograde status). Complete enough to call correctly, though it doesn't clarify defaults for house system or aspect output beyond include_aspects.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so every parameter is already documented. The description's method/converse notes largely restate the schema text; only the credit surcharge for include_visual adds genuinely new semantic information. Baseline 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('returns progressed planet positions, house cusps, aspects and retrograde status') and grounds it in concrete user phrasings. It is clearly distinguishable from natal, transit and solar-return siblings.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Provides explicit trigger utterances ('my secondary progressions', 'solar arc directions') and explains the method choice, which gives clear context for when to use it. It stops short of naming which sibling to use instead (e.g., ephemeris_transits or ephemeris_solar_return), so no explicit exclusion rules.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Deploy Server

Progressed Chart

Instructions

Input Schema

Schema Changelog

TDQS

Other Tools