Mesoamerican Astrology MCP Server by RoxyAPI

List the 20 Aztec trecenas - Tonalpohualli thirteen day period API

get_mesoamerican_astrology_aztec_trecenas

Read-only

Retrieve all twenty trecenas, the thirteen day periods the 260 day tonalpohualli divides into. Each entry returns the period number, the day sign it opens on and a composed reading of what the period carries. Built for Aztec calendar apps, energy period trackers and content planners that work in thirteen day blocks.

Example tool call

This call uses example arguments supplied in the tool’s input schema.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "get_mesoamerican_astrology_aztec_trecenas"
  }
}

Input Schema

Name	Required	Description	Default
`lang`	No	Response language (BCP 47). Supported: en, tr, de, es, hi, pt, fr, ru, zh-Hans, zh-Hant. Defaults to en. Coverage varies by domain, and a field with no translation in the requested language returns English.	en
`limit`	No	Maximum items to return per page. Range: 1-20, default 20.
`offset`	No	Number of items to skip for pagination. Default 0.
`compact`	No	Set true for the same data in a compact shape: arrays of same-shaped objects arrive columnar as {"__cols":[names],"__rows":[[values]]}. Lossless, typically 40 to 52 percent fewer tokens.

Output Schema

Name	Required	Description	Default
`limit`	Yes
`total`	Yes
`offset`	Yes
`trecenas`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed2 schema fields changedSep 23, 2026
- addedInput schema / properties / offset / default
```
Added value: +0
```
- addedInput schema / properties / offset / minimum
```
Added value: +0
```
Changed3 schema fields changedSep 20, 2026
- removedInput schema / properties / offset / default
```
Removed value: -0
```
- removedInput schema / properties / offset / minimum
```
Removed value: -0
```
- changedInput schema / properties / offset / type
```
Previous value: -[
-  "integer",
-  "null"
-]New value: +"integer"
```

Changed1 schema field changedSep 20, 2026

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "properties": {
+    "limit": {
+      "type": "number"
+    },
+    "offset": {
+      "type": "number"
+    },
+    "total": {
+      "type": "number"
+    },
+    "trecenas": {
+      "items": {
+        "properties": {
+          "length": {
+            "type": "number"
+          },
+          "number": {
+            "type": "number"
+          },
+          "reading": {
+            "type": "string"
+          },
+          "startSign": {
+            "type": "string"
+          },
+          "startSignName": {
+            "type": "string"
+          }
+        },
+        "required": [
+          "number",
+          "startSign",
+          "startSignName",
+          "length",
+          "reading"
+        ],
+        "type": "object"
+      },
+      "type": "array"
+    }
+  },
+  "required": [
+    "total",
+    "limit",
+    "offset",
+    "trecenas"
+  ],
+  "type": "object"
+}

First observedSep 6, 2026

TDQS

A3.9/5.0

Behavior4/5

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safe-read nature is covered. The description adds useful behavioral context by specifying what each returned entry contains: 'the period number, the day sign it opens on and a composed reading of what the period carries.' This goes beyond the structured data without contradicting it.

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

Conciseness4/5

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

The description is appropriately short and front-loaded with the action and resource. The first sentence states exactly what the tool does, the second describes the return shape, and the third gives intended audience. The final sentence is useful but slightly promotional, adding mild non-essential content.

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?

Given the output schema exists and the annotations cover safety, the description provides enough context for an agent to invoke the tool correctly. It explains what trecenas are, what the response entries contain, and the intended use context. It does not mention pagination or language fallback, but those are fully covered by the schema.

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 all four parameters are already fully documented. The description does not add parameter-level meaning beyond the schema, which matches the baseline expectation. It adds no extra detail about language coverage, pagination, or compact mode, but those are already in the schema.

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

Purpose4/5

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

The description uses a specific verb ('Retrieve all twenty trecenas') and a clear resource with domain context ('the thirteen day periods the 260 day tonalpohualli divides into'). It clearly describes a list-all operation, but it does not explicitly distinguish itself from the sibling tools such as get_mesoamerican_astrology_mayan_trecenas or the single-trecena variant, so it stops short of full sibling differentiation.

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?

The description gives clear context for when to use the tool: it is 'Built for Aztec calendar apps, energy period trackers and content planners that work in thirteen day blocks.' It also makes clear this returns all twenty trecenas, implying use when a full list is needed. However, it does not explicitly name alternatives or state when-not-to-use conditions, so it lacks explicit exclusion guidance.

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

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