Polygon Io

Market Status

market_status

Read-onlyIdempotent

Current market status.

Input Schema

TableJSON Schema

Name	Required	Description	Default
No arguments

Output Schema

TableJSON Schema

Name	Required	Description	Default
`market`	No
`exchanges`	No
`afterHours`	No
`currencies`	No
`earlyHours`	No
`serverTime`	No
`indicesGroups`	No

Schema Changelog

Changes observed during successful MCP inspections.

Changed9 schema fields changedSep 21, 2026

addedOutput schema / properties / afterHours
```
Added value: +{
+  "type": "boolean"
+}
```

addedOutput schema / properties / currencies

Added value: +{
+  "properties": {
+    "crypto": {
+      "type": "string"
+    },
+    "fx": {
+      "type": "string"
+    }
+  },
+  "type": "object"
+}

addedOutput schema / properties / earlyHours
```
Added value: +{
+  "type": "boolean"
+}
```

addedOutput schema / properties / exchanges

Added value: +{
+  "properties": {
+    "nasdaq": {
+      "type": "string"
+    },
+    "nyse": {
+      "type": "string"
+    },
+    "otc": {
+      "type": "string"
+    }
+  },
+  "type": "object"
+}

addedOutput schema / properties / indicesGroups

Added value: +{
+  "properties": {
+    "cccy": {
+      "type": "string"
+    },
+    "cgi": {
+      "type": "string"
+    },
+    "dow_jones": {
+      "type": "string"
+    },
+    "ftse_russell": {
+      "type": "string"
+    },
+    "msci": {
+      "type": "string"
+    },
+    "mstar": {
+      "type": "string"
+    },
+    "mstarc": {
+      "type": "string"
+    },
+    "nasdaq": {
+      "type": "string"
+    },
+    "s_and_p": {
+      "type": "string"
+    },
+    "societe_generale": {
+      "type": "string"
+    }
+  },
+  "type": "object"
+}

addedOutput schema / properties / market
```
Added value: +{
+  "type": "string"
+}
```

removedOutput schema / properties / results

Removed value: -{
-  "description": "Current market status",
-  "properties": {
-    "after_hours": {
-      "description": "After-hours status",
-      "type": "boolean"
-    },
-    "exchanges": {
-      "description": "Exchange statuses",
-      "items": {
-        "properties": {
-          "name": {
-            "description": "Exchange name",
-            "type": "string"
-          },
-          "status": {
-            "description": "Exchange status",
-            "type": "string"
-          },
-          "tape": {
-            "description": "Tape identifier",
-            "type": "string"
-          }
-        },
-        "type": "object"
-      },
-      "type": "array"
-    },
-    "market": {
-      "description": "Overall market status",
-      "type": "string"
-    },
-    "pre_market": {
-      "description": "Pre-market status",
-      "type": "boolean"
-    },
-    "status": {
-      "description": "Market status (open/closed)",
-      "type": "string"
-    }
-  },
-  "type": "object"
-}

addedOutput schema / properties / serverTime
```
Added value: +{
+  "type": "string"
+}
```

removedOutput schema / properties / status

Removed value: -{
-  "description": "API response status",
-  "type": "string"
-}

Changed2 schema fields changedMay 27, 2026

addedInput schema / examples
```
Added value: +[
+  {}
+]
```

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "properties": {
+    "results": {
+      "description": "Current market status",
+      "properties": {
+        "after_hours": {
+          "description": "After-hours status",
+          "type": "boolean"
+        },
+        "exchanges": {
+          "description": "Exchange statuses",
+          "items": {
+            "properties": {
+              "name": {
+                "description": "Exchange name",
+                "type": "string"
+              },
+              "status": {
+                "description": "Exchange status",
+                "type": "string"
+              },
+              "tape": {
+                "description": "Tape identifier",
+                "type": "string"
+              }
+            },
+            "type": "object"
+          },
+          "type": "array"
+        },
+        "market": {
+          "description": "Overall market status",
+          "type": "string"
+        },
+        "pre_market": {
+          "description": "Pre-market status",
+          "type": "boolean"
+        },
+        "status": {
+          "description": "Market status (open/closed)",
+          "type": "string"
+        }
+      },
+      "type": "object"
+    },
+    "status": {
+      "description": "API response status",
+      "type": "string"
+    }
+  },
+  "type": "object"
+}

First observedMay 20, 2026

TDQS

C2.3/5.0

Behavior2/5

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

Annotations already declare readOnly, idempotent, and non-destructive behavior, but the description adds no behavioral detail beyond the word 'current.' It does not say whether the status is real-time, delayed, or what aspects of the market it covers.

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

Conciseness2/5

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

The description is very short, but the brevity comes from restating the title rather than from earning its place with useful content. This is under-specification, not effective conciseness.

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

Completeness2/5

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

The phrase 'current market status' is ambiguous: it could mean open/closed status, index performance, market sentiment, or something else. The description does not clarify its scope or relationship to sibling tools, so an agent cannot confidently know what question this tool answers.

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

Parameters4/5

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

The tool has zero parameters, so the description has no parameter documentation burden. This meets the baseline for a no-parameter tool, though it adds no additional semantic value.

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

Purpose2/5

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

The description is a noun phrase that essentially restates the tool's name and title: 'Market Status' becomes 'Current market status.' It has no clear verb and does not define what kind of status is returned, nor does it distinguish this tool from siblings like daily_open_close, previous_close, or market_holidays.

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

Usage Guidelines2/5

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

There is no guidance about when to use this tool versus alternatives. With many sibling tools covering related market data, the absence of any when-to-use or when-not-to-use context leaves an agent without a basis for selecting this tool.

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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