Google_calendar

Gcal List Calendars

gcal_list_calendars

Read-onlyIdempotent

List all accessible calendars. Returns calendar IDs, names, time zones, and your access level for each. Use to identify which calendar to query or modify.

Input Schema

TableJSON Schema

Name	Required	Description	Default
No arguments

Output Schema

TableJSON Schema

Name	Required	Description
`etag`	No	ETag of the resource
`kind`	No	Resource kind identifier
`error`	No	Error code if connection failed
`items`	No	List of calendars
`message`	No	Error message if connection failed

Schema Changelog

Changes observed during successful MCP inspections. Dates show when Glama detected each change.

Changed1 schema field changedMay 8, 2026

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "properties": {
+    "error": {
+      "description": "Error code if connection failed",
+      "type": "string"
+    },
+    "etag": {
+      "description": "ETag of the resource",
+      "type": "string"
+    },
+    "items": {
+      "description": "List of calendars",
+      "items": {
+        "properties": {
+          "accessRole": {
+            "description": "User's access level",
+            "enum": [
+              "owner",
+              "writer",
+              "reader",
+              "freeBusyReader"
+            ],
+            "type": "string"
+          },
+          "defaultReminders": {
+            "description": "Default reminders",
+            "items": {
+              "properties": {
+                "method": {
+                  "description": "Reminder method",
+                  "type": "string"
+                },
+                "minutes": {
+                  "description": "Minutes before event",
+                  "type": "number"
+                }
+              },
+              "type": "object"
+            },
+            "type": "array"
+          },
+          "description": {
+            "description": "Calendar description",
+            "type": "string"
+          },
+          "etag": {
+            "description": "Calendar ETag",
+            "type": "string"
+          },
+          "id": {
+            "description": "Calendar ID",
+            "type": "string"
+          },
+          "kind": {
+            "description": "Calendar resource kind",
+            "type": "string"
+          },
+          "primary": {
+            "description": "Whether this is the primary calendar",
+            "type": "boolean"
+          },
+          "summary": {
+            "description": "Calendar name",
+            "type": "string"
+          },
+          "timeZone": {
+            "description": "Calendar time zone",
+            "type": "string"
+          }
+        },
+        "type": "object"
+      },
+      "type": "array"
+    },
+    "kind": {
+      "description": "Resource kind identifier",
+      "type": "string"
+    },
+    "message": {
+      "description": "Error message if connection failed",
+      "type": "string"
+    }
+  },
+  "type": "object"
+}

Changed1 schema field changedMay 6, 2026
- addedInput schema / examples
```
Added value: +[
+  {}
+]
```
First observedApr 22, 2026

TDQS

A4.3/5.0

Behavior3/5

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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, destructiveHint. Description adds that it returns specific fields, which is helpful but not critical beyond annotations.

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?

Two concise sentences, no fluff, front-loaded with action and key details.

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

Completeness5/5

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

Tool has no parameters and an output schema. Description fully explains what it does and what it returns, sufficient for an agent to understand and use it.

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?

No parameters, so schema coverage is 100%. Description has nothing extra to add, baseline 4 applies.

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 specific verb 'list' and resource 'accessible calendars', and enumerates returned fields (IDs, names, time zones, access level). Clearly distinguishes from sibling tools that create or modify events.

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?

Explicitly says 'Use to identify which calendar to query or modify', giving context for when to use. No direct comparison to alternatives, but the purpose is clear enough.

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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