blockscout-mcp-server

Get NFT Tokens by Address

nft_tokens_by_address

Read-only

Retrieve NFT tokens (ERC-721, ERC-404, ERC-1155) owned by an address, grouped by collection.
Provides collection details (type, address, name, symbol, total supply, holder count) and individual token instance data (ID, name, description, external URL, metadata attributes).
Essential for a detailed overview of an address's digital collectibles and their associated collection data.
**SUPPORTS PAGINATION**: If response includes 'pagination' field, use the provided next_call to get additional pages.

Input Schema

TableJSON Schema

Name	Required	Description
`cursor`	No	The pagination cursor from a previous response to get the next page of results.
`address`	Yes	NFT owner address
`chain_id`	Yes	The ID of the blockchain
`session_id`	No	Opaque session identifier.

Output Schema

TableJSON Schema

Name	Required	Description
`data`	Yes	The main data payload of the tool's response.
`notes`	No	A list of important contextual notes, such as warnings about data truncation or data quality issues.
`pagination`	No	Pagination information, present only if the 'data' is a single page of a larger result set.
`content_text`	No	Optional human-readable summary used for MCP content responses.
`instructions`	No	A list of suggested follow-up actions or instructions for the LLM to plan its next steps.
`data_description`	No	A list of notes explaining the structure, fields, or conventions of the 'data' payload.

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedSep 10, 2026

addedInput schema / properties / session_id

Added value: +{
+  "anyOf": [
+    {
+      "type": "string"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "description": "Opaque session identifier.",
+  "title": "Session Id"
+}

Changed11 schema fields changedMay 1, 2026

removedInput schema / $schema

Removed value: -"http://json-schema.org/draft-07/schema#"

removedInput schema / additionalProperties
```
Removed value: -false
```
addedInput schema / properties / address / title
```
Added value: +"Address"
```
addedInput schema / properties / chain_id / title
```
Added value: +"Chain Id"
```

addedInput schema / properties / cursor / anyOf

Added value: +[
+  {
+    "type": "string"
+  },
+  {
+    "type": "null"
+  }
+]

addedInput schema / properties / cursor / default
```
Added value: +null
```

changedInput schema / properties / cursor / description

Previous value: -"Pagination cursor"New value: +"The pagination cursor from a previous response to get the next page of results."

addedInput schema / properties / cursor / title
```
Added value: +"Cursor"
```
removedInput schema / properties / cursor / type
```
Removed value: -"string"
```

addedInput schema / title

Added value: +"nft_tokens_by_addressArguments"

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "$defs": {
+    "NextCallInfo": {
+      "description": "A structured representation of the tool call required to get the next page.",
+      "properties": {
+        "params": {
+          "additionalProperties": true,
+          "description": "A complete dictionary of parameters for the next tool call, including the new cursor.",
+          "title": "Params",
+          "type": "object"
+        },
+        "tool_name": {
+          "description": "The name of the tool to call for the next page.",
+          "title": "Tool Name",
+          "type": "string"
+        }
+      },
+      "required": [
+        "tool_name",
+        "params"
+      ],
+      "title": "NextCallInfo",
+      "type": "object"
+    },
+    "NftCollectionHolding": {
+      "description": "Represents an address's holding in a single NFT collection.",
+      "properties": {
+        "amount": {
+          "description": "The number of tokens from this collection owned by the address.",
+          "title": "Amount",
+          "type": "string"
+        },
+        "collection": {
+          "$ref": "#/$defs/NftCollectionInfo",
+          "description": "The details of the NFT collection."
+        },
+        "token_instances": {
+          "description": "A list of the specific NFT instances owned by the address.",
+          "items": {
+            "$ref": "#/$defs/NftTokenInstance"
+          },
+          "title": "Token Instances",
+          "type": "array"
+        }
+      },
+      "required": [
+        "collection",
+        "amount",
+        "token_instances"
+      ],
+      "title": "NftCollectionHolding",
+      "type": "object"
+    },
+    "NftCollectionInfo": {
+      "description": "Represents the metadata for an NFT collection.",
+      "properties": {
+        "address": {
+          "description": "The smart contract address of the NFT collection.",
+          "title": "Address",
+          "type": "string"
+        },
+        "holders_count": {
+          "description": "The number of unique addresses that hold a token from this collection.",
+          "title": "Holders Count",
+          "type": "integer"
+        },
+        "name": {
+          "anyOf": [
+            {
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "description": "The name of the collection.",
+          "title": "Name"
+        },
+        "symbol": {
+          "anyOf": [
+            {
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "description": "The symbol of the collection.",
+          "title": "Symbol"
+        },
+        "total_supply": {
+          "description": "The total number of tokens in the collection.",
+          "title": "Total Supply",
+          "type": "integer"
+        },
+        "type": {
+          "description": "The token standard of the collection.",
+          "title": "Type",
+          "type": "string"
+        }
+      },
+      "required": [
+        "type",
+        "address",
+        "holders_count",
+        "total_supply"
+      ],
+      "title": "NftCollectionInfo",
+      "type": "object"
+    },
+    "NftTokenInstance": {
+      "description": "Represents a single NFT instance with its metadata.",
+      "properties": {
+        "description": {
+          "anyOf": [
+            {
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "description": "The description of the NFT, extracted from its metadata.",
+          "title": "Description"
+        },
+        "external_app_url": {
+          "anyOf": [
+            {
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "description": "A URL to an external site or application related to the NFT.",
+          "title": "External App Url"
+        },
+        "id": {
+          "description": "The unique identifier of the NFT token instance.",
+          "title": "Id",
+          "type": "string"
+        },
+        "image_url": {
+          "anyOf": [
+            {
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "description": "A URL for the NFT's image, from its metadata.",
+          "title": "Image Url"
+        },
+        "metadata_attributes": {
+          "anyOf": [
+            {
+              "items": {},
+              "type": "array"
+            },
+            {
+              "additionalProperties": true,
+              "type": "object"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "description": "The metadata attributes (traits) associated with the NFT.",
+          "title": "Metadata Attributes"
+        },
+        "name": {
+          "anyOf": [
+            {
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "description": "The name of the NFT, extracted from its metadata.",
+          "title": "Name"
+        }
+      },
+      "required": [
+        "id"
+      ],
+      "title": "NftTokenInstance",
+      "type": "object"
+    },
+    "PaginationInfo": {
+      "description": "Contains the structured information needed to retrieve the next page of results.",
+      "properties": {
+        "next_call": {
+          "$ref": "#/$defs/NextCallInfo",
+          "description": "The structured tool call required to fetch the subsequent page."
+        }
+      },
+      "required": [
+        "next_call"
+      ],
+      "title": "PaginationInfo",
+      "type": "object"
+    }
+  },
+  "properties": {
+    "content_text": {
+      "anyOf": [
+        {
+          "type": "string"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "default": null,
+      "description": "Optional human-readable summary used for MCP content responses.",
+      "title": "Content Text"
+    },
+    "data": {
+      "description": "The main data payload of the tool's response.",
+      "items": {
+        "$ref": "#/$defs/NftCollectionHolding"
+      },
+      "title": "Data",
+      "type": "array"
+    },
+    "data_description": {
+      "anyOf": [
+        {
+          "items": {
+            "type": "string"
+          },
+          "type": "array"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "default": null,
+      "description": "A list of notes explaining the structure, fields, or conventions of the 'data' payload.",
+      "title": "Data Description"
+    },
+    "instructions": {
+      "anyOf": [
+        {
+          "items": {
+            "type": "string"
+          },
+          "type": "array"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "default": null,
+      "description": "A list of suggested follow-up actions or instructions for the LLM to plan its next steps.",
+      "title": "Instructions"
+    },
+    "notes": {
+      "anyOf": [
+        {
+          "items": {
+            "type": "string"
+          },
+          "type": "array"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "default": null,
+      "description": "A list of important contextual notes, such as warnings about data truncation or data quality issues.",
+      "title": "Notes"
+    },
+    "pagination": {
+      "anyOf": [
+        {
+          "$ref": "#/$defs/PaginationInfo"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "default": null,
+      "description": "Pagination information, present only if the 'data' is a single page of a larger result set."
+    }
+  },
+  "required": [
+    "data"
+  ],
+  "title": "ToolResponse[list[NftCollectionHolding]]",
+  "type": "object"
+}

Changed10 schema fields changedMar 12, 2026
- addedInput schema / $schema
```
Added value: +"http://json-schema.org/draft-07/schema#"
```
- addedInput schema / additionalProperties
```
Added value: +false
```
- removedInput schema / properties / address / title
```
Removed value: -"Address"
```
- removedInput schema / properties / chain_id / title
```
Removed value: -"Chain Id"
```
- removedInput schema / properties / cursor / anyOf
```
Removed value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]
```
- removedInput schema / properties / cursor / default
```
Removed value: -null
```
- changedInput schema / properties / cursor / description
```
Previous value: -"The pagination cursor from a previous response to get the next page of results."New value: +"Pagination cursor"
```
- removedInput schema / properties / cursor / title
```
Removed value: -"Cursor"
```
- addedInput schema / properties / cursor / type
```
Added value: +"string"
```
- removedInput schema / title
```
Removed value: -"nft_tokens_by_addressArguments"
```
First observedJan 31, 2026

TDQS

A4.3/5.0

Behavior4/5

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

Annotations already declare readOnlyHint=true and destructiveHint=false. The description adds useful behavioral context: grouping by collection, providing collection details and token instance data, and explicit pagination instructions ('If response includes 'pagination' field, use the provided next_call'). This goes beyond annotations without contradicting them.

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?

Four sentences, front-loaded with the core action, then details and pagination note. Every sentence contributes value; no fluff or repetition. The structure is scannable and efficient.

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?

Given the output schema exists, the description needn't restate return values. It explains the collection grouping, included fields (type, address, name, symbol, total supply, holder count, token instance data), and pagination behavior. Complete for a read-only NFT query tool.

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 coverage is 100%, with each parameter already described (e.g., cursor is 'pagination cursor from previous response'). The description reinforces the cursor usage but doesn't add new meaning beyond the schema. Baseline of 3 is appropriate because the schema carries the semantic load.

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?

The description clearly states the tool retrieves NFT tokens (ERC-721, ERC-404, ERC-1155) owned by an address, grouped by collection. The verb 'Retrieve' and specific resource distinguish it from sibling tools like get_tokens_by_address (which likely handles fungible tokens) and get_token_transfers_by_address.

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 says it's 'Essential for a detailed overview of an address's digital collectibles and their associated collection data,' implying use for NFT-focused queries. It does not explicitly mention alternatives or exclusions, but the standard list and context differentiate it from siblings. Clear context but no explicit when-not-to-use.

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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