Blockstream Info

Address Txs

address_txs

Read-onlyIdempotent

Blockstream.info Esplora API — the most recent Bitcoin transactions touching one address, covering both unconfirmed mempool entries and confirmed ones, on mainnet or testnet. Each transaction returns its txid, inputs and outputs with values and scripts, fee, size and confirmation status with block height. Answers what this Bitcoin address has sent or received lately.

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": {
      "address": "1A1z7agoat4JpiLvH5NNRZTweLaqLFJ5d"
    },
    "name": "address_txs"
  }
}

Input Schema

Name	Required	Description	Default
`address`	Yes
`network`	No

Output Schema

Name	Required	Description	Default
`count`	Yes	Number of items returned.
`items`	Yes	List of transactions for address

Schema Changelog

Changes observed during successful MCP inspections.

Changed2 schema fields changedMay 27, 2026

addedInput schema / examples

Added value: +[
+  {
+    "address": "1A1z7agoat4JpiLvH5NNRZTweLaqLFJ5d"
+  }
+]

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "properties": {
+    "count": {
+      "description": "Number of items returned.",
+      "type": "integer"
+    },
+    "items": {
+      "description": "List of transactions for address",
+      "items": {
+        "properties": {
+          "fee": {
+            "description": "Transaction fee in satoshis",
+            "type": "number"
+          },
+          "locktime": {
+            "description": "Lock time",
+            "type": "number"
+          },
+          "size": {
+            "description": "Transaction size in bytes",
+            "type": "number"
+          },
+          "status": {
+            "properties": {
+              "block_hash": {
+                "type": "string"
+              },
+              "block_height": {
+                "type": "number"
+              },
+              "block_time": {
+                "type": "number"
+              },
+              "confirmed": {
+                "type": "boolean"
+              }
+            },
+            "type": "object"
+          },
+          "txid": {
+            "description": "Transaction ID",
+            "type": "string"
+          },
+          "version": {
+            "description": "Transaction version",
+            "type": "number"
+          },
+          "vin": {
+            "items": {
+              "type": "object"
+            },
+            "type": "array"
+          },
+          "vout": {
+            "items": {
+              "type": "object"
+            },
+            "type": "array"
+          },
+          "weight": {
+            "description": "Transaction weight",
+            "type": "number"
+          }
+        },
+        "type": "object"
+      },
+      "type": "array"
+    }
+  },
+  "required": [
+    "items",
+    "count"
+  ],
+  "type": "object"
+}

First observedMay 13, 2026

TDQS

A3.7/5.0

Behavior4/5

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

The description adds detail beyond the annotations by specifying the return fields (txid, inputs/outputs, fee, size, confirmation status) and coverage (mempool + confirmed). This helps manage expectations about output structure. It does not contradict the readOnlyHint, idempotentHint, or openWorldHint annotations, and the no-destructive hint is consistent. No need to discuss side effects for a read-only API.

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 reasonably concise, using three sentences that front-load the API source and then explain the output and intended use. The mention of 'Blockstream.info Esplora API' is slightly extraneous but provides context. No redundancy with the input schema is present, and the structure is logical.

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

Completeness3/5

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

For a simple read-only tool with an output schema present, the description covers return fields and the scope of results. However, it leaves out important details such as pagination limits, parameter constraints, and how to request testnet vs mainnet. These gaps matter for correct invocation, but the presence of the output schema reduces the burden on the description to explain all return values.

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

Parameters2/5

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

Schema description coverage is 0%, so the description must compensate. It only vaguely references the address and network ('one address', 'mainnet or testnet') without explaining accepted formats, defaults, or possible values. The 'network' parameter is especially ambiguous—does it accept 'mainnet'/'testnet' strings, or maybe 'btc'/'test'? The address format (P2PKH, P2SH, bech32) is not specified either.

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 returns the most recent Bitcoin transactions for a single address, including both unconfirmed and confirmed entries. It explicitly distinguishes from related tools like 'address', 'transaction', and 'block' by focusing on address transaction history. The phrase 'Answers what this Bitcoin address has sent or received lately' reinforces the specific purpose.

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

Usage Guidelines3/5

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

The description implies the tool is for retrieving recent transaction history for an address, and mentions support for mainnet/testnet. However, it does not explicitly state when to use this tool over alternatives, nor does it mention any exclusions (e.g., not for full historical data, not for address balances). The context is clear but under-specified.

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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