SQD

Official

by subsquid-labs

Overview Schema Related Servers Score Discussions

TypeScript

Remote

Get the latest block

portal_get_head

Read-only

Retrieve the current indexed head block or slot for any network, either latest or finalized, to determine where to start building a manual block range.

Instructions

Get just the latest indexed head block or slot for a network.

COMMON USER ASKS:

Latest head
Finalized head

FIRST CHOICE FOR:

getting the current indexed head before building a manual block range

WHEN TO USE:

You only need the current block or slot number.
You need the current head before building a raw block-range query.

DON'T USE:

You want to know if the network is caught up, behind, fresh, or what tables are available.

EXAMPLES:

Latest head: {"network":"base-mainnet"}
Finalized head: {"network":"ethereum-mainnet","type":"finalized"}

Input Schema

TableJSON Schema

Name	Required	Description	Default
`type`	No	Block type	latest
`network`	Yes	Network name or alias

Output Schema

TableJSON Schema

Name	Required	Description
`_ui`	No	Optional chart, table, and follow-up presentation metadata.
`_llm`	No	Hints that help an AI client locate the primary evidence.
`_meta`	No	Network, block range, timing, and row-count metadata.
`error`	No	Structured failure details when the tool cannot complete the request.
`items`	No	Primary result rows when the tool returns a list.
`value`	No	Primary result when the tool returns a scalar value.
`answer`	No	Concise answer grounded in the returned blockchain data.
`_notice`	No	Important limitation or truncation notice.
`display`	No	Plain-language labels for presenting the result.
`_notices`	No	Important limitations or truncation notices.
`_summary`	No	Human-readable summary of the result.
`_coverage`	No	Completeness of the requested window and result set.
`_evidence`	No	Replayable arguments, exact-data digest, row count, and completeness receipt.
`_ordering`	No	Ordering guarantees for the returned data.
`_execution`	No	Bounded execution and scan details.
`_freshness`	No	Freshness and finality information for the returned data.
`next_steps`	No	Safe follow-up actions and continuation guidance.
`_pagination`	No	Pagination state and an optional continuation cursor.
`investigation`	No	Evidence paths, useful pivots, and result limitations.
`pipes_handoff`	No	Optional SQD Pipes guidance for custom data needs.
`_tool_contract`	No	Tool identity, intent, and supported blockchain families.

Schema Changelog

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

Changed1 schema field changedv0.8.3Aug 30, 2026

addedOutput schema / properties / _evidence

Added value: +{
+  "additionalProperties": {},
+  "description": "Replayable arguments, exact-data digest, row count, and completeness receipt.",
+  "propertyNames": {
+    "type": "string"
+  },
+  "type": "object"
+}

Changed3 schema fields changedv0.8.2Aug 29, 2026

changedInput schema / $schema

Previous value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"

removedInput schema / additionalProperties
```
Removed value: -false
```

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "additionalProperties": {},
+  "properties": {
+    "_coverage": {
+      "description": "Completeness of the requested window and result set."
+    },
+    "_execution": {
+      "additionalProperties": {},
+      "description": "Bounded execution and scan details.",
+      "propertyNames": {
+        "type": "string"
+      },
+      "type": "object"
+    },
+    "_freshness": {
+      "description": "Freshness and finality information for the returned data."
+    },
+    "_llm": {
+      "description": "Hints that help an AI client locate the primary evidence."
+    },
+    "_meta": {
+      "additionalProperties": {},
+      "description": "Network, block range, timing, and row-count metadata.",
+      "propertyNames": {
+        "type": "string"
+      },
+      "type": "object"
+    },
+    "_notice": {
+      "description": "Important limitation or truncation notice.",
+      "type": "string"
+    },
+    "_notices": {
+      "description": "Important limitations or truncation notices.",
+      "items": {
+        "type": "string"
+      },
+      "type": "array"
+    },
+    "_ordering": {
+      "description": "Ordering guarantees for the returned data."
+    },
+    "_pagination": {
+      "additionalProperties": {},
+      "description": "Pagination state and an optional continuation cursor.",
+      "propertyNames": {
+        "type": "string"
+      },
+      "type": "object"
+    },
+    "_summary": {
+      "description": "Human-readable summary of the result.",
+      "type": "string"
+    },
+    "_tool_contract": {
+      "additionalProperties": {},
+      "description": "Tool identity, intent, and supported blockchain families.",
+      "propertyNames": {
+        "type": "string"
+      },
+      "type": "object"
+    },
+    "_ui": {
+      "description": "Optional chart, table, and follow-up presentation metadata."
+    },
+    "answer": {
+      "description": "Concise answer grounded in the returned blockchain data.",
+      "type": "string"
+    },
+    "display": {
+      "additionalProperties": {},
+      "description": "Plain-language labels for presenting the result.",
+      "propertyNames": {
+        "type": "string"
+      },
+      "type": "object"
+    },
+    "error": {
+      "additionalProperties": {},
+      "description": "Structured failure details when the tool cannot complete the request.",
+      "properties": {
+        "code": {
+          "type": "string"
+        },
+        "origin": {
+          "type": "string"
+        },
+        "retry_after_ms": {
+          "type": "number"
+        },
+        "retryable": {
+          "type": "boolean"
+        },
+        "suggestions": {
+          "items": {
+            "type": "string"
+          },
+          "type": "array"
+        },
+        "summary": {
+          "type": "string"
+        }
+      },
+      "required": [
+        "code",
+        "origin",
+        "summary",
+        "retryable",
+        "suggestions"
+      ],
+      "type": "object"
+    },
+    "investigation": {
+      "additionalProperties": {},
+      "description": "Evidence paths, useful pivots, and result limitations.",
+      "propertyNames": {
+        "type": "string"
+      },
+      "type": "object"
+    },
+    "items": {
+      "description": "Primary result rows when the tool returns a list.",
+      "items": {},
+      "type": "array"
+    },
+    "next_steps": {
+      "additionalProperties": {},
+      "description": "Safe follow-up actions and continuation guidance.",
+      "properties": {
+        "actions": {
+          "items": {
+            "additionalProperties": {},
+            "propertyNames": {
+              "type": "string"
+            },
+            "type": "object"
+          },
+          "type": "array"
+        },
+        "continuation": {
+          "additionalProperties": {},
+          "propertyNames": {
+            "type": "string"
+          },
+          "type": "object"
+        },
+        "custom_data": {
+          "additionalProperties": {},
+          "propertyNames": {
+            "type": "string"
+          },
+          "type": "object"
+        }
+      },
+      "required": [
+        "actions"
+      ],
+      "type": "object"
+    },
+    "pipes_handoff": {
+      "description": "Optional SQD Pipes guidance for custom data needs."
+    },
+    "value": {
+      "description": "Primary result when the tool returns a scalar value."
+    }
+  },
+  "type": "object"
+}

First observedv0.7.9Jun 25, 2026

TDQS

A4.7/5.0

Behavior4/5

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

With annotations already declaring readOnlyHint=true and destructiveHint=false, the description adds useful behavioral context by noting this returns the *indexed* head, not a live chain-tip or status indicator. It further clarifies limitations through the DON'T USE section, which is valuable beyond the annotation fields.

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?

The description is structured with short, purposeful sections and every snippet adds information: scope, common asks, when to use, when not to use, and examples. It is efficient despite being longer than average because no redundant content is present.

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?

For a simple two-parameter tool with an output schema and read-only annotations, the description covers accepted inputs, selection of latest vs finalized, examples, and missuse cases. Nothing essential is missing for an agent to invoke this tool correctly.

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?

Schema description coverage is 100%, so the baseline is 3. The description goes further by showing concrete example payloads for 'latest' vs 'finalized' and calling out the typical use case of preceding a block-range query, making the parameters' real meaning clear.

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 opens with a specific verb and resource: 'Get just the latest indexed head block or slot for a network.' It clearly distinguishes this lightweight head lookup from network status, table availability, and other sibling query tools via the COMMON USER ASKS and DON'T USE sections.

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

Usage Guidelines5/5

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

The description provides explicit WHEN TO USE bullets, a FIRST CHOICE FOR statement, and a DON'T USE exclusion. This gives an agent clear decision rules for calling this tool instead of using it for status or table-inspection tasks.

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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