graph-polymarket-mcp

check_subgraph_freshness

Verify subgraph freshness by measuring lag from chainhead before relying on current data, preventing stale responses.

Instructions

Report how far behind chainhead a subgraph is, by reading its _meta block. Worth calling before trusting any 'current' or 'latest' number, because a lagging subgraph returns stale data rather than an error — it succeeds, it is just answering about the past.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "subgraph": "<subgraph>"
    },
    "name": "check_subgraph_freshness"
  }
}

Input Schema

Name	Required	Description	Default
`subgraph`	Yes	Which subgraph to check

Schema Changelog

Changes observed during successful MCP inspections.

Addedv2.1.2Aug 10, 2026

TDQS

A4.2/5.0

Behavior4/5

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

With no annotations, the description carries the behavioral burden. It discloses the critical non-obvious behavior that a lagging subgraph returns stale data rather than an error, and that the tool succeeds but answers about the past. It doesn't detail return format or units, but the provided context is valuable.

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 sentences, front-loaded with the main purpose, followed by a concise rationale. Every word earns its place with no redundancy or filler.

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

Completeness4/5

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

For a low-complexity tool with one enum parameter and no output schema, the description covers the core purpose, when to use it, and a critical behavioral nuance. It could mention the unit of 'how far behind' (e.g., blocks vs seconds), but the phrase 'chainhead' implies block distance, so it is reasonably complete.

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?

The schema already fully describes the single parameter (subgraph enum with 'Which subgraph to check'), so the description adds no extra parameter semantics. Baseline 3 is appropriate since schema coverage is 100%.

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 uses a specific verb ('Report') and names the exact resource (subgraph) and metric (how far behind chainhead by reading _meta block). It clearly distinguishes itself from sibling data-getter tools by focusing on freshness rather than data content.

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 gives explicit situational guidance: 'Worth calling before trusting any current or latest number' and explains why (stale data returns successfully). It doesn't explicitly name alternative tools, but the context of sibling data getters makes the use case clear.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.