YC GraphQL MCP

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yc_describe_type

Read-onlyIdempotent

Inspect a GraphQL type's arguments, input fields, enums, interfaces, and deprecation details to understand schema structure before writing queries or mutations.

Instructions

Inspect an actual GraphQL type, including arguments, input fields, enums, interfaces, and deprecation details.

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": {
      "name": "<name>"
    },
    "name": "yc_describe_type"
  }
}

Input Schema

Name	Required	Description	Default
`name`	Yes
`includeDeprecated`	No

Output Schema

Name	Required	Description	Default
`ok`	Yes
`data`	No
`error`	No
`untrustedContent`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv2.1.0Nov 12, 2026

TDQS

A3.6/5.0

Behavior3/5

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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and openWorldHint, so the safety profile is fully covered structurally. The description adds that deprecated members can be surfaced, which is mild extra context, but says nothing about failure behavior (e.g. unknown type names) or cost of the open-world lookup. An output schema exists, so return-shape disclosure is rightly omitted.

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?

A single front-loaded sentence with the verb and scope first and the enumerated coverage second. Every phrase carries information about what is returned; there is no 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 two-parameter, read-only lookup with a full output schema and rich annotations, the description covers what the tool produces and enough scope to call it correctly. The remaining gap is sibling disambiguation rather than anything about invoking this tool itself.

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 description coverage is 0% for both parameters, so the description must compensate. It does so partially: 'Inspect an actual GraphQL type' makes clear that 'name' is the type to look up, and 'deprecation details' hints at what includeDeprecated governs. However, it never explains the toggle behavior (whether deprecated members are hidden by default or merely annotated), leaving the second parameter's semantics largely to the schema default.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description gives a specific verb ('Inspect') and resource ('an actual GraphQL type') and enumerates what the inspection surfaces (arguments, input fields, enums, interfaces, deprecation details). It does not name or distinguish itself from the similarly named siblings yc_describe_schema and yc_introspect_schema, so the agent must infer the boundary.

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?

Usage is only implied: an agent can infer 'call this when you need details about one named GraphQL type'. There is no explicit when-to-use statement, no exclusion, and no pointer to the obvious alternatives (yc_describe_schema or yc_introspect_schema) that would tell an agent which lookup to pick.

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