Postman

Official

by postmanlabs

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TypeScript

Hybrid

Get a spec's definition

getSpecDefinition

Read-onlyIdempotent

Retrieve the complete contents of an OpenAPI or AsyncAPI specification definition using its unique spec ID.

Instructions

Gets the complete contents of an OpenAPI or AsyncAPI specification's definition.

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": {
      "specId": "<specId>"
    },
    "name": "getSpecDefinition"
  }
}

Input Schema

Name	Required	Description	Default
`specId`	Yes	The spec's ID.

Schema Changelog

Changes observed during successful MCP inspections.

First observedJan 14, 2026

TDQS

B3.4/5.0

Behavior3/5

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

Annotations already indicate this is a read-only, idempotent, non-destructive operation. The description adds the scope 'complete contents' and the supported spec types (OpenAPI or AsyncAPI), but it does not disclose output format, error behavior, or any additional behavioral nuances.

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 a single, front-loaded sentence with no filler or redundant wording. It communicates the essential action and resource efficiently.

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?

This is a simple one-parameter read tool, and the annotations plus schema cover most important context. The description sufficiently states what is returned ('complete contents of a definition'), though it could be improved by clarifying how it differs from getSpec and getSpecFile.

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 input schema fully describes the single parameter 'specId' with a clear description ('The spec's ID.'). The tool description adds no extra parameter-level information, so the schema carries the load and the baseline score applies.

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 uses a specific verb ('Gets') and names the resource ('OpenAPI or AsyncAPI specification's definition'), making the core purpose clear. It does not explicitly differentiate itself from sibling tools like getSpec or getSpecFile, which introduces slight ambiguity.

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

Usage Guidelines2/5

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

There is no guidance on when to use this tool instead of alternatives. Given the many sibling tools that also deal with specs, the description provides no context or exclusions to help an agent choose correctly.

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