postgres-mcp

get_function_definition

Get the full CREATE OR REPLACE source of a PostgreSQL function or procedure. Disambiguate overloaded names by providing argument types.

Instructions

Full source (CREATE OR REPLACE ...) of a function or procedure. If the name is overloaded, pass arguments (e.g. "integer, text") to disambiguate.

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": "get_function_definition"
  }
}

Input Schema

Name	Required	Default
`name`	Yes
`schema`	No	public
`arguments`	No

Output Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.2.0Jun 21, 2026

TDQS

A3.7/5.0

Behavior2/5

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

No annotations are provided, so the description must carry the full burden. It only mentions retrieving source code, but does not explicitly state that the operation is read-only (non-destructive), what happens on missing function, or any permission requirements.

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 two concise sentences with critical information front-loaded. The first sentence states the purpose, the second provides disambiguation guidance. No redundant or unnecessary text.

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?

Given that an output schema exists (not shown), the description need not explain return values. It covers the core behavior (full source retrieval and disambiguation). Minor gap: no mention of error conditions or system source (e.g., PostgreSQL).

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 adds meaning for the `arguments` parameter (disambiguation example) but does not elaborate on `name` or `schema` (default 'public') beyond what the schema provides.

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 'Full source (CREATE OR REPLACE ...) of a function or procedure', specifying the verb (retrieve), resource (function or procedure), and output (full source). This distinguishes it from sibling tools like list_functions which only list names.

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 provides a clear usage guideline for overloaded names: 'If the name is overloaded, pass `arguments` (e.g. "integer, text") to disambiguate.' However, it does not explicitly state when not to use this tool or suggest alternatives.

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

Deploy Server