Substack MCP Server

get_publication

Read-only

Fetch a Substack publication’s projected identity and configured settings, while verifying the publication host. Read-only operation: no account or content changes are made.

Instructions

Read projected identity and selected settings for this publication. Verifies the returned publication host; does not verify your account identity or admin role. Missing API fields are named explicitly. No changes are made.

Input Schema

TableJSON Schema

Name	Required	Description	Default
No arguments

Output Schema

TableJSON Schema

Name	Required	Description	Default
`data`	Yes
`publication`	Yes
`identity_scope`	Yes
`publication_url`	Yes
`fields_not_returned_by_api`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

AddedSep 8, 2026

TDQS

A4/5.0

Behavior4/5

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

The annotation indicates readOnlyHint, and the description reinforces this by stating 'No changes are made.' It additionally reveals verification behavior and how missing API fields are handled, providing useful behavioral context beyond the annotation.

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 brief and to the point, consisting of two sentences that cover the purpose, verification, and read-only nature without unnecessary detail.

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 the simple nature of the tool (no parameters, read-only), the description provides enough context about what it reads and how it behaves. It could mention the output format, but the description already notes that missing fields are named explicitly, which is helpful. Overall, it is complete for its complexity.

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 has no parameters, so all parameters are documented (none). The description does not add parameter-specific information, but this is not needed. Baseline of 3 is appropriate.

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 the tool's function: reading projected identity and selected settings for the publication. It uses a specific verb ('read') and identifies the resource ('publication'), distinguishing it from sibling tools that deal with posts, drafts, or notes.

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?

The description does not explicitly mention when to use this tool over alternatives, but it provides context about what it verifies (host) and what it does not (account identity, admin role). This gives some implicit guidance, but lacks explicit comparison to sibling tools.

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