Skip to main content
Glama
Sign In
thenavidm

substack-mcp

by thenavidm
OverviewSchemaSourceRelated ServersDiscussionsAdmin
TypeScript
Hybrid

Read a published post

get_post
Read-onlyIdempotent

Read a published Substack post in full by its slug, including posts from any public publication, to review your own or a competitor's content.

Instructions

Read a published post in full by its slug. Works on any public Substack, not just your own, so it doubles as a way to read a competitor's post.

Input Schema

NameRequiredDescriptionDefault
slugYesThe post slug, which is the last part of its URL after /p/.
body_formatNoHow to return the body.markdown
publicationNoWhich connected publication to act on, matched loosely against its hostname (for example 'example.substack.com' or just 'example'). Defaults to the first connected publication.
publication_urlNoWhich publication to read from, for example 'example.substack.com'. Defaults to your own.

Schema Changelog

Changes observed during successful MCP inspections.

  1. Changed2 schema fields changedv3.0.1
    • removedInput schema / $schema
      Removed value: -"http://json-schema.org/draft-07/schema#"
    • removedInput schema / additionalProperties
      Removed value: -false
  2. First observedv2.1.1

TDQS

A3.8/5.0
Behavior4/5

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

Annotations already cover the safety profile (readOnly, idempotent, openWorld, non-destructive), so the bar is lower. The description still adds real behavioral context: it reads the post 'in full' and works against any public publication, not only connected ones. It omits auth/rate-limit details, but that is minor against the annotation coverage.

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, zero waste, with the core action front-loaded and the cross-publication capability immediately following. Appropriately sized.

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 read-only retrieval tool with annotations covering safety and a fully documented schema, the description covers the key ambiguity (cross-publication reads). The remaining gap is the publication vs publication_url distinction, which is left entirely to the schema.

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 100%, so the schema already documents all four parameters, and the description only reinforces slug as the lookup key. It does not disambiguate the two similar parameters (publication vs publication_url), which is the one place added meaning would help. Baseline 3 is appropriate.

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?

States a specific verb (read), resource (published post), and lookup key (slug), and additionally declares cross-publication scope ('any public Substack, not just your own'). The 'published' qualifier and 'by its slug' implicitly separate it from get_draft and get_post_by_id, though no sibling is named.

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?

Provides a usage scenario ('doubles as a way to read a competitor's post'), which is useful context, but gives no explicit when-not-to-use guidance and never names the adjacent alternatives (get_post_by_id, get_reader_post, scrape_post) that an agent must choose between. Usage is implied rather than directed.

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

Deploy Server

Other Tools