Crawlora MCP

substack_publication_contributors

Read-only

List the writers credited on a Substack publication, ranked as Substack ranks them. Rows include each writer's handle, profile URL, and bestseller badge tier, so a publication can be fanned out into individual substack_user lookups. Large publications return several hundred contributors on the first page.

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": {
      "publication": "<publication>"
    },
    "name": "substack_publication_contributors"
  }
}

Input Schema

Name	Required	Description	Default
`page`	No	Zero-based page.
`publication`	Yes	Required publication subdomain or custom domain.

Output Schema

Name	Required	Description	Default
`data`	Yes	The tool result payload (shape varies per tool; see each tool's docs resource).

Schema Changelog

Changes observed during successful MCP inspections.

First observedOct 7, 2026

TDQS

A4.1/5.0

Behavior4/5

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

Annotations already cover the safety profile (readOnlyHint=true, openWorldHint=true), so the bar is lower. The description adds genuinely useful behavior: results are ranked as Substack ranks them, the row shape includes handle, profile URL, and badge tier, and large publications can return several hundred contributors on the first page — a pagination/volume caveat the annotations do not convey.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Three sentences, front-loaded with the core action, followed by the return shape and a volume caveat. Each sentence carries information, though the field enumeration slightly overlaps with the output schema.

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?

With an output schema present, the return values need not be spelled out, and the description still summarizes the key fields plus a fan-out workflow and a large-publication caveat. Complete for a read-only listing tool, with only minor room to clarify pagination semantics.

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 both parameters (publication, page) are already documented in the schema. The description implies ordering and mentions the 'first page,' which lightly reinforces the page parameter, but adds no format or syntax detail beyond the schema. Baseline 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?

States a specific verb and resource: 'List the writers credited on a Substack publication.' It also distinguishes itself from the sibling substack_user tool by framing the output as an input to individual user lookups, so an agent can place it in a workflow without opening either schema.

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?

Provides clear usage context: the result 'can be fanned out into individual substack_user lookups,' which tells the agent this is a discovery step. It does not, however, name when NOT to use it or an explicit alternative for listing contributors another way, so it stops short of full when/when-not guidance.

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

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