reddit-mcp

Submit a comment / reply

reddit_submit_comment

Reply directly to any Reddit post or comment by providing the parent fullname and text. The comment is posted immediately without confirmation.

Instructions

Posts a real comment reply to a post or comment immediately. No confirmation step.

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": {
      "parentId": "<parentId>",
      "text": "<text>"
    },
    "name": "reddit_submit_comment"
  }
}

Input Schema

Name	Required	Description	Default
`text`	Yes
`parentId`	Yes	Fullname of the post (t3_...) or comment (t1_...) being replied to

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Jul 28, 2026

TDQS

A3.5/5.0

Behavior3/5

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

With no annotations, the description takes full burden. It informs that the action is immediate and irreversible ('No confirmation step'), but lacks disclosure of authentication requirements, rate limits, or error handling. Basic transparency is provided, but gaps remain.

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?

The description is concise with a single sentence containing the core action and a key behavioral trait. It is front-loaded and avoids unnecessary words, though it could be slightly more structured.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the simple tool (2 params, no output schema, no annotations), the description covers the basic action and immediacy but omits return value details, error handling, and prerequisites. It is minimally complete but not exhaustive.

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 50%: only 'parentId' has a description. The tool description does not add meaning for the 'text' parameter (e.g., formatting, length limits), which is undocumented in both schema and description. Thus, it insufficiently compensates for the gap.

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 title and description clearly state the verb 'Submit' and the resource 'comment / reply'. It specifies posting a real comment reply immediately, distinguishing it from siblings like 'reddit_submit_post' (new post) and 'reddit_vote' (vote).

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?

Usage is implied by the tool name and description but not explicitly stated. The description mentions 'No confirmation step' but does not provide clear when-to-use or when-not-to-use guidance compared to alternatives like 'reddit_send_message' or 'reddit_submit_post'.

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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