reddit-mcp

Vote on a post or comment

reddit_vote

Upvote, downvote, or clear your vote on any Reddit post or comment using its fullname.

Instructions

Casts an upvote, downvote, or clears a vote immediately.

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": {
      "id": "<id>",
      "direction": "<direction>"
    },
    "name": "reddit_vote"
  }
}

Input Schema

Name	Required	Description	Default
`id`	Yes	Fullname (t1_ comment or t3_ post)
`direction`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Jul 28, 2026

TDQS

A3.8/5.0

Behavior2/5

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

No annotations are provided, so the description carries the full burden. It mentions the vote is cast 'immediately' but does not disclose authentication requirements, rate limits, or effects of clearing a vote. Minimal behavioral disclosure.

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 a single concise sentence that front-loads the key action, with no extraneous information.

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 simple tool with 2 parameters and no output schema, the description is nearly complete. It covers the main action, but lacks mention of prerequisites like user authentication or that the ID must be a fullname (though schema covers this).

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 coverage is 50% (only 'id' has description). The description mentions 'upvote, downvote, or clears' which matches the enum for 'direction', but adds no further syntax or format beyond what the schema provides. Baseline 3 applies given partial schema coverage.

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 action ('casts an upvote, downvote, or clears a vote'), the resource ('vote on a post or comment'), and is specific. It distinguishes from sibling tools like reddit_submit_post, which are for different actions.

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 implies usage for voting on Reddit content, but does not explicitly compare with sibling tools or state when not to use it. However, the context of sibling tools makes the intended use obvious.

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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