social-pulse

trending_topics

What is SURGING on Reddit + Hacker News right now. Returns a ranked list of terms/topics by real-time momentum (recency-weighted engagement across newest posts), scoped to a subreddit or overall. Use to answer 'what's trending on r/' / 'what is the internet talking about today'. Live data from Arctic Shift (Reddit) + HN Algolia — no stale snapshot.

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "trending_topics"
  }
}

Input Schema

Name	Required	Description	Default
`limit`	No	Max trending terms (default 15).
`subreddit`	No	Limit to one subreddit, e.g. 'wallstreetbets' or 'r/SaaS'. Omit for overall (Reddit + HN).

Schema Changelog

Changes observed during successful MCP inspections.

First observedJun 21, 2026

TDQS

A4/5.0

Behavior3/5

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

With no annotations, the description must fully convey behavioral traits. It mentions live data sources, recency-weighted engagement, and absence of stale snapshots. However, it does not disclose potential rate limits, authentication requirements, or what happens on errors. The description covers the core behavior adequately but lacks comprehensive transparency.

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 extremely concise: two sentences covering purpose, scope, use case, and data freshness. Every sentence is informative with no filler. It is front-loaded with the key action ('What is SURGING') and immediately states the output.

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 tool's simplicity (2 optional params, no output schema), the description covers purpose, scope, use cases, and data sources. It explains the algorithm ('recency-weighted engagement') and data freshness. Missing details like pagination or response size limits are minor given the ranked list nature. Overall, it is quite 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?

Schema description coverage is 100%, so the baseline is 3. The description reinforces the param meanings (e.g., 'scoped to a subreddit or overall') and adds real-time context, but does not provide additional semantics beyond the schema's parameter descriptions. It marginally adds value but is not necessary for understanding the params.

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 verb (returns), resource (trending topics from Reddit and Hacker News), and scope (subreddit or overall). It provides specific use cases ('what's trending on r/<x>'), distinguishing the tool from generic search. The mention of 'real-time momentum' differentiates it from static lists, and the naming of data sources adds clarity.

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 gives explicit usage context: answering questions about trending topics on Reddit/HN, with ability to scope to a subreddit. It implies when to use (for real-time trends) but does not explicitly state when not to use or list alternatives. However, the sibling tools (emerging_terms, mention_pulse, whats_being_said) suggest complementary functions, but no direct exclusion is provided.

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

All social-pulse tools Inspect

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