Search for subreddits on a topic and get their self-promotion rules and promo thread flags.
Find subreddits about a topic, each with its self-promotion rules flagged and whether it mentions a promo thread. Use a few words, e.g. 'bakery marketing' or 'indie games'.
| Name | Required | Description | Default |
|---|---|---|---|
| limit | No | ||
| topic | Yes |
Changes observed during successful MCP inspections.
v0.2.6Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the burden. It discloses that results include self-promotion rules and promo-thread mentions, which is useful behavioral output context. However, it doesn't disclose whether this is a read-only operation, rate limits, or what happens with no results. The description adds some value but not rich behavioral context.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two sentences with no filler. The core purpose is front-loaded, and the usage example is compact and immediately actionable. Every sentence earns its place.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a simple 2-parameter tool with no output schema, the description covers the main intent and topic phrasing. However, it lacks any mention of the 'limit' parameter's behavior, result ordering, or edge cases (e.g., no matches). It's adequate but has clear gaps.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 0%, so the description must compensate. It explains the 'topic' parameter well with examples, but says nothing about 'limit' beyond its schema default. The description adds meaning for one of two parameters, leaving the other to the schema's minimal title/default.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description states a specific verb ('Find') and resource ('subreddits about a topic'), and adds the distinctive output detail (self-promotion rules flagged, promo thread mention) that differentiates it from generic search tools. It doesn't explicitly name a sibling to distinguish from, but the topic-based search intent is clear.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description gives concrete usage guidance: 'Use a few words, e.g. 'bakery marketing' or 'indie games''. This tells the agent how to phrase the topic parameter. It doesn't explicitly state when not to use it or name alternatives, but the examples imply the intended query style.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.