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

Beyond the readOnlyHint/openWorldHint annotations, it discloses that only saved data is read, that no scan or AI call is triggered and no credits are spent, that topics stay empty until the first scan, that an empty subreddit filter means all subreddits, and that checkNowAvailableAt null means 'now'. That is exactly the kind of side-effect and state semantics annotations cannot express.

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?

The purpose is front-loaded and nothing is outright filler, but the middle is one long comma-chained parenthetical enumerating return fields, which makes it hard to parse at a glance. Splitting the field inventory from the behavior guarantees would read considerably better.

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?

With no output schema, the description takes on the burden of describing the return payload and does so field by field, plus edge-case semantics (empty topics, empty filter, null timestamp). For a one-parameter read tool, an agent has everything needed to call and interpret it.

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?

There is a single parameter whose schema coverage is 100% and whose description already points to list_sites for obtaining the value; the prose adds no syntax, format, or edge-case detail about projectId. Baseline 3 applies when the schema carries the load.

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 opens with a specific verb and resource ('Returns the Reddit Opportunities settings of a site') and then enumerates exactly which settings are returned, so an agent can distinguish it from sibling mutation tools like update_reddit_settings without inspecting the schema.

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?

It anchors usage to a familiar surface ('the same as the Reddit Opportunities page') and rules out adjacent behaviors by stating it starts no scan, calls no AI model and spends no credits — implicitly steering away from scan_reddit and the update tools. It never names an explicit alternative or says when to prefer one, so it falls short of a full 5.

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