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

The annotations already declare readOnlyHint, idempotentHint and openWorldHint, so "read-only: returns public data and changes nothing" largely restates structured data. The genuinely additive fact is the per-request credit cost, which is real decision-relevant context but is the only piece of it.

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?

Three short, front-loaded sentences with no filler, and the cost note is placed where it will be read. The read-only sentence is redundant with annotations, slightly reducing the value of the space it occupies.

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?

Given five well-documented parameters and no output schema, the description covers the basics but omits how results are scoped compared with search_all/search_comments and says nothing about result volume or pagination beyond what the cursor field already states. Adequate but with 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 100% and both enums (sort, time) are documented inline, so the schema carries parameter semantics fully. The description adds no further meaning about query syntax, pagination or filtering behavior.

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 and resource ("Search Reddit posts"), which is unambiguous on its own. However, it never distinguishes itself from close siblings such as reddit_search_all or reddit_list_subreddit_posts, so an agent must infer the boundary from the name alone.

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?

There is no guidance on when to use this tool versus its many siblings, nor any exclusions or prerequisites. The only contextual cues (subreddit filter, sort order) live in the schema, not the description.

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