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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the restated "Read-only: returns public data and changes nothing" is largely redundant. The credit-cost disclosure ("1 credit per request") is genuine added context not present in any structured field, which lifts this above the annotation-covered baseline.

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 short sentences, front-loaded with purpose, then safety, then cost. No filler or repeated phrasing beyond the mild redundancy of restating read-only.

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 five-parameter search with full schema coverage and rich annotations, the description covers purpose, safety and cost adequately. The main omission is the absence of any output schema and no hint at result shape or how the three entity types are returned/paginated, though cursor pagination is documented in the schema.

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%, including enum values, defaults and the note that subreddit only applies to post search, so the schema does all the parameter work. The description adds no parameter meaning of its own; baseline 3 applies.

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 names a specific verb and resource ("Search Reddit") and states its scope across posts, communities and users. However, it never distinguishes itself from the closely named siblings reddit_search_posts, reddit_search_comments, reddit_search_communities and reddit_search_users, which an agent must choose between.

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 phrase "across posts, communities and users" implies a broad, cross-entity search versus the narrower sibling searches, but the description never says when to pick this over those alternatives or how results across entity types are combined. Usage guidance is only inferable, not stated.

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